Open Collections

UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

Genetic studies of earliness and growth stages of Lycopersicon esculentum Mill. Li, Shin-Chai 1975

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Item Metadata

Download

Media
831-UBC_1975_A1 L05.pdf [ 9.31MB ]
Metadata
JSON: 831-1.0093715.json
JSON-LD: 831-1.0093715-ld.json
RDF/XML (Pretty): 831-1.0093715-rdf.xml
RDF/JSON: 831-1.0093715-rdf.json
Turtle: 831-1.0093715-turtle.txt
N-Triples: 831-1.0093715-rdf-ntriples.txt
Original Record: 831-1.0093715-source.json
Full Text
831-1.0093715-fulltext.txt
Citation
831-1.0093715.ris

Full Text

GENETIC STUDIES OF EARLINESS AND GROWTH STAGES OF LYCOPERSICON ESCULENTUM MILL.  BY SHIN-CHAI LI B.Sc., University of Taiwan, 1965 M.Sc., University of B r i t i s h Columbia, 1969  A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOGT'OR OF PHILOSOPHY  i n the Department of Plant  Science  We accept t h i s thesis as conforming t o the required standard  THE UNIVERSITY OF BRITISH COLUMBIA MARCH 1975  In presenting this thesis  in partial fulfilment of the requirements for  an advanced degree at the University of B r i t i s h Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this  thesis  for scholarly purposes may be granted by the Head of my Department or by his representatives.  It  is understood that copying or publication  of this thesis for financial gain shall not be allowed without my written permission.  Department of The University of B r i t i s h Columbia Vancouver 8, Canada  ii ABSTRACT  I t i s d e s i r a b l e t o develop tomato C Lycopersicon esculeritum M i l l . ) c u l t i v a r s which have the c h a r a c t e r i s t i c s o f e a r l i n e s s t o f i t the r e l a t i v e l y short and c o o l growing season i n Canada. E a r l i n e s s was studied by p a r t i t i o n i n g the l i f e c y c l e o f the tomato p l a n t i n t o 7 component growth stages and using these as a basis f o r attempts t o recombine q u a n t i t a t i v e genes which c o n t r o l the e a r l i n e s s of d i f f e r e n t stages from d i f f e r e n t parents t o obtain progeny e a r l i e r than both parents. The mode o f inheritance o f the e a r l i n e s s i n the 7 growth component stages was studied w i t h 3 approaches. 'First, a complete d i a l l e l cross experiments'' used 3 p a r e n t a l c u l t i v a r s : Bonny Best, Immur P r i o r Beta and Cold Set. The progenies were grown under 2 temperature regimes (17.0-21.0°C and 10.0-13.0°C). The data f o r days required f o r each stage were analyzed f i r s t by the Hayman and J i n k s method which estimated the f o l l o w i n g 4 genetic parameters; v a r i a t i o n due t o d i f f e r e n c e s i n a d d i t i v e and donrinant gene a c t i o n ; asymmetry o f p o s i t i v e and negative effects of genes; r e l a t i v e frequencies of dominant and r e c e s s i v e a l l e l e s ; and 5 genetic estimators: average degree o f donrinance; proportion o f dominant and recessive a l l e l e s ; r a t i o of the t o t a l numbers o f dominant t o r e c e s s i v e genes i n the parents; number o f e f f e c t i v e f a c t o r s which e x h i b i t some degree o f dativinance and t h e h e r i t a b i l i t y . The c a l c u l a t e d genetic parameters and estimators d i f f e r e d i n the 2 tenperature regimes i n d i c a t i n g there could be d i f f e r e n c e s i n gene a c t i o n such as overdominant instead of p a r t i a l dominant gene a c t i o n depending on  iii the temperature c o n d i t i o n s . There were d i f f e r e n c e s i n h e r i t a b i l i t i e s f o r the component stages, and some o f t h e longer stages had p o t e n t i a l l y u s e f u l high h e r i t a b i l i t i e s . The data were a l s o analyzed by the G r i f f i n g method which estimated the general combining a b i l i t y and s p e c i f i c combining a b i l i t y . The analyses showed t h a t both the a d d i t i v e and dominant gene a c t i o n had s i g n i f i c a n t e f f e c t s i n most o f the component stages, and i n most cases, the a d d i t i v e variance was l a r g e r than t h e dominant variance. The second approach employed r e c i p r o c a l cross experiments w i t h 2 p a r e n t a l c u l t i v a r s , Bonny Best and Immur P r i o r Beta, and t h e i r r e c i p r o c a l hybrids under t h e 2 temperature regimes i n greenhouses and growth chambers. The nuclear and/or cytoplasmic e f f e c t on the 7 growth component stages, net photosynthesis r a t e and l e a f area were studied. There was some evidence t h a t cytoplasmic e f f e c t s were r e l a t i v e l y important f o r some o f these c h a r a c t e r i s t i c s , and these e f f e c t s were more n o t i c e a b l e i n the c o o l regime. I n the t h i r d approach, f i e l d s e l e c t i o n experiments on the ,earliness of 2 major stages were commenced i n t h e F^ o f Bonny Best and Immur P r i o r Beta r e c i p r o c a l cross populations. The mean values f o r both stages i n the F^ r e c i p r o c a l populations were e a r l i e r than the 2 o r i g i n a l parents i n d i c a t i n g recombination o f genes f o r e a r l i n e s s from p a r e n t a l c u l t i v a r s . These r e s u l t s i n d i c a t e t h a t the methods which were used i n these studies are a f e a s i b l e way t o increase the q u a n t i t a t i v e c h a r a c t e r i s t i c of e a r l i n e s s i n the tomato.  iv TABLE OF CONTENTS  INTRODUCTION  '  page1  •  LITERATURE REVIEW ...... .... • • A. D i a l l e l Crosses B. 'Reciprocal Crosses ... C. S e l e c t i o n I n P l a n t Breeding . D. Growth Component Stages And Temperature E f f e c t s E. Genetic A n a l y s i s Of Growth And E a r l i n e s s Of Tomato  • •.  MATERIALS AND METHODS ................... • • ... MATERIALS • . ' ' METHODS . ............ A. Greenhouse Experiments '.B.- Growth Chamber Experiments C. F i e l d Experiments STATISTICAL METHODS • A. Analyses Of Data From The D i a l l e l Crosses B. Analyses Of Data From The R e c i p r o c a l Crosses C. Analyses Of. Data From The F i e l d Experiments EXPERIMENTAL RESULTS D i a l l e l Cross Experiments R e c i p r o c a l Cross Experiments F i e l d Experiments  ....  DISCUSSION ......... D i a l l e l Cross Experiments Reciprocal Cross Experiments F i e l d Experiments .; SUMMARY LITERATURE CITED APPENDIX.  '.  ' • .  ' .•  ....  . 3 • 3 5 7 10 26 29 • • 29 31 31 33 31+ 37 37 • 42 '. 44 45 45 88 99 -106 106 117 ..120 124 127  '  144  V  LIST OF TABLES Table 1.  P § a  The second degree s t a t i s t i c s f o r a d i a l l e l set (Mather and Jinks, 1971).  e  38  .2.  Analysis of variance f o r combining a b i l i t y giving expectation of mean squares f o r the assumption of a fixed model. M-1  3.  Mean number of days required f o r each of the 7 stages i n the d i a l l e l cross tested i n warm and cool temperature.regimes i n greenhouse experiment I . 46  4.  Calculated mean values of V and W for the 7 stages i n the d i a l l e l cross tested i n warm and cool regimes i n greenhouse experiment I .  47  5.  Uniformity test of. W -V values by analyses of variance f o r 48 a l l the characters investigated i n the d i a l l e l cross experiments.  6.  Correlation coefficient between parental values (y ) and W +V for a l l characters investigated i n the d i a l l e l cross experiment s.  52  7.  Mean number of days required f o r stages 5 and 6 i n the d i a l l e l cross tested i n warm and cool regimes i n greenhouse 60 experiment I I .  8.  Calculated mean values of V and W for stages 5 and 6 i n the d i a l l e l cross tested i n warm and cool regimes i n greenhouse 60 experiment I I .  9.  Mean number of days required per.plastochron i n the d i a l l e l cross tested i n warm and cool regimes i n greenhouse experiment II. 63  10.  Calculated mean values of V and W f o r the days required per plastochron i n the d i a l l e l cross tested i n warm and cool regimes i n greenhouse experiment I I . 63  11. Mean f r u i t weight (g) and f r u i t diameter (mm) i n the d i a l l e l cross tested i n warm and cool regimes i n greenhouse experiment II. 65 12.  Calculated mean values of V and W f o r the f r u i t weight and r r f r u i t diameter m the d i a l l e l cross tested m warm and cool regimes i n greenhouse experiment I I .  65  vi 13.  Means and standard d e v i a t i o n s f o r the d i a l l e l cross parameters derived from the data on days required f o r 7 growth stages i n the warm regime o f the greenhouse experiment I .  69  14.  The d i a l l e l cross estimators f o r the data o f the warm regime of the greenhouse experiment I .  69  15.  Means and standard d e v i a t i o n s f o r the d i a l l e l cross parameters derived from the data on days required f o r 7 growth stages i n the c o o l regime of the .greenhouse experiment I .  73  16.  The d i a l l e l cross estimators from the data of the c o o l regime of the greenhouse experiment I .  73  17.  Means and standard d e v i a t i o n s f o r the d i a l l e l cross parameters and estimators from warm and c o o l regimes i n greenhouse experiment I I .  77  Means and standard deviations f o r t h e d i a l l e l cross parameters and estimators from warm and cool.regimes•for days r e q u i r e d per plastochron.  79  Means and standard deviations f o r the d i a l l e l cross parameters and estimators f o r warm and c o o l regimes f o r f r u i t weight and f r u i t diameter.  79  Mean squares f o r general (G.C.A.) and s p e c i f i c (S.C.A.) combining a b i l i t y f o r the growth component stages i n warm and c o o l regimes.  82  Mean squares f o r general (G.C.A.) and s p e c i f i c (S.C.A.) combining a b i l i t y f o r the stages 5 and 6 a f t e r h a n d - p o l l i n a t i o n treatment i n warm and c o o l regimes-.  82  Mean squares f o r general (G.C.A.) and s p e c i f i c (S.C.A.) c o n f i n ing a b i l i t y e f f e c t s f o r days r e q u i r e d per plastochron i n warm and c o o l regimes.  84  Mean squares f o r general (G.C.A.) and s p e c i f i c (S.C.A.) combining a b i l i t y e f f e c t s f o r f r u i t weight and diameter i n warm and c o o l regimes.  84  24.  Net photosynthesis r a t e and l e a f area i n growth chamber experiment I i n warm regime.  86  25.  Net photosynthesis r a t e and l e a f area i n growth chamber experiment I i n c o o l regime.  87  18.  19.  20.  21.  22.  23.  vii  26.  The non-orthognal comparisons f o r the seven growth component stages i n the r e c i p r o c a l cross experiment I under warm and c o o l regimes.  89  The non-orthognal comparisons f o r the net photosynthesis r a t e i n the r e c i p r o c a l cross experiment I I under warm and c o o l regimes.  91  28.  The non-orthognal comparisons f o r the l e a f area i n the r e c i p r o c a l cross experiment I I under warm and c o o l regimes.  96  29.  Mean days required f o r stages A and C i n the f i e l d experiment I , p a r t 1.  99  27.  30. 31.  The mean number o f days required f o r stages A and C i n the f i e l d experiment I , p a r t 2.  100  Means, h e r i t a b i l i t y , i n F^ generations:  101  s e l e c t i o n progress and genetic progress  32.  Mean days required f o r s e l e c t i o n s made f o r stages A and C i n the Fj- o f the f i e l d experiment I I I .  103  33.  Summary o f the f i e l d experiments, mean days r e q u i r e d f o r stage A.  105  Summary o f the f i e l d experiments, mean days r e q u i r e d f o r stage C.  105  34.  LIST OF FIGURES Figure 1.  (V ,W ) graph f o r stage 1, greenhouse experiment I warm regime.  2.  CV ,W ) graph f o r stage 2, greenhouse experiment I warm regime.  3.  (V ,W ) graph f o r stage 3, greenhouse experiment I warm regime.  4.  (V »W ) graph f o r stage 4, greenhouse experiment I warm regime.  5.  CV ,W ) graph f o r stage 5, greenhouse experiment I warm regime.  6-i'  (V ,W ) graph f o r stage 6, greenhouse experiment I warm regime.  7.  CV ,W ) graph f o r stage 7, greenhouse experiment I warm regime.  8.  CV »W ) graph f o r stage 1, greenhouse experiment I c o o l regime.  .9.  CV Wp) graph f o r stage 2, greenhouse experiment I c o o l regime.  10.  CV ,W ) graph f o r stage 3, greenhouse experiment I c o o l regime.  11.  CV^jWp) graph f o r stage 4, greenhouse experiment I c o o l regime.  12.  CV jW^) graph f o r stage 5, greenhouse,experiment I c o o l regime.  13.  CV ,W ) graph f o r stage 6, greenhouse experiment I c o o l regime.  14.  CV ,W^,) graph, f o r stage 7, greenhouse experiment I c o o l regime.  r  r  r  (V ,W ) graph f o r stage 5, greenhouse experiemnt I I , warm regime. (V ,W ) graph f o r stage 6, greenhouse experiment I I , warm regime. (V ,W ) graph f o r stage 5, greenhouse experiment I I , cool regime'. (V ,W ) graph f o r stage 6, greenhouse experiment I I , cool regime. (V ,W ) graph f o r days required per plastochron,.greenhouse experiment I I , warm regime. (V ,W ) graph f o r days required per plastochron, greenhouse experiment I I , cool regime. CV ,W) graph f o r f r u i t weight, greenhouse experiment I I , warm regime. r  (V ,W ) graph f o r f r u i t weight,greenhouse experiment I I , cool regime.' CV ,W ) graph f o r fruit•:diameter, greenhouse experiment I I , warm regime. (V ,W ) graph f o r f r u i t diameter, greenhouse experiment I I , cool regime. Net. photosynthesis rate f o r each plastochron of four lines i n the warm regime. Net photosynthesis rate f o r each plastochron of four lines i n the cool regime. Leaf area at- each plastochron among the lines i n the warm regime. Leaf area at each plastochron among the lines i n the cool regime.  X  ACKNOWLEDGEMENT I wish t o express my sincere thanks t o the f o l l o w i n g persons, whose assistance i n the preparation o f t h i s t h e s i s has contributed, s i g n i f i c a n t l y t o whatever merits i t may have. To Dr. C.A.Hornby, Associate Professor o f P l a n t Science, who n o t only suggested.the t o p i c f o r t h i s t h e s i s but a l s o spent many hours reviewing the manuscript. Moreover, during a l l phases o f my. graduate study, he has given guidance and valuable personal a s s i s t a n c e / To Professors V.C.Brinks., K.Cole, G.W.Eaton, C.W.Roberts and V.C. Runeckles, Chairman o f the t h e s i s committee, thanks are expressed f o r t a k i n g the time t o review t h i s work and f o r o f f e r i n g many h e l p f u l suggestions. F i n a l l y , t o my w i f e , Rose, whose love and confidence contributed to the t i m e l y completion o f t h i s work. As a s m a l l token o f my g r a t i t u d e .for her devotion, I dedicate t h i s study t o my. w i f e .  INTRODUCTION  The tomato (Lycopersicon esculentum . M i l l . ) i s one o f the most important vegetable crops i n North America.  This crop i s s t r o n g l y  thermoperiodic i n i t s environmental response (Went, 1957) and i s not w e l l adapted f o r short and f r e q u e n t l y c o o l growing seasons i n Canada, therefore f a s t e r growing and e a r l i e r crops t o l e r a n t t o c o o l temperatures are a primary r e q u i s i t e i n the production o f Canadian tomatoes. Breeding f o r increased e a r l i n e s s and c o o l temperature t o l e r a n c e has been done f o r many years, but f u r t h e r improvement f o r both c h a r a c t e r i s t i c s i s needed i n order t o have an expanding tomato production program i n Canada. Powers e t a l . (1950) s t u d i e d tomato e a r l i n e s s by p a r t i t i o n ing the l i f e c y c l e i n t o 3 stages: bloom; b) second stage: stage:  a) f i r s t stage:  seeding t o f i r s t  f i r s t bloom t o f i r s t f r u i t set and c) t h i r d  f i r s t f r u i t set t o f i r s t r i p e f r u i t .  They proposed t h a t r e -  combination o f e a r l y stages could r e s u l t i n e a r l i e r c u l t i v a r s .  These  designated f i r s t and t h i r d stages were r e l a t i v e l y long and the genetic mechanisms which c o n t r o l l e d these stages s t i l l need t o be c l a r i f i e d . For t h i s study, t h e l i f e c y c l e o f 3 c u l t i v a r s :  Bonny Best,  Immur P r i o r Beta and Cold Set was f u r t h e r p a r t i t i o n e d i n t o 7 stages: 1) seeding t o ge:mfeation;':2>) germination f o f i r s t t r u e l e a f ; 3) f i r s t t r u e l e a f t o flower bud formation; M-) flower bud formation t o f i r s t flower; 5) f i r s t flower t o f i r s t f r u i t s e t ; 6) f i r s t f r u i t set t o c o l o r change; 7) c o l o r change t o r i p e n i n g . The objectives;;of the present experiments were 1) t o evaluate  1  the ,7 growth component stages using the d i a l l e l ' cross technique t o estimate gene a c t i o n , h e r i t a b i l i t y  and numbers of genes^ associated  w i t h each stage; 2) t o use r e c i p r o c a l crosses t o a s c e r t a i n whether any d i f f e r e n c e s could be a t t r i b u t e d t o cytoplasmic e f f e c t s ; 3) t o contrast warm and c o o l temperature regimes inathe genetics studies i n the d i a l l e l and r e c i p r o c a l cross experiments and 4) t o u t i l i z e the genetic knowledge i n a f i e l d s e l e c t i o n program f o r e a r l i n e s s recombinations i n the t h i r d to f i f t h generations.  2  LITERATURE REVIEW  A.  Diallel  Crosses  J i n k s and Hayman (1953) and Hayman (1954), based on methods o f Mather (1949), and using d i a l l e l c r o s s i n g , showed how variances and covariances among pure l i n e s could be used t o provide estimates o f the o v e r a l l degree o f dominance i n t h e parents, an estimate o f h e r i t a b i l i t y and other genetic parameters.  Accordingly, t h e d i a l l e l cross t e c h -  nique has been widely used by p l a n t breeders as a method f o r studying continuous v a r i a t i o n .  Johnson (1963) pointed out t h a t t h e d i a l l e l  cross has 2 main advantages:  a) experimentally, i t i s a systematic  approach, and b) a n a l y t i c a l l y , i t has a genetic e v a l u a t i o n t h a t i s .-, p r a c t i c a l f o r i d e n t i f y i n g the I'erossesiwith the best s e l e c t i o n p o t e n t i a l i n e a r l y generations. G r i f f i n g (1956a) showed how the d i a l l e l a n a l y s i s provides information about t h e variance o f general combining a b i l i t y (a|).' and s p e c i f i c combining a b i l i t y (a*).  G r i f f i n g (1956b) demonstrated  that when a set o f inbred l i n e s i s used i n a d i a l l e l c r o s s i n g system, a genetic i n t e r p r e t a t i o n i n terms o f q u a n t i t a t i v e i n h e r i t a n c e i s made p o s s i b l e by the f a c t t h a t the a n a l y s i s i s r e a l l y a 'gamete' combining a b i l i t y a n a l y s i s . Thus i n the d i a l l e l s t a t i s t i c a l a n a l y s i s , t h e method may regard t h e genotypic e f f e c t o f any i n d i v i d u a l as the summation o f e f f e c t s contributed by each gamete ( i . e . set o f genes i n t h e gamete) and t h e i n t e r a c t i o n o f gametes ( i . e . the i n t e r a c t i o n o f t h e genes i n one gamete w i t h those i n the o t h e r ) . Kempthorriie (1956) c r i t i c i z e d the Jinks-Hayman a n a l y s i s on  the b a s i s t h a t "the d i a l l e l cross must be i n t e r p r e t e d i n terms o f some population which has given r i s e t o the homozygous parents i n inbreeding. I f such a population does not e x i s t then the whole a n a l y s i s i s l i k e l y t o lead nowhere, and a l s o one may question the value of estimating genetic v a r i a n c e , unl e s s the estimated q u a n t i t i e s are measures of the characteri s t i c of a d e f i n i t e population". Since the parents of s e l f - p o l l i n a t e d crops w i l l u s u a l l y not have been derived by inbreeding from the d e f i n i t e p o p u l a t i o n , Kempthorne e v i dently considers t h a t the Jinks-Hayman type o f a n a l y s i s of d i a l l e l crosses has l i t t l e p r a c t i c a l value as an a i d i n the improvement o f s e l f - p o l l i n a t e d crops.  Hayman (1957, 1958 and 1960) has  considered  these c r i t i c i s m s and has discussed some a d d i t i o n a l aspects o f the theory by removing the r e s t r i c t i o n t h a t the inbred l i n e s must be f i x e d . G i l b e r t (1958) has evaluated the d i a l l e l c r o s s , and pointed out t h a t t h i s technique does give more information than t h a t obtained from the parents only:  the d i a l l e l a n a l y s i s provides a d d i t i o n a l information  on dominance and r e c e s s i v e r e l a t i o n s , on genie i n t e r a c t i o n , and on probable linkage a s s o c i a t i o n s . The use of the d i a l l e l a n a l y s i s t o study q u a n t i t a t i v e l y i n h e r i t e d c h a r a c t e r i s t i c s of crops has received considerable a t t e n t i o n during the l a s t 20 years.  Many i n v e s t i g a t o r s have a p p l i e d the J i n k s -  Hayman and/or G r i f f i n g approaches on various crops, i n c l u d i n g snap beans (Dickson, 1967); cotton (Verhalen e t a l . , 1971; A l - R a r v i and Kohel, 1970); tobacco ( J i n k s , 1954; P o v i l a i t i s ' , > 1966; Legg e t a l . , :  1970; Matzinger e t a l . , 1971); ryegrass (Lewis, 1970); forage crops (England, 1968; F e j e r , 1971); weeds ( W i l l i a m s , 1962); maize (Eberhart e t a l . , 1964; P o n e l e i t and Bauman, 1970; Rosenbrood and Ankrew, 1971); cabbage (Chiang, 1969); wheat ( A l l a r d , 1962; Kronstad and Foote, 4  1964;  Hsu and S o s u l s k i , 1969; Bhatt, 1971); b a r l e y (Johnson and A k s e l , 1959); f l a x (Shehata and Comstock, 1971); l i n s e e d (Ahand and Murty, 1969). In tomato, the d i a l l e l cross a n a l y s i s has been a p p l i e d t o many c h a r a c t e r i s t i c s , such as l o c u l e number (Ahuja, 1968; Andrasfalvy, 1971); f r u i t s i z e (Horner and Lana, 1956; K h e i r a l l a and Whittington, 1962; Peat, 1963; K h a l f - A l l a h , 1970; Andrasfalvy,, 1971); y i e l d (Horner and Lana, 1956) and s o l u b l e s o l i d s i n f r u i t (Stoner and Thompson, 1966). B.  R e c i p r o c a l Crosses In h i s book "Extrachromoscmal Inheritance", J i n k s (1964)  defined r e c i p r o c a l crosses as crosses i n which the sources o f male and female gametes are reversed.  When p a r e n t a l l i n e s d i f f e r o n l y by chromo-  somal genes, i t i s g e n e r a l l y unimportant whether these genes go i n t o male o r female gametes; the progeny o f r e c i p r o c a l crosses between such p a r e n t a l / l i n e s are g e n e t i c a l l y i d e n t i c a l .  However, d i f f e r e n c e s i n c e r -  t a i n q u a n t i t a t i v e characters between r e c i p r o c a l crosses do a r i s e . Some examples o f such characters are:  o i l and f a t t y a c i d contents,  g r a i n y i e l d , m a t u r i t y , p l a n t and ear h e i g h t s , and number o f ears p e r p l a n t i n maize (Bhat and Dhawan,197l; Garwood e t a l . .,1970); f l o w e r i n g time and p l a n t height i n N i c o t i a n a r u s t i c a ( J i n k s e t al.,1972); seed p r o t e i n content i n soybeans (Singh and Hadley ,19.72); i n tomato, seed germination ( E l Hassan,1972); f r u i t s i z e (Halsted 1918, Cram 1952; Shumaker e t _ a l . .,1970); e a r l y maturity ( L i and Hornby, 1972; Shumaker et al.1970); e a r l y y i e l d (Driver,1937; Meyer and Peacock,1941; Moore and Qirrence,1950; Cram,1952;.Shumaker e t al.,1970). The e a r l i e s t work on r e c i p r o c a l breeding i n tomatoes was reported by Halsted (1918) on f r u i t s i z e . 5  He concluded t h a t i f a  small f r u i t c u l t i v a r was used as a female parent, the Yi produced smaller f r u i t , whereas i f the female parent was the l a r g e - f r u i t c u l t i v a r , the F  x  produced l a r g e r .fruit.,  Moore and Currence (1950) studied  21 p a i r s o f r e c i p r o c a l hybrids i n tomatoes.  They found that 6 p a i r s  showed s i g n i f i c a n t d i f f e r e n c e s between r e c i p r o c a l s i n e a r l y y i e l d , whereas f r u i t s i z e and t o t a l y i e l d d i f f e r e d s i g n i f i c a n t l y i n t h i r t e e n and three p a i r s r e s p e c t i v e l y .  D r i v e r (1937) and Meyer and Peacock  (194-1) demonstrated d i f f e r e n c e s between p a i r s o f r e c i p r o c a l s f o r e a r l i ness and t o t a l y i e l d i n F i h y b r i d tomatoes. the  Cram (1952) claimed t h a t  d i f f e r e n c e s between tomato r e c i p r o c a l hybrids r e s u l t e d from some  maternal o r cytoplasmic i n f l u e n c e .  E l Hassan (1972) reported t h a t the  r e c i p r o c a l d i f f e r e n c e s were found between F i and F2 generations, i n tomato, f o r sprouting a t 10.0°C.but not at 35.0°C. He concluded t h a t the r e c i p r o c a l d i f f e r e n c e s were a t t r i b u t a b l e t o the ^ c o n t r i b u t i o n o f the embryo genotype, maternal e f f e c t s and i n t e r a c t i o n o f maternal genotype and cytoplasmic e f f e c t s .  L i and Hornby (1972) p a r t i t i o n e d the tomato  l i f e c y c l e i n t o 3 growth component stages under 2 d i f f e r e n t temperature regimes, they found t h a t the days r e q u i r e d t o complete each o f the growth component stages i n r e c i p r o c a l hybrids responded d i f f e r e n t l y . •P.  Evidence f o r cytoplasmic i n h e r i t a n c e has been reported f o r  d i f f e r e n t p l a n t s by many workers i n c l u d i n g A s h r i (1964), Beale (1966), Granick (1965), Katsuo and Mizushima (1958), Koopmans (1959), M i c h a e l i s (1954) and Sager (1965). Bhat and'Dhawan (1970, 1971), Brown (1961), Fleming e t a l . (I960) and Singh (1965, 1966), working w i t h maize-y, have shown that the ;;  expression o f some p o l y g e n i c a l l y i n h e r i t e d t r a i t s may be governed by the cytoplasm.  6  J i n k s e t a l . (1972) reported that there are 2 kinds o f d i f ferences between r e c i p r o c a l crosses, t r a n s i e n t and p e r s i s t e n t . may be maternal o r paternal e f f e c t s .  These  Differences i n the maternal  environment can give r i s e t o t r a n s i e n t r e c i p r o c a l d i f f e r e n c e s .  Such  differences are known i n the animal kingdom where they ''were traced t o differences i n the maternal genotypes (Mather and J i n k s , 1971).  Per-  s i s t e n t r e c i p r o c a l deferences; u s u a l l y a r i s e through unequal contrib-. u t i o n s o f cytoplasmic determinants from the female and male gametes t o the zygotes. C.  Such differences are prevalent i n the plant kingdom.  S e l e c t i o n I n Plant Breeding The h i s t o r y o f crops has been influencecl considerably by  man's augmentation o f s e l e c t i o n .  I t was understood t h a t many crop  c h a r a c t e r i s t i c s were being modified by s e l e c t i o n . Walker i n h i s 1969 review, stated t h a t there were only three b a s i c f a c t o r s o f s e l e c t i o n even when the genetic s i t u a t i o n i s h i g h l y complex.  F i r s t , s e l e c t i o n operates because'^-some i n d i v i d u a l s are  favoured i n reproduction a t the expense o f others; secondly, s e l e c t i o n acts through h e r i t a b l e d i f f e r e n c e s ; and t h i r d l y , s e l e c t i o n works_ upon v a r i a t i o n already present i n the organism.  Mather (1953) summarized  the e f f e c t s o f s e l e c t i o n on a population as being d i r e c t i o n a l s t a b i l i z i n g or disruptive. Many c h a r a c t e r i s t i c s such as y i e l d and e a r l i n e s s are easy t o measure, but they are the products o f i n t e r a c t i o n s a t both t h e genetic and environmental l e v e l s . considered t o be b a s i c a l l y  These c h a r a c t e r i s t i c s have been  c o n t r o l l e d by genes w i t h small e f f e c t s ,  which may be modified by environmental f l u c t u a t i o n and subsequently  7  the data l e a d t o v a r i a b l e estimates o f h e r i t a b i l i t y .  Hazel and Lush  (1942) showed.that s e l e c t i o n f o r a t o t a l score i s much more e f f i c i e n t than s e l e c t i o n f o r one t r a i t a t a time.  They a l s o showed t h a t s e l e c -  t i o n f o r s e v e r a l t r a i t s by using indepenent c u l l i n g l e v e l s f o r each i s more e f f i c i e n t than random s e l e c t i o n f o r each t r a i t one a t a time. In c o n t r a s t , Mather (1960) proposed t h a t the s e l e c t i o n procedure begin w i t h the p a r t i t i o n i n g o f complex c h a r a c t e r i s t i c s i n t o subunits (component a n a l y s i s ) and, w i t h the use o f b i o m e t r i c a l g e n e t i c s , modify the s e l e c t i o n procedure as r e q u i r e d .  The best r e s u l t s from component  a n a l y s i s have been achieved when subunits a c t i n m u l t i p l i c a t i v e f a s h i o n ; f o r i n s t a n c e , the y i e l d o f the tomato p l a n t can be expressed i n terms o f f r u i t number and f r u i t s i z e ( G i l b e r t , 1961).  S i m i l a r l y , Powers  et a l . (1950) p a r t i t i o n e d the tomato l i f e c y c l e i n t o 3 major component stages: set,  1) seeding t o f i r s t f l o w e r , 2) f i r s t f l o w e r t o f i r s t f r u i t  and 3) f i r s t f r u i t s e t t o f i r s t f r u i t r i p e n i n g . They found l i t t l e  evidence, t h a t these subunits were determined by a s u f f i c i e n t l y s m a l l number of l o c i t o permit simple Mendelian a n a l y s i s . I n reviewing t h e i r data, i t appeared t h a t the b i o m e t r i c a l t e s t sometimes showed t h a t the subunits could be considered under more simple c o n t r o l than the complex c h a r a c t e r i s t i c s o f t o t a l y i e l d and e a r l i n e s s . P e i r c e and Currence (1959) reported on the r e s u l t s o f s e l e c t i o n f o r 3 q u a n t i t a t i v e characters:  e a r l i n e s s , y i e l d and f r u i t s i z e  i n segregating populations o f tomato p l a n t s .  T h e i r data showed that1  one generation o f s e l e c t i o n r e s u l t e d i n a considerable g a i n i n f r u i t s i z e , a s i g n i f i c a n t increase i n y i e l d and l i t t l e change i n e a r l i n e s s . As expected the estimates o f h e r i t a b i l i t y f o r e a r l i n e s s were low whereas the other two c h a r a c t e r i s t i c s had higher h e r i t a b i l i t y values.  8  One major s e l e c t i o n system developed t o maintain a higher l e v e l of genetic v a r i a b i l i t y w i t h i n the breeding population i s r e current s e l e c t i o n .  This system has been proposed as a promising method  f o r e f f e c t i n g stepwise changes i n gene frequency w i t h i n a population as opposed t o the development of inbred l i n e s which gave homozygosity under continuous s e l f - p o l l i n a t i o n .  Comparative studies conducted  by Comstock et a l . (1949), Lonquist and M c G i l l (1956), Sprague e t a l . (1952) have demonstrated the s u p e r i o r i t y of r e c u r r e n t s e l e c t i o n over s e l e c t i o n w i t h i n s e l f - f e r t i l i z e d progenies.  The r a p i d approach to-=~  ward homozygosity apparently d i d not allow adequate Opportunity f o r s e l e c t i o n ; t h e r e f o r e , A l l a r d (1960) suggested t h a t some l e s s intense form o f inbreeding, such as sib-mating might a i d i n the s e l e c t i o n o f superior genotypes from a given foundation population.  Khalf-Allah  and P e i r c e (1964) a p p l i e d t h i s method i n tomato and found t h a t the progenies developed by sib-mating g e n e r a l l y maintained h i g h e r g e n e t i c v a r i a b i l i t y f o r f r u i t s i z e , e a r l i n e s s and t o t a l y i e l d than d i d s e l f pollinated selections.  Recurrent s e l e c t i o n has a l s o been a p p l i e d t o  improve the s p e c i f i c combining a b i l i t y o f breeding l i n e s i n many other crops, e s p e c i a l l y i n maize ( H u l l , 1945; Horner et a l . , 1972). The d i f f i c u l t y a r i s i n g from s e l e c t i o n f o r a s i n g l e t r a i t i s the genetic and cenvironmerital c o r r e l a t i o n w i t h other t r a i t s , but t h i s can be p a r t i a l l y r e s o l v e d by the use of a s e l e c t i o n index.  Such an  index has been widely used by the animal breeders, but has been l i t t l e used by the p l a n t breeders.  Andrus and Bonn (1967) used an index i n  a mass s e l e c t i o n program w i t h muskmelon.  This index was a simple '  s c o r i n g method w i t h equivalent economic weight attached t o each character.  P l a n t s w i t h the l a r g e s t t o t a l score or highest index were  selected.  P e i r c e (1968) reviewed s e l e c t i o n procedures and the problems 9  involved. an-index  He noted that the estimates o f parameters used t o construct are u s u a l l y d i f f e r e n t f o r each c u l t i v a r population i n a  breeding program, and these estimates, p a r t i c u l a r l y o f genetic correl a t i o n s , are subject t o considerable e r r o r .  He states  that*  "The concept o f s e l e c t i o n by index i s a v i a b l e one and should not be discarded". He also stated  that  "An index i s p a r t i c u l a r l y s u i t e d t o those crops i n which value i s determined by r e a d i l y measureable a t t r i b u t e s . And f o r those measureable characters c o n t r i b u t i n g t o the balanced genotype, a f f e c t e d by d i f f i c u l t c o r r e l a t i o n s , an index may help". Another aspect t h a t must be considered by the p l a n t breeders as a f f e c t i n g s e l e c t i o n i s the magnitude o f the genotype/environment interaction.  Allard  (196M-)  summarized t h i s problem as f o l l o w s :  "The genotype and environment i n t e r a c t i o n i s always a component o f v a r i a t i o n . I n t e r a c t i o n s , such as v a r i e t y x l o c a t i o n , v a r i e t y x treatment are frequently p r e d i c t a b l e , and one can u s u a l l y breed plants that w i l l excel i n a s p e c i f i c e n v i r onment. The v a r i e t y x year e f f e c t s are not p r e d i c t a b l e , and the breeders must attempt t o minimize the impact o f such i n t e r a c t i o n by testiingy. v a r i e t i e s over a s e r i e s o f years and locations". Further emphasis on t h i s i n t e r a c t i o n was expressed by Cornst6ck and M o l l  (1963)  as f o l l o w s :  "Because genetic f a c t s are i n f e r r e d from observations on phenotype, because s e l e c t i o n i s based on phenotype and becaused there .is a p o t e n t i a l c o n t r i b u t i o n o f genotype and environment i n t e r a c t i o n e f f e c t s on the phenotype o f a l l q u a n t i t a t i v e characters; genotype x environment i s i n some way involved i n most problems o f q u a n t i t a t i v e genetics and many problems o f plant breeding, t h e r e f o r e , a l l o f i t s possi b l e i m p l i c a t i o n s deserve a t t e n t i o n . " D.  Growth Component Stages And Temperature E f f e c t s 1.  Stage 1: From Seeding t o Gernrination In e a r l i e r s t u d i e s , v a r i a t i o n i n the r a t e o f seed germination 10  at d i f f e r e n t temperatures has been observed in;;many vegetable crops. Kotowski (1926) reported that speed o f germination f o r 17 d i f f e r e n t kinds o f vegetables increased as the temperature rose.  The optimum  temperature f o r tomato was 18.0°C and the nuxiimum was between 11.0°C and 18.0°C. Went (1957) found the time r e q u i r e d f o r tomato seed germination depended g r e a t l y on temperature, and the lower the temperature then the longer the time required f o r gernrination. W h i t t i n g t o n et a l . (1965) reported t h a t time f o r germination showed a genetic component, but the r e l a t i o n s h i p s between d i f f e r e n t genotypes was much i n f l u e n c e d by environmental f a c t o r s .  The e f f e c t o f temperature on  seed germination was h i g h l y s i g n i f i c a n t , and the time r e q u i r e d f o r germination being greatest a t the lower temperatures.  W h i t t i n g t o n and  F i e r l i n g e r (1972) i n d i c a t e d the i n h e r i t a n c e o f time t o germination o f tomato seed was l a r g e l y a d d i t i v e and-closely r e l a t e d t o seed s i z e . P o l l a c k and Larson (1956) i n d i c a t e d that speed o f tomato seed germi n a t i o n depended p r i m a r i l y upon environmental f a c t o r s , and t h a t w i t h i n one c u l t i v a r seed s i z e has l i t t l e o r no e f f e c t . The existence o f genetic d i f f e r e n c e s i n the c a p a b i l i t y o f tomato seed t o germinate a t low temperature has been mentioned by various i n v e s t i g a t o r s .  Smith and M i l l e t t (1964) reported t h a t s i g -  n i f i c a n t d i f f e r e n c e s were observed among 10 v a r i e t i e s a t constant temperatures o f 15.0°C and 10.0°C but not a t 20.0°C. Kemp (1968) reported t h a t the a b i l i t y o f some tomato c u l t i v a r s , such as ' E a r l i n o r t h ' and 'Rocket', t o germinate a t low temperatures may be i n h e r i t e d ; and at 10.0°C o r lower, the percentages o f germination o f a l l c u l t i v a r s was reduced s i g n i f i c a n t l y .  Berry (1969) reported d i f f e r e n c e s i n germ-  i n a t i o n response a t 35.0°C and the existence o f a h e r i t a b l e a s s o c i a t i o n 11  between h i g h and lew temperature response.  E l Hassan (1972) reported  t h a t sprouting a t 10.0°C, germination percentage a t 35.0°C, and r a t e of germination a t 35.0°C are i n h e r i t e d characters and c o n t r o l l e d by a t l e a s t 3, 2 and 1 gene(s) r e s p e c t i v e l y .  He a l s o reported a h i g h corv  r e l a t i o n between germination a t low and h i g h temperatures and the probable existence o f 2 d i f f e r e n t genetic systems which are recombinable. Cannon e t a l . (1973) reported the a b i l i t y o f tomato l i n e P I 341988 t o germinate a t 10.09C i s c o n t r o l l e d by a r e c e s s i v e gene ( l t g ) . E l Sayed andj©&pii (1973) pointed out t h a t germination o f tomato seed needs a t l e a s t the accumulation of 160 d a i l y heat u n i t s .  They found  the c h a r a c t e r i s t i c o f germination a t low temperature f o r the Fr :and F2 :  progenies was intermediate between t h e i r c o n t r a s t i n g parents.  Inherit-  ance was found t o be q u a n t i t a t i v e and an estimate o f 24 gene p a i r s d i f f e r e n t i a t e d the parents f o r germination. There was strong evidence f o r a d d i t i v e gene a c t i o n although dominance and e p i s t a s i s were not r u l e d out.  They a l s o i n d i c a t e d t h a t the same gene system appears t o  c o n t r o l emergence o f seeds a t both low (10.0°C) and h i g h (20.0°C) temperatures w i t h a h e r i t a b i l i t y o f 25-40% and s e l e c t i o n f o r emergence at low temperature could be achieved a t h i g h temperature.  Phatak  (1970) i n d i c a t e d t h a t the seed from p l a n t s s e l e c t e d f o r normal germi n a t i o n a t 10.0°C night and 12.0°C day showed a d e f i n i t e improvement i n c o l d germinating a b i l i t y . 2.  Stage 2:  From Germination t o F i r s t -Shme Leaf Appearance  V a r i a t i o n i n growth o f the seedling could be expected t o be i n f l u e n c e d by i n i t i a l embryo s i z e (Ashby 1930, 1937).-  However, East  (1936), L u c k w i l l (1939) and Hatcher (1940) found t h a t some tomatoes which showed h e t e r o s i s f o r e a r l y seedling growth d i d not have any  12  apparent d i f f e r e n c e i n embryo s i z e and concluded t h a t the s i z e of the embryo was not the index of h e t e r o s i s . Whaley (1939) made a study of growth r a t e s of the parents and hybrids i n two Lycopersicon species crosses showing h e t e r o s i s .  I n both crosses the hybrids grew f a s t e r  than e i t h e r parent i n the e a r l y post-embryonic stage, he a l s o noted •. t h a t h e t e r o s i s was not always accompanied by the possession o f a l a r g e r embryo i n the h y b r i d .  I n a second paper (1939) he presented evidence  showing t h a t there was no r e l a t i o n s h i p e i t h e r i n the embryo or during development, between the volume o f the a p i c a l meristem and h e t e r o s i s . Whittington e t a l . (1965) using hybrids from L. esculentum and L. p i m p i n e l l i f o l i u m found t h a t the h y b r i d hypocotyl although i t s emergence was delayed by l a t e r germination, came t o exceed i n length t h a t o f L. p i m p i n e l l i f o l i u m .  Since hypocotyl extension i n tomatoes i n the  dark i s by c e l l elongation r a t h e r than by c e l l d i v i s i o n , i t i s l i k e l y t h a t t h i s r e s u l t i s due t o an enhanced r a t e of extension of i n d i v i d u a l c e l l s i n the hybrids.• I t was thought t h a t the s i g n i f i c a n t d i f f e r e n c e between the parent and h y b r i d was due t o the greater c e l l number i n the h y b r i d hypocotyl. 3. (A)  Stage 3:  '  From F i r s t True Leaf t o Flower Bud Appearance  Leaf Development Throughout the h i s t o r y of research on crop p l a n t s many workers  have sought t o f i n d some observation o r system o f measurements t h a t would accurately r e f l e c t the growth response caused by the environmental f a c t o r s , f o r i n s t a n c e , f l u c t u a t i o n of temperature has been evaluated i n various ways w i t h respect t o the e f f e c t s on p l a n t growth such as p l a n t h e i g h t , l e a f area, phenological development, e t c .  As  e a r l y as 1735, Reaumur attempted t o c o r r e l a t e changes i n temperature  13  w i t h p l a n t development.  Since then, the r e s u l t a n t c o r r e l a t i o n s o f  growth and temperature data were developed.  Went (1944, 1945), Verkerk  (1955), Lewis (1953), Calvert 0-9SB", 1959) have demonstrated t h a t the e a r l y development o f the tomato i s a f f e c t e d by the temperature and l i g h t i n t e n s i t y during the f i r s t few weeks from germination.  Calvert  (1957, 1959) has shown t h a t the number o f leaves formed between the cotyledons and the''first i n f l o r e s c e n c e , increases w i t h temperature but decreases w i t h l i g h t i n t e n s i t y .  Hussey (1963) reported t h a t temper-  ature had a greater e f f e c t on l e a f growth than on l e a f number; however, more leaves were formed before f l o w e r i n g a t 25.0°C than a t 15.0°C. He a l s o observed the e f f e c t s o f h i g h temperature i n delaying the enlargement o f the apex and of i n c r e a s i n g the number o f leaves produced before flowering. The day and night temperature requirements f o r the tomato were iinVe^stigatedd by Went (1944) who^' • found t h a t optimal growth occurs when the temperature during the dark period i s lower than that during the d a i l y l i g h t period. thermoperiodicity.  This k i n d of temperature response, he termed  Hussey (1965) i n d i c a t e d t h a t the average day temp-  erature a f f e c t e d l e a f growth one and h a l f times as much as n i g h t . temperature. To e s t a b l i s h the process which c o n t r o l s the growth o f tomato p l a n t s i s o f some i n t e r e s t , because i t may a s s i s t the p l a n t breeder i n choosing the d i r e c t i o n f o r developing improved -'cultivars • Went (1944) studied the c o r r e l a t i o n between various p h y s i o l o g i c a l processes and growth i n the tomato p l a n t .  He found the elongation r a t e of tomato  stems decreased sharply during the day, and photosynthesis reached i t s optimum near 10,764 l u x and was only s l i g h t l y lower a t 18.0°C 14  than a t 26.5°C, but was s i g n i f i c a n t l y lower a t 8.0°C.  Translocation  of sugars was low a t 26.5°C, and s t e a d i l y increased as the temperature decreased t o 8.0°C. (B)  Plastochron In developmental studies one can u s u a l l y r e l a t e only the  simplest aspects o f the developing organism o r organ t o time d i r e c t l y . The term 'plastochron' proposed by Askenasy (1880) has gained f a i r l y wide usage (Esau, 1953).  She defined plastochron as:^  "The p e r i o d between i n i t i a t i o n o f successive leaves i n the shoot o f a higher p l a n t which appear p e r i o d i c a l l y " . When successive plastochrons are equal i n d u r a t i o n , the plastochron may be made t o serve as the u n i t o f a developmental s c a l e . Ericksron and M i c n e l i n i (1957) defined a plastochron as the time i n t e r v a l between i n i t i a t i o n o f two successive leaves.  Thus the p l a s t o -  chron might be more broadly defined as the i n t e r v a l between c o r r e s ponding stages o f development o f successive leaves, and one might choose i n i t i a t i o n , maturity o r any intermediate stage o f development as the stage o f reference. (C)  Photosynthesis The y i e l d o f each a g r i c u l t u r a l crop i s d i r e c t l y a f f e c t e d  by the r a t e and production o f photosynthesis.  The production and the  r a t e o f photosynthesis are a f f e c t e d by the s o i l and c l i m a t i c condit i o n s , e s p e c i a l l y the l a t t e r ; f o r example, l i g h t ( P o r t e r , 1937; T a i l i n g , 1961; Hesketh and Moss, 1963; Hesketh and Baker, 1967; Peat, 1970; Scott e t a l . , 1970); temperature (Wassink, 1945; Kramer andKerzlowski, 1960; Alberda, 1969; Hew e t a l . , 1969; Machold, 1969; Treharne and Eagles, 1970); C0 concentration (Gaastra-a, 1962; Brun and Cooper, 2  15  1967; Bishop and Whittingham, 1968). In s p i t e o f the importance o f photosynthesis, no serious attempt was made u n t i l r e c e n t l y t o e s t a b l i s h the genetic v a r i a b i l i t y i n photosynthetic e f f i c i e n c y among crop< p l a n t s .  A p l a n t breeder must  understand thoroughly the masking e f f e c t o f t h e various f a c t o r s (both e x t e r n a l and i n t e r n a l ) r e g u l a t i n g photosynthetic r a t e s and in^.turn obscuring the genetic p o t e n t i a l i t y o f t h i s character i n crop improvement programs.  The evidence f o r genetic v a r i a b i l i t y o f photosynthetic  e f f i c i e n c y among species has been demonstrated i n numerous s t u d i e s . Hesketh (1963) and Hiesey and M i l n e r (1965) reported d i f f e r e n c e s i n photosynthesis, amongg species such as Ricinus communis L., Helianthus annus L., Zea mays L.,-^Dactylis glomerata L., T r i f o l i u m pratense L., Acer saccharum Marsh., and Quercus rubra L. Differences f o r photosynthetic r a t e have been shown amonggcultivars w i t h i n a species as inethe case ;  of r i c e (Noguti, 1941); b a r l e y (Ekdahl, 1944); wheat (Asana and'.Kani, 1950); cotton (Muramoto e t a l . , 1965); blueberry (Forsyth and H a l l , 1965); sugarcane ( I r v i n e , 1967); oats (Jennings and S h i b l e s , 1968; Lawes and Treharne, 1971);;s©rghum ( E a s t i n and S u l l i v a n , 1969); a l f a l f a (Eearoeei e t a l . ,1969); bean (Wallace and Munger, 1966); maize (Duncan and Hesketh, 1968; Garg e t a l . , 1969); tobacco ( Z e l i t c h and Day, 1973). In tomato, Stambera and P e t r i k o v a (1970) found a d i f f e r e n c e i n photosynthetic r a t e between determinate and indeterminate tomato v a r i e t i e s , and they a l s o found t h a t the h i g h e f f i c i e n c y o f the a s s i m i l a t i v e apparatus can be observed i n the p e r i o d from the beginning o f f l o w e r i n g t i l l the beginning o f f r u i t formation.  Breznev and Tagmazjav  (1969) reported t h a t i n the m a j o r i t y o f h y b r i d s , photosynthetic acti v i t y during bud formation and f l o w e r i n g was higher than i n t h e 16  p a r e n t a l v a r i e t i e s and t h a t the hybrids were s u p e r i o r i n y i e l d .  Kirk  and Tilney-Bassett (1967) i n d i c a t e d t h a t there was the p o s s i b i l i t y of genetic c o n t r o l o f formation o f photosynthetic apparatus i n the p l a s t i d , which apparently i n f l u e n c e d the photosynthetic r a t e among the cultivars.  They a l s o discussed a number of instances of mutations i n  nuclear genes which might p o s s i b l y be r e g u l a t o r genes, as f o r example, the green-flesh and the l u t e s c e n t mutations i n tomato. Went (1957) pointed out t h a t under normal f i e l d conditions young tomatoes probably l o s e l e s s than 10 percent of t h e i r photosynthates i n r e s p i r a t i o n , the remaining 90% going i n t o the b u i l d i n g of the tomato p l a n t and f r u i t growth.  Evans (1969) was of the opinion t h a t  photosynthetic r a t e constituted the primary l i m i t a t i o n t o p r o d u c t i v i t y i n tomato under most c o n d i t i o n s .  Donald (1962) expressed the opinion  that p l a n t breeders have been paying i n s u f f i c i e n t a t t e n t i o n t o photosynthesis as a b a s i c process a f f e c t i n g crop y i e l d .  A l s o he pointed  out t h a t p l a n t form or h a b i t can a f f e c t photosynthetic gain.  Moss  (1969). i n d i c a t e d that breeding f o r photosynthetic e f f i c i e n c y requires the i d e n t i f i c a t i o n of d e s i r a b l e p a r e n t a l stocks.  Non-genetic v a r i -  a b i l i t y on photosynthetic measurements i s important.  When measuring  the photospiitihetdiG:: r a t e , one has t o consider the environmental e f f e c t s and t r y t o c o n t r o l t h i s v a r i a t i o n . t h a t the net photosynthesis  K r i s t o f f e r s e n (1963) pointed out  i n tomato was so g r e a t l y a f f e c t e d by  en-  vironmental f l u c t u a t i o n during the time periods used t o make the measurements, that the net photosynthesis  r a t e from such procedures were i n -  e f f i c i e n t f o r i d e n t i f y i n g p a r e n t a l l i n e s w i t h the genotypes f o r h i g h net photosynthesis  rates. 1717  (D)  Flower I n i t i a t i o n There are s e v e r a l reports about the i n f l u e n c e of temperature  and l i g h t on f l o r a l i n i t i a t i o n i n the tomato.  Went (1941) reported  :  t h a t the optima o f normal day temperature and lower n i g h t temperature d i d not m a t e r i a l l y increase o r decrease the number o f flowers i n i t i ated per i n f l o r e s c e n c e .  Phatak (1966) compared two regimes, 15.5°C  t o 18.5°C and 18.5°C t o 21.1°C during the p e r i o d from the seedling t o the appearance o f the f i r s t i n f l o r e s c e n c e , and reported that the number of flowers was s i g n i f i c a n t l y increased under the c o o l e r regimes. Lewis (1959) reported t h a t temperature was the main f a c t o r which a f fected the number of flowers i n a tomato i n f l o r e s c e n c e .  He a l s o i n -  d i c a t e d t h a t a l t e r n a t i o n o f warm days and c o o l n i g h t s , and v i c e v e r s a , as opposed t o a uniform temperature, had no e f f e c t on flower number i n p l a n t s grown under n a t u r a l l i g h t , but both temperature combinations had a depressing e f f e c t on flower /.production under a r t i f i c i a l l i g h t . Wittwer and Teubner (1956) and C a l v e r t (1958) reported t h a t e a r l i e s t flowering was i n i t i a t e d when the day and night temperatures were equal. Lake (1965) suggested t h a t various p l a n t processes such as vegetative growth, flower i n i t i a t i o n , f l o r a l growth and f r u i t growth may have d i f f e r e n t temperature requirements. 4.  Stage 4:  From Flower Bud Appearance t o F i r s t  Flowering  Wittwer and Aung (1969) reviewed the development o f the tomato flower and i n d i c a t e d t h a t a s m a l l protuberance of meristematic t i s s u e develops from the p e d i c e l of the preceding flower.  The p o r t i o n  of t h i s p e d i c e l p o s t e r i o r t o the protuberance becomes part o f the peduncle.  The meristematic protuberance o r - a x i l -fortsbhelfirst flower  of the c l u s t e r o r i g i n a t e s i n the a x i l of the l e a f .  18  The p e d i c e l which  supports a s i n g l e flower, as w e l l as the peduncle from which i t a r i s e s , i s composed o f a rather t h i c k cortex, a r i n g o f vascular t i s s u e and a c e n t r a l p o r t i o n o f p i t h t i s s u e (Cooper, 192-7).  Smith (1935) s i m i l a r l y  observed t h a t the protuberance o f the f i r s t flower o f the i n f l o r e s c e n c e arose i n the a x i l o f the l e a f .  The succeeding flowers o f the c l u s t e r  each a r i s e from s i m i l a r protuberances which grow out from the p e d i c e l s of the preceding flower. There are reports about the environmental e f f e c t s o f temperature on flower development.  Z i e l i n s k i (1948) reported t h a t low temp-  erature environment (7?28GCand 12.8°C) i n f l u e n c e d perianth development i n the tomato, r e s u l t i n g i n f a s c i a t i o n o f perianth components, and frequently i n adhesion o f stamens t o the c o r o l l a o r calyx and and cohesion o f the a n t h e r i d i a l f i l a m e n t s . w i t h aborted p o l l e n occurred frequently.  Rudimentary anther sacs Rick (1946) observed t h a t  under c o o l temperature, tomato flowers o f t e n drop without s e t t i n g f r u i t , and one o f the main reasons may be abortion o f the p i s t i l . 5.  Stage 5:  From F i r s t Flower t o F r u i t Set  Although the days required f o r t h i s stage are r e l a t i v e l y few, there are s e v e r a l developmental processes which occur during t h i s stage.  Besides the existence o f v i a b l e p o l l e n i n the anthers,  there i s the need f o r t r a n s f e r o f p o l l e n from the anthers t o the stigma, p o l l e n germination, p o l l e n tube growth, f e r t i l i z a t i o n and e a r l y f r u i t development. A comprehensive  study o f f a c t o r s a f f e c t i n g sporogenesis and  the development o f p o l l e n grains was made by Hewlett (1936).  Using  c y t o l o g i c a l techniques he found t h a t under conditions o f severe carbohydrate d e f i c i e n c y , sporogenous t i s s u e i n some anthers f a i l e d t o  19  reach m e i o t i c d i v i s i o n .  I n a d d i t i o n t o t h i s e a r l y e f f e c t , degener-  a t i o n of mature p o l l e n grains was a l s o a frequent occurrence ( C a l v e r t , 1964).  Anthers which were subnormal i n s i z e and were not the normal  deep yellow c o l o r i n v a r i a b l y contained only s t e r i l e p o l l e n g r a i n s . Went (1957) i n d i c a t e d t h a t abnormal p o l l e n was produced when temperatures were lower than 13°C,  and he considered t h i s t o be the major  f a c t o r causing u n f r u i t f u l n e s s i n tomatoes grown a t low night temperatures.  On the other hand, p o l l e n can be produced normally, but  not be released from the anthers due t o morphological  may  abnormalities.  Larson and Paur (1948) studied t h i s f u n c t i o n a l m a l e - s t e r i l e tomato, and reported t h a t the connate form of the p e t a l s r e s u l t e d i n considerable c o n s t r i c t i o n of the anthers and tended t o h o l d them i n c l o s e contact w i t h the p i s t i l , thus preventing rupture of the stromium and the subsequent release of the p o l l e n . The p o s i t i o n of the stigma w i t h i n the anther tube and the i n t e r n a l dehiscence of the anthers favors a high degree of s e l f - p o l lination.  A number of workers have observed t h a t w i t h c e r t a i n c u l t -  i v a r s i n c e r t a i n environments, the stigma may p r o j e c t beyond the openi n g of the anther tube, (White, 1918; Bouquet, 1919; Smith, 1935). More r e c e n t l y Williams CESSiDl) observed t h a t both day length and temperature a f f e c t e d the r a t i o n o f c a r p e l length t o stamen length.  He  a l s o observed the degree of u n f r u i t f u l n e s s l i k e l y t o r e s u l t from s t i g ma-'exsertion, f o r example, one c u l t i v a r which had a c a r p e l length/,;'' stamen length r a t i o ^ o f 1.12  set only 16.2% of f l o w e r s , whereas another  c u l t i v a r w i t h a r a t i o n of 0:96  set 60% of the flowers.  The time of dehiscence and the period during which the stigma remains r e c e p t i v e are c r i t i c a l f a c t o r s i n the p o l l i n a t i o n and  20  f e r t i l i z a t i o n o f inbreeding species such as t h e tomato.  Smith (1935)  stated t h a t i n summer the c o r o l l a remained open and t h e stigma r e c e p t i v e f o r about 4 days.  Judkins (1940) found the stigma t o be r e c e p t i v e about  2 days before a n t h e s i s , and a p e r i o d o f 2-3 days u s u a l l y elapsed between p o l l i n a t i o n and f e r t i l i z a t i o n a t normal greenhouse temperatures (16.0i'20.0°C). Koot and R a v e s t i j n (1963) found t h e r e c e p t i v i t y o f t h e stigma t o be adversely a f f e c t e d by dry sunny weather, but i n d u l l humid weather l i t t l e p o l l e n was l i b e r a t e d from the anthers. The r e c e p t i v i t y o f t h e stigma and t h e a b i l i t y o f p o l l e n t o germinate appears t o be s t r o n g l y i n f l u e n c e d by temperature.  Exper-  iments i n which p o l l e n was germinated a t 4- temperatures, namely 10.0°, 21.1°, 29.4° and 32.8°C were reported by Smith (1935) and Smith and Cochran (1935).  They found t h a t p o l l e n remained i n a c t i v e f o r s e v e r a l  hours a f t e r being deposited on t h e stigma. A t 21.1° and 29.4°C s h o r t tubes formed a f t e r 6 hours, but a t 32.8°C only 0.1% o f the p o l l e n had germinated during the f i r s t 12 hours and only 3.9% a f t e r 84 hours. Germination was best a t 29.4°C but only s l i g h t l y b e t t e r than 21.1°C. Koot and R a v e s t i j n (1963) assessed the degree o f f e r t i l i z a t i o n by the percentage o f p o l l e n grains germinating on the stigma 2 hours a f t e r pollination.  ::  They found t h a t both the degree and speed o f germination  were l a r g e l y dependent on temperature.  Dempsey (1969) reported tomato  p o l l e n germination occurred a f t e r 40 minutes a t 35.0°C, and a t 5.0°C the time was increased t o 20 hours.  Hornby and Charles (1962) r e -  ported "fe^t the need f o r a nanimum s i z e o f p o l l e n a p p l i c a t i o n , and noted c u l t i v a r d i f f e r e n c e s i n the minima. A f t e r germination o f t h e p o l l e n g r a i n , growth o f t h e p o l l e n tube through t h e s t y l e i s the most important p a r t o f the sequence  21  of events during the progamic phase o f f e r t i l i z a t i o n .  Tube growth  i s concerned w i t h p r o t e i n s y n t h e s i s , formation o f w a l l m a t e r i a l , as w e l l as oriented growth toward the micropyle o f the embryo sac. For e x t e r n a l f a c t o r s , temperature was found t o have a marked e f f e c t on the genirination percentage o f p o l l e n as w e l l as on the r a t e o f p o l l e n • tube growth.  The maximum r a t e o f p o l l e n tube growth occurred a t 21.1°C  w i t h 29.4°, 10.0° and 32.0° ranging i n decreasing order (Smith and Cochran, 1935).  P r e i l and Reimann-Philipp (1969) reported t h a t the  p o l l e n tubes reached the ovary i n about 12 hours a t 20.0-25.0°C and i n 48 hours a t 10.0°C. Temporary low temperature (0°-2.0°C/15 hours) d i d not i n j u r e the p o l l e n tubes and they began t o grow again when the temperature  had r i s e n .  Judkins (1940) reported the time involved  i n p o l l e n tube growth appears t o increase during the f a l l and w i n t e r when l i g h t i s o f low i n t e n s i t y .  Dempsey (1969) s t a t e d t h a t t h e ex-  t e n s i v e p o l l e n tube growth only occurred i n the 10.0-35.0°C range. At 37.0°C p o l l e n tubes grew abnormally and l a t e r ceased growth w h i l e i n the s t y l e .  He concluded t h a t growth was i n v e r s e l y r e l a t e d t o temp-  erature because p o l l e n tubes entered the micropyles 7 hours a f t e r p o l l i n a t i o n a t 35.0°C but r e q u i r e d 34 hours a t 10.0°C. The sequence of events between p o l l i n a t i o n a n d * ' f e r t i l i z a t i o n was c a r e f u l l y observed and reported by Smith (1935). About 50 hours a f t e r pollen-.:reached the stigma, one o f the male n u c l e i fused w i t h the p o l a r n u c l e i , the other f u s i n g w i t h the egg.. the  After f e r t i l i z a t i o n  zygote d i d not begin d i v i s i o n f o r 36 t o 48 hours.  sac g r e a t l y enlarged i n the meantime.  The embryo  The primary endosperm nucleus,  began d i v i s i o n i n advance o f the embryo.  A t 66 hours a f t e r p o l l i n -  a t i o n , when the zygote was s t i l l a s i n g l e c e l l , the endosperm 22  consisted o f 8 c e l l s w i t h d e f i n i t e w a l l s separating them. 6.  Stage 6:  From F i r s t F r u i t Set t o F i r s t Change o f F r u i t Color  There has been considerable d i s c u s s i o n and s p e c u l a t i o n on the general problem o f the f r u i t s e t t i n g and the development o f young f r u i t i n r e l a t i o n t o the growth o f the p l a n t and d i f f e r e n t f a c t o r s of the environment.  Shan'gina (1961) s t a t e d t h a t r e l a t i v e l y poor  f r u i t s e t on the lower t r u s s of - the tomato may be a t t r i b u t e d t o the small storage reserves in- plants grown under the poor l i g h t conditions of e a r l y s p r i n g .  Such- n u t r i t i o n a l d e f i c i e n c i e s have been suggested  as the p o s s i b l e cause o f f a i l u r e o r poor s e t f o r the f i r s t i n f l o r e s censes t o produce f r u i t i n tomato a f t e r t r a n s p l a n t i n g (White, 1930; Rick, 1946; Leopold and S c o t t , 1952).  Murneek (1939) pointed out  t h a t food reserves are o f great importance i n the i n i t i a t i o n and development o f the reproductive phase i n tomato p l a n t s . Regarding the environmental e f f e c t s , Went (1944) reported t h a t i n the f i r s t and second c l u s t e r s , f r u i t s e t was abundant only when the n i g h t temperatures were between 10.0° and 20.0°C; and w i t h lower o r higher night temperatures, f r u i t i n g was reduced o r even absent.  Lake (1965) studied the temperature e f f e c t on f r u i t s e t t i n g ,  and claimed the day temperature appeared more important than the night temperature.  Robinson e t a l . (1965) reported t h a t c o l d temperature  appeared t o a f f e c t f r u i t s e t t i n g o f tomato p r i m a r i l y through i t s i n fluence on microsporogenesis.  They a l s o reported t h a t high temper-  ature had a s i m i l a r effect.^ suggesting t h a t the same genetic system determined f r u i t s e t t i n g response t o e i t h e r h i g h o r low temperatures. This c o o l temperature e f f e c t on f r u i t set was a l s o reported by Learner and Wittwer (1953), C a l v e r t (1958), Wedding and Vines (1959), Schaible  23  (1962), Curme (1962) and Lake (.1967). ' Most v a r i e t i e s o f tomatoes w i l l produce parthenocarpic f r u i t at a r e l a t i v e l y low temperature, but not a t r e l a t i v e l y warm temperature.  Osborne and Went (1953) found parthenocarpic f r u i t a t a low  temperature w i t h a h i g h l i g h t i n t e n s i t y .  Daubeny (1955) found t h a t  poor p o l l e n germination and/or growth may e x p l a i n the parthenocarpic f r u i t produced by tomato cul±£\%>tBonny Best a t the c o o l temperature (10.0° t o 12.8°C) despite hand p o l l i n a t i o n . Leopold and S c o t t (1952) pointed out t h a t tomato f r u i t s e t was s t r o n g l y and q u a n t i t a t i v e l y dependent upon the presence o f mature leaves.  Darkened mature leaves were l e s s e f f e c t i v e than l i g h t e r  ones f o r promoting f r u i t s e t . . Agreement has not been reached as t o the stage o f development a t which m i t o s i s a c t u a l l y ceases i n the developing f r u i t .  Smith  and Cochran (1935) reported t h a t c e l l d i v i s i o n proceeded a c t i v e l y i n the f r u i t f l e s h f o r approximately 2 weeks a f t e r p o l l i n a t i o n .  Hough-  t a l i n g (1935) as w e l l as Gustafson and Houghtaling (1935) concluded t h a t f r u i t growth a f t e r p o l l i n a t i o n was a r e s u l t o f c e l l enlargement only.  MacArthur and B u t l e r (1938) reported that ovary growth was  e n t i r e l y by c e l l d i v i s i o n p r i o r t o p o l l i n a t i o n , and t h a t subsequent growth was c h i e f l y by c e l l expansion, c e l l d i v i s i o n being atfrninor f a c t o r t h a t j u s t s u f f i c e d t o maintain the t i s s u e containing non^expanding epidermal c e l l s .  Groth (1910) had p r e v i o u s l y reported t h a t  young and mature f r u i t s contained the same number of epidermal c e l l s , and that m i t o s i s played l i t t l e p a r t i n the enlargement o f the tomato f r u i t skin.  Clendenning (1948) reported t h a t growth o f the f r u i t i n -  cludes a phase of r e s i d u a l m i t o t i c a c t i v i t y t h a t :;.pers'ists - c.for f :  24  approximately  1 week a f t e r s e t t i n g .  There i s a r e l a t i o n s h i p between f r u i t p o s i t i o n w i t h i n the t r u s s and f r u i t growth.  Beadle (1937) considering the f i r s t 6 f r u i t s  i n the trusses o f c u l t i v a r Kondine Red, found t h a t the nearer the f r u i t was t o the main stem then the shorter was the maturation  period.  S i m i l a r reports were made by Kidson and Stanton (1935), Kerr (1955) and Cooper (1959). There are a l s o some r e l a t i o n s h i p s between growth r a t e , s i z e of f r u i t and other p h y s i o l o g i c a l characters.  Cooper (1959) pointed  out t h a t f r u i t s which begin t o s w e l l r a p i d l y a t the beginning o f f r u i t development have a shorter maturation period than those f r u i t s which have a period o f i n i t i a l l a g before r a p i d growth begins.  Gustafson  and S t o l d t (1936) pointed out t h a t i n c r e a s i n g the l e a f area, can r e s u l t i n the s i z e o f f r u i t being increased a f t e r t h e time o f s e t t i n g . Clendenning (1942) reported t h a t the growth o f f r u i t was found t o be associated w i t h an absolute increase i n r e s p i r a t i o n crate. 7.  Stage 7: From F i r s t Change i n F r u i t Color t o F r u i t Ripening Color changes i n tomato f r u i t are the most obvious s i g n s o f  ripening.  These changes are p r i m a r i l y due t o degradation o f the c h l o r -  o p h y l l s and the synthesis o f carotenoid pigments.  Duggar (1913) and  Sando (1920) reported t h a t normal temperature and oxygen supply were the e s s e n t i a l requirements f o r f r u i t r i p e n i n g .  High temperatures over  32.0°C and low temperatures under 10.0°C were reported t o delay o r even h a l t the r i p e n i n g (Tomes, 1962; Pharr and Kattan, 1971; Walkof, 1962). A d d i t i o n a l t o the c o l o r changes i n r i p e n i n g f r u i t , Pattersen (.1970) emphasized two major changes:  25  1) t e x t u r a l changes r e s u l t i n g  from environment and c u l t u r a l p r a c t i c e s t h a t a f f e c t c e l l morphology during growth; and 2) f l a v o r changes i n which there i s a perception of a combination o f sweetness, a c i d i t y and astringency i n conjunction . w i t h the odorous v o l a t i l e s . E.  Genetic A n a l y s i s Of Growth And E a r l i n e s s Of Tomato Investigations on s i z e and shape i n the development o f p l a n t  organs have g i v e n - f u r t h e r i n s i g h t i n t o the more fundamental aspects o f t h e i r i n h e r i t a n c e . K h e i r a l l a and Whittington ( 1 9 6 2 ) and Mallah e t a l . (1970)  pointed out t h a t s i g n i f i c a n t d i f f e r e n c e s i n growth r a t e s were  found between c u l t i v a r s and between the r e c i p r o c a l i n t e r - s p e c i f i c h y b r i d s , and t h a t l a t e r t h i s growth r a t e was found t o be i n h e r i t e d ada d i t i v e l y w i t h a l a r g e dominance component (Peat and w h i t t i n g t o n , 1 9 6 3 ) . K h e i r a l l a ( 1 9 6 1 ) reported t h a t delayed germination o f L. frlnfeine-I-lif o l i u m x L. esculentum r e l a t i v e t o L. p i m p i n e l l i f o l i u m may a l l o w a r e l a t i v e l y greater t r a n s l o c a t i o n o f reserves t o the shoot o f the hybrid.  The growth r a t e o f the hypocotyl i n t h i s h y b r i d was found t o  be higher f o r a l i m i t e d p e r i o d p r i o r t o emergence.  This may be an  explanation f o r the "undefined biochemical s u p e r i o r i t y " which Lewis Q!9j5}3>) suggested r e s u l t e d i n the h y b r i d having a s h o r t e r " l a g phase" i n the attainment o f i t s growth r a t e . L u c k w i l l (.MW) and K h e i r a l l and Whittington ( 1 9 6 2 ) comparing hybrids and t h e i r parents reported t h a t the hybrids had a l a r g e r l e a f area which was r e l a t e d t o a greater f r u i t y i e l d .  Whaley ( 1 9 3 9 ) pointed  out that the leaves o f hybrids were intermediate i n s i z e between parents and tended t o be greater than the mean of the parents.  Mallah  et a l . ( 1 9 7 0 ) reported t h a t a dominant gene actioniwas found i n t h e 26  i n h e r i t a n c e of l e a f area, whereas f o r f r u i t s i z e both dominant and a d d i t i v e gene a c t i o n were present. Whaley (1939) reported t h a t the s i z e of flower i n tomato hybrids was intermediate between those o f the parents.  Somewhat sim-  i l a r r e s u l t s were reported by Williams (1959), who found that none of the tomato hybrids exceeded the b e t t e r parent f o r such c h a r a c t e r i s t i c s as number of f l o w e r s , f r u i t s i z e and number of f r u i t s ; w i t h the one exception of y i e l d per p l a n t . The study o f e a r l i n e s s l e d Powers and Eyi>h (194-1) t o p a r t i t i o n the f o l l o w i n g 3 stages of the l i f e c y c l e , 1) seeding t o f i r s t bloom; 2) f i r s t bloom t o f i r s t f r u i t set and 3) f i r s t f r u i t s e t t o f i r s t ripe f r u i t .  Later Powers e t a l . (1950) concluded from the use  of 2 parentadiscultivars and t h e i r hybrids t h a t the f i r s t 2 stages' were each c o n t r o l l e d by 3, and the t h i r d stage by t>2o major gene p a i r s . Honma et a l . (1963) reported t h a t only 1 major gene p a i r c o n t r o l l e d the f i r s t growth stage. Burdick (1954) reported t h a t the time of f l o w e r i n g f o r hyb r i d s was approximately intermediate between the parents.  Similar  r e s u l t s were a l s o reported by Williams (1959) and Young (1966). The opinions about the genetic mechanisms c o n t r o l l i n g component stages are v a r i e d .  C o r b e i l (1965) found t h a t e a r l y maturity  genes were completely dominant t o t h e i r l a t e phase a l l e l e s i n the second and t h i r d stages and p a r t i a l l y dominant i n the f i r s t stage:.' Peat and Whittington (1965) and Mallah e t a l . (1970) found a d d i t i v e gene a c t i o n w i t h various degrees of dominant gene a c t i o n f o r the f i r s t stage.  Young (1966) claimed t h a t dominant gene a c t i o n f o r the f i r s t  stage was  lacking.  Burdick (1954) s t a t e d the f o l l o w i n g : "The maturity genes o f both parents appear t o be expressing themselves, a t d i f f e r e n t stages i n seme hybrids. This would support the view t h a t dominance i s a r e l a t i v e phenomenon, depending on the stage of development and the environmental circumstances under which i t i s measured, and t h a t the excellence o f hybrids may be a t t r i b u t a b l e t o the co-expression of the a l l e l e s from both parents, made p o s s i b l e by the existence of dominance along w i t h ontogenetic and environment g r a d i e n t s . " Burdick's idea was. supported by L i and Hornby (1972) who showed t h a t c e r t a i n hybrids e x h i b i t e d e a r l i n e s s h e t e r o s i s under a c o o l temper-  ' \  ature environment (10.0°-12.0°C) but responded intermediately between parents under normal c u l t u r e temperature conditions (19.0°-21.0°C). A number of workers have reported an a s s o c i a t i o n between e a r l i n e s s and c e r t a i n other tomato characters.  Alpat'ev  (1957),  Daubeny (1959) and Yeager and Meader (1937) reported t h a t s e l e c t i o n based on e a r l y f l o w e r i n g was the most e f f i c i e n t method i s o l a t i n g e a r l y tomato segregates.  Bernier and Ferguson (1962) studied the  r e l a t i o n s h i p s of developmental characters of the tomato w i t h e a r l i ness, and they found t h a t the days t o f i r s t flower (Stage 1) were negatively c o r r e l a t e d w i t h e a r l i n e s s (Stages 1, 2 and 3) f o r the c u l t i v a r s 'Imun P r i o r ' and 'Early Lethbridge'.  Days r e q u i r e d f o r  Stage 3 were not c o r r e l a t e d w i t h e a r l i n e s s except f o r the c u l t i v a r s ,  Earlinorth  ,  and 'Early Lethbridge', therefore they concluded t h a t  Stage 3 cannot be regarded as a good index of e a r l i n e s s .  28  MTERIALS AND METHODS  MATERIALS Three true breeding tomato c u l t i v a r s which were used as p a r e n t a l l i n e s , and a l l p o s s i b l e combinations of t h e i r crosses were evaluated. The p a r e n t a l l i n e s were Bonny Best ( B ) , Cold Set (C) and Immur P r i o r Beta ( I ) .  They have the f o l l o w i n g h i s t o r y and character-  istics. 1.  Bonny Best (B) According t o Boswell (1933) t h i s c u l t i v a r was introduced  by the f i r m of Johnson and Stokes df P h i l a d e l p h i a , U.S.A. i n 1908. I t l i s very w e l l known on the North American continent.  B has i n -  determinate growth h a b i t w i t h round, f l e s h y and uniform colored f r u i t s . Boswell (1933) pointed out t h a t maturation of B f r u i t was delayed ' considerably under c o o l temperatures o r other unfavorable c o n d i t i o n s . T y p i c a l l y , there are 4 or 5 flowers per c l u s t e r w i t h 2 or 3 f r u i t s being set per c l u s t e r .  This c u l t i v a r was used because i n the past  years a considerable amount o f research has been done, i n which t h i s popular c u l t i v a r was the t e s t p l a n t . 2.  Cold Set (C) I t i s a e r e l i t i v e l y new tomato c u l t i v a r f o r d i r e c t seeding,  developed by Professor T. 0. Graham, at the U n i v e r s i t y of Guelph, Ontario, Canada and r e l e a s e d i n 1962. F i r e b a l l and F i l i p i n o #2.  I t came from a cross between  Both of C's parents are t o l e r a n t t o Very warm  29  and cold temperal^jres. Young (1963) reported that i t i s resistant to cold temperature, and w i l l set f r u i t at a night temperature of 7.2°C. This c u l t i v a r can set i t s flowers under both cold and warm conditions.  I t also has indeterminate growth, and uniformly colord  f r u i t of medium size. • 3.  Immur Prior Beta (I) The origin of this c u l t i v a r i s not known. Curme (1968)  and Reynard (1968) believed that this c u l t i v a r was developed by Dr. A. K a l l i o , University of Alaska art Fairbanks, Alaska, U.S.A., however K a l l i o (1968) said he obtained the seed i n 1951 from the Horticultrure Department of the University of North Dakota, U.S.A., and he also thought that this c u l t i v a r might have come from Europe. This c u l t i v a r has the potato leaf t r a i t .  I t i s indeterminate i n  growth habit, and i s very tolerant t o low temp.er.atures (e.g. 10.0°C12.0°C) for f r u i t set and vine growth. The f r u i t i s r e l a t i v e l y small (60-90g) with flattened globe shape, somewhat angular with green shoulders.  Dirikel (1966) stated that this c u l t i v a r i s one of the  best f o r summer production i n heated glass houses i n the Alaska latitudes. The three parental lines were crossed i n a l l possible combinations, thus there were s i x F i hybrids. For convenience, these . s i x d i a l l e l cross hybrids were abbreviated with the female parent indicated f i r s t as follows: B x l , (BI); IxB, (IB); BxC, (BC); CxB, (CB); Cxi, (CI); and IxC, (IC).  30  30  METHODS A. Greenhouse Experiments 1.  Experiment I A d i a l l e l cross experiment employing the 3 parental and  6 Fi hybrids was conducted i n the winter of 1969!-1970 to observe growth stages under ' &2o temperature regimes. One greenhouse was kept i n the optimum range of 17.0°C-21.0°C and was considered to be the warm regime, i n contrast to the second house which was kept i n the 10.0°-13.0°C range and considered to be the cool regime. Seeds were sown on October 20 i n each of the 2 greenhouses. Seedlings were pricked out 2 weeks l a t e r and set i n 5 x 5 cm veneer bands i n f l a t s .  Temperatures i n the 2 houses were recorded on ther-  mographs throughout the experiment (Table 2 in Appendix). On November 30, the plants were placed i n the s o i l beds i n 2 greenhouses. The plants were 50 cm apart within the row and 4-5 cm between the rows.  Supplementary l i g h t was provided by 4 300-watt fluorescent  tubes i n s t a l l e d i n pairs over the s o i l beds to ensure a 14-hour photoperiod.  Pollination was allowed to occur naturally. A randomized block design was used with 4 blocks of 1-plant  per plot f o r each of the 9 lines (see Table 1, Appendix). Earliness was recorded as the number of days required f o r each of the following: Stage 1:  seeding to germination - germination was recorded when 50% of the t o t a l of 50 seeds per l i n e had emerged and expanded their cotyledons to a horizontal l e v e l .  Stage 2*:i\ germination to f i r s t true leaf emergence - which was  31  considered t o be when the f i r s t t r u e l e a f had reached a length o f 10mm. Stage 3:  f i r s t t r u e l e a f t o flower bud emergence.  Stage 4:  flower bud emergence t o f i r s t f l o w e r i n g - the flower was considered open when the c o r o l l a was b r i g h t yellow and had begun t o r e f l e x .  Stage 5:  f i r s t f l o w e r i n g t o f i r s t f r u i t s e t - which was considered to be when the f i r s t f r u i t had reached a diameter o f 5mm.  Stage 6:  f i r s t f r u i t s e t t o f r u i t changing c o l o r - when the f i r s t orange-pink c o l o r was shown a t the blossom end.  Stage 7:  f r u i t changing c o l o r t o f r u i t r i p e n i n g - when the c o l o r hadd changed t o r e d , the f r u i t was .considered t o be r i p e . I n Stage 3, the i n t e r v a l between f i r s t t r u e l e a f t o flower  bud emergence was subdivided i n t o plastochron u n i t s .  The f i r s t p l a s t o -  chron was considered t o be the age when the p l a n t ' s f i r s t l e a f had reached t h e length o f 10mm.  When the second l e a f reached the'length  of 10mm, i t was considered t o be plastochron two, and so on. The number o f days were a l s o recorded f o r the i n t e r v a l s between p l a s t o chrons. 2.  Experiment I I The second experiment was done i n the w i n t e r o f 1970-1971  and the purpose o f t h i s experiment was t o f u r t h e r the study o f Stages 5 and 6 by using c o n t r o l l e d p o l l i n a t i o n procedures t o ensure t h a t a l l the l i n e s had a uniform s t a r t i n g p o i n t f o r t h e i r f r u i t development. The flowers were emasculated 1 day before anthesis by t a k i n g away p e t a l s and anthers w i t h a p a i r o f tweezers. 32  P o l l e n was c o l l e c t e d  on microscope s l i d e s , and transferred to the stigmas with a needle. The date of hand pollination was considered as the f i r s t day of Stage 5. The second and t h i r d flower of the second cluster were used f o r this experiment. When the f r u i t reached 5mm diameter, i t was considered as the f i r s t day Stage 6. When r i p e , the individual f r u i t s were weighed and measured f o r diameter. The management regimes including temperature d i f f e r e n t i a l s for this experiment were similar to those i n the f i r s t experiment. Seeds of the 9 lines.were sown on Novemberr- 1, and the plants were set i n the s o i l beds on December 12. The same design was employed as i n Experiment I with a new randomization (see Table 3, Appendix). 3. Experiment I I I . This experiment used a larger population size but had t o be limited to the two more promising parental c u l t i v a r s , B and I , and their reciprocal hybrids.  The management regimes including temp-  erature'were similar to those i n the f i r s t 2 experiments. Seeds of the 4 lines B, I and their reciprocal hybrids were sown on October 29, 1971. Plants were set on the s o i l beds on December 9 and a randomized block design was arranged with 10 blocks of the 4 l i n e s . There was 1-plant per plot (see Table 5, Appendix). The same data were collected as i n Experiment I . B. Growth Chamber Experiments. 1. Experiment I This experiment was conducted to contrast the response of the plant materials at the cool temperature of 12.0°C with the more optimum one of 21.0°C. Seeds of 3 parental lines and t h e i r 6 d i a l l e l 33  hybrids f o r a t o t a l o f 9 l i n e s were sown on May 11, 1970.  Seedlings  were p r i c k e d out and s e t i n 7x7 cm p l a s t i c pots and placed i n growth chambers u n t i l the eighth plastochron stage was reached when the experiment was terminated. per plastochron.  There was only one r e p l i c a t i o n per l i n e  The p l a n t s were s h i f t e d around w i t h i n the chambers  every other day t o minimize the environmental  effects.  Data were c o l l e c t e d f o r plastochron ages s t a r t i n g from the 4th t o 8th i n c l u s i v e l y .  Plants were watered a t 9:00 a.m. and  net photosynthesis r a t e was measured a t 10:30 a.m. Analyzer (Beckman model 15A) was used.  An L/B I n f r a r e d  The l e a f area was measured  i n an a i r f l o w planimeter. 2.  Experiment I I This experiment used a l a r g e r population s i z e than i n Ex-  periment I , but was l i m i t e d t o the more promising p a r e n t a l c u l t i v a r s B and I , and t h e i r r e c i p r o c a l h y b r i d s .  Plants o f the 4 l i n e s were  arranged a t random i n the growth chamber w i t h 4 r e p l i c a t i o n s f o r each plastochron.  Seeds were sown on May 1, 1971 and the management  was s i m i l a r t o t h a t i n Experiment I , and s i m i l a r data were c o l l e c t e d on the 4th t o 8th plastochrons i n c l u s i v e . C.  F i e l d Experiments 1.  Experiment I This experiment was conducted i n 2 parts i n f i e l d p l o t s  ,at The U n i v e r s i t y o f B r i t i s h Columbia i n the summer o f 1971.  The  f i r s t p a r t comprised B and I and t h e i r r e c i p r o c a l r crosses, f o r a t o t a l o f 8 l i n e s (B, I , B l , .IB, B I x I , I B x I , BIxB, IBxB). plants per l i n e were used.  Twelve  The seeds were sown on A p r i l , 17,..and  34  transplanted t o the f i e l d on May 10. This p l a n t i n g was about 1 t o 2 weeks e a r l i e r than gardeners would s e t out p l a n t s , and i t was expected t h a t the plants would be under t e s t t o a s c e r t a i n whether the plants could set f r u i t i n the l e s s than optimum growing c o n d i t i o n s . The data were recorded f o r t h i s and subsequent f i e l d experiments on i n d i v i d u a l plants as number o f days required f o r each o f the f o l l o w i n g stages: Stage A;, seeding t o f i r s t flowering - the flower was considered open when the c o r o l l a was b r i g h t yellow and had begun t o reflex. Stage B:  f i r s t flowering t o f i r s t f r u i t s e t - the f r u i t was considered s e t when the diameter reached 5mm.  Stage C:  f i r s t f r u i t s e t t o f r u i t r i p e n i n g - a f r u i t was considered r i p e when the f r u i t c o l o r changed t o r e d . SinceeStage B i s very short r e l a t i v e t o Stages A and C, i t  was assumed t h a t Stage B may not be as important as Stages A and C i n breeding f o r e a r l i n e s s , therefore Stage B was not considered f o r f u r t h e r study. The second part was used t o observe the segregation o f F  2  and F  3  from IB and BI r e c i p r o c a l crosses, and a d d i t i o n a l l y t o do  s e l e c t i o n among the F  3  plants.  The s e l e c t i o n was f o r e a r l i n e s s and  tolerance o f e a r l y s p r i n g c o o l temperatures.  There were 6 and 11  plants s e l e c t e d i n the IB and BI l i n e s r e s p e c t i v e l y .  The s e l e c t i o n  c r i t e r i a i n t h i s 2nd part o f the experiment were f o r segregates which were e a r l i e r than both parents, B and I , i n Stages, A cv and/or Stage C. 2.  Experiment I I The s e l e c t e d plants from the F 35  3  generation o f r e c i p r o c a l  populations IB and BI were reproduced and evaluated.  Thus there  was the F^;. f o r 6 lines from IB selection and 11 lines from the BI selection plus two parents I and B, to give a t o t a l of 19 lines i n this experiment. Seeds were sown on March 30, 1972 and transplanted to the f i e l d on May 15. There were 5 plants per plot, 19 plots per block and t o t a l of 5 blocks.  The experimental design of the random-  ized complete block i s shown i n Table 8 of the Appendix. 3. Experiment I I I This f i e l d experiment was conducted i n two parts.  In the  f i r s t part, seeds from the e a r l i e s t 10% of the Fi* of the IB and BI l i n e s , which were pedigree selected i n Experiment I I , were used i n a simulated mass selection programme.  Equal amounts of seed from,  the e a r l i e s t 15 plants selected i n the Fit of the IB l i n e were mixed and a sample of the mixture was used to grow 125 plants which was the F 5 of the IB l i n e .  Similarly, seeds from 25 plants of the Fit  of the BI l i n e were mixed, and 250 plants were grown to provide the F  5  of the BI l i n e . In the. second part, selected individual plants f o r e a r l i -  ness were compared to the individual plants selected f o r lateness i n the F i t generation.  There were 6 plants from the F4 generation  selected f o r earliness and 2 plants selected f o r lateness. These represented the extremes i n the F i t population.  Seeds were sown on  March 30, 1973 and transplanted to the f i e l d on May 11. Plants were arranged i n special blocks as shown i n Table 9 of the Appendix. Data f o r Stages A, B and C were collected as i n Experiment I .  36  STATTSTTCAL METHODS  A. Analyses Of Data From The D i a l l e l Crosses Hayman (1954a; 1954b); Jinks (1954); Jinks and Hayman (1953) developed the analysis f o r the Fi generation of a d i a l l e l cross.  The theory for t h e i r method can be divided into 2 parts.  The f i r s t part proposes a p i c t o r i a l presentation i n which Jinks (1954) stated that "the covariance of array means on the common parent of the array gives the array covariance (W )". The W values f o r each r  array were plotted against the variance of the array (V ). In order for the basic assumptions f o r this analysis to be met, these points should l i e along a l i n e of unit slope and within a parabola defined as ."W= V x variance of parents". 2  r  The position of the l i n e gives  an estimate of the degree of dominance. When the interception i s through the o r i g i n , complete dominance i s concluded.  The intercep-  t i o n above or below the origin indicates p a r t i a l dominance and overdominance respectively. The-second part proposed a numerical analysis (Table 1) i n which the variances and covariances available from the d i a l l e l table were defined i n terms of the components D, H  ls  H , F and E 2  ( f i r s t designated by Mather, 1949), where D was the weighted component of variationndue to differences i n additive gene effects, Hj was the weighted components due to dominance, H indicated the 2  asymmetry of positive and negative effects of genes, F was a component due to the r e l a t i v e frequencies of dominant and recessive  37  TABLE 1.  The second degree s t a t i s t i c s f o r a d i a l l e l s e t . (Mather and J i n k s , 1971)  Statistics  Model  V . p V r W r  D + E •  %D -%F + 1/9:^E hp +  Vr Hi = 4 Vr + V p H-2 = 4 V r F  h£) + J^Hx -hF + 5/9 E  = 2 V p  - 4 W r  - M-V- + r - 4 W r  u n  1 )  z  " n  +  2  5/81 E  - ^2±i-£ E n  2 ( n 2  2 ( n  -"*H  2 )  E E  V r  the variance o f an array  W r W" r  parent-offspring covariance o f members o f the same array  V r V P  mean o f Vj-  Vr E  the variance o f array means  D  the weighted component o f variaffeionhdue t o differences -in additive gene e f f e c t s  Hi  the weighted components due t o dominance  Hjj.  the asymmetry o f p o s i t i v e and negative effects o f genes  F  the r e l a t i v e frequencies o f dominant and recessive a l l e l e s  mean o f W  r  variance o f parents  environment e f f e c t , derived from the block interactions of the family-.means (from analysis o f variance of d i a l l e l t a b l e ) , i t has the same value f o r each block;V  38'  a l l e l e s , (being p o s i t i v e when dominant a l l e l e s are more frequent, and negative when r e c e s s i v e a l l e l e s are the more f r e q u e n t ) , and E was the component due t o environmental e r r o r . D<H  t i o n may be gained: F>0,  A d d i t i o n a l informa-  , overdominance; D>Hi., p a r t i a l dominance.  1  i n d i c a t e s t h a t the parents c a r r i e d an excess of dominant over  r e c e s s i v e genes, a l s o ( H / D ) '  i n d i c a t e s the average degree of  2  1  dominance.  I f t h i s value i s greater than one, there i s overdominance;  i f equal t o one, complete dominance; i f l e s s than one, p a r t i a l domFurthermore, H /4Hi i s an estimate of the average propor-  inance.  2  t i o n of dominant and r e c e s s i v e a l l e l e s over a l l p a r e n t a l l i n e s .  When,  i t i s lower than i t s maximum value of 0 . 2 5 , the gene frequency of both dominant (u) and r e c e s s i v e (v) genes i s not equal a t a l l l o c i . The f u n c t i o n (4DH] ) +F/(4DHi ) - F estimates the r a t i o o f the t o t a l 2  2  number o f dominant t o r e c e s s i v e genes i n a l l parents. h /H , 2  The v a l u e ,  i s an estimate of the number o f genes which c o n t r o l s the  character and e x h i b i t s dominance t o some degree.  The estimate of the  heterozygote value h i s c a l c u l a t e d as 2 (rn^i - m ^ ) ,  where m^?, i s .the  2  mean of a l l d i a l l e l (n ) progeny and m^Q parents.  i s the mean of d i a l l e l (n)  The h e r i t a b i l i t y of the t r a i t i s c a l c u l a t e d as  HD/(kD+^Hi-  !$F+E) (Crumpacker and A l l a r d , 1 9 6 2 ) . The theory underlying the p a r t i t i o n of the h e r e d i t a r y variance of the d i a l l e l crosses i n t o the above components uses 6 assumpt i o n s (Hayman, 1 9 5 4 ) :  (.1)  between r e c i p r o c a l s ; C3) (4)  d i p l o i d segregation; ( 2 )  no d i f f e r e n c e s  independent a c t i o n of n o n - a l l e l i c genes; homozygous parents; ( 6 )  no m u l t i p l e a l l e l i s m ; C5)  genes i n -  dependently d i s t r i b u t e d between the parents. This method of a n a l y s i s should only be a p p l i e d i f these  39  underlying assumptions are met.  When the data do not f u l f i l l any of  the assumptions there w i l l be a d e v i a t i o n of the W V  regression l i n e  from a slope of 1, o r an acurvature of the l i n e , o r increase scat-: t e r i n g o f points around the l i n e .  When the graphed p o i n t s give a  l i n e o f u n i t slope, the d i f f e r e n c e between W  r  and'V  A t e s t o f the assumptions i n the u n i f o r m i t y o f W -V experimental b l o c k s .  w i l l be constant. over arrays and  Lack o f u n i f o r m i t y gives no information as t o  which assumption may have f a i l e d , although some ideas can be suggested from the W V.^ graph. The methods used and problems attacked by the d i a l l e l cross techniques have been d i v e r s e .  One maj o r system was developed by  J i n k s and Hayman (1953) who were concerned w i t h gene l e v e l as men^. t i o n e d p r e v i o u s l y . Another system developed by G r i f f i n g (1956) was concerned w i t h gametlevjkevel known as general and s p e c i f i c combining a b i l i t y a n a l y s i s (G.C.A. and S.C.A. r e s p e c t i v e l y ) . For the purpose of comparison, both systems of s t a t i s t i c a l methods were used on the data of t h i s presentation. The terms general and s p e c i f i c combining a b i l i t y were o r i g i n a l l y defined by Sprague and Tatum (1942), but without a generali z e d genetic i n t e r p r e t a t i o n o f the combining a b i l i t y e f f e c t s .  Until  1956, G r i f f i n g used a d i a l l e l c r o s s i n g system i n q u a n t i t a t i v e i n h e r i t ance f o r the purpose- o f estimating genetic parameters of the popu l a t i o n from which the inbreds were derived. tions:  (1)  He proposed two assump-  the s i t u a t i o n i n which the p a r e n t a l l i n e s simply o r the  experimental m a t e r i a l as a whole are assumed t o be a random sample from some population about which inferences may be made (random model), and C2)  the s i t u a t i o n i n which the l i n e s are d e l i b e r a t e l y chosen and  40  TABLE 2. A n a l y s i s o f variance f o r coirbining a b i l i t y g i v i n g expecta t i o n o f mean squares f o r the assumption o f a f i x e d model.  expected mean sum o f mean squares 'square square  source o f variance  d.f.  G.C.A.  p-l=2  S.C.A.  p(p-l)/2=3  Reciprocal effects  p(p-l)/2=3  c  M  S g S  a2 ^Cp-2)C^ ]Eg? H  g  r  *s ^ p T F 3 ) ^ i j  s  ]  [  S  S  RError  r S S e S  m=27  Me a %  2  where  S =W?(X s  X .) -  CX., X )* . } . x;.  2  ij+  j  +  t i  ( p  1  ( p  2 )  s^zCx-.-x..)*  Testing f o r o v e r a l l d i f f e r e n c e s among the various classes o f e f f e c t s can be accomplished as f o l l o w s : (1)  t o t e s t G.C.A. e f f e c t s use _ i ) , m " g  (2)  tostestCS^C.A. e f f e c t s  (3)  t o t e s t f o r r e c i p r o c a l e f f e c t s use ( _ ) / 2 , m  F  M  / M e  ( p  ^  :  ^  ^  A  ^  2  F  p  MI  p  1  % =  M  r  / M  e  cannot be regarded as a random sample from any population ( f i x e d model).  These two d i f f e r e n t assumptions give r i s e t o d i f f e r e n t es-  t i m a t i o n problems and d i f f e r e n t t e s t s o f hypotheses regarding combining a b i l i t y effects.  I n t h i s p r e s e n t a t i o n , only assumption (2)  was considered',. (Table 2). The mathematical model f o r the combining a b i l i t y i s assumed t o be:  analysis  x. . = u + g. + g. + s.. + r . . + 1/b I e. .,  where x ^ j = i t h i n d i v i d u a l o f j t h p a r e n t a l l i n e u = o v e r a l l population mean s  i ^ j^ g  =  t h e  ^-.CA. e f f e c t f o r the i t h ( j t h ) parent  i , j = 1,.. .3 s.. = the S.C.A. e f f e c t f o r the cross between -' the i t h and j t h parents 1  r - • = the r e c i p r o c a l e f f e c t i n v o l v i n g t h e r e c i p -' r o c a l crosses between the i t h and j t h parents 1  e.., = the environmental e f f e c t associated w i t h the i j k t h i n d i v i d u a l observations b = t h e number o f b l o c k s , k=l,...4 B:' Analyses Of Data From R e c i p r o c a l Crosses Some o f the data from the greenhouse (Experiment I I I ) and growth chamber (Experiment I I ) experiments were analyzed p a r t i t i o n i n g the variance as f o l l o w s : The mathematical model f o r the r e c i p r o c a l cross a n a l y s i s i s assumed t o be: where  y ^ j - ' ^ u + 1^ + b^ + e^.. = j t h observation i n i t h l i n e - u = the o v e r a l l population mean 1^ = an e f f e c t due' t o i t h l i n e , i = l , . . . 4  42  tu = an e f f e c t due t o j t h block, j=l,...10 e.. = an e f f e c t p e c u l i a r t o j t h i n d i v i d u a l o f i t h "-' line L  source ••of van' mce. Block  d.f.  '  9  Line  3  Error  27  By 'the method o u t l i n e d by S t e e l and T o r r i e (1960) •; • the source :  of l i n e variance was f u r t h e r p a r t i t i o n e d i n t o non-orthogonal comparisons as f o l l o w s : B  I  BI  IB  Nucleus  XX  YY  XY  YX  Cytoplasm  Pi  P  p  Line pedigree ' N/ic^euE  2  l : P  2  No. o f comparisons 1.  B vs. I  +1  -1  o  o  2.  BI vs. IB  o  o  +1  -1  3.  I vs'sIBIB-  o  +1  o  -1  4.  B vs. BI  +1  o  -1  o  Following i s an o u t l i n e o f comparisons t e s t e d f o r s i g n i f icance : 1.  B vs. I :  2.  BI vs. IB:  the i n t e r - p a r e n t a l comparison the F j i n t r a - r e c i p r o c a l comparison.  Since  the r e c i p r o c a l s have t h e same nuclear compo s i t i o n , the differences between them w i l l be only due t o cytoplasmic e f f e c t . 384.  I vs. IB and B vs. BI:  t h e maternals and t h e i r o f f s p r i n g  comparisons.  Since they have same cytoplasm,  the differences w i l l be due t o nuclear compositions.  43  C. Analyses Of Data From F i e l d Experiments B a s i c a l l y the f i e l d experiments were designed w i t h the purpose o f determiriing the extent o f v a r i a t i o n w i t h i n each generation, and the s e l e c t i o n progress was c a l c u l a t e d i n t h e f o u r t h generation. Data from a l l the f i e l d experiments were used t o c a l c u l a t e the mean and standard d e v i a t i o n .  I n the f i e l d Experiment I I , s e l e c t i o n pro-  gress (AG) and genetic progress (crG) were c a l c u l a t e d f o r both IB and BI populations based on the formulae a f t e r Falconer (1967) and Pirchner (1969): a - i hAG = i a h p where  S  2  aG = AG/ih  i = s e l e c t i o n i n t e n s i t y (1.75) a = phenotypic v a r i a t i o n expressed i n standard P deviation h  = heritability  2  The estimate o f h e r i t a b i l i t y was c a l c u l a t e d using t h e variance components from the a n a l y s i s o f variance a f t e r Robinson e t a l . (1949); and Grafius e t a l . (1952). source variance  d.f. .  mean square  Line  r-1  Mi  Block  s-1  M  CT  •  (r-1)(s-1) h  h  (note:  2 2  M  . v c V i V - - a£ 2  = cT /(a 2:  g  2;  g  +  s  + so e g CT + ra£ e ;b o e M 2  2  2  ? z  Error .  expected mean square  2  3  _  = i -  _  M  3  x  h = square r o o t o f h e r i t a b i l i t y h , and d i f f e r s from Hayman and J i n k s 'h' genetic value o f d i a l l e l analysis.) 2  44  EXPEPJJ^ENTAL RESULTS  D i a l l e l Cross.?-- Experiments The data f o r the d i a l l e l cross experiments show the number of days r e q u i r e d f o r each o f the component growth stages as they occurred under the 2 temperature regimes, designated as warm and cool.  The data were analyzed by the J i n k s and Hayman (1953) and  G r i f fi n g A. (A)  (1956) methods.  Hayman - J i n k s Method Greenhousel€b<periment I This experiment was concerned w i t h the days r e q u i r e d f o r  p l a n t s t o progress through 7 growth component stages i n 2 d i f f e r e n t temperature regimes.  The means f o r the 7 stages i n both warm and c o o l  regimes are presented i n Table 3. The o r i g i n a l data are shown i n Tables 10 and l l o f the Appendix. For  each growth stage, d i a l l e l t a b l e s were s e t out f o r each  of the f o u r b l o c k s , and W and V values c a l c u l a t e d from them (Table r r 4); and the means were used t o estimate the parameters and estimators. The d i f f e r e n c e s , W -V , were obtained, and t h e i r u n i f o r m i t y was t e s t e d r r by analyses o f variance. The u n i f o r m i t y t e s t o f W -V f o r each o f t h e c h a r a c t e r i s t i c s r r i n Experiment I revealed t h a t only Stage 3 i n warm, and Stage 6 i n c o o l showed s i g n i f i c a n t d i f f e r e n c e s among arrays (Table 5 ) , i n d i c a t i n g t h a t these 2 c h a r a c t e r i s t i c s l a c k u n i f o r m i t y .  The analyses gave no  information as t o which o f the assumptions may have f a i l e d .  45  I t was  TABLE 3. Mean number of days required f o r each of the 7 stages i n the d i a l l e l cross tested i n warm and cool temperature regimes i n greenhouse Experiment I . Female parent Male parent +  B  t  Temperature  Stage warm  cool  warm  cool  warm  cool  8.7  18.5  6.5  15.9  6.9  14.8  3  9.2 32.6  9.5 36.7  . 8.5 22.4  8.4 23.4  11.0 20.2  4 5 6 7  21.8 9.0 44.8 6.8  70.8 22.9 63.9 7.8  21.3 6.4 37.7 5.2  59.3 17.0 . 45.0 6.8  17.8 7.2 44.2 5.3  10.6 28.6 52.8 18.1 64.6 7.3  1 2 3 4 • 5  7.0 9.1 21.5  •7.3 9.0 17.3 18.5 6.5  16.3 9.5  27.3 6.0  5.1 8.6 23.3 51.3 8.8  6.3 10.0 18.5 17.8 6.7  15.7 10.8 19.2 47.5 18.8  6  40.7  42.4  35.9 .  39.8  58.1  5.0  9.6  7.4 9.2  15.8  1 2  20.1 58.0 20.0  7  5.1  7.6  5.0  48.9 7.5  1 2  7.2  16.4 8.9  6.4  15.8  10.2  11.2  76.1  18.8  18.8 59.3  3  8.7 21.8  4  20.8  52.8  17.0  5  •28.0.  6  45.9 5.6  18.0 64.8  6.2 - 17.9 58.8 39.8 8.8 5.0  7  7.1  B, Bonny Best I , Immur Prior Beta C, Cold Set 46  22.1 22.8 7.4 48.1 6.4  12.4 26.7 51.8 18.3 53'. 0 ; 8.3  TABLE 4.  Calculated mean values o f V and W f o r the 7 stages i n the d i a l l e l cross t e s t e d i n warm and c o o l regimes i n greenhouse Experiment I . r  Temperature  Array Stage  C  W +V -r r  W -V r r  W  V  B  r  warm  cool  -1.2  2.4  6.4  -0.4  0.0  0.6  1.4  55.6  4.8  7.1  89.6  104.1  1.9  92.5  -3.0  -3"; 3  6.8  188.3  7.9  -1.8  6.2  -0.2  -1.7  3.8  14.1  11.4  142.5  20.1  63.8  8.7  -78.7  31.5  206.3  7  0.8  2.4  0.9  1.7  -0.1  -0.7  1.7  4.1  1  0.3  2.7  -0.1  -0.6  -0.4  -1.3  0.2  0.1  2  0.6  1.6  0.1  1.9  -0.5  30.33  0.7  3.5  3  6.5  5.8  18.9  5.9  12.4  0.1  25.4  21.7  4  2.8  7.1  0.1  4.8  ~>  -2.3  2.9  11.9  5  0.1  ill.2  -0.1  -0.5  -0.2  -1.7  0.1  0.7  6  5.6  55.8  14.5  -33.4  -8.9  -89.2  20.1  22.4  7  0.1  4.1  0.1  -0.3  0.0  -4.4  0.2  3.8  1  0.4  0.3  0.2  -0.1  -0.2  -0.4  0.6  0.2  2  0.3  2.0  -0.1  2.0  -0.4  0.0  0.2  4.0  3  4.6  22.8  7.5  33.1  2.9  10.3  12.1  55.9  4  7.9  2.0  6.5  4.6  -1.4  2.6  14.4  6.6  5  0.8  0.2  :.1.0  -0.4  0.2  -0.6  1.8  0.2  6  18.4  44.7  29.8  33.7  11.4  -10.0  48.2  78.4  7  0.1  0.8  0.1  -1.0  0.0  -1.8  0.2  -0.2  warm  cool-  warm  cool  1  1.5  3.8  0.9  2.6  -0.6  2  0.5  0.7  0.1  0.7  3  42.4  48.5  47.2  4  4.9  95.8  5  2.0.  6  see Table 3 n o t a t i o n  47  warm  2  7  cool  TABLE 5. Urviformity t e s t o f W^-V values by analyses o f variance f o r a l l the characters i n v e s t i g a t e d i n the d i a l l e l cross experiments.  Trait  mean square  Stage 1 i n warm  0.02  2  0.02  3  85.67*  4  0.63  5  0.33  6  0.05  7  0.01  Stage 1 i n c o o l  1.10  2  0.10  3  3.43  ^  40.85 1.86  5  6  927.59* 1.33  7  days required p e r plastochron i n warm  0.02  days required p e r plastochron i n c o o l  0.01  days f^qlairgd f o r Stage 5 i n warm ( p o l l i n a t i o n treatment).6 .i n warm 1  F  c  days required f o r stage 5 i n c o o l ( p o l l i n a t i o n treatment) g  ± n  0  0.17 i, c 3.45 0.21  c q o 1  f r u i t weight i n warm  6477.58  f r u i t diameter i n warm  353.10  f r u i t weight i n c o o l  17016.20*  f r u i t •diameternin c o o l  72.57  * s i g n i f i c a n t a t the 5% l e v e l  48  recognized that sample e r r o r could have produced these s i g n i f i c a n t r e s u l t s . Nevertheless, i t was advisable t o proceed w i t h the t o t a l a n a l y s i s ; however, some caution should be attached t o i n t e r p r e t a t i o n o f results. Ca)  Graphical I n t e r p r e t a t i o n o f the genetic Parameters The regressions o f W  on  are shown i n F i g . 1-4- and pro-  vides the f o l l o w i n g information. Stage 1, warm:  The regression c o e f f i c i e n t was 1.005 which was not  s i g n i f i c a n t l y d i f f e r e n t from one. t a t i c gene a c t i o n .  This showed a low l e v e l o f e p i s -  Since the l i n e o f u n i t slope moved downward from  o r i g i n t o the r i g h t , then overdominance i s suggested.  J i n k s (1954)  and Hayman (1954) i n d i c a t e d that the p o s i t i o n s o f the array p o i n t s along the l i n e o f r e g r e s s i o n o f W  r  on V  r  depend on the r e l a t i v e pro-  p o r t i o n o f dominant and r e c e s s i v e a l l e l e s present i n the common parent o f each array.  Parents w i t h a preponderance o f dominant a l l e l e s  w i l l have a low array variance and covariance, and w i l l l i e near the origin.  On the other hand, parents w i t h r e c e s s i v e a l l e l e s w i l l have  a l a r g e array variance and covariance, and w i l l l i e a t the opposite end o f the r e g r e s s i o n l i n e .  F i g . 1 i n d i c a t e d t h a t the B parent had  r e l a t i v e l y low, and C and I had r e l a t i v e l y high l e v e l s o f dominance Hayman (1954) s t a t e d t h a t : "A measure o f a s s o c i a t i o n between the signs o f dominant genes i s the c o r r e l a t i o n between p a r e n t a l s i z e and p a r e n t a l order o f dominance. .The p a r e n t a l measurement, (y ) , i s c l o s e l y c o r r e l a t e d w i t h the number o f p o s i t i v e homozygotes i n the parent w h i l e (W +V ) bears the same r e l a t i o n t o the number o f r e c e s s i v e homozygotes." When the c o r r e l a t i o n between y^ and (W +V ) i s nearly one, the r e cessive genes must be mostly p o s i t i v e ; when the c o r r e l a t i o n i s minus  49  Fig. 1 .  (V ,W ) graph f o r Stage 1 . greenhouse Experiment I , warm regime.  Fig-  (V ,W ) graph f o r Stage 3 greenhouse Experiment I , warm regime. 50  Fig. 2.  (V ,W ) graph f o r Stage 2, greenhouse Experiment I , warm regime.  graph f o r Stage 4. greenhouse Experiment I , warm regime. r  5  W  r  )  one, the dominant genes are p o s i t i v e ; when the c o r r e l a t i o n i s s m a l l , equal proportions their effects.  o f the dominant genes are p o s i t i v e and negative i n  As shown i n Table 6, t h i s c o r r e l a t i o n between -y and r J  f o r Stage 1 warm was 0.99, and i n d i c a t e s that most o f the r e cessive a l l e l e s i n the parents are a c t i n g i n the d i r e c t i o n o f late-^ ness and the dominant a l l e l e s i n the d i r e c t i o n o f e a r l i n e s s . Stage 2, warm:  The regression c o e f f i c i e n t was 0.35 which was s i g n i f -  i c a n t l y d i f f e r e n t from both one and zero ( F i g . 2 ) . This value i n d i cates that both dominant and a d d i t i v e genes must be operating.  Since  i s r e l a t e d t o V by a s t r a i g h t ! regression l i n e , i t could be conc l u d e d ' ^ ^ e p i s t a t i c gene a c t i o n was minimal; and since the r e g r e s s i o n l i n e cuts the W suggested.  a x i s downward from the o r i g i n , overdorninance was  Although the p o s i t i o n s o f the array points B, I and C  were close together, C i s c l o s e r t o the p o i n t o f o r i g i n i n d i c a t i n g dominance over B and I . The c o r r e l a t i o n between y 2p  and W +V i s negr r  a t i v e (Table 6 ) , but the r e l a t i v e l y small value o f -0.19 i n d i c a t e s p r a c t i c a l l y equal proportions  o f the dominant genes contribute t o  e a r l i n e s s (negative) o r lateness ( p o s i t i v e ) . Stage 3, warm: As i n d i c a t e d before (Table 5) the a n a l y s i s o f v a r i ance f o r  w  -V^ f a i l e d t o prove uniformity among a r r a y s , i n d i c a t i n g  that one o f the assumptions may not have been met; however, some j, i d e a o f gene a c t i o n may be gained from the W  graph ( F i g . 3 ) . The  regression c o e f f i c i e n t was o.92 which i s not s i g n i f i c a n t l y d i f f e r e n t from one and thus shows-'-absence o f appreciable e p i s t a t i c gene a c t i o n . The l i n e o f u n i t slope cuts the  a x i s upwards from the o r i g i n and  thus i n d i c a t e s t h a t p a r t i a l dominance i s f u n c t i o n i n g .  From the graph,  i t may be concluded t h a t B was a c t i n g r e c e s s i v e l y and I and C dominantly. 51  TABLE 6.  C o r r e l a t i o n c o e f f i c i e n t between p a r e n t a l values (y ) and W +V f o r a l l characters i n v e s t i g a t e d i n the d i a l l e l cross  Stage 1 i n warm  0*99  2  -0-19  3  0.86  4  0.85  5  0.96  6  0.82  7  0.97  Stage 1 i n c o o l  0.93 0.49  2  3  -0v98  4  0.94  5  0.96  g  o:;,99  7  0.78  days r e q u i r e d p e r plastochron i n warm  0.52  days r e q u i r e d p e r plastochron i n c o o l  0.93  days r e q u i r e d f o r Stage 5 i n warm ( p o l l u t i o n treatment) _ i.n warm 6  0.84  y  days r e q u i r e d f o r Stage 5 i n c o o l ( p o l l u t i o n treatment) g  ±  n  c  q  q  1  n  0.79 n Q  0.79 q  ^  q  f r u i t weight i n warm  0.92  f r u i t diameter i n warm  °-  53  f r u i t weight i n c o o l fruit-"diameter i n c o o l  0.83  52  The c o r r e l a t i o n c o e f f i c i e n t between y  r  and W^+V^  was 0.86 and because  i t was p o s i t i v e and r e l a t i v e l y c l o s e t o one, i t appears t h a t the r e cessive a l l e l e s i n the parents are a c t i n g i n the d i r e c t i o n o f lateness and the dominant a l l e l e s i n the d i r e c t i o n of e a r l i n e s s . Stage 4, warm:  The r e g r e s s i o n c o e f f i c i e n t was 0.44 ( F i g . 4) and was  s i g n i f i c a n t l y d i f f e r e n t from both one and zero, which i n d i c a t e d t h a t both dominant and a d d i t i v e genes were f u n c t i o n i n g . lated to  Since W  i s re-  by a s t r a i g h t r e g r e s s i o n l i n e , i t could be concluded t h a t  n o n - a l l e l i c gene i n t e r a c t i o n was absent, and s i n c e the r e g r e s s i o n l i n e was downward r i g h t from the o r i g i n , then overdominance must be present.  The p o s i t i o n s o f array points f o r B, I and C i n d i c a t e i n -  termediate, high and low l e v e l s o f dfcnnnanee; respectively., The corr e l a t i o n between y^ and W^+V  was 0.85 which' was p o s i t i v e and h i g h ,  hence p r o v i d i n g evidence t h a t r e c e s s i v e a l l e l e s are a c t i n g i n the d i r e c t i o n of lateness and the dominant a l l e l e s i n the opposite .' : - • direction. Stage 5, warm:  The r e g r e s s i o n c o e f f i c i e n t was 0.94 ( F i g . 5) which  was not s i g n i f i c a n t l y d i f f e r e n t from one, and i n d i c a t e d absence o f e p i s t a t i c gene a c t i o n .  The l i n e o f u n i t slope which almost goes  through the o r i g i n , i n d i c a t e d p r a c t i c a l l y complete dominance.  The  array points show t h a t B,C and I were a c t i n g at r e l a t i v e l y low, i n termediate and h i g h l e v e l s o f dominance r e s p e c t i v e l y . The c o r r e l a t i o n between y  and W +V  was 0.96 which was p o s i t i v e and h i g h , and  provides evidence t h a t the r e c e s s i v e a l l e l e s i n the parents were a c t i n g i n the d i r e c t i o n of lateness. Stage 6, warm:  The r e g r e s s i o n c o e f f i c i e n t was 0.98 ( F i g . 6) which  was not s i g n i f i c a n t l y d i f f e r e n t from one; t h e r e f o r e , absence of e p i s t a t i c gene a c t i o n was expected.  The l i n e o f u n i t slope which i s \ 53  /  F i g . 7.  CV^  ) graph f o r Stage 7, greenhouse Experiment I  warm. regime. ;  54  very close t o the p o i n t o f o r i g i n i n d i c a t e d p a r t i a l t o complete dominance.  The p o s i t i o n o f the array p o i n t s i n d i c a t e d t h a t there was  a sequence o f C, B and I which ranged from low t o high l e v e l s o f dominance.  The c o r r e l a t i o n c o e f f i c i e n t between y  r  and W^+V^was 0.82  which provides evidence that recessive genes were a c t i n g i n the d i r e c t i o n o f lateness. Stage 7, warm:  The regression  c o e f f i c i e n t was 0.97 ( F i g . 7) which  was not s i g n i f i c a n t l y d i f f e r e n t from u n i t y which i n d i c a t e d an absence of e p i s t a t i c gene a c t i o n .  The regression  l i n e c u t the W  a x i s upward  r  l e f t from t h e o r i g i n and i n d i c a t e d p a r t i a l l y dominant gene a c t i o n . The p o s i t i o n of the array p o i n t s showed that C and I had a r e l a t i v e l y high l e v e l o f dominance compared w i t h the low l e v e l f o r B. r e l a t i o n between y  and W^+V  The cor-  was 0.97, again provided evidence t h a t  most o f the recessive a l l e l e s i n the parents must have been a c t i n g i n the d i r e c t i o n o f lateness. Stage 1, c o o l :  The regression  c o e f f i c i e n t was 0.71 ( F i g . 8) which  was not s i g n i f i c a n t l y d i f f e r e n t from one.  This l i n e showed the same  gene a c t i o n and sequence o f dominance as Stage 1 i n warm conditions. S i m i l a r l y the c o r r e l a t i o n c o e f f i c i e n t o f 0.93 was e s s e n t i a l l y the same as f o r Stage l,warm. Stage 2, c o o l :  The regression  c o e f f i c i e n t was 0.87 ( F i g . 9) which  was not s i g n i f i c a n t l y d i f f e r e n t from one^ i n d i c a t i n g absence o f e p i s t a t i c gene a c t i o n .  The regression  l i n e cuts the  a x i s , l e f t and  upward from the o r i g i n , i n d i c a t i n g p a r t i a l dominance  Th level of e  dominance f o r the parents ranged from low t o h i g h i n the order of C, I and B.  I t was noted t h a t f o r the f i r s t time B showed the h i g h -  est l e v e l o f dominance.  The c o r r e l a t i o n between y^ and  w  55  + r  ^  w r  a  s  Fig. 8.  (V ,W ) g^aph f o r Stage 1, greenhouse Experiment -I, cool regime. r  r  56  F i g . 9.  (V^V^) graph f o r Stage 2, greenhouse Experiment I , cool regime.  0.49 which was small, indicating there were equal proportions of the doniinant genes which were positive or negative.  In other words, the  dominant genes did not work entirely i n the direction of earliness, but about one h a l f must have been contributing to lateness. Stage 3, cool:  The regression coefficient was 0.98 (Fig. 10) i n -  dicating the same gene action as above f o r Stage 2 i n cool.  The se-  quence f o r the l e v e l of dominance from low to liigh was B, C and I . The correlation coefficient between y and W +V was 0.98 indicating r r the recessive genes were acting i n the direction of lateness. Stage 4, cool:  The regression coefficient between  and  was 0.96  (Fig. 11) which was the same as that f o r Stage 5, warm. Thus there was no appreciable epistatic gene action, but complete dominance was indicated.  The graph shows that B had a very low l e v e l of dominance  whereas C and I had a very high l e v e l .  In other words, C and I w i l l  be acting as dominant over B. The correlation coefficient between y  and W^+V.^ was 0.94, which was high and positive indicating that  dominant gene action was i n the direction of earliness. Stage 5, cool:  The regression coefficient between W and V was 0.89 r  p  (Fig. 12) and suggested the same gene action as f o r Stage 1, cool. The correlation coefficient between y cand;W+V was 0.96 indicating r r r that the recessive genes.were acting i n the direction of lateness. Stage 6, cool:  As i n the case of Stage 3 i n warm, the analysis of  variance f a i l e d to prove the uniformity of W^V^over arrays i n Stage 6 i n cool.  Thus one of the assumptions f o r t h i s d i a l l e l cross theory  did not f i t . Nevertheless, some idea may s t i l l be gained from the W^V^ graph (Fig. 13). The regression coefficient between 57  and  12.  (V ,W ) graph f o r Stage 5, greenhousk Experiment I r  p  cool regime  Fig. 14.  Fig. 13.  (V ,W ) graph f o r Stage 6, greenhouse Experiment I , cool regime.  (V , W ) graph f o r Stage 7, greenhouse Experiment I , cool regime. 58  was 0.69 which was s i g n i f i c a n t l y d i f f e r e n t from one.  This c o e f f i s '  c i e n t i n d i c a t e d that some e p i s t a t i c gene a c t i o n and a d d i t i v e gene a c t i o n may be present. I t can be seen t h a t C and I were r e l a t i v e l y dominant over B.  The c o r r e l a t i o n c o e f f i c i e n t between y  and W +V  T  J  r  r  was 0.99 i n d i c a t i n g that the recessive genes were a c t i n g i n the d i r e c t i o n o f lateness. Stage 7, c o o l : (Fig.  The regression c o e f f i c i e n t between W  and  was 1.48  14) which was not s i g n i f i c a n t l y d i f f e r e n t fromone, i n d i c a t i n g  the same gene a c t i o n as Stages 1 and 5 i n c o o l .  The c o r r e l a t i o n co-  e f f i c i e n t was 0.78 from which i t may be concluded that the recessive genes were a c t i n g i n the d i r e c t i o n o f lateness but may be a c t i n g ambidirectionally. (B) Greenhouse Experiment I I This experiment was mainly concerned w i t h Stages 5 and 6, and t o ensure f r u i t set p o t e n t i a l , ^ p o l l e n was t r a n s f e r r e d by hand w i t h i n the same c u l t i v a r .  The mean values f o r both warm and c o o l regimes  are presented i n Table 7. The o r i g i n a l data are shown i n Tables 9 and 10 o f the Appendix.  The design and a n a l y s i s were the same as f o r  Experiment I , but the management employed a r t i f i c i a l p o l l i n a t i o n t o ensure a uniformity o f f i r s t days, i . e . beginning o f Stage 5.  Table  7 n"eeds the comparison o f the c o n t r o l l e d p o l l i n a t i o n w i t h the n a t u r a l p o l l i n a t i o n treatment employed i n Experiment I..(.Table 3 ) . The c a l c u l a t e d W and V values are shown i n Table 8, the r r p i c t o r i a l regression l i n e s i n F i g s . 15, 16, 17 and 18. The genetic information was e s s e n t i a l l y the same as Experiment I , i n o t h e r words, although these two experiments d i f f e r e d i n p o l l i n a t i o n methods, the gene a c t i o n was s i m i l a r . 59  TABLE 7. Mean number of days required f o r Stages 5 and 6 i n the d i a l l e l cross tested i n warm and cool regimes i n greenhouse Experiment I I . Female parentt B Male parent f  Temperature  Stage  cool  warm  warm  cool  warm  cool  B  5 6  8.0 40.0  6.6 58.6  6.3 35.3  7.9 53.8  6.8 42.5  7.9 62.9  I .  5  7.5 54.3  6.3 31.5  9.3 52.5  6.5  8.6  6  6.1 35.5  36.4  55.4  5 6  8.0 38.8  7.6 64.9  6.5 37.0  10.0 58.3  6.1 43.2  7.5 57.8  C  see Table 3 notation  +  TABLE 8. Calculated mean values of V and f o r Stages 5_and 6 i n the d i a l l e l cross tested i n warm and cool regimes i n greenhouse Experiment I I . W Array Stage_ warm BJ  C  +  warm  cool  warm  cool  warm  cool 1.1 46.5  14.3  -0.1 9.3  0.1 -17.9  : 1.7 32.9  0.1  0.9  -0.2  -0.3  0.4  2.1  7.8  20.6  5.6  0.7  -2.2  31.5  13.4  1.5  0.7 17.6  1.2  0.2  1.2  2.7  9.7  5.3  0.3 -6.4  29.9  25.8  5 0.9 6 11.8  0.5 32.2  0.8  0.6  21.1  0.3  1.2  6 10.9 5 0.5 6 12.3  5  I  cool  W +V r r  W -V r r Temperature  16.1  see Table 3 notation  60  1.5  F i g . 15. (V ,W ) graph f o r Stage 5,  10  F i g . 16.  20  (V ,W ) graph f o r Stage 6, r  r  greenhouse Experiment I I ,  greenhouse Experiment I I ,  warm regime.  warm regime.  Days Required per Plastochron,' warm:  Days r e q u i r e d per plastochron  i n both temperature regimes were measured from the 3rd t o 8th p l a s t o chron (Table 9, plus Tables 11 and 12 of the Appendix).  There was  no s i g n i f i c a n t differences:.-, among arrays f o r the W -V^ u n i f o r m i t y t e s t (Table 5).  The regression c o e f f i c i e n t between W^ and  was  ( F i g . 19) which was not s i g n i f i c a n t l y d i f f e r e n t from one, the absence of e p i s t a t i c gene a c t i o n .  0.81  indicating  The r e g r e s s i o n l i n e cut the  o r i g i n of the a x i s meaning t h a t there was complete dominance.  The  sequence f o r the l e v e l of dominance f o r the parents was C, B and I from low t o high. was 0.52  The c o r r e l a t i o n c o e f f i c i e n t between y  and W V +  r  (Table 5) which was s m a l l , i n d i c a t i n g equal proportions of  the doniinant genes were p o s i t i v e and. negative. Days Required per Plastochron ,-c®olr:: The r e g r e s s i o n c o e f f i c i e n t between W  and  f o r the days r e q u i r e d per plastochron i n the c o o l r e -  gime was 0.91  ( F i g . 20), which was not s i g n i f i c a n t l y d i f f e r e n t from  one, i n d i c a t i n g the absence of e p i s t a t i c gene a c t i o n .  The r e g r e s s i o n  l i n e cut the W  axis downward from the o r i g i n meaning t h a t there was  overdominance.  The sequence f o r the l e v e l of dominance from low t o  1  high was C, I and B. was 0.93  The c o r r e l a t i o n c o e f f i c i e n t between y^ and  VM-  (Table 6>), which was p o s i t i v e and high i n d i c a t i n g t h a t  the r e c e s s i v e genes were working i n the d i r e c t i o n o f more days r e quired per plastochron  (lateness).  F r u i t Weight and F r u i t Diameter i n Both Regimes:  The mean values  f o r both temperature regimes are presented i n Table 11 and the o r i g i n a l data are shown i n Table 13 of the Appendix.  The u n i f o r m i t y .  t e s t showed a s i m i l a r trend f o r the value of W -V between arrays r r • CTable 5), i n d i c a t i n g the assumptions of the theory were met i n the  62  TABLE 9.  Mean number o f days required p e r plastochron i n t h e d i a l l e l cross t e s t e d i n warm and c o o l regimes i n greenhouse Experiment I I .  :  f  Female parent B Temperature  Male parent warm  cool  warm  cool  warm  cool  B  4.4  6.0  3.7  5.9  4.1  5.4  I  3.6  5.3  3.7  5.9  4.1  5.7  C  3.8  5.9  3.9  5.7.  4.1  6.3  see Table 3 n o t a t i o n  TABLE 10. Calculated mean values o f V and W f o r the days r e q u i r e d per plastochron i n the d i a l l e l cross t e s t e d i n warm and ; c o o l regimes i n greenhouse Experiment I I . r  Array  warm  cool  -0.01  0.25  0.09  -0.11  -0.02  0.13  0.08  -0.04  -0.06  0.38  0.22  warm  warm  cool  ;.warm  cool  0.13  0.05  0.12  0.04  -0.01  I  0.12  0.05  0.01  0.03  c  0.21  0.14  0.17  0.08  •  W +V r r  W -V .r r Temperature  W  V  r  see Table 3 n o t a t i o n  63  cool  ••  2  Fig. 21. CV ,W ) graph f o r f r u i t weight, 'Fig. 22. (V ,W ) graph f o r f r u i t greenhouse .'Experiment I I ,  diameter, greenhouse  warm regime.  Experiment I I , warm regime.  64  TABLE 11. Mean f r u i t weight (g) and f r u i t diameter (mm) i n the d i a l l e l cross tested i n warm and cool regimes i n greenhouse Experiment I I . Female parent I.  B Male parent  11'CU. L  +  cool  warm  Temperature cool warm  warm  cool  55.9 92.8  73.0 202.5  41.0 37.7  48.9 62.5  54.3 80.3  55.8 98.4  di. wt.  42.0  45.5 52.4  37.5 28.5  42.4 40.5  47.8  39.0  33.9 21.2  di. wt.  57.1 99.6  56.3 91.5  40.5 37.8  46.1 51.5  52.1 76.8  52.9 76.9  B  di. wt.  I  C  s  C  +  55.3  . di.v= f r u i t diameter  T' wt. = f r u i t weaight  TABLE 12. Calculated mean values of V and W .for the f r u i t weight and f r u i t diameter i n the d i a l l e l cross tested i n warm and cool regimes i n greenhouse Experiment I I . r  V  di.+  I  C  Temperature cool warm  cool  warm  cool  12.6  59.0  171.2  418.6  warm  cool  warm  79.3  179.8  91.9  238.8  5767.4 1061.2  6810.9  Tf  • wt. 1015.6  Wr +V r  r -V r  W  W  Array Trait  B  r  46.4 1043.5  2076.8 12578.3 87.0 120.0 565.5 1353.6  di.  29.2  34.7  57.8  85.3  28.6  50.6  wt.  138.6  272.7  426.9  1080.9  288.3  808.2  79.1 wt. . 1009.0 . 453.3. .1242.5 1745,8  25.2  54.3  172.4  103.9  233.5  1292.5  2251.5  2199.1  di.  73.6  24.8  = f r u i t diameter = f r u i t weight  98.8  65  present experiment for both f r u i t weight and diameter i n both the temperature regimes except the case of f r u i t weight i n cool which f a i l e d the uniformity test.  The f r u i t weight i n warm had a regres-  sion coefficient of 0.87 (Fig. 21) which was not s i g n i f i c a n t l y d i f ferent from one, indicating the absence of epistatic gene action. The regression':,line cut the W axis upward from the origin pointing to p a r t i a l dominant gene action.  The sequence f o r the l e v e l of dom-  inance i s C, B and I from low to high, meaning I cMCfiivar-"i s dominant ;  over the C and B. The correlation coefficient between v„ and W+V was 0.92, which was positive and high, meaning the recessive genes operated i n the direction of heavier f r u i t weight. Fruit diameter i n warm had a regression coefficient of 0.85 (Fig. 22) which was not s i g n i f i c a n t l y different from one and hence the same gene action as that for the f r u i t weight i n warm. The c o r r e l ation coefficient was 0.53 which was positive but not very high, i n dicating that almost equal proportions of the dominant genes were positive or negative.  Regarding f r u i t weight i n cool, although the  differences between arrays f o r W -V f a i l e d to meet the uniformity test, nevertheless some genetic information may be gained from examining Fig. 23, and noting that gene action was apparently similar to that f o r f r u i t weight i n warm. The only difference from warm regime results was the sequence f o r the l e v e l of dominance from low to high among the parents which was B, C and I rather than C, B and I as i n the warm regime.  The correlation coefficient between y^ and W^+V^  was 0.97, which was positive and high thus indicating that recessive genes were functioning i n the direction of heavier f r u i t weight. Fruit diameter i n cool had a regression coefficient of 1.04  66  Fig. 23.  CV,W ) graph f o r f r u i t weight, greenhouse "Experiment I I , cool regime. r  200  IOO  V  r  Fig. 24.• CV ,W ) graph f o r f r u i t diameter, greenhouse Experiment I I , cool regime. 67  which was not s i g n i f i c a n t l y d i f f e r e n t from one ( F i g . 24-), and app a r e n t l y there was the same gene a c t i o n as f o r f r u i t diameter i n warm.  The l e v e l o f dominance f o r parents was B, I and C from low  t o high.  The c o r r e l a t i o n c o e f f i c i e n t was 0.83 i n d i c a t i n g t h e r e -  cessive genes were operating i n t h e d i r e c t i o n o f increased diameter  :  of the f r u i t . (b)  Genetic Parameters and Estimators Considering the growth component stages i n both temperature  regimes, t h e components o f v a r i a t i o n and t h e i r p r o p o r t i o n s , upon which the g r a p h i c a l treatment was based, are given i n Tables 13 t o 16. The proportions should r e f l e c t and i n p a r t summarize t h e r e s u l t s o f the g r a p h i c a l a n a l y s i s .  The genetic parameters and estimators f o r ':  the experiment i n the warm regime as shown i n Tables l 3,cand"14 can be :  summarized f o r each stage as f o l l o w s : Stage 1, warm:  Exanuning the genetic parameters (Table 13) i t i s  seen t h a t TxHi , which i n d i c a t e d overdominance; and F<0, which i n d i c a t e d the r e l a t i v e frequencies o f r e c e s s i v e a l l e l e s were h i g h . Considering t h e estimators (Table 14), the H2/4H1 value o f 0.25, i n d i c a t e d t h a t the average p r o p o r t i o n o f dominant and r e c e s s i v e a l l e l e s was equal i n the parents; (Hi /D)' , as an estimate o f t h e average de1  a  gree o f dominance over a l l l o c i , and i n t h i s stage has a value o f h 1.58, which being l a r g e r than one i n d i c a t e d overdominance; (4DHi)  +  F / ( 4 D H i ) - F was 0.99, which was near enough t o one, t o imply t h a t 2  the r a t i o o f the t o t a l number o f dominant and r e c e s s i v e a l l e l e s i n the parents was equal; the h e r i t a b i l i t y was 0.2 which i s r e l a t i v e l y low; and t h e h / H 2  2  value was 1.4 i n d i c a t i n g t h a t a t l e a s t one t o 2  68  TABLE 13. Means and standard deviations f o r the d i a l l e l cross parameters derived from the data on days required f o r 7 growth stages i n the warm regime of the greenhouse Experiment I .  Stage  Parameter H  D  F  2  1.41±J0.52 1.28±00;31 26.89+17.63  .1.45±":0."55  1 2 3 4 5  0.58±0.17 -0.05±0.10 60.69±5.88 4.47±2.50 1.68±0.34  6 7  40.78±4.20 • 0.89±0.20  1.51*00333 30.03±18.69 13.16± 7.96 1.49± 1.07 3.66±13.35 0.43± 0.63  11.46± 7.51 1.38± 1.01 3.41±12.59 • 0.40± 0.60  -0.01±l0.46 -0.11±00':27 25.65±15.67 2.68± 6.68 0.16± 0.90 :  0.89±11.19 0.33± 0.53  TABLE 14. The d i a l l e l cross estimators from the data of the warm regime of the greenhouse Experiment I.,-, (Table 13). Estimator Stage  (RVD)  1  1.58  2 3 4 5 6 7  5 2  H /4Hi 2  (4BHi^+F  5.61 0.70  0.99 0.65  1.72-  0.22  1.42  & 0.94  0.23  1.11 1.08 1.74  0.23 0.24  h /H 2  ( W i ^ T  0.25 0.21 0;22  0.30 0.69 •  heritability  1.86  69  0.21 -0.02 0.84 0.15  1.4 1.6 2.8  0.39 •  2.0 3.6  0.83 0.63  3.6 4.0  2  genes controlling this stage exhibited some degree of dominance. Stage 2, warm: The values' of parameters (Table 13) indicated the same genetic information as from Stage 1, warm. Considering the estimators, (H /D) = 5.61 (Table 14), and being larger than one, means 2  7  overdominance over a l l l o c i ; (Ufflx) +F/(4DH ) -F was 0.65, which was 2  1  less than one,,and indicated more recessive than dominant genes i n the parents. There was a very low and negative h e r i t a b i l i t y of -0.02 for t h i s stage, and h /H = 1.6 indicating at least 2 genes exhibited 2  2  some degree of dominance. Stage 3, Warm: The summary of results was  J>Ei  (Table 13), which  indicated partial•dominance; F>0 which indicated that the parents carried an excess of dominant over recessive genes; and Hi>H , mean2  ing unequal a l l e l e frequencies. The estimators showed H /4Hi = 0.222  (Table 14) which indicated a highly asymmetrical, distribution of the dominant and recessive a l l e l e s i n the parents; (Hi/D) was 0.70, and being greater than zero but less than one, indicated p a r t i a l dominance; (4DH ): ,+F/(4DH ) -F was 1.86, and being larger than one, indicated 2  1  2  1  more dominant than recessive genes controlled this stage.  The h e r i t -  a b i l i t y was 0.84 indicating that highly inheritable genetic variation existed.  A value of 2.8 for h /H , means that there were at least 2  2  3 genes exhibiting some degree of dominance. Stage 4, warm: The parameters (Table 13) showed D<H , which indicated 1  overxiominance, and F>0 showing that the parents carried more dominant , than recessive genes t o affect t h i s stage.  The estimators (Table  14) show E2/mx = 0.22, and t h i s low value indicated a highly asymmetrical distribution of the dominant and recessive a l l e l e s i n the parents'; also H was smaller than 2  70  , hence there were unequal  a l l e l e frequencies.  (Hi/D) : was 1.72 which i s l a r g e r than one,  therefore overdominance was present; and (4DH i) +F/(4DHi) -F was 2  2  1.4-2, which being l a r g e r than one, i n d i c a t e d an excess o f dominant over r e c e s s i v e genes.  The h e r i t a b i l i t y f o r t h i s stage was very low,  only 0.15; and the h /H2 value o f 2.0 means t h a t there were a t l e a s t 2  2 genes showing some degree o f dominance. Stage 5, warm:  The parameters i n Table 13 showed  fi>x\\  slightly,  which i n d i c a t e d p a r t i a l t o complete dominance, and F>0 which i n d i c a t e d t h a t the parents c a r r i e d more dominant than r e c e s s i v e genes c o n t r o l l i n g t h i s stage; and H >H , meaning unequal a l l e l e frequencies. n  The estimators show r\lkY\  -  2  0.23 (Table 14) which i n d i c a t e d a h i g h l y  asymmetrical d i s t r i b u t i o n o f the dominant and r e c e s s i v e a l l e l e s i n \ the parents.  (F^/D) was 0.94, and being smaller than but very c l o s e 2  t o one, i n d i c a t e d that the estimate o f the average degree o f dominance over a l l l o c i was p a r t i a l but almost complete.  (4DHi) +F/(4DHi) -F 2  2  was 1.11, and being a l i t t l e l a r g e r than one, i n d i c a t e d a s l i g h t l y greater number o f dominant over r e c e s s i v e genes a f f e c t e d Stage 5. The h e r i t a b i l i t y f o r t h i s stage was 0.39, and a value o f 3.6 f o r '. _ h /H 2  2  means t h a t there were a t l e a s t 4 genes showing some degree o f  dominance. Stage 6, warm:  The parameters from t h i s stage had the same trends  as those f o r Stage 3, warm, t h e r e f o r e must have the same gene a c t i o n . The estimators show H^AR^ =0.23 (Table 14), which i n d i c a t e d an asymmetrical d i s t r i b u t i o n ; (H^/D)^ was 0.30 and being l a r g e r than zero but s m a l l e r than one, i n d i c a t e d p a r t i a l dominance.  (4BH )^+F/(4DHj 1  was 1.08, s l i g h t l y l a r g e r than one i n d i c a t i n g a s l i g h t l y g r e a t e r number o f dominant than r e c e s s i v e genes.  71  The h e r i t a b i l i t y f o r t h i s  stage was very h i g h , being 0.83; and t h e h / H was 3.6 i n d i c a t i n g 2  2  t h a t a t l e a s t 4 genes were e x h i b i t i n g some degree o f dominance. Stage 7, warm: The c h a r a c t e r i s t i c s o f the parameters f o r t h i s stage were s i m i l a r t o those f o r Stage 6, warm.  The estimators show n ^ A H ^ .  0.24" (Table 14), which i n d i c a t e d a h i g h l y asymmetrical d i s t r i b u t i o n o f the dominant and r e c e s s i v e a l l e l e s ' l i n the parents.  (H^/D) = 0.69  which i n d i c a t e d p a r t i a l dominance; and (4DHi) +F/(4DHi) -F 2  2  was 1.74  which being l a r g e r than one, i n d i c a t e d more dominant than r e c e s s i v e genes.  The h e r i t a b i l i t y was 0.63 and h /H2 was 4.0 i n d i c a t i n g t h a t 2  at l e a s t 4 genes showed some degree o f dominance. Stage 1., c o o l :  The parameters  (Table 15) showed D<H!, which i n d i c a t e d  overdominance; and F=1.75,- which being l a r g e r than zero i n d i c a t e d the parents c a r r i e d more dominant than r e c e s s i v e genes which a f f e c t e d growth i n t h i s stage. quencies.-  Fh_>H , hence there were unequal a l l e l e f r e 2  H A R i = 0.22 (Table 16) and t h i s low value i n d i c a t e d an 2  asymmetrical d i s t r i b u t i o n o f the dominant and r e c e s s i v e a l l e l e s i n the parents. overdominance.  ( H i / D ) =1.70, which i s l a r g e r than one and i n d i c a t e d 2  (4DHi) +F/(4DHi) -F 2  = 1.84, which i n d i c a t e d more  2  dominant than r e c e s s i v e genes a f f e c t e d t h i s growth stage.  The h e r i -  t a b i l i t y was 0.25 and the h / H was 2.8 i n d i c a t i n g t h a t a t l e a s t 3 2  2  genes were e x h i b i t i n g some degree o f dominance. Stage 2,, c o o l :  E£ i s seen t h a t D>H :  1  (Table 15), which i n d i c a t e d par-  t i a l dominance; F=-0.95, and being l e s s than zero i n d i c a t e d t h a t r e l a t i v e frequencies o f r e c e s s i v e a l l e l e s were higher than those f o r dominant a l l e l e s .  H >H , thus the p o s i t i v e and negative a l l e l e s 1  2  f o r the l o c i c o n t r o l l i n g t h i s stage were not i n equal proportions. H^AH-L  = 0.22 (Table 16), and such a low value i n d i c a t e d a h i g h l y  72  TABLE 15. Means and standard deviations f o r the d i a l l e l cross parameters derived from the data on days required f o r 7 growth stages i n the cool regime of the greenhouse Experiment I .  Stage  D  H  Parameter H  l  F  2  1 2  1.74± 0.46 2.34* 0.26  5.05± 1.48  4.54± 1.39  1.75± 1.24  1.22± 0.83  1.07± 0.78  -0.95+ 0.70  3  68.28± 5.79  4  92.53± 7.10  25.30±18.43 93.77+22.58  5 6  5.38± 0.58 59.25±16.77  7  1.23± 0.43  25.01±1738  -0.87± 1.55  85.98±21.30  52.25±18.94  10.30± 1.84  9.58± 1.73  282.7 ±53.31  226.1 ±50.30  3.94± 1.54 34.87±44.71  5.72± 1.36  4.70± 1.28  2.26± 1.14  TABLE 16. The d i a l l e l cross estimators from the data of the cool regime of the greenhouse Experiment I., (Table 15).. Estimator Stage  OVD)  15  H /4Ri 2  ^DH^+F  heritability  h /H 2  (iHHi)'VF  1.70. 0.72  0.22  1.84  0.25  2.8  0.22  0.56  0.37  2.4  0.61  0.25  0.98  0.64  5.6  0.22  1.78  0.65  3.6  5  1.01 1.38  0.23  1.72  0..42  3.6;  6  2.18  0.20  1.31  0.19  0.8  7  2.15  0.21  2.47  0.20  0.8  1 2 3 . 4  73  2  asymmetrical d i s t r i b u t i o n o f the dominant and r e c e s s i v e a l l e l e s i n 1^  the parents.  (H^/D) = 0.72, being smaller than one, i n d i c a t e d par2  t i a l dominance; ( 4 D H ) + F / ( 4 D H ) - F =0.56 and being smaller than i5  J5  1  1  one, i m p l i e d more r e c e s s i v e than dominant genes were i n v o l v e d .  The  h e r i t a b i l i t y was 0.37 and h / H was 2.4 which i n d i c a t e d at l e a s t 2  2  2 t o 3 genes were e x h i b i t i n g some degree o f dominance. Stage 3, c o o l :  The parameters f o r t h i s stage (Table- 15) showed the  same trends as those f o r Stage 2, c o o l , and t h e r e f o r e both stages must have had the same gene a c t i o n .  H^AHj =0.25 (Table 16) and i n -  dicated t h a t the average p r o p o r t i o n o f dominant and r e c e s s i v e a l l e l s was equal i n the parents.  (H^/D) was 0.61 and, being l e s s than one 2  but more than zero, suggested p a r t i a l dominance i n a c t i o n over a l l ( 4 D R i ) + F / ( 4 D H i ) - F = 0.98, which was near enough t o one t o  loci.  2  2  imply t h a t *here was an equal number o f r e c e s s i v e and dominant genes involved.  The h e r i t a b i l i t y was 0.64, and there were a t l e a s t 6 genes  e x h i b i t i n g some degree of dominance. Stage 4, c o o l :  The parameters f o r t h i s stage (Table 15) showed the  same c h a r a c t e r i s t i c s as those f o r Stage 1, c o o l , t h e r e f o r e both stages must have had the same gene a c t i o n .  The estimators (Table 16) showed  Hj/4H2 = 0.22, a r e l a t i v e l y low v a l u e , which i n d i c a t e d a h i g h l y asymmetrical d i s t r i b u t i o n o f donrinant and r e c e s s i v e a l l e l e s i n the parents.  ( H i / D ) was 1.01, almost equal t o one, thus i n d i c a t i n g t h a t 2  complete dominance was present.  (4DHi) +F/(4DHi) -F 2  = 1.78,- and  being greater than one, i n d i c a t e d a greater number o f dominant than r e c e s s i v e genes were i n v o l v e d . The h e r i t a b i l i t y was 0.65, and the h / H was-3.6 implying t h a t at l e a s t 4 genes showed some degree o f 2  2  dominance.  74  Stage 5, c o o l :  The c h a r a c t e r i s t i c s of the parameters f o r Stage 5,  cool (Table 15) were s i m i l a r t o those f o r Stage 4, c o o l , i n d i c a t i n g s i m i l a r gene a c t i o n i n both stages. E /kEi  The estimators (Table 16) showed  = 0.23, meaning a h i g h l y asymmetrical d i s t r i b u t i o n o f the  2  dom-  inant and recessive a l l e l e s i n the parents; (Hr/D) was 1.38, and being 2  l a r g e r than one, implied overdominance; and (M-DHT) +F/(4DH!) -F was 2  2  1.72, which i n d i c a t e d that more dominant than recessive genes were a f f e c t i n g t h i s stage.  The h e r i t a b i l i t y was 0.4-2, and the h / H 2  2  was  3.6 implying t h a t a t l e a s t 4 genes showed some degree o f dominance. Stage 6, c o o l :  Again the c h a r a c t e r i s t i c s o f the parameteis f o r Stage .  6, (Table 15) c o o l , were s i m i l a r t o those Stage 4, c o o l , thus gene a c t i o n must have been s i m i l a r i n Stages 4, 5 and 6, i n c o o l . i n Table 16 showed H^AR}  Values  = 0.20 and i n d i c a t e d unequal d i s t r i b u t i o n  of the dominant and recessive a l l e l e s i n the parents; (R^/D)  2  = 2.18  which being l a r g e r than one, implied overdominance was present; and (4DHj) +F/(4DHi) -F was 1.31, and being l a r g e r than one, i n d i c a t e d 2  2  more dominant than recessive genes a f f e c t i n g e a r l i n e s s o f t h i s stage. The h e r i t a b i l i t y f o r t h i s stage was 0.19 and the h / H was 0.8 imp2  2  l y i n g that a t l e a s t one gene was e x h i b i t i n g some degree o f dominance. Stage 7, c o o l :  I t i s seen (Table-15) t h a t D^Hj, which i n d i c a t e d over-  dominance; F=2.26, and being l a r g e r than one, i n d i c a t e d the parents c a r r i e d more dominant than recessive genes a f f e c t i n g t h i s stage. Hi>H and a l s o H^AHj = 0.21 (Table, 16) which i n d i c a t e d an asymmet2  r i c a l d i s t r i b u t i o n o f the dominant and recessive a l l e l e s i n the parents; ( H j / D ) =2.15, and being l a r g e r than one, i n d i c a t e d overdom2  inance; and (4DHi) +F/(4DHi) -F was 2.47 which being l a r g e r than.one, 2  2  75  i n d i c a t e d a greater number o f dominant than r e c e s s i v e genes i n v o l v e d . H e r i t a b i l i t y was 0.20 f o r t h i s stage, and t h e value o f h / H was 0.8 2  2  which i n d i c a t e d a t l e a s t one gene e x h i b i t e d some degree o f dominance. (B)  Greenhouse Experiment I I Greenhouse Experiment I I was concerned w i t h the days r e -  quired f o r p l a n t s t o progress through growth Stages 5 and 6 i n two . temperature regimes, and using a r t i f i c i a l p o l l i n a t i o n throughout the experiment. Stage 5, warm:  The parameters f o r t h i s stage (Table 17) showed t h e  same trends as those f o r greenhouse Experiment I , t h e r e f o r e both H /4HT = 0.19 and i n -  stages must have had the same gene a c t i o n .  2  dicated an asymmetrical d i s t r i b u t i o n o f the dominant and r e c e s s i v e a l l e l e s i n the parents; (H"i/D) = 0.98, very c l o s e t o one, i n d i c a t e d 2  almost complete dominance.  (4DH}) +F/(4DH!) -F was 1.72 and being 2  2  l a r g e r than one i n d i c a t e d more dominant than r e c e s s i v e genes a f f e c t e d earliness.  The h e r i t a b i l i t y was 0.39, and a t l e a s t one o f the genes  involved i n the e a r l i n e s s e x h i b i t e d some degree o f donunance. Stage 6, warm:  Again the same gene a c t i o n as i n Stage 6, warm, i n  the greenhouse Experiment I i s shown by the c h a r a c t e r i s t i c s o f the parameters  (Table 17).  H /4Hi = 0.24, and t h i s very low value i n 2  dieates an asymmetrical d i s t r i b u t i o n ; ( H j / D ) = 0.18 and being l a r g e r 2  than zero i m p l i e d p a r t i a l dominance (4-DH! ) +F/(4DH )^-F = 1.72, and Js  1  being l a r g e r than one, i n d i c a t e d more dominant than r e c e s s i v e genes were i n v o l v e d . The h e r i t a b i l i t y was the high value o f 0.77, and t h e h / H was 4.80 which i n d i c a t e d a t l e a s t 5 genes e x h i b i t e d some degree 2  2  of dominance.  76  TABLE 17. Means and standard deviations f o r the d i a l l e l cross parameters and estimators from warm and c o o l regimes i n greenhouse Experiment I I . Temperature Stage  Parameter/Estimator  1.06*4 0.18  1.85-±0.44  H!  1.02**0.58  1.47'-±1.39  0.79t±0.55  1.20 ±1.31  2 F  •0 J5!5±0.49  1.04  0.19  0.20  (Uffll^+F/C+ffli^-F  1.72  0.93  heritability  0.39  0.27  h2/H  0.80  0.40  40.16±11.46  9Q03± 5 i l 2 ;  2  D l H H  2  F 6  -0.10 ±1.17  0.98 •  (Hi  •  cool  D  H  5  warm  -1.29± 3.64  34,78±16.27  -1.35±33v43  28,14±15.35  3.81± 3.05  -14.78±13.64  0.18  1.96  0.24 •  0.20  1.72  0.41  heritability  0.77  0.12  h2/H  4.80  0.40  (Hj/D) ' 1  H  1  2 l (4IH )^+F/(l4ffl )^-F / 4 H  1  1  v  1  2  77  Stage 5, c o o l :  The parameters f o r t h i s stage show the same trends  as those f o r Stage 5 i n greenhouse Experiment I ; thus the same gene 1,  a c t i o n must have been present.  (Hj/D) = ;1.04 2|?,  (Table 17), and being  l a r g e r than one, i n d i c a t e d overdominance; and r^AR^ = 0.20, and t h i s low value i n d i c a t e d an asymmetrical d i s t r i b u t i o n o f the dominant and r e c e s s i v e a l l e l e s i n the parents.  (M-DH^ )^+F/(4-DHj )^-F = .0.93,  which i m p l i e d almost equal numbers o f dominant and r e c e s s i v e a l l e l e s among parents, and the r e c e s s i v e genes had a l i t t l e higher frequency than the dominant.  The h e r i t a b i l i t y was 0.27 and a t l e a s t one gene  showed some degree o f dominance. Stage 6, c o o l :  The parameters f o r t h i s stage (Table 17) show the  same trends as the greenhouse Experiment I Stages 6, thus t h e same gene a c t i o n was present.  (R^/D) = 1.96, which i n d i c a t e d overdom2  inance; H /4Hi = 0.20 and t h i s low value i n d i c a t e d a h i g h l y asymme2  t r i c a l d i s t r i b u t i o n o f the dominant and r e c e s s i v e a l l e l e s .  (4DH})  2  +F/(4DH ) ^-F = 0.41, and being smaller than-one, i n d i c a t e d more r e c e s s i v e than 1  1  dominant genes a f f e c t i n g e a r l i n e s s .  The h e r i t a b i l i t y was 0..12, and  at l e a s t one gene showed some degree o f donrinance. Days Required per Plastochron i n Both Temperature Regimes In the warm regime the parameters (Table 18) show D was almost equal t o H} i n d i c a t i n g complete dominance; Hj <H , t h e r e f o r e 2  there were not equal proportions o f p o s i t i v e and negative a l l e l e s i n the parents, and F<0, meaning t h a t the r e l a t i v e frequencies o f r e cessive a l l e l e s were high.  ( H i / D ) i s 0.92 which i s very near t o 2  one and means almost complete dominance was present.  H /4Hi = 0.19, 2  and t h i s low value i n d i c a t e d an asymmetrical d i s t r i b u t i o n o f the  78  TABLE 18. Means and standard deviations f o r the d i a l l e l cross parameters and estimators from warm and cool regimes for days required per plastochron. Parameter and Estimator D Hi H F (Hi/D)^ 2  Temperature warm  cool  -0.15±0.08 -0.13±0.24 -0.10±0.23 -0.20±0.20 • 0.92 0.19  0.01±0.02 . 0.16±0.06 0.16±0.06 0.03±0.05 4.90 0.26  0.15 -0.16 2.0  0.38 0.02  (M-DHi^+'F/CMffii^-F heritability h /H 2  2  5.6  TABLE 19: Means and standard deviations f o r the d i a l l e l cross parameters and estimators from warm and cool regimes f o r f r u i t weight and f r u i t diameter. Temperature Parameter« and Estimator:.-  warm fruit weight  Cool fruit diameter  D  1423.9±246.4  Hi H F  334.1+783.6  130.4±21.0 7.9± 6.7  264.5±739.3 -459.3±657.1  4.-7± 6.3 -40.H55.9  2  84.0±60.4 73.0±57.0 102.7±50.7  0.23 0.48  1.83 0.91  1.92 0.97  0.4  8.8  2.8  2.-0  (MDHi^+F/CMffli^-F heritability h /H  2  3583.6±1564.9 3196.5±1476.4 3150.9±1312.3  0.50 0.44  0.20  2  315.2+19.0  0.15  H /4H! 2  7992.5±449211  0.52  0.25  2  fruit diameter  0.67 0.22  0.48 -  OVD)*  fruit weight  79  0.22  dominant and recessive a l l e l e s .  (4-DHj) +F/(4DH ) -F = 0.15, and since 2  2  1  t h i s value was l e s s than one, there must have been more r e c e s s i v e than doniinant genes involved.  The h e r i t a b i l i t y was -0.16 and at l e a s t  2 genes showed some degree o f dominance. In the c o o l regime D<H  1  (Table 18), i n d i c a t i n g overdominance;;  Hj was equal t o H , meaning t h a t p o s i t i v e and negative genes were 2  present i n equal numbers; and F<0, which i n d i c a t e d r e l a t i v e of r e c e s s i v e a l l e l e s were high.  (R^/D) = 4.9, and being 2  frequencies  greater  than one, i n d i c a t e d overdominance; and H^AHx = 0.19, a very low .' value associated w i t h a h i g h l y asymmetrical d i s t r i b u t i o n o f the dominant and r e c e s s i v e a l l e l e s i n the parents.  (4DHj)r+F/(4DH ) -F = 2  1  0.38, and being l e s s than one, i n d i c a t e d a greater number o f recess i v e than dominant genes were involved.  The•heritability for this  stage was very low, only 0.02, and at l e a s t 6 genes e x h i b i t e d some degree o f dominance. F r u i t Weight and Diameter i n Both Temperature Regimes In the warm regime, the values i n Table 19 show t h a t D>Hi , which i n d i c a t e d p a r t i a l dominance; Hi>H , which i n d i c a t e d unequal 2  numbers o f dominant and r e c e s s i v e genes were i n v o l v e d ; and F<0, which meant t h a t r e l a t i v e frequencies o f recessive a l l e l e s were h i g h ; ( (Hj/D)  2  = 0.48 and 0.25, and both being l a r g e r than zero but smaller  than one i n d i c a t e d p a r t i a l dominance; H /4Hj f o r both cchara'cteristics was 2  very low, 0.20 and 0.15, and i n d i c a t e d asymmetrical d i s t r i b u t i o n o f . dominant and recessive genes; and (4DHj) +F/(4DH}) -F = 0.50 and 0.23, 2  2  whichhwere smaller values than one, therefore there must have had more r e c e s s i v e than dominant genes a f f e c t i n g each o f the c h a r a c t e r i s t i c s .  80  H e r i t a b i l i t y f o r f r u i t weight was 0.44 and f o r f r u i t diameter was 0.48, and at l e a s t one gene and nine genes were e x h i b i t i n g some degree o f dominance a f f e c t i n g f r u i t weight and diameter r e s p e c t i v e l y . In the c o o l regime, the values i n Table.19 show that D>H , X  which suggested p a r t i a l dominance; H >H , thus unequal numbers o f 1  2  p o s i t i v e and negative a l l e l e s were involved; and F>0, which i n d i c a t e d more  that the parents c a r r i e d dominant than recessive genes which m f l u 3^ enced the c h a r a c t e r i s t i c s .  The estimators ( H / D ) 1  2  =0.67 and 0.52 •  f o r f r u i t weight and diameter r e s p e c t i v e l y , and both values were between zero and one which i n d i c a t e d p a r t i a l dominance; and  E /^i 2  f o r both characters was 0.22, a very low value which i n d i c a t e d asymm e t r i c a l d i s t r i b u t i o n o f the dominant and recessive a l l e l e s i n the parents.  (4DH ) +F/(4DH ) -F = 1.83 and 1.82, and both values being ls  1  i5  1  l a r g e r than one, i n d i c a t e d more dominant genes than recessive genes influenced f r u i t weight and diameter.  The h e r i t a b i l i t y values f o r  these two c h a r a c t e r i s t i c s were 0.91 and 0.97, and h / H values i n 2  2  dicated a t l e a s t 3 and 2 genes weee e x h i b i t i n g some degree o f dominance i n f r u i t weight and diameter r e s p e c t i v e l y . B.  G r i f f i n g ' i S Method The r e s u l t s from the a p p l i c a t i o n o f G r i f f i n g ' s method showed  a large number o f s i g n i f i c a n t e f f e c t s f o r general combining a b i l i t y (G.C.A.) and s p e c i f i c combining a b i l i t y (S.C.A.) which emphasize hereditary differences i n the i n d i v i d u a l stages o f d i f f e r e n t genotypes o r c u l t i v a r s .  G.C.A. and S.C.A. f o r each o f the •Kegrowth  component stages i n the warm regime were a l l s i g n i f i c a n t (Table 20). A l s o the differences between r e c i p r o c a l crosses were only s i g n i f i c a n t  81  TABLE 20. Mean squares f o r general (G.C.A.) and specific (S.C.A.) combining a b i l i t y f o r the growth component stages i n warm and cool regimes.  G.C.A. ' Stage warm  cool  S.C.A. Temperature cool warm  Reciprocal Effects warm  cool  1  3.3*  3.6*  3.1*  8.9*  0.2  1.6  2  1.8*  88.3*  2.7*  38.7*  5.9*  68.4*  3  230.5*  419.2*  56.3*  56.1*  2.5  4.3  4  17.9*  293.0*  26.1*  172.1*  7.0  34.7*  5  7.8*  13.4*  3.2*  18.9*  0.6  1.7*  6  242.6*  489.0*  7.4*  453.5*  8.0*  4.6  7  3.6*  1.0*  11.8*  0.1  0.9*  0.4  * significant at 5% l e v e l  TABLE 21:> Mean squares f o r general (G.C.A.) and specific (S.C.A.) combining a b i l i t y for the Stages 5 and 6 after handpollination treatment i n warm and cool regimes.  G.C.A. Stage warm 5  4.7*  6  217.5*  cool 11.8*  S.C.A. Temperature warm cool 1.9*  2.0  2.1  61.8*  188.4*  * significant at 5% l e v e l  82  Reciprocal Effects warm .  cool  1.1*  1.4  10.1  9.7  in.Stages 2 and 6.  I n the c o o l regime, both G.C.A. and S.C.A. i n  a l l stages showed s i g n i f i c a n t e f f e c t s except f o r Stage 7 (Table 20), and f o r the r e c i p r o c a l crosses, Stages 2, 4-, 5 and 7 showed s i g n i f icant differences. Regarcling days required f o r Stages 5 and 6 a f t e r the hand p o l l i n a t i o n treatment (Tablet) 21), there were s i g n i f i c a n t e f f e c t s f o r the G.C.A. I n both regimes; however the S.C.A. was l e s s v a r i a b l e and only Stage 5, warm, and Stage 6, c o o l , showed s i g n i f i c a n t e f f e c t s . The r e c i p r o c a l e f f e c t s were not s i g n i f i c a n t except f o r Stage 5, warm. Considering days r e q u i r e d per plastochron, the G.-C.A., S.C.A. and r e c i p r o c a l e f f e c t s were s i g n i f i c a n t (Table 22) i n the warm r e gime, whereas i n the c o o l regime, only the S.C.A. and r e c i p r o c a l e f f e c t s were s i g n i f i c a n t . Considering f r u i t weight and diameter, t h e G.C.A. showed s i g n i f i c a n t e f f e c t s under both temperature regimes (Table 23), however the S.C.A. showed s i g n i f i c a n t e f f e c t s on the two c h a r a c t e r i s t i c s i n the c o o l regime only.  No d i f f e r e n c e s were s i g n i f i c a n t between  the r e c i p r o c a l s f o r f r u i t weight and diameter i n e i t h e r temperature regime. C. Net Photosynthesis Rate i n Warm and Cool Regime Growth Chambers Space l i m i t a t i o n precluded r e p l i c a t i o n , thus the data i n t h i s experiment were not analyzed s t a t i s t i c a l l y .  Inspection o f the  data from the warm regime (Table 24) shows t h a t the net photosynthesis r a t e f l u c t u a t e d w i t h the d i f f e r e n t plastochrons, and had a peak and a•• lowest point every 2 t o 4 plastochrons.  For example, B had an  increased photosynthesis r a t e s t a r t i n g from the 4th plastochron t o  83  TABLE 22. Mean squares f o r general (G.C.A.) and s p e c i f i c (S.C.A.) combining a b i l i t y e f f e c t s f o r days required per p l a s t o chron i n warm and c o o l regimes.  Temperature — cool  Source o f variance  > warm  •  G.C.A. •  0.3*  0.2  S.C.A.  0.3*  0.4*  Reciprocal Effects  0.1*  0.4*  :  * s i g n i f i c a n t a t 5% l e v e l  TABLE 23: Mean squares f o r general (G.C.A.) and s p e c i f i c (S.C.A.) combining a b i l i t y e f f e c t s f o r f r u i t weight and diameter i n warm and c o o l regimes.  Temperature cool  warm Source of Variance G.C.A.  Trait fruit weight 11756.8*  fruit diameter  fruit , weight.  fruit diameter  1058.1 ' 5  31336.1*  1329.4*  6508.2*  154.5*  S.C.A.  686.8  26.5  Reciprocal Effects  254.4  8.5  s i g n i f i c a n t a t 5% l e v e l  84  109.8  9.9  t o the 6th and then dropped down a t the 7th and then rose again . 1  The I c u l t i v a r , had the lowest p o i n t a t the 6th plastochron and then increased i t s r a t e . differentiation.  These f l u c t u a t i o n s may be r e l a t e d t o f l o r a l  The hybrids BI and IB showed h e t e r o s i s i n some  stages and the f l u c t u a t i o n patterns were very c l o s e t o those o f I . The net photosynthesis r a t e f o r c u l t i v a r C was somewhat d i f f e r e n t from those o f I and B, and had a peak every other plastochron, which again may be r e l a t e d t o f l o r a l d i f f e r e n t i a t i o n , because i n accordance w i t h t h e growth p a t t e r n o f c u l t i v a r C, t h e flower c l u s t e r s appeared very c l o s e l y , one a f t e r another, and there was only one l e a f between each o f the f i r s t 3 t o 4 c l u s t e r s . The l e a f area data from t h i s d i a l l e l cross experiment •', (Table 24) show some trends.  Taking the 8th plastochron f o r an ex-  ample, c u l t i v a r B had the l a r g e s t l e a f area and I had the s m a l l e s t , and a l l t h e hybrids were intermed'iatee' between- t h e i r parents except i n the case o f CB.  There was an increase i n l e a f area f o r a l l the  l i n e s associated w i t h the increase i n plastochron number.  I n most  cases, there was a slow increase followed by a marked increase i n l e a f area. In the c o o l regime growth chamber, the net photosynthesis r a t e (Table 25) f o r a l l the l i n e s was lower than i n the warm regime The hybrids showed h e t e r o s i s i n some plastochron ages and the f l u c t u a t i o n o f the net photosynthesis r a t e v a r i e d w i t h the h y b r i d l i n e . The l e a f area, as i n the case o f the 8th plastochron f o r example, was greatest f o r c u l t i v a r B and the smallest f o r I. were imtermediate  A l l the hybrids  i n l e a f area between t h e i r parents, w i t h the '.  85  TABLE 24.' Net photosynthesis r a t e and l e a f area i n growth chamber Experiment I i n warm regime.  Plastochron Lines  B  I Bl  IB  C BC  CB  IC  CI  4  Trait  5  10.5  12.2  l e a f areaf  72  109  ps. ratet-  11.1  10.0  44  76  12.9  9.5  47  88  13.6  13.0  ps. r a t e *  leaf areaf ps. r a t e l e a f area ps. r a t e l e a f area  47  111  ps. r a t e  9.3  10.0  l e a f area  51  93  ps. r a t e  8.2"  9.0  l e a f area  46  78  ps. r a t e  9.6  10.3  l e a f area  41  84'  ps. r a t e  7.1  6.3  l e a f area  57  82  ps. r a t e  8.3  8.7  l e a f area  42  96  .  6  7  12.8  9.8  148 5.5 147  322  11,1  12.0  159  242  7.8  7.5 135  8.1  233  9.8  300  10.3  158  9.4 279  220  8.0  9.4  8.4  254  168  301  11.7  9.6  9.0  202  109 9.7  305  9.1  8.0  189  112  265  8.4  6.0 147  8.-9 258  175 9.5  5ft 7  '  186  140  ps. r a t e - net photosynthesis r a t e - mg C0 /hr/dm  Y  l e a f area - cm  2  86  10.9  202  t  2  8  7.5 260  2  TABLE 25; Net photosynthesis r a t e and l e a f area i n growth chamber Experiment I i n c o o l regime.  Plastochron Lines  B  I BI  IB  C BC  CB  IC  CI  Trait  4  5  6  7  8  ps. r a t e t  6.9  6.9  7.4  4.2  5.1  l e a f areaV  48  96  ps. r a t e  5.9  6.8  l e a f area  48  70  ps. r a t e  6.7  8.6  l e a f area  66  ps. r a t e  6.7  l e a f area  65  ps. r a t e  6.4  l e a f area  49  ps. r a t e  7.5  l e a f area  68  ps. r a t e  7.5  6.2  l e a f area  66  81  ps. r a t e  3.5  4.3  l e a f area.. . . 72 ps. r a t e  4.9  l e a f area  64  102 7.1 100 7.3 102 6.7 123  124 4.4 107  165  298  3.7  441  3.2  134  3.9 257  179  4.9  4.2  183  4.4  217  4.7  414  4.6  170  .  247  4.2  325  5.3  .4.8  237  150 '  332  5.0  6.3 165  4.6  207  5.1  318  5.4  161  4.8  282  4.6  382  3.3  184  279  3.8  3.1 .  3.8  142  t  ps. r a t e - net photosynthesis r a t e - mg C0 /hr/dm  ¥  l e a f area - cm  2  87  357 5.5  238  2  4.1  296 2  exception o f BC which was smaller and IC which was l a r g e r than both parents.  A l s o a t the 8th plastochron the l e a f areas between r e c i p -  r o c a l s showed very l a r g e d i f f e r e n c e s .  Reciprocal Cross'.^ Experiments 1.  Growth Component Stages  A.  Warm Regime The data f o r the r e c i p r o c a l cross experiment (Table 26, and  -V^ppendix Tab'les i & angte!S).y) showedttheffdllowingiimportant d i f f e r ences under the warm regime.  The i n t e r - p a r e n t a l comparisons between  B and I showed s i g n i f i c a n t d i f f e r e n c e s f o r a l l component stages except f o r Stage 5. The means show t h a t f o r the 2 p a r e n t a l c u l t i v a r s , there were large d i f f e r e n c e s because I was c o n s i s t e n t l y e a r l i e r than B even f o r Stage 5 where the d i f f e r e n c e was not s i g n i f i c a n t .  The  i n t r a - r e c i p r o c a l comparisons between the r e c i p r o c a l s BI._and. IB, which had the same nuclear composition, but a d i f f e r e n c e i n cytoplasm, showed no s i g n i f i c a n t d i f f e r e n c e i n e a r l i n e s s f o r any o f the 7 stages (Table 26). P  2  I n other words, the cytoplasms-P^  (from c u l t i v a r B) and  (from c u l t i v a r I) had the same e f f e c t s on the days r e q u i r e d per  stage.  Differences between the maternal parents and t h e i r o f f s p r i n g  could be a t t r i b u t e d t o d i f f e r e n c e s i n nuclear gene composition because both generations have the same cytoplasniic composition.  In  the case o f I vs. IB, only Stage 3 showed a s i g n i f i c a n t d i f f e r e n c e and f o r B vs. B I S t a g e s ences f o r e a r l i n e s s .  1, 2, 3, 4 and 7 showed s i g n i f i c a n t d i f f e r -  I n other words, the d i f f e r e n c e s between •  88  TABLE 26. The non-orthognal comparisons f o r the seven growth component stages i n the r e c i p r o c a l cross Experiment I under warm and c o o l regimes.  Stage  Line;.- Mean B  1  2  Bl IB  7.2 (17.8)  B  7.9 ( .9.7) 6.4 ( 9.2)  1  Bl IB B  3  1  Bl IB  6  I vs IB  4.1*  0.1 (5.0*)  0.1 (6.1*)  4.1* (45.0*)  11.3* (1.3)  0.5 (1.8)  1.8 (7.2*)  7.2* (6.1*)  858.1* (708.1*)  14.5 (48.1*)  245.0* (423.2*)  304.2* (168.2*)  361.3* (1155.2*)  5.0 (217.8*)  B vs B l •  (48.1*)  6.7 ( 8.6) 7.0 ( 8.0) • 32.1 (31.2) 19.0 (19.3) 24.3 (25.4) 26.0 (28.5)  Bl IB  23.9 (57.3)  B  7.2 ( 9.5)  1  6.4 (10.2)  3'i2  2.5  0.1  0.2  Bl  7.0 ( 9.1)  (2.5)  (0.2)  (9.8)  (0.8)  IB  6.3 ( 8.8)  B  35.6 (59.7)  1  32.4 (51.7)  135.2*  0.2  45.0  Bl  32.6 (41.3)  (320.0*)  28.8 (16.2)  72.2* (0.2)  0.2 (4.1)  1  5  B l vs IB  32.8 (65.0) 24.3 (49.8) 24.9 (50.7)  B  4  B .vs I  8.1 (20.1)1 7.2 (17.0) 7.2 (17.1)  1  Sums o f squares  0.8 312.1* (281.3*) (1022.5*).  (369.8*) (1692.8*)  IB. . . .30.2 (43.1)  7 •  B  9.4 ( 9.8)  1  5.6 ( 9.5)  Bl  5.5 ( 9.4)  IB  . .5.3 ( 8.5)  0.5 (7.2)  76.1* (0.1)  *  s i g n i f i c a n t a t 5% l e v e l  t  Means and sums o f squares i n brackets are from data from the c o o l regime t o contrast w i t h the unbracketed values from the warm regime. 89  nuclear compositions XY and YY were not as great as the d i f f e r e n c e s between XY and XX. B.  Cool Regime The data f o r the r e c i p r o c a l cross experiment (Table 26)  showed the f o l l o w i n g important d i f f e r e n c e s under the c o o l regime, . and some contrasts w i t h the r e s u l t s o f the same l i n e s grown i n the warm regime.  The i n t e r - p a r e n t a l comparisons between B and I were  s i g n i f i c a n t l y d i f f e r e n t f o r Stages 1, 3, 4 and 6 only.  Cultivar B  required more days t o complete each stage except f o r Stage 5, i n which the r e s u l t s are the reverse o f the observations f o r the warm regime. Stage 7 showed no s i g n i f i c a n t d i f f e r e n c e between B and I although I was e a r l i e r than B, f o l l o w i n g the same trend as i n the warm regime. For the T  1  i n t r a - r e c i p r o c a l comparison between BI and I B , s i g n i f i c a n t  d i f f e r e n c e s i n e a r l i n e s s f o r Stages 1, 3 and 4 were observed, and such d i f f e r e n c e s were not observed i n the warm regime.  I n t h e case  of maternal parents and o f f s p r i n g ( I vs. IB and B vs. BI) d i f f e r e n c e s were s i g n i f i c a n t f o r Stages 1, 2, 3, 4 and 6. 2.- Net Photosynthesis Rate A. Warm Regime The d i f f e r e n c e s i n net pptotosynthesis r a t e between the parents B and I (Table 27 and Appendix Tables 16 and 18) were not s i g n i f i c a n t u n t i l plastochrons 6, 7 and 8 developed.  The d i f f e r e n c e s  between the r e c i p r o c a l hybrids were not s i g n i f i c a n t u n t i l plastochron 5 and l a t e r , 8 were developed.  Considering the maternal parents v s .  o f f s p r i n g comparisons, I vs. I B , showed d i f f e r e n c e s which were a l l  90  TABLE 27. The non-orthoghal comparisons f o r the net photosynthesis rate i n the reciprocal cross Experiment I I under warm and cool regimes, (mg C0 /dm /hr). 2  2  P.A.  4  1  Line  Mean  B I BI  10.6 12.7 16.4 17.2  ( 9.9) ( 9.0) (10.3)  15.9 14.7 14.0 16.5  ( 8.7) (9.2)  IB B 5  • I BI IB  6  7  10.9 6.1 9.4 IB . . 11.2  B I BI  BI BI IB  8  B vs I  B vs BI  f  8.8 (1.4)  1.3 (1.3)  39.4* (8.6*)  65.7* (0.4)  3.0 (0.4)  12.6* (28.5*)  6.7 (36.9*)  7.2  45.7*  51.7*  (76.9*)  6.2 (0.4)  193.7*  20.6  191.7*  19.9  (51.8*)  (0.8)  (9.5)  (10.3)  2.6* (12.4*)  8.2* (4.4)  (11.1)  ( 9.7) (13.5) ( 5.7) (11.9) • (10.9) (11.3)  10.6 (10.5) 20.5 ( 5.4) 7.5 ( 8.2) 10.7 ( 7.5)  BI  8.3 ( 5.4) 9.4 ( 7.9) 6.5 ( 3.4)  IB  8.4 (A.8)  B I  Sums of squares I vs IB BI vs-IB  t P.A. = plastochron age ¥ see Table 26 notation * significant at 5% l e v e l  91  (0.6)  1.8* (18.9*)  (1.9)  4.3 (53.8*)  6. 8* (8.6*)  s i g n i f i c a n t except i n plastochron 5; however, i n the case o f B vs. B l , only plastochrons 4 and 8 showed s i g n i f i c a n t d i f f e r e n c e s . The f l u c t u a t i o n patterns f o r the net photosynthesis r a t e i n the r e c i p r o c a l Q  hybrids are shown i n F i g . 25.  Both hybrids showed h e t e r o s i s i n p l a s -  tochron 4 and then a decrease u n t i l the 8th plastochron, a t which stage the h y b r i d IB was intermediate between the parents, but B l was lower than e i t h e r parent.  C u l t i v a r I had i t s lowest point at p l a s t o -  chron 6 and a peak at plastochron 7 whereas the other l i n e s d i d not show such marked f l u c t u a t i o n . B.  Cool Regime The d i f f e r e n c e s i n net photosynthesis r a t e between B and I  (Table 27) were s i g n i f i c a n t a t plastochrons 6, 7 and 8 as was the case i n the warm regime, but the d i f f e r e n c e s between the r e c i p r o c a l s were s i g n i f i c a n t only at plastochron 5.' The I vs. IB comparison showed s i g n i f i c a n t d i f f e r e n c e s i n plastochrons 4, 5 and 8.  I n the  case o f B vs. B l only the 6th and 8th plastochrons showed s i g n i f i c a n t differences.  In F i g . 26, i t can be seen t h a t the r e c i p r o c a l hybrids  showed h e t e r o s i s f o r net photosynthesis r a t e at plastochrons 4 and 5.' Then the r a t e was intermediate between parents i n plastochrons 6 and 7, and f i n a l l y lower than both parents a t the 8th plastochron.  Cultivar  I had the lowest net photosynthesis r a t e at the 4th plastochron, a t t a i n e d a peak at the 6 t h , then decreased markedlylat the 7th and f i n a l l y increased sharply again. tochron and then  C u l t i v a r B had a peak a t the 7th p l a s -  decreased.  3.'  92  93  3.  Leaf Area  A.  Warm Regime The l e a f area d i f f e r e n c e s between parents B and I were  s i g n i f i c a n t f o r plastochrons 5 t o 8 (Table 28 and Appendix Tables 17 and 19).  There were no s i g n i f i c a n t d i f f e r e n c e s between the r e c i -  procals i n any o f the plastochrons.  Comparing maternal parents and  t h e i r o f f s p r i n g , I vs. IB, showed s i g n i f i c a n t d i f f e r e n c e s f o r a l l plastochrons except i n the 4th, and i n the case o f B vs. B l , only the 4th and 8th plastochrons showed s i g n i f i c a n t d i f f e r e n c e s i n l e a f areas.  I n F i g . 27, a t plastochron 4, c u l t i v a r B had the l a r g e s t  l e a f area, and the r e c i p r o c a l hybrids had smaller l e a f areas than both parents.  Leaf area i n a l l the l i n e s increased sharply from  the 5th plastochron, except I which increased sharply a t the 6th. Thy h y b r i d , B l , showed h e t e r o s i s f o r l e a f area a t the 7th and 8th plastochrons. B.  Cool Regime The l e a f area d i f f e r e n c e s between parents B and I (Table  28) were s i g n i f i c a n t f o r a l l plastochrons.  There were s i g n i f i c a n t  d i f f e r e n c e s between the r e c i p r o c a l hybrids a t the 7 t h and 8th p l a s ochrons only.  Comparing the d i f f e r e n c e s i n l e a f area between mat-  e r n a l parents and t h e i r o f f s p r i n g , I vs. IB^ had s i g n i f i c a n t d i f f e r ences a t a l l plastochrons except a t the 5 t h , but i n the case o f B vs. B l , only the d i f f e r e n c e s a t the 5th and 8th plastochronswere significant.  I n F i g . 28, i t i s obvious t h a t both hybrids showed  h e t e r o s i s when t h e i r l e a f areas increased sharply a t plastochrons 7 and 8.  C u l t i v a r I had the smaller l e a f areas from the 4th t o the  8th plastochron. 95  TABLE 28;- The non-orthoghal comparisons f o r the leaf area i n the reciprocal cross Experiment I I under warm and cool regimes. (cm ). 2  P.A.  T  "4  Sums of squares•  Mean  Line B  62.2 ( 57.5)  I  50.5 ( 36.8)  B vs I  BI vs IB  I vs IB  B vs BI  ¥  31,2' >.7.020.( 60.0)  276.1  36.1  112.5  (861.1*) (128.0) (1081.1*)  450 .1* (60 .5)  'IB..Q ,"43?00<i 52.0)  5  6  B  95.2 (114.3)  I  65.7 ( 88.5)  1770.1*  0.5  1512.5*  BI  93.8 ( 98.5)  (1526.1*)  (98.0)  (200.0)  (1035.1*)  IB  93.2 ( 91.5)  B  154.0 (166.5)  I  97.0 (115.8)  6498.0*  112.5  5050.1*  406.1  BI  139.7 (156.0)  (5151.1*)  (3240.1*)  (253.1)  IB  147.2 (155.3)  11552.0*  180.5  (1.1)  6 .1  -0"RS '(186.8) £ 2'u : '242:5 2  7  8  5  12324.5*  288.0  i  164.5 (165.3)  BI  252.0 (224.3)  IB  240.0 (197.5)  B  373.0 (213.8)  I  284.0 (191.3)  15931.1*  BI  403.1 (274.0)  (1012.5*) (2043.0*)(13695.0*) (1596.1*)  IB  391.7 (242.0)  (924.5*) (1431.1*) (6962.0*) (231.1)  f P.A. = plastochron age see Table 26 notation significant at 5% l e v e l  96  288.0  23220.0*  1810.5*  97  300  "~4  5  6  7  8  PLASTOCHRON  F i g . 28. Leaf area o f each plastochron among the l i n e s i n c o o l re^ffie?.tux\^ ? regime.  98  F i e l d Experiments I."  Experiment I F i e l d Experiment I was handled i n two p a r t s .  Part 1 exam-  ined 8 l i n e s which included parents, B and I ; t h e i r r e c i p r o c a l hybrids IB and B I , and the backcrosses I B x I , B I x I , BIxB and IBxB.  The days  r e q u i r e d f o r the Stages. A and C were recorded f o r a l l T.2 -slants i n each l i n e and the data are shown i n Table 23- of the Appendix. The comparison among the l i n e means (Table 29) showed l a r g e d i f f e r ences i n the days • r e q u i r e d f o r both stages f o r the .••..2 '• parents, I and B, and I was e a r l i e r than B.  The d i f f e r e n c e s between r e c i p r o c a l hy-  b r i d s were very s m a l l and both o f the hybrids were intermediate between t h e i r parents.  Both the r e c i p r o c a l hybrids were e a r l i e r i f  backcrossed t o the e a r l y parent, I , than i f backcrossed t o the l a t e parent B.  One o f the backcross progenies I?Bxi'Iwas very c l o s e t o the  e a r l y parent I f o r the t2ra stages, whereas another progeny BIxB was  TABLE 29: Mean days r e q u i r e d f o r Stages A and C i n the f i e l d Experiment I , p a r t 1.  Line Stage  I  B  IB  A  68.9  80.8  74.6  B  47.3  59.7 ' 52.3  IBxI  BIxI  IBxB  BIxB  74.8 . 69.5  70.6  76.8  79.5  51.0  50.5  53.3  55.5  BI  48.4  c l o s e r t o the l a t e parent B i n Stages A and C. Part 2 examined t2/u, segregating generations o f the r e c i p r o c a l s BI and IB, denoted B I F , I B F , B I F 2  2  99  3  and I B F . 3  The means f o r  the e a r l i n e s s i n Stages A and C f o r each o f the 4 progenies were based on 100 plants i n each progeny.  The mean number o f days r e q u i r e d f o r  BIF2 and IBF2 i n both stages (Table 30) were very s i m i l a r , but these r e c i p r o c a l s showed l a r g e r d i f f e r e n c e s i n the F3 generation, and were e a r l i e r than t h e F  2  generation.  The  standard deviations f o r t h e  F3 were l a r g e r than those f o r t h e F , which i n d i c a t e d t h a t segregation 2  was continuing. F  2  Since there were l a r g e r ranges f o r the F3 than f o r t h e  i n both stages, then the s e l e c t i o n f o r e a r l i n e s s would be more.ef-  f e c t i v e i n the E.3.  The p l a n t s which were e a r l i e r than the parents  f o r Stages A and/or C were subjected t o pedigree s e l e c t i o n , t h a t i s -  seed from each i n d i v i d u a l p l a n t s e l e c t i o n was kept separate f o r t h e next generation.  I n the IBF3, p o p u l a t i o n , 6 e a r l y p l a n t s were s e l -  ected, and s i m i l a r l y i n the BIF3, 11 e a r l y p l a n t s were s e l e c t e d .  TABLE 30: The mean number o f days r e q u i r e d f o r Stages A and C i n the f i e l d Experiment I , part 2.  Line  Stage A  Stage C  Bl F  2  75.1+4.0  49.9±4.8  IB F  2  75.6±4.8  49.1+4.6  Bl F  3  72.1+8.7  49.2±5.5  IB F  3  70.7±7.7  51.1+5.1  ji'i'i  Experiment I I The progenies from the i7vmiividHa^p^anis. s e l e c t e d "  from the F| r e c i p r o c a l populations i n Experiment I , p a r t 2 (1971), were grown i n the f i e l d (1972) i n p l o t s w i t h 25 p l a n t s p e r progeny.  100  •The mean f o r the IB F  4  Stage A was 66.6 ±5.7 days and f o r Stage C  was 49.5 ± 3.4 days (Table 31).  The B l F^ Stage A was 66.8 ± 6.8  days and Stage C 47.3 ± 4.7 days.  These means were a l l intermediate  between those o f the o r i g i n a l parents B and I , but had the tendencyt o be c l o s e r t o the e a r l y parent I . Approximately 10% o f the e a r l i e s t segregates o f the IB F^ and B l F^ were pedigree s e l e c t e d f o r e a r l i n e s s and used t o provide the F 5 progenies.  TABLE 31: Means, h e r i t a b i l i t y , selectioneprogress and genetic proggress auidJgegeheratibns.  IB  T  Bl  h  Fit  Stage A  Stage C  Stage A  Stage C  66.6±5.7  49. 5±3.4  66.8±6.8  •47.3±4.7  0.63  0 .57  0.81  0.66  op (days)  5.70  3 .40  6.80  4.70  i  1.75  1 .75  1.75  1.75  AG (days)  6.30  3 .40  9.60  5.40  oG (days)  4.60  2 .60  6.20  3.80  Mean  The h e r i t a b i l i t i e s f o r both Stages A and C i n the r e c i p r o c a l cross populations were r e l a t i v e l y h i g h , but Stage A had h i g h e r h e r i t a b i l i t i e s than Stage C (.Table 31).  The c a l c u l a t e d o r expected  s e l e c t i o n progress, AG, ^ f o l l o w i n g the models o f Falconer (1967) and P i r c h n e r (1969), as shown on -pagewas  6.30 days i n Stage A and  3.40 days i n Stage C f o r IB F^ s e l e c t i o n s , and 9.60 days and 5.40 days f o r B l F4 s e l e c t i o n s i n Stages A and C r e s p e c t i v e l y .  101  The genetic  progress, q G , was 4.60 days and 2.60 days f o r Stages A and C r e s p e c t i v e l y i n the IB F ; but was 6.20 and 3.80 days f o r Stages A and C i n the BI F .  /..3 - ' Experiment I I I Part 1. Seed from the e a r l i e s t 10% o f the IB F  k  and BI F  4  which were pedigree s e l e c t e d i n 197.2 was used i n t h i s Part o f the experiment.  The means (Table 32) f o r Stages A and C i n the IB F were 5  60.3 and 50.5 days r e s p e c t i v e l y , and s i m i l a r l y 61.0 and 49.2 days f o r the same stages of the BI F  5  i n 1973.  A l l these means were ear-  l i e r than both o f the parents, B and I , i n d i c a t i n g t h a t s e l e c t i o n f o r the shortest length recombinations was being r e a l i z e d . Part 2.  S i x l i n e s from the F generation s e l e c t e d f o r e a r l 4  iness ( i n 1972) were compared t o ±Wo l i n e s s e l e c t e d f o r lateness from the F  4  generation.^ (Tables 32). The means o f the £6bt s e l e c t e d e a r l y  l i n e s f o r both stages A and C were a l l e a r l i e r than both parents, except one l i n e (11-22-13) showed one day l a t e r than the e a r l i e r parent I i n Stage A.  The f2/6 l a t e s t l i n e s i n both stages were a l l i n t e r -  mediate between t h e i r o r i g i n a l parents B and I , but showed the tendency o f being c l o s e r t o the l a t e r parent B.  A l l the means o f these  selected F5 pedigree genes f o r e a r l i n e s s were no e a r l i e r than t h e i r F4 parents, although some o f t h e p l a n t s w i t h i n each l i n e were c l o s e t o the parent value.  These d i f f e r e n c e s are^confounded w i t h season,  but the data may i n d i c a t e a minimal number o f days are r e q u i r e d t o grow through a c e r t a i n stage, and s e l e c t i o n may not able t o go beyond t h i s t h r e s h o l d .  102  TABLE 32: Mean days required f o r selections, ira.de f o r Stages A and C i n the F5 of the f i e l d Experiment I I I . " Part 1. Mass Populations  Stage  Parental l i n e  A  C  Mean (days)  B  74.0+.2.0  I Bl F  62.0+2.2 61.0+3.5  5  IB Fs B  60.313.3  I  52.6±3.7  61.0+.4.4  5  49.213.7  -IB F§  50.51.4.4  Bl F  Part 2 . Pedigree Populations Stage  A  Parental l i n e B I IB Bl Bl Bl  F F F F  Bl F IB F  5  B I IB F  T  62.012.2 5 9 . 6 1 3 . 3  5  60.613.2  5  11-53-19  60.811.9  5  11-53-22  61.813.2  II-22-1 11-22-13  58.312.8 63.214.0  5 5  1-26-16 11-50-23  71.211.9  73.811.9 61.014.4  5  1-48-18  52.613.7 50.613.4  11-53-20  48.614.6  5  11-53-19  5  11-53-22  46.812.9 48.213.8 52.013.6  BIT5  F F F F F F  1-48-18 11-53-20  BIF5  Bl Bl Bl Bl IB Bl  Mean (days) 7 4 . 0 1 2 . 0  BKF5  n  Line No.t  5 5 5 5  TI-22-1 11-22-13  1-26-16 11-50-23  4 9 . 6 1 5 . 5  58.813.1 58.613.4  Line No. 1-48-18, 11-53-20, 11-53-19, 11-53-22, selected from F the e a r l i e s t lines f o r Stage A. Line No. II-22-1, 11-22-13 selected from F^ the e a r l i e s t lines for Stage C. Line No. 1-26-16, 11-50-23 selected from F^ the latest lines for Stages A and C. 4  103  4.. Results o f s e l e c t i o n i n the f i e l d experiments Stage A.  As shown i n Table 33, the random samples were taken  from the T and F , and s e l e c t i o n f o r e a r l i n e s s i n Stage A was begun l  i n the F  2  i n which 6% and 11% were chosen i n the IB F  3  pectively.  3  and BI F  3  res-  The IB F mean f o r e a r l i n e s s was 66.6 days, which was 6 4  days e a r l i e r than B, but 3 days l a t e r than I ; whereas the BI F^ mean was 66.8 days, which was 5.9 days e a r l i e r than B, and 3.5 days l a t e r than I .  The e a r l i e s t o f the 10% o f the  plants were s e l e c t e d i n these  r e c i p r o c a l s , and the r e c i p r o c a l F5 populations were e a r l i e r than both o r i g i n a l parents.  The IB F was 13.7 days e a r l i e r than B and 1.7 days 5  e a r l i e r than I , and BI F  5  showed 12.9 days e a r l i e r than B, and 1 day  e a r l i e r than I . Stage C.  S i m i l a r s e l e c t i o n procedures were used as f o r Stage  A, and the IB F^ means (Table 34) were 6.5 days e a r l i e r than B and :;3..1 days l a t e r than I ; whereas the BI F^ showed 8.7 days e a r l i e r than B''and 0.9 days l a t e r than I .  A f t e r the e a r l i e s t 10% o f the F^ plants were  s e l e c t e d , the means f o r the F  5  progenies were e a r l i e r than both parents.  The IB F was 10.6 days e a r l i e r than B and 2.1 days e a r l i e r than I , ' v 5  whereas the BI F was 12.1 days e a r l i e r than B and 3.6 days e a r l i e r than 5  I. The means f o r e a r l i n e s s o f the F  5  generation progenies o f  both r e c i p r o c a l populations were smaller than the e a r l i e s t o r i g i n a l parent, i n d i c a t i n g t h a t there was recombination f o r e a r l i n e s s between the two stages.  I n other words, the shortest stages had been brought  together i n the F r e c i p r o c a l h y b r i d populations tojprdduce.the- e a r l y 5  segregants."  104  TABLE 33: IB T  1  4-  IB F  IB F  74.612.3 random sample taken  2  4  IB F  Summary of the f i e l d experiments, mean days required for Stage A.  3  75.614.8 Handom sample taken 70.7+.7.7 different from B-9.1; I +117  4  (6% selected)  BI Fj 4  random sample taken  BI F  2  4  BI F  BI  3  5  75.H4.0 random sample taken 72.H4.0 different from B -8.7; I +3.1  F  h  66.615.7  IB F  74.8H.5  different from B -6.1; I +33CJG BI F (10% selected) 60.3±1.6 different from B -13.7: I -1.7  5  (11% selected) 66.8±6.8 different from B -5.9; I +3.5 (10% selected).  .61.0+4.6 different from B =12.9: I -1.0 TABLE 34: Summary of the f i e l d experiments, mean days required for Stage C. IB F i 4  IB F  random sample taken 2  4  IB F  IB F  3  49.1±4.6 random sample taken 5111*511 different from B -8.6; I +3.7  4  m IB F  52.312.3  5  (6% selected)  BI F i 51.011.0 random sarandomasample taken BI F  2  49.9±4.8  randomssampiettiaken BI F  3  BI  h  F  49.5±3.4 + different from B -6.5; I +3.1 BI F (10% selected) 50.5+2.3 different from B -10.6: I -2.1  105  49.213.5 different from B -10.5; I =1.9 (11% selected) 47.314.7  different from B -8.7; I -0.9 (10% selected)  5  49.016.7 different from B -12.1; I -3.6  DISCUSSION  D i a l l e l Cross Experiments In the breeding o f s e l f - p o l l i n a t e d crop p l a n t s , the e f f i c iency depends on accurate i d e n t i f i c a t i o n o f the h y b r i d combinations t h a t have the p o t e n t i a l o f producing maximum improvement.  The present  experiments were undertaken t o determine whether d i a l l e l a n a l y s i s o f p a r e n t a l and F -^data could provide information u s e f u l f o r producing a maximum e a r l i n e s s . The data from the d i a l l e l cross experiments were subjected t o 2 a n a l y t i c a l procedures.  I n the "Hayman and J i n k s method" a l l  the assumptions are t e s t e d i n i t i a l l y by the uniformity o f W -V among r  arrays.  r  Hayman (1957, 1958) reported t h a t only when the t e s t reveals  a lack o f uniformity i s there need f o r f u r t h e r t e s t s t o i n v e s t i g a t e which assumption i s not v a l i d .  One o f the common ways i s t o e l i m i n a t e  c e r t a i n p a r e n t a l l i n e data and analyze the remaining data again.  Due  t o l i m i t e d resources f o r t h i s experiment, there were only 3 p a r e n t a l l i n e s i n v o l v e d ; t h e r e f o r e , when data f o r c e r t a i n c h a r a c t e r i s t i c s i n the present experiments f a i l e d t o pass the u n i f o r m i t y t e s t , i t was not p o s s i b l e t o e]jjirinate a p a r e n t a l l i n e and apply a f u r t h e r t e s t . As shown i n Table 5, there were 3 out Of 24- c h a r a c t e r i s t i c s which 1: f a i l e d the uniformity t e s t .  Nevertheless  these 3 p a r t i a l f a i l u r e s  seemed u n l i k e l y t o introduce gross b i a s i n t o the t o t a l genetic i n formation t o be gained from the d i a l l e l experiments; t h e r e f o r e , i t was assumed t h a t these p a r t i a l f a i l u r e s would not detract from the t o t a l information gained.  106  According to Hayman  (1954),  the interaction between environment  and:the genotype-in a d i a l l e l cross'is.revealed by the amount of heterogeneity of the variances within parental and Fi families.  Such heter-  ogeneity may be handled by considering the environmental effects (E) which i s estimated from differences between blocks, and subtracted from the genetic parameters, as shown i n Table 1.  Peat (1964) repor-  ted that i t i s d i f f i c u l t to separate the environmental effect from the genetic effect on certain characteristics, and that using the phenotypic variance w i l l result i n a bias.  In greenhouse Experiments  I and I I , there were two negative D values; Stage 2, warm (Table 13) and days required per plastochron, warm (Table 18).  These negative  values are a result of sample error and also the subtraction of the r e l a t i v e l y large environmental effect E from the parental variance, V , ( i . e . D=V -E; as shown i n Table 1). Since both these characterP P i s t i c s , Stage 2 (from seed germination to f i r s t true l e a f ) , and the days required per plastochron (the mean of 3rd to 8th plastochron) both occurred before transplanting to the benches when the distance between seedlings was only 2 inches, then, there was the p o s s i b i l i t y of competition between the seedlings which may have caused the E value to be so large. . Hayman and Jinks d i a l l e l cross theory proposed the use of the parameters F, Hj and H , expecting them to be accurate i n a large 2  d i a l l e l cross experiment.  Hayman (1956) suggested that when the num-  ber of parents i s less than 10 none of the components of variation i n the d i a l l e l cross analyses would be significant estimates of population parameters.  However, i n this experiment, the individual par-  ents and crosses were the main interest, and no attempt was made to  107  measure the population parameters, thus the genetic information was limited t o parental cultivars I , B and C only. The analysis of a d i a l l e l cross experiment i s somewhat different from the usual analysis of variance because the former- estimates the components separately from within each replicate, but the l a t t e r from over a l l replicates. The value of the numerical method of analysis i s that the relative importance of dominance and additive effects and some information on the distribution of a l l e l e s within the parental population can be obtained i n numerical form, and from these, further estimates such as the degree of dominance can be obtained.  In these experiments,  the numerical analysis indicated that i n the warm regime, overdominance occurred i n Stages 1, 2 and 4, p a r t i a l dominance i n Stages 3, 6 and 7, and only Stage 5 showed v i r t u a l l y complete dominance. Previous studies by other workers on earliness did not p a r t i t i o n the l i f e cycle into as many component stages as the present work. In general the intensive partitioning results do agree with some of thecearlier reports on larger component stages.  The present F 's were usually;?earlier x  than the earliestjparent i n both flowering and f r u i t set, s i m i l a r t o the reports by Hayes and Jones (1917). and Lyon (1941).  Wellington (1922), and Powers  The earliness, expressed as days to f i r s t flower  appears to be a result of overdominance i n Stages 1, 2 and 4, and ; these are a large part of the stage described by Burdick (1954) and Young (1966) who reported that time of flowering i n hybrids i s approximately intermediate between the two parents and t h e i r results would exclude overdominance action.  Either t h e i r parental types behave  differently, or the f a i l u r e t o p a r t i t i o n growth eomponent stages  108  s u f f i c i e n t l y prevented them from observing the overdominance as found i n Stages 1, 2 and 4 of the present experiments. These stages account f o r about one h a l f of the time period between germination to flowering, thus the importance of t h i s period f o r earliness i s s e l f evident.  In this experiment Stage 5 showed almost complete dominant  gene action wMeh?vwas i n agreement with Corbeil (1965) and Corbeil and Butler (1965), who reported that the early maturity genes were completely dominant f o r the f i r s t bloom to f i r s t f r u i t set stage which i s the  ;  same as Stage 5 i n the present study. In.the cool regime, results were quite different.  Over-  dominance f o r earliness was shown i n Stages 1, 5, 6 and 7; p a r t i a l dominance i n Stages 2 and 3, and complete dominance i n Stage 4.  Com-  paring the results under the 2 different temperature regimes, the genetic parameters were the same i n only Stages Land 3 i n which there was overdominance and p a r t i a l dominance respectively, and a l l other component stages had different gene";action. These differences are thus indicated to be due to the genotypeeenvironment interaction. In the warm regime, the frequency of recessive genes f o r earliness was higher than dominant genes f o r Stages laand 2, and the opposite way f o r Stages 3, 4, 5, 6 and 7.  The gene number involved  i n the. seven component stages was r e l a t i v e l y low, i n the warm regime only one or 2 gene pairs exhibited some degree of dominance f o r Stages 1} 2, 3-and 2 gene pairs f o r Stages 2, 3 and 4 respectively5 and 4 gene pairs f o r Stages 5, 6 and 7.  These results were somewhat d i f -  ferent from those of Honma>'e£-.al. (1963), who reported only one major gene pair f o r days required from seeding to f i r s t flower.  109  In contrast,  Powers e t a l . (1950) and Fogel and Currence (1950) suggested 3 o r more gene p a i r s c o n t r o l l e d t h i s character o f e a r l i n e s s o f f l o w e r i n g , and the former a l s o reported t h a t 2 major genes appeared t o c o n t r o l the stage f o r f r u i t s e t f r u i t r i p e n i n g . t o  In the c o o l regime, a l a r g e r number o f genes appeared t o be involved i n the e a r l i n e s s o f most stages. Comparing the r e s u l t s i n Tables 14 and 16, i t i s seen t h a t i n the c o o l regime, a l a r g e r number o f genes were involved i n each o f Stages 1 t o 4 i n c l u s i v e than i n the warm regime which represented usual growing conditions f o r the commercial crop and previous research work. stages, Stage 5 had the same h / H 2  2  At the l a t e r  value under both regimes, and  Stages 6 and 7 had lower values under the c o o l regime i n d i c a t i n g probably one gene p a i r only showed some measure o f dominance.  These  d i f f e r e n c e s i n gene numbers e x h i b i t i n g some degree o f dominance depending on the temperature l e v e l are evidence that p l a n t breeders should r e a l i z e t h a t such responses can be studied i n t h e i r breeding programmes.  I d e n t i f i c a t i o n o f genotypes o f s p e c i a l value f o r c o o l  climates o r growing seasons i s a "problem f o r the p l a n t breeders "screening procedures" i n i d e n t i f y i n g u s e f u l genotypes f o r p r o v i d i n g wider adaptation t o l e s s favourable temperature conditions. The h e r i t a b i l i t i e s f o r Stages 3 and 6 i n ^ t h e warm regime are h i g h suggesting that s e l e c t i o n " i n the e a r l y generations such as the F  2  could be expected t o show progress i n increased e a r l i n e s s .  These two stages are very long components o f the l i f e c y c l e , theref o r e , they should provide a good opportunity t o make progress w i t h earliness.  The other stages i n the warm regime, and a l l stages i n  the c o o l regime, had lower h e r i t a b i l i t i e s , thus e a r l y generation  110  s e l e c t i o n could not be expected t o make much progress i n the d i r e c t i o n o f increased e a r l i n e s s . Greenhouse Experiment I I This experiment contrasted Stages 5 and 6 o f the previous greenhouse Experiment I where.natural s e l f - p o l l i n a t i o n occurred, w i t h r e s u l t s o f greenhouse Experiment I I where p o l l e n was t r a n s f e r r e d by hand. Although the data f o r the two experiments, show s m a l l d i f f e r e n c e s f o r Stages 5 and 6, these d i f f e r e n c e s were undoubtedly a r e s u l t o f v a r i a t i o n i n the two seasons, and both experiments showed the same responses when genetic parameters and estimators were c a l c u l a t e d .  I n other words,  the d i f f e r e n c e s i n e a r l i n e s s as a f f e c t e d by n a t u r a l o r a r t i f i c i a l p o l l i n a t i o n were not large enough t o a f f e c t the genetic information on earliness.  Apparently s p e c i a l p o l l i n a t i o n handling was not needed, and  growth studies can depend on n a t u r a l p o l l i n a t i o n t o produce a uniform base f o r plants i n t h e i r Stage 5. As expected, days r e q u i r e d per p l a s tochron, which were recorded from 4-th t o 8th plastochron, '.'were markedly a f f e c t e d by the temperature regimes.  The r e l a t i o n s h i p o f the D and E  1  parameters > (Table 18) i n d i c a t e d complete dominance f o r e a r l i n e s s i n the warm temperature regime, but overdcminance i n the c o o l temperature regime.  The gene number involved i n t h i s e a r l i n e s s d i f f e r e d w i t h temp-  e r a t u r e , being 2 and 6 i n the warm and c o o l regimes r e s p e c t i v e l y , and the h e r i t a b i l i t i e s were both very low.  Nevertheless i t could be impor-  t a n t t o know the temperature-genotype i n t e r a c t i o n s t o a i d the p l a n t breeder i n choosing breeding procedures; f o r example,. the true-breeding c u l t i v a r s could be s e l e c t e d f o r the daninant a c t i o n f o r e a r l i n e s s , under warm c o n d i t i o n s ; however under the s t r e s s o f c o o l regimes the use of  111  F]_ h y b r i d c u l t i v a r s could be the d e s i r a b l e c h o i c e , p a r t i c u l a r l y t o get the overdominance' • f o r e a r l i n e s s . In contrast t o the character of e a r l i n e s s , the genetic parameters f o r the f r u i t weight and diameter show the same response i n both temperature regimes.  The smaller s i z e and diameter of f r u i t  of Fj hybrids compared w i t h the parents (Table 11) were apparently the r e s u l t of p a r t i a l dominant gene a c t i o n (Table 19 and F i g . 21 t o 24-), and such r e s u l t s are i n agreement w i t h the r e p o r t s o f Fogle and Currence (1950) and K h e i r a l l a and Whittington (1962) on tomato; f r u i t size inheritance. The p i c t o r i a l analyses,, wraehhare genetic analyses using d i a l l e l cross graphs ( F i g . 1-24), are bases on the value o f W The value o f W -V  -V^.  i s equal t o ^ D - H i ) (Hayman, 1954), and must be  constant among the arrays t o meet the assumption o f the d i a l l e l cross theory.  I f the value of ^(D-Hi) does not change and remains constant,  then W =  constant +V ,  r  l i n e o f u n i t slope.  r  and the r e g r e s s i o n of W^ upon V  When V  = 0, then W^ = ^(D-Hi).  i s a straight Thus on the  d i a l l e l l o r o s s (W ,V ) graphs, the i n t e r c e p t on the W^ a x i s i s an i n d i c a t o r y o f the average degree o f dominance i n the progeny.  With par-  t i a l dominance, the W^ i n t e r c e p t i s p o s i t i v e ; w i t h overdominance the W  i n t e r c e p t i s negative.  Therefore the (W ,V ) graph provides e v i -  dence of the presence of dominance (b^O) and the average degree o f dominance (+ o r - value o f a ) .  In the present experiment the r e s u l t s ,  of p i c t o r i a l analyses r e v e a l t h a t the average degree of dominance i n a l l the characters i n v e s t i g a t e d was i n agreement w i t h the r e s u l t s o f the numerical analyses.  Besides t h i s p o i n t , the p i c t o r i a l analyses  provide f u r t h e r information which i s not obtained from the numerical  112  procedure. For example, the position of the regression l i n e related to the origin (W ,V ) gives a good idea of the degree of dominance; and the position of points along the l i n e reveals the distribution of dominant and recessive a l l e l e s within the parental populations. Points near the o r i g i n (W ,V ) represent parents with mostly dominant a l l e l e s , whereas points near the upper end of the regression l i n e represent parents with mostly recessive a l l e l e s . From Fig. 1 - 7 , i t may be concluded that i n the warm temperature regime, the I c u l t i v a r carried dominant genes for earliness i n a l l the 7^component stages, and B carried recessive genes which were acting i n the direction of lateness. On.the other hand, Fig.8-14 show that i n the cool temperature regime, I c u l t i v a r carried genes f o r earliness i n only Stages 3,4,5 and 6, whereas i n Stage 2 dominant earliness was shown by c u l t i v a r B; and the. dominant earliness for Stages 1 and 7 was manifested by c u l t i v a r Cv This variation from results i n the warm regime could be due to different genotype-environment interactions, and certain genes i n certain cultivars were more suitable f o r growth i n the cool temperature environment. I t has already been reported (Young, 1963) that C c u l t i v a r seed i s able to germinate at the cool temperature of set f r u i t at  7.5°C  10.0°C  and  night temperature.  From the plant breeder's point of view, the p i c t o r i a l analysis supplies information about the gene distribution pattern among parents and such information i s not obtained i n the numerical analyses. In this experiment, c u l t i v a r I i s desirable for the breeding of earliness,.because i t carries dominant genes i n most of the growth component stages, and these dominant genes are i n the direction of earliness.  113  A d d i t i o n a l t o the Hayman-Jinks procedure f o r d i a l l e l cross experiments, the G r i f f i n g ' s method was a l s o used, and i t i s concerned w i t h the general combining a b i l i t y (G.C.A.) and s p e c i f i c combining a b i l i t y (S.C.A.).  According t o Spragueand latum (194-2) t h e v a r i -  ance f o r G.C.A. I s l a r g e l y a d d i t i v e genetic variance, whereas S.C.A. i s l a r g e l y dominance variance.  Horner and Lana (1956) i n d i c a t e d  t h a t both G.C.A. and S.C.A. contain e p i s t a t i c variance w i t h the l a t t e r containing considerably more than the former. From the r e s u l t s (Tables 20 and 21), i t i n d i c a t e d t h a t i n the warm regime, t h e estimates o f variances f o r G.C.A. were s i g n i f i cant a t t t h e 5% l e v e l f o r a l l 7 component growth stages, i n d i c a t i n g the presence o f a d d i t i v e gene a c t i o n . Although s i g n i f i c a n t estimates o f S.C.A. were a l s o obtained, when compared t o G.C.A.,,- t h e estimates o f non-additive genetic variance (S.C.A.) were g e n e r a l l y s m a l l e r , e s p e c i a l l y i n Stages 3 and 6.  I n the c o o l regime, the estimates o f  G'i-C.A. f o r a l l the component stages were s i g n i f i c a n t except f o r Stage 7 whereas-the estimates o f S.C.A. were a l l s i g n i f i c a n t .  The mean  squares o f the S.C.A. were l a r g e r than those f o r G.C.A. i n Stages 1, 5 and 7 which i n d i c a t e d t h a t non-additive.  The s i g n i f i c a n t non-  a d d i t i v e gene a c t i o n should make a r e c u r r e n t s e l e c t i o n more e f f i c i e n t f  x  in;.the e a r l y generations i f s e l e c t i o n i s f o r e a r l i n e s s under a c o o l regime. The foregoing demonstrates the contrast i n gene a c t i o n under d i f f e r i n g temperature regimes, and choice o f breeding methods should obviously be r e l a t e d t o the o b j e c t i v e s and use o f growing conditions f o r p l a n t breeding programmes.  114  Considering the days r e q u i r e d per plastochron (Table 22) i n the warm regime, t h e G.C.A. and S.C.A. values were both s i g n i f i cant whereas i n the c o o l regime, t h e S.C.A. value was l a r g e r than and hence more important than the G.C.A. This h i g h S.C.A. value ' i n d i c a t e d t h a t t h i s c h a r a c t e r i s t i c o f e a r l i n e s s can be considered as r e l a t i v e l y e a s i l y t o s e l e c t and evaluate i n a population under selection.  This conclusion i s s i m i l a r t o t h a t o f K h a l f - A l l a h (1970),  K h a l f - A l l a h and P e i r c e (1962), P e i r c e and Currence (1959), who a l s o reported t h a t t h e S.C.A. values were l a r g e r than those f o r G.C.A. although t h e i r p a r t i t i o n i n g o f the l i f e c y c l e was d i f f e r e n t from the present work andddid not i n c l u d e plastochrons. In the warm regime, f r u i t weight and f r u i t diameter both had s i g n i f i c a n t values f o r G.C.A. only (Table 23), whereas i n t h e c o o l regime both the G.C.A. and S.C.A. were s i g n i f i c a n t .  A l s o under  both temperature regimes, t h e estimates o f S.C.A. were both much lower than those f o r G.C.A. i n d i c a t i n g the f r u i t weight and diameter were l a r g e l y c o n t r o l l e d by a d d i t i v e gene a c t i o n .  This r e s u l t was not t h e  same as t h a t obtained by K h a l f - A l l a h (1970), who reported t h a t f o r f r u i t s i z e , G.C.A. and S..G.A. showed approximately s i m i l a r values. Although the same data from the d i a l l e l crosses were used i n each o f two d i f f e r e n t a n a l y t i c a l procedures, t h e methods are not a l t e r n a t i v e s , but r a t h e r means t o e x t r a c t d i f f e r e n t genetic information. The Hayman-Jinks method provided s e v e r a l parameters and estimators which were based on data from parents and t h e i r F generations, and 1  which could be used as p r e d i c t i o n values f o r s e l e c t i n g among s u p e r i o r lines.  Thus a l a r g e number o f l i n e s could be s e l e c t e d a t an e a r l y  generation, p o s s i b l y the F , and the unpromising l i n e s could be 2  115  discarded, a l l o w i n g breeders t o concentrate on a r e l a t i v e l y few l i n e s w i t h the expectation o f r a p i d achievment o f the breeders' o b j e c t i v e s . As already i n d i c a t e d t h i s e v a l u a t i o n procedure might w e l l be adequate f o r many breeding programmes, i n c l u d i n g the ijnprovement o f e a r l i n e s s i n tomatoes. The second a n a l y s i s , G r i f f i n g ' s method provided i n f o r m a t i o n on the combining a b i l i t i e s o f a l l p a r e n t a l l i n e s i n the d i a l l e l cross. There i s an estimate o f t h e importance o f a d d i t i v e and dominant gene a c t i o n , which may be o f great value t o t h e p l a n t breeder when he has t o estimate t h e progeny segregation range i n order t o decide on t h e s i z e o f the population r e q u i r e d , and a l s o t o p r e d i c t t h e progeny phenotypic values. As pointed out i n the , l i t e r a t u r e review, the Hayman-Jinks technique was concerned w i t h the gene l e v e l whereas G r i f f i n g ' s method was concerned w i t h the gametic l e v e l .  In 'Other words, the G r i f f i n g  method can be regarded as the combination o f gene i n t e r a c t i o n s o f t h e 2 genomes i n the zygote.  Thus t h e G r i f f i n g ' s a n a l y s i s regarded t h e  genotypical e f f e c t o f an i n d i v i d u a l as t h e combination o f e f f e c t s contributed by each gamete and the i n t e r a c t i o n o f gametes, whereas Hayman-Jihks regarded the gene e f f e c t which may d i r e c t t h e phenotypic expression.  The p l a n t breeder may view the G r i f f i n g method as a  ' t e s t i n g ' procedure t o study and compare the performances of p a r e n t a l l i n e s i n h y b r i d combination, and the Hayman-Jihks method i n d i c a t e s the genetic c h a r a c t e r i s t i c s o f the p a r e n t a l l i n e s . The p l a n t breeders should keep i n mind t h a t there are d i f f e r e n t c o n t r i b u t i o n s from both methods, and i d e a l l y any d i a l l e l cross experiment should employ both methods t o help p l a n t breeders t o ' ~ -u'i^.^u'jaHtativs characters i n order t,o*£.J>:i* 116  s e l e c t any q u a n t i t a t i v e characters i n order t o achieve the goal. Reciprocal Cross Experiments, There /were d i f f e r e n t responses i n some growth stages i n the r e c i p r o c a l crosses a t t h e 2 temperature regimes i n the greenhouses. In the warm regime, there were no s i g n i f i c a n t d i f f e r e n c e s between r e c i p r o c a l s (Table 26) so f a r as e a r l i n e s s could be measured. Apparently the i d e n t i c a l nuclear genes o f the r e c i p r o c a l s c o n t r o l l e d the  growth, and d i f f e r e n c e s imcytoplasm had l i t t l e i f any e f f e c t .  The responses i n the c o l d temperature regime (Table 26) showed t h a t Stages 1, 3 and 4 were a f f e c t e d by the cytoplasm which parent B cont r i b u t e d , and these stages took longer t o develop than i n t h e h y b r i d where I had contributed the cytoplasm. the  Although the T hybrids had l  same nuclear gene c o n s t i t u t i o n , there i s apparently a cytoplasmic-  genic i n t e r a c t i o n such t h a t cytoplasm from B under c o o l temperatures provides an unsuitable c o n d i t i o n f o r thesexpression o f the genes contributed by both parents t o the the  r e c i p r o c a l hybrids.  Thus under  s t r e s s o f cooler c o n d i t i o n s , the cytoplasm appeared t o have some  importance, and t h i s i s o f p a r t i c u l a r i n t e r e s t when there i s every p r o b a b i l i t y t h a t future greenhouse growers w i l l e i t h e r wish o r be required t o produce crops w i t h minimum use o f f u e l f o r heating. The means f o r e a r l i n e s s f o r tiheireciprocaiksbihhbQth:..temperature regimes i n a l l the stages, w i t h only the one exception o f Stage 5, c o o l , showed a tendency t o be c l o s e r t o the e a r l i e r parent I .  These  r e s u l t s suggest that the n u c l e a r genes were more important i n cont r o l l i n g p l a n t growth than the cytoplasmic c o n t r i b u t i o n which was o f l i t t l e importance f o r growth except under a s t r e s s c o n d i t i o n .  117  These  r e s u l t s were somewhat d i f f e r e n t from those o f Shumaker e t a l . (1970), who concluded t h a t most d i f f e r e n c e s between r e c i p r o c a l F j ' s f o r e a r l i ness showed matroclinous  tendencies.  P o s s i b l e cytoplasmic d i f f e r e n c e s could be associated w i t h v a r i a t i o n i n c h l o r o p h y l l content as r e f l e c t e d by net photosynthesis rates.  The measurement o f these r a t e s i n the growth chamber E x p e r i -  ment I I showed the f o l l o w i n g trends.  Differences i n the net photo-  synthesis r a t e s o f parents B and I were not s i g n i f i c a n t u n t i l the plants had reached the 6th plastochron and then r a t e s were s i g n i f i c a n t l y d i f f e r e n t through t o the 8th plastochron a t the end o f the experiment (Table 27). This response was s i m i l a r i n both temperature regimes.  The r e c i p r o c a l hybrids showed fewer d i f f e r e n c e s than the par-  ents , and the differencesvower^ssignxf-ieahttat the 5th and 8th p l a s t o chrons i n the warm regime and only a t the 5th plastochron i n the c o o l regime.. The small proportion (3 out o f 10 comparisons) o f s i g n i f i cant d i f f e r e n c e s between r e c i p r o c a l s suggests t h a t the cytoplasmic influences o r e f f e c t s are hardly large enough t o concern the p l a n t breeder.  I t i s notedthat i n s p i t e o f the n o n - s i g n i f i c a n t d i f f e r e n c e s ,  there i s a trend (only one exception out o f 10 comparisons) f o r the I cytoplasm o f IB h y b r i d t o be associated w i t h higher net photosynt h e s i s r a t e s than i s the case f o r the r e c i p r o c a l B l which.has the B cytoplasm.  This apparently small c o n t r i b u t i o n by the cytoplasm i s  i n general agreement w i t h the evidence presented by Levine (1969), McGinnis and Taylor (1961), Chang and Sadanage (1964) and Izhar and Wallace (1967), who have pointed out t h a t the production o f c h l o r o p h y l l , although located i n the cytoplasm, i s c o n t r o l l e d by nuclear genes.  118  As shown i n F i g . 25 and 26, t h e net photosynthesis r a t e f o r a l l t h e l i n e s f l u c t u a t e d from the 4-th t o 8th plastochrons.  The f l u c -  t u a t i o n o f net photosynthesis r a t e could be r e l a t e d t o the developmental phaseoof the p l a n t .  There are s e v e r a l r e p o r t s regarding the  e f f e c t s o f f l o r a l d i f f e r e n t i a t i o n on photosynthesis r a t e .  Duncan and  Hesketh (1968) using c o m , Forsyth and H a l l (1965) w i t h blueberry, and Richardson (1967) using cotton, a l l reported t h a t when f l o r a l d i f f e r e n t i a t i o n was o c c u r r i n g , there was a decrease i n t h e net photosynthesis r a t e .  In -the tomato when t h e reproductive phase i s under-  way, there can be r e t a r d a t i o n i n t h e vvegetative growth (Krausy and K r a y b i l l , 1918), and t h i s r e t a r d a t i o n o f vegetative growth may a f f e c t the photosynthesis r a t e , as reported by Sweet and Wareing (1966). In t h e present experiment, under the warm temperature regime ( F i g . 25), the photosynthesis r a t e decreased i n c u l t i v a r B from the 5th p l a s t o chron, and t h i s decrease may be associated w i t h t h e f l o r a l d i f f e r e n t i a t i o n which took place from t h i s plastochron age.  S i m i l a r l y the  r e s u l t s o f the d i a l l e l cross i n growth chamber Experiment I suggested an a s s o c i a t i o n o f decreased net photosynthesis r a t e and f l o r a l d i f f e r e n t i a t i o n i n c u l t i v a r C. Considering the l e a f area i n both temperature regimes, (Table 28), there were d i f f e r e n c e s between t h e two parents B and I , ( I having the smaller leaf/area) which were a l l s i g n i f i c a n t except f o r t h e f o u r t h plastochron i n the warm regime.  None o f the d i f f e r -  ences between r e c i p r o c a l s were s i g n i f i c a n t except those f o r l e a f areas i n t h e 7th and 8th plastochrons i n the c o o l regime, which i n dicated t h a t t h e cytoplasmic d i f f e r e n c e s between these two r e c i p r o c a l s  119  had a s l i g h t e f f e c t on the l e a f area, whereas the s i g n i f i c a n t d i f f e r ences between I vs. IB and B vs. B l i n d i c a t e d the nuclear genes were the major c o n t r o l f o r l e a f area development. From the r e s u l t s o f t h i s r e c i p r o c a l cross experiment, i t may be concluded that under normal growing temperature regimes, t h e cytoplasmic e f f e c t was not as important as the nuclear e f f e c t ; however, under s t r e s s c o o l temperature conditions, the cytoplasmic, e f f e c t may r e v e a l some importance e s p e c i a l l y f o r the e a r l i n e s s o f several growth component stages.  I t .is advisable therefore, that cytoplasmic  e f f e c t s and genie-cytoplasm i n t e r a c t i o n s be studied and c a r e f u l l y considered by plant breeders working on s e l e c t i o n f o r e a r l i n e s s under s t r e s s temperature  conditions.  F i e l d S e l e c t i o n Experiments The  f i e l d Experiments I - I I I dealt w i t h s e l e c t i o n and the  search f o r evidence o f recombination among the short growth stages. E a r l y generation s e l e c t i o n and t e s t i n g have been reported as p a r t i c u l a r l y s u i t a b l e f o r evaluating ( K h a l f - A l l a h and P e i r c e , 1964).  such a crop as•the tomato  Peirce and Currence (1959) had con-  cluded that e a r l y t e s t i n g f o r q u a n t i t a t i v e l y i n h e r i t e d characters, such as e a r l i n e s s , was o f d e f i n i t e value i n improving tomato plant performance.  I n the present f i e l d experiments, pedigree s e l e c t i o n  was s t a r t e d i n the F  3  f o r Stages A and C (as defined on page^3'5)  and the top 6% and 11% were selected from r e c i p r o c a l populations IB and B l r e s p e c t i v e l y .  I n the F^ generation, the means f o r both  r e c i p r o c a l populations d i d not exceed the mean o f the e a r l i e r parent I.  The h e r i t a b i l i t i e s f o r the e a r l i n e s s c h a r a c t e r i s t i c s i n t h e FL,  120  f o r both r e c i p r o c a l populations were r e l a t i v e l y h i g h , and higher i n Stage A than i n Stage C.  These h e r i t a b i l i t y d i f f e r e n c e s i n d i c a t e d  t h a t Stage A w i l l respond t o s e l e c t i o n f o r e a r l i n e s s more e f f i c i e n t l y than w i l l Stage C.  The t h e o r e t i c a l l y expected s e l e c t i o n progress,  AG, i n t h e IB population was 6.3 days f o r Stage A and 3.4 days f o r Stage C (Table 31); whereas i n the BI population, these values were 9.6 days f o r Stage A and 5.4- days f o r Stage C.  These s e l e c t i o n pro-  gress values do not mean t h a t the f o l l o w i n g generation w i l l be improved f o r e a r l i n e s s e x a c t l y as c a l c u l a t e d , but these values show the r e l a t i v e tendency t h a t , under the s e l e c t i o n i n t e n s i t y employed, the population means w i l l be s h i f t e d i n ' the expected d i r e c t i o n by a c e r t a i n amount. In selection-work, the genetic progress, aG, i s l e s s than s e l e c t i o n progress, AG, althbuglBtheyuareihighiliy c o r r e l a t e d w i t h t h e h e r i t a b i l i t y , h , ( P i r c h n e r , 1969). 2  tomato s e l e c t i o n experiment  I n the F^ generation o f t h e  (Table 31), the genetic progress was c a l -  culated as 4.6 days i n Stage A and 2.6 days i n Stage C f o r t h e IB population; and 6.2 days i n Stage A and 3.8 days i n Stage C f o r the BI population.  This genetic progress i n d i c a t e d t h a t under the s e l -  e c t i o n i n t e n s i t y employed, the genotypic value f o r e a r l i n e s s  will  be changed i n the expected d i r e c t i o n i n the F . 5  Pedigree s e l e c t i o n was continued i n the F  4  and the top 10%  of e a r l y p l a n t s was s e l e c t e d again from both r e c i p r o c a l populations. The means o f the F mass populations (which were from;selected F 5  4  p l a n t s ) were e a r l i e r than both o r i g i n a l p a r e n t a l c u l t i v a r s (Tables 33 and 34).  These e a r l i e r F population means i n d i c a t e d t h a t 5  121  recombination o f some genes f o r e a r l i n e s s had occurred. the means f o r the F  5  Although  r e c i p r o c a l populations IB and B l were e a r l i e r  than o r i g i n a l parents I and B, there were d i f f e r e n c e s i n the behaviour of reciprocal lines.  Within the mass population o f IB F , the standard 5  d e v i a t i o n was 1.6 f o r Stage A (Table 33) and 2.3 f o r Stage C (Table 34), and both these values were smaller than s i m i l a r values f o r the F^ generation, i n d i c a t i n g t h a t the segregation i n the F u l a t i o n had been reduced.  5  o f the IB pop-  On the other hand, i n t h e B l population  F , both the standard d e v i a t i o n s f o r Stages A and 'C were l a r g e r than 5  those;':for the F^, and t h i s comparison i n d i c a t e s t h a t segregation was continuing. Al^inggi' the F  5  population mean f o r each o f the r e c i p r o c a l  h y b r i d populations was earlier than the mean o f each o f the o r i g i n a l parents (Tables 33 and 34).  5  F  5  p l a n t s demonstrated t h a t recom-  b i n a t i o n o f genes f o r e a r l i n e s s had occurred.  The F  h y b r i d populations were apparently not i d e n t i c a l .  5  reciprocal  The standard de-  v i a t i o n f o r IB F population i n both Stages A and C showed a reduc5  t i o n from the IB F  4  value, however the B l F population had a s l i g h t l y 5  l a r g e r standard d e v i a t i o n than the B l F^. These standard d e v i a t i o n s i n d i c a t e d t h a t the segregation i n IB F had been reduced whereas 5  i n the B l F  5  segregation was continuing and producing a wider range  o f segregates.  I t i s suggested t h a t mass s e l e c t i o n can be continued  i n the IB population t o maintain o r increase the e a r l i n e s s , but p e d i gree s e l e c t i o n should be a p p l i e d t o the B l population t o observe f u r t h e r segregations which should allow increased chances f o r more d e s i r a b l e recombinations f o r e a r l i n e s s t o appear.  122  The s e v e r a l experiments showed t h a t d i f f e r e n t c u l t i v a r s proceeded through various growth component stages a t d i f f e r e n t r a t e s . Genetic parameters and estimators were c h a r a c t e r i s t i c s which: f r e quently i n d i c a t e d d i f f e r e n t i a l genetic behaviour i n each o f two d i f ferent temperature regimes, and among these c h a r a c t e r i s t i c s , h i g h h e r i t a b i l i t i e s were c a l c u l a t e d f o r e a r l i n e s s i n the more important or lengthy growth stages. These c h a r a c t e r i s t i c s were used t o choose parental l i n e s and t o employ e a r l y generation s e l e c t i o n .  The F^  generation s e l e c t i o n i n two r e c i p r o c a l cross populations provided a good example o f the r e s u l t s o f e a r l y generation s e l e c t i o n t o obtain recombination o f genes from two parents t o produce p l a n t s ( i n F ) 5  which had t h e shortest growth Stages A and C and which were e a r l i e r than e i t h e r parent. This increased e a r l i n e s s o f some recombinations provides an example o f the p o t e n t i a l success t o be gained from using shorter component stages from many d i f f e r e n t p a r e n t a l c u l t i v a r s t o o b t a i n recombinations which would achieve the o b j e c t i v e o f breeding f o r e a r l i n e s s t o adapt the tomato t o short and c o o l growing seasons i n Canada.  123  SUMMARY  The inheritance o f 7 growth component stages and other p h y s i o l o g i c a l c h a r a c t e r i s t i c s i n tomatoes was studied i n (a) d i a l l e l crosses among 3 c u l t i v a r s , Bonny Best, Immur P r i o r Beta and Cold Set; and (b) r e c i p r o c a l crosses between 2 c u l t i v a r s , I and B. These experiments were conducted i n 2 temperature regimes, 10-13°C and 17-21°C. S e l e c t i o n was applied s t a r t i n g i n the F through t o the F 3  5  i n the  f i e l d , toeseek evidence o f genetic recombination between component stages and the response t o s e l e c t i o n f o r the e a r l i n e s s . Data on growth stages from the d i a l l e l crosses were subjected t o 2 a n a l y t i c a l procedures.  The f i r s t procedure used the J i n k s  and Hayman (1953) model t o provide parameters and estimators which i n dicated gene a c t i o n i n the several growth stages. The a c t i o n r e vealed v a r i e d among the 7 stages and between the 2 temperature ve~ gimes. . Stages d i f f e r e d as t o whether overdominance, p a r t i a l o r comp l e t e dominance was present". The dominant and recessive a l l e l e f r e quencies were not equal i n any stages and v a r i e d i n d i f f e r e n t stages. The h e r i t a b i l i t y f o r e a r l i n e s s o f most stages was r e l a t i v e l y high. Temperature had considerable e f f e c t on the a c t i o n . The second procedure, G r i f f i n g ' s method (1956), provided an estimate o f the General XGomb'ini^  Combining  Ability.,and t h e i r values d i f f e r e d s i g n i f i c a n t l y i n d i f f e r e n t stages and also i n d i f f e r e n t temperature regimes i n d i c a t i n g t h a t both addit i v e and dominant gene a c t i o n were important i n most o f the component stages, although the temperature regimes a f f e c t e d t h i s • a c t i o n such  124  t h a t i n some stages i n the c o o l regime, the dominant a c t i o n was more evident. The r e c i p r o c a l cross experiments showed t h a t although par^ ents had s i g n i f i c a n t d i f f e r e n c e s i n most o f the component stages i n both temperature regimes, t h e i r r e c i p r o c a l cross progeny showed no s i g n i f i c a n t d i f f e r e n c e s among any o f the component stages i n the warm regime, but showed s i g n i f i c a n t d i f f e r e n c e s i n Stages 1, 3 and 4 i n the c o o l regime.  Thus cytoplasmic d i f f e r e n c e s appeared t o have  some importance under the s t r e s s o f the c o o l regime. The net photosynthesis  r a t e i n parents I and B showed s i g -  n i f i c a n t d i f f e r e n c e s i n plastochron ages 6 t o 8 i n c l u s i v e l y , but the r e c i p r o c a l progenies showed s i g n i f i c a n t d i f f e r e n c e s a t the 5th and 8th i n the warm regime and only a t the 5th i n the c o o l regime. The d i f f e r e n c e s i n some o f the genetic parameters and estimators i n the 2 temperature regimes i n the d i a l l e l crosses, and the d i f f e r e n c e s ;be"tween r e c i p r o c a l crosses, provide knowledge t o a i d the plant breeder t o choose breeding procedures f o r improving the q u a n t i t a t i v e characters i n c l u d i n g appropriate t e s t i n g procedures t o i d e n t i f y valuable segregants.  The demonstrated e f f e c t s o f tempera-  ture on gene a c t i o n make i t important t h a t the environmental f a c t o r be c a r e f u l l y considered i n the breeding programme. Three seasons o f f i e l d experiments were used t o s e l e c t f o r e a r l i n e s s i n growth Stages A (seeding t o . f i r s t flower) and C ( f r u i t set t o r i p e n i n g ) .  S e l e c t i o n was done inivthe F , i n 2 r e c i p r o c a l 3  cross populations, IB and BI. The F progenies from the s e l e c t e d k  plant had means f o r e a r l i n e s s which were intermediate between the parents I and B, w i t h a consistent tendency t o be c l o s e r t o the  125  e a r l i e r parent. f o r the F parents.  5  S e l e c t i o n was continued i n the F , and the means 4  r e c i p r o c a l populations were e a r l i e r than the o r i g i n a l This F  5  response must have r e s u l t e d from favourable recom-  binations o f genes f o r the q u a n t i t a t i v e c h a r a c t e r i s t i c s o f e a r l i n e s s i n the 2 component growth stages o f the o r i g i n a l parents. Further progress i n i n c r e a s i n g the e a r l i n e s s c h a r a c t e r i s t i c should be p o s s i b l e i f f u r t h e r component growth stages are studied and recombinations o f shortest stages are continued, but d i f f e r e n t r e s ponses and r e s u l t s may be influenced by choice o f temperature  126  regimes.  LITERATURE CITED  Ahuja, Y. R. 1968. D i a l l e l a n a l y s i s o f l o c u l e number i n tomato. I and I I . Indian J . Genet. PI. Breeding 28_: 313-331. Alberda, T. "1969. The e f f e c t of low temperature on dry matter production c h l o r o p h y l l concentration and photosynthesis o f maize plants of d i f f e r e n t ages. Acta Bota. Neerl. 18: 39-49. A l l a r d , R. W. 1960. P r i n c i p l e s of plant breeding. Sons, Inc. N.Y. 485 pp.  John Wiley and  A l l a r d , R. W. 1964. Implications o f genotype-environmental i n t e r actions i n a p p l i e d p l a n t breeding. Crop S c i . 4_: 503-508. Alpat'ev, A. V. 1957. P r i n c i p l e s of selecting i n i t i a l material f o r the development o f e a r l y tomatoes through h y b r i d i z a t i o n . Doklady vs€§<§j\WZ^ Akad. S e l j s k . Nauk, 22(6): 3-9. ( c i t e d i n Hort. Abst. 28: 482.) Al-Rawi, K. M. and Kohel, P. J . 1970. Gene a c t i o n i n the i n h e r i t ance o f f i b e r properties i n i n t e r v a r i e t a l d i a l l e l crosses o f upland cotton. Crop S c i . 10_: 82-84. Anand, I . J . and Murty, B. Rl 1969. S e r i a l a n a l y s i s o f combining a b i l i t y i n d i a l l e l and f r a c t i o n a l d i a l l e l crosses i n l i n seed. T h e o r e t i c a l and Applied Genet. 39_: 88-94. Andrasfalvy, A. 1971.' Inheritance of q u a n t i t a t i v e properties o f the tomato studied by d i a l l e l a n a l y s i s , ( i n Hungarian). l^tiEoornHort; BResdiilms;fefrsBudapesiti5822 : 10. ( c i t e d i n PI*::/.. Breeding Abst. 42: 6585) Andrus, C. F. and Bohn,S:G. W. 11967. Cantaloup b r e e d i n g : s h i f t s i n population means and v a r i a b i l i t y under mass s e l e c t i o n . Proc. Amer. Soc. Hort. S c i . 90_: 209-222. Asana, R. D. and Mani, V. S. 1950. Studies i n p h y s i o l o g i c a l analys i s of y i e l d . 1. V a r i e t a l d i f f e r e n c e s i n photosynthesis i n the l e a f , stem and ear o f wheat. P h y s i o l . P l a n t . 3_: 22-29. Ashby, E.  1930. Studies on the i n h e r i t a n c e o f p h y s i o l o g i c a l chara c t e r s . I. A p h y s i o l o g i c a l i n v e s t i g a t i o n o f the nature of h y b r i d v i g o r i n maize. Ann. Bot. 44_: 457-467.  127  Ashby, E.  1 9 3 7 . Studies on the i n h e r i t a n c e o f p h y s i o l o g i c a l characters. I I I . Hybrid v i g o r i n tomatoes. Ann. Bot. 1:. 1 1 - 4 0 .  A s h r i , A.  1 9 6 4 . Intergenic and genic-cytoplasmic i n t e r a c t i o n s a f f e c t i n g growth h a b i t i n peanuts. Genetics 5_0_: 3 6 3 - 3 7 2 .  Askenasy, E. 1 8 8 0 . Uber eine neue methods, urn d i e v e r t h e i l u n g der waschsthumsintensitat i n waehsenden t h e i l e n zu bestimmen. Ver. Naturh-medic. ver. Heidelberg 2_: 7 0 - 1 5 3 . ( c i t e d i n 'Plant Physiology', by E. C. M i l l e r , 1 9 3 8 ) . Beadle, N. C. W. 1 9 3 7 . Studies i n the growth and r e s p i r a t i o n i n tomato f r u i t and t h e i r r e l a t i o n s h i p t o carbohydrate conc e n t r a t i o n . Aust. J . Exp. B i o l . Med. S c i . 15_: 1 7 3 . Beale, G. H. Soc.  1 9 6 6 . The r o l e o f cytoplasm i n h e r e d i t y . Proc. Roy. Ser.  B  164:  209-218.  B e r n i e r , C. C. and Ferguson, A.C. 1 9 6 2 . A study o f the a s s o c i a t i o n between e a r l i n e s s , f r u i t s i z e and e a r l y y i e l d i n determinate tomatoes. Can. J . P I . S c i . 42_: 6 3 5 - 6 4 1 . Berrey, S. Z. X 1 9 6 9 . Germinating response o f the tomato a t high temperature. Hor^Sciehoe, 4:: 2 1 8 - 2 1 9 . L  Bhat, B. K. and Dhawan, N. L. 1 9 7 1 . The r o l e o f cytoplasm i n the manifestation o f q u a n t i t a t i v e characters o f maize. Genetica 42:  165-174.  Bhat, B. K. and Dhawan, N. L. 1 9 7 0 . Cytoplasmic v a r i a t i o n i n geog r a p h i c a l races o f maize and i t s e f f e c t on q u a n t i t a t i v e characters. Indian J . Genet. 3 0 : 4 4 6 - 4 5 0 . ' Bhatt, G. M. 1 9 7 1 . H e t e r o t i c performance and combining a b i l i t y i n . a d i a l l e l cross among s p r i n g wheats. Aust. J . Agr. Res. _22:  350-359.  Bishop, P. M. and Whittingham, C. P. 1 9 6 8 . The photosynthesis o f tomato p l a n t s i n a carbon d i o x i d e enriched atmosphere. Photosynthetica 2 : 3 1 - 6 8 . Bowsell, V. R. 1 9 3 3 . Descriptions o f types o f p r i n c i p a l American v a r i e t i e s o f tomatoes. U. S. Dept. Agr. Misc. Pub. 1 6 0 . Bouquet, A. G. B. 1 9 1 9 . P o l l i n a t i o n o f tomatoes. Sta. B u l l . 1 5 8 .  Ore. Agr. Exp.  Breznev, D. D. and Tagmazjav, I . V. 1 9 6 9 . Photosynthesis and e a r l y expression o f h e t e r o s i s i n tomatoes. Vestn. Sel-hoz. Nauki. 14: 113-120. ( i n Russian) ( c i t e d i n Hort. Abst. 4 0 : 6 4 8 3 ) .  128  Brown, W. L. 1961. A cytoplasiracally inherited abnormality i n maize. Iowa Acad. Sci. Proc. 68_: 90-94. Brun, W. A. and Cooper, R. L. 1967. Effects of l i g h t intensity and CCk concentration on photosynthetic rate of soybean. Crop Sci. ]_: 451-454. Burdick, A. B. 1954. Genetics of heterosis f o r earliness i n .the tomato. Genetics 39_: 488-505. Calvert, A. 1958. Effect of the early environment on development . of flowering i n the tomato. I. Temperature. J . Hort. Sci. 33_: 9-17. Calvert, A. 1959. Effect of the early environment on the develop*. ment of flowering i n tomato. I I . Light and temperature interactions. J . Hort. Sci. 34: 154-162. Calvert, A. 1964. Growth and flowering of the tomato i n relation t o natural l i g h t conditions. J . Hort. Sci. 39_: 182-193. Cannon, 0. S., Gatherum, D. M. and Miles, W. G. 1973. H e r i t a b i l i t y of low temperature seed germination i n tomato. HortS.cience 8_: 404-405. Chang, T. D. and Sadanage, K. 1964. Grosses of s i x ^monosomies- Avena sativa L. with v a r i e t i e s , species and chlorophyll mutants. Crop,Sci. _4: 589-593. Chiang, M. S, 1969. D i a l l e l analysis of the inheritance of quant i t a t i v e characters i n cabbage. Can. J . Genet. Cytol. 11: 103-109. . Clendenning, K. A. 1942. The respiratory and ripening behaviour of the tomato f r u i t on the plants. Can. J . Res. Sec. C. 20: 197-203. Clendenning, K. A. 1948. Growth studies on normal and parthenocarpic tomato f r u i t s . Can. J . Res. Sec. C. 26_: 507-513. Comstock, R. E. and Moll, R. H. 1963. Genotype-environment interaction, i n Hanson and Robinson (eds.) S t a t i s t i c a l genetics and plant breeding. Nat. Acad. Sci. Pub. No. 982. Comstock, R. E. , Robinson, H. F. and Harvey, P. H. 1949. A breeding procedure designed to make maximum use of both general and specific combining a b i l i t y . Agron. J . -4_: 360-367. Cooper, D. C. 1927. Anatomy and development of the tomato flower. Bot. Gaz. 83: 399-411.  129  Cooper, A. J . 1959. Observations on the growth o f the f r u i t on glasshouse tomato p l a n t s between March and September.• J . Hort. S c i . 34: 96-103. C o r b e i l , R. R. 1965. A genetic a n a l y s i s o f maturation i n tomatoes i n terms o f components o f e a r l i n e s s . Diss. Abst. 26B: 2423-2424. C o r b e i l , R. R. and B u t l e r , L. 1965. A genetic a n a l y s i s o f time t o maturity i n a cross between species o f the genus Lycopers i c o n . Can. J . Genet. C y t o l . 7_: 341-348. Cram, W. H. 1952. Hybrid v i g o r o f the Redskin tomato i n r e c i p r o c a l crosses. Proc. Amer. Soc. Hort. S c i . 60: 415-418. Crumpacker, D. W. and A l l a r d , R. W. of heading date i n wheat.  1962. A d i a l l e l cross a n a l y s i s H i l g a r d i a 32: 27-318.  Curme, J . H. 1962. E f f e c t o f low temperature on tomato f r u i t s e t . Campbell Soup Co. P I . S c i . Sym. Proc. p. 99-108. Curme, J . H. • 1968.  (Horticulturist).  Personal cjommunication.  Daubeny, H. A. 1955. Some e f f e c t s o f c o o l temperature on flower production, p o l l e n production and p o l l e n germination i n c e r t a i n l i n e s o f the tomato. M.S.A. Thesis,,Dept. P I . S c i . , Univ. B. C., Vancouver, B. C. Dempsey, W. H. 1969. Temperature e f f e c t s on p o l l e n tube growth and f r u i t s e t i n the tomato. Abst. Paper XI Ihternat. Bot. Congr. Proc. p. 44. Dickson, M. H. 1967. D i a l l e l a n a l y s i s o f seven economic characters i n snap beans. Crop S c i . 7_: 121-124. D i n k e l , D. H. 1966. Tomatoes-varieties and c u l t u r e f o r Alaska greenhouses. Alaska Agr. Exp. Stat B u l l . 38.-' Donald, C. M. 1962. I n search o f y i e l d . 171-178.  J . Aust. Agr. S c i . 28_:  D r i v e r , C. M. 131937. The commercialization o f h y b r i d v i g o r i n the tomato. N. Z. J . A g r i . 55: 352-364. Duggar, B. M. 1913. Lycopersicon, the r e d pigment o f tomato, and the e f f e c t s ox conaitions upon i t s development. Wash. Univ. Studies 1: 22-45. Duncan, W. G. and Hesketh, J . D. 1968. Net photosynthetic r a t e s , r e l a t i v e l e a f growth r a t e s and l e a f numbers of^-twenty-two races o f maize grown a t eight temperatures. Crop S c i . • 8: 670-674.  130  East, E. M.  1936.  Heterosis.  Genetics .21: 375-397.  E a s t i n , J . D. and S u l l i v a n , C. Y. 1969. Carbon-dioxide exchange i n 'compact and semi-open Sorghum inflorescences.. Crop S c i . 9_: 165-166. Eberhart, S. A., Penny, L. H. and Sprague, G. E. 1964. I n t r a - p l o t competition among maize s i n g l e crosses. Crop S c i . 4: 461-471. Ekdahl, T.  1944. Comparative studies i n the physiology of d i p l o i d and t e t r a p l o i d b a r l e y . A r k i v . Bot. 31A: 1-45.  E l Hassan, G. M. 1972. Inheritance studies o f low and h i g h temperature germination o f tomato. Diss.- Abst. 32B: 5631. E l Sayed, M. N. and John, C. A. 1973. H e r i t a b i l i t y studies o f tomato emergence at d i f f e r e n t temperatures. J . Amer. Soc. Hort. S c i . 98_: 440-443. England, F. J . W. - 1968. Competition i n mixtures o f herbage grasses. J . Appl. E c o l . 5_: 227-242. E r i c k s o n , R. 0. and M i c h e l i n i , F. J . Amer. J . Bot. 44: 297-305. Esau, K.  1953. Plant anatomy. 735 pp.  1957.  The plastochron index.  John Wiley and Sons, Inc., N. Y.  Evans, L. T. E. • 1969. C o n t r o l l e d environments i n a n a l y s i s o f phots y n t h e t i c c h a r a c t e r i s t i c s , i n ".Prediction and measurement o f photosynthetic p r o d u c t i v i t y " , p. 421-426., Proc. IBP/OP Tech. Meeting, Trebon. Falconer, D. S. 1967. I n t r o d u c t i o n t o q u a n t i t a t i v e genetics. Ronald Press Co. N. Y. 365 pp. •• ?  F e j e r , S. 0. 1971. - D i a l l e l t e s t s o f competition on e s t a b l i s h i n g forage stands. Veg. Acta Geobotanica 22: 185-199. Fleming, A. A., K o z e i n i c k y , G. M. and Brown, E. B. 1960. Cytoplasmic e f f e c t s on agronomic characters i n i a double-cross maize hybrids. Agr. J . 52: 112-114. " ;  Fogel, H. W. and Currence, T. M. 1950. Inheritance o f f r u i t weight and e a r l i n e s s i n a tomato cross. Genetics'35: 363-380. Forsyth, F. R. and H a l l , I . V. 1965. E f f e c t o f l e a f maturity,tempe r a t u r e , carbon-dixide concentration?and l i g h t i n t e n s i t y on r a t e oft,photosynthesis i n c l o n a l l i n e s o f thee&wbush' bleuberry, Vaccinium 8ah~gustifolium A i t . under l a b o r a t o r y c o n d i t i o n s . Can. J . Bot. 43: 893-900.  131  Gaastra, P. 1962. Photosynthesis o f . leaves ' o f f i e l d crops: J . Agr. S c i . 10: 311-324.  Neth.  Garg, L., H e i c h e l , H. and Musgrave, R. B. 1969. V a r i e t a l d i f f e r ences i n net photosynthesis of Zeanays L. Crop S c i . 9: 483-486. &  Garwood, D. L., Weber, E. J . , Lambert, R. J . and Alexander, D. E. 1970. E f f e c t s o f d i f f e r e n t cytoplasms on o i l , f a t t y a c i d s , plant height and ear h e i g h t i n maize. Crop S c i . 10: 39-41; G i l b e r t , N. 1961. 361-372.  A tomato s e l e c t i o n experiment. .  G i l b e r t , N. E. G. 1958. 12: 477-492.  Genet. Res. 1\ ~  D i a l l e l cross i n p l a n t breeding.  Heredity  G r a f i u s , J . E., Nelson, W. L. and D i r k s , V. A. •.131952. The h e r i t a b i l i t y o f y i e l d o f b a r l e y as measured by e a r l y generation bulked progenies. Agron. J . 44: 253-257. Granick, S. 1965. 911-913.  Cytoplasmic u n i t s o f i n h e r i t a n c e .  Science 147: .  G r i f f i n g , B. 1956a. A generalized treatment o f the use. o f d i a l l e l crosses i n q u a n t i t a t i v e i n h e r i t a n c e . Heredity 10: 31-50. G r i f f i n g , B. 1956b. Concept of - general and s p e c i f i c combining a b i l i t y i n r e l a t i o n t o d i a l l e l c r o s s i n g systems. Aust. J . B i o l . S c i . 9_: 463-493. Groth, B. H. A. 1910. Structure o f tomato s k i n s . Sta. B u l l . 228.  N. J . Agr, Exp.  Gust af son, F. G. and Houghtaling, H. B. 1939. R e l a t i o n between f r u i t s i z e and food supply i n the tomato. P I . P h y s i o l . 14: 321-332 Gustafson, F. G. and S t o l d t , E. • 1936. Some r e l a t i o n s between l e a f area and f r u i t s i z e i n tomatoes. P I . P h y s i o l . 11: 445-451. Halsted, B. D. 1918. 9_: 169-173.  R e c i p r o c a l breeding i n tomatoes.  J . Hered.  Hatcher, Edwin S. J . 1940. Studies i n the i n h e r i t a n c e o f physior l o g i c a l characters.V. Hybrid v i g o r i n the tomato. Part 3, A c r i t i c a l examination o f the r e l a t i o n o f embryo development t o the manifestation o f h y b r i d v i g o r . Ann, Bot. 4: 735-765. Hayes, H. K. and Jones, D. F. 1917. f e r t i l i z a t i o n i n tomatoes. 305-318.  132  The e f f e c t s o f c r o s s - and s e l f Conn. Agr. Exp. S t a . Ann. Rept.  Hayman, B. I . 1954a. The a n a l y s i s o f variance o f d i a l l e l t a b l e s . • Biometrics ..10: 235-244. Hayman, B. I . 1954b. The theory and a n a l y s i s o f d i a l l e l crosses. Genetics 39_: 78-809. Hayman, B. T. X 1957. I n t e r a c t i o n , h e t e r o s i s and d i a l l e l crosses. Genetics 42: 336-355. Hayman, B. I . 1958. The theory and a n a l y s i s o f d i a l l e l crosses I I . Genetics -43_: 63-85. Hayman, B. I . 1960. The theory and a n a l y s i s o f d i a l l e l crosses I I I . Genetics 45_: 155-172. Hayman, B. I . 1963. Notes on d i a l l e l - c r o s s theory, i n Hanson and Robinson (eds.) S t a t i s t i c a l genetics and p l a n t breeding. Nat. Acad. S c i . - Nat. Res. C o u n c i l , Wash. D.C.,. 623 pp. Hazel, L. N. and Lush, J . L. 1942. T h e • e f f i c i e n c y o f three methods of s e l e c t i o n . .J. Hered. 33 :• 393-399. Hesketh, J . D. and Baker, D. 1967. Light.and carbon a s s i m i l a t i o n by p l a n t communities. Crop S c i . 7_: 285-293. Hesketh, J . D. and Moss, Dale N. 1963. V a r i a t i o n i n the response o f photosynthesis t o l i g h t . Crop S c i . 3_: 107-110. Hew, Choy-Sin, Krotkov, G. and Canvin, D. T. 1969. E f f e c t s o f temperature on photosynthesis and CO^ e v o l u t i o n i n l i g h t and darkness by green leaves. P I . Physiol".' 44: 671-677. . Hiesey, W. H. and M i l n e r , H. W. 1965. Physiology o f e c o l o g i c a l races and species. Ann. Rev. PI.-. P h y s i o l . 16_: 203-216. Honma, S., Wittwer, S. H. and Phatak, S. C. 1963. Flowering and e a r l i n e s s i n the tomato. J . Hered. 54_: 212-218. Hornby, C. A. and Charles, W. B. 1962. P o l l e n germination as a f fected by v a r i e t y and number o f p o l l e n grains.- Report o f the Tomato Genet. Coop. 16:. I l l Horner, E. S., Chapman, W. H., Lundy, H. W. and L u t r i c k , M. C. 1972. Commercial u t i l i z a t i o n o f the products o f r e c u r r e n t s e l e c t i o n f o r s p e c i f i c combining a b i l i t y i n maize. Crop S c i . 12: 602-604. Hoyner, T. W. a r i d Lana, E. P. 1956. A.three year study o f general and s p e c i f i c combining a b i l i t y i n tomatoes. Proc. Amer. Soc. Hort. S c i . 69: 378-387.  13 3 :  Houghtaling, H. B, 1935. A developmental a n a l y s i s o f s i z e and shape . i n tomato f r u i t . Torrey Bot. Club B u l l . 62: 242-252. Howlett, F. S. 1936. The e f f e c t o f carbohydrate and o f nitrogen. d e f i c i e n c y upon the microsporogenesis and the development : o f the male gametophyte i n the tomato, Lycopersicon e s c u l entum, M i l l . Ann. B o t . 50: 767-83. "~ 0  Hsu, C. S. and S o s u l a s k i , F. W. 1969. Inheritance o f p r o t e i n content and sedimentation value i n d i a l l e l crosses o f spring wheat. Can. J . Genet. C y t o l . 11: 967-976. H u l l , F. H. 1945. Recurrent s e l e c t i o n f o r s p e c i f i c combining a b i l i t y . Agron.' J . '37: 134-135. Hussey, G. 1963. Growth and development i n the young tomato. I . The e f f e c t o f temperature and l i g h t i n t e n s i t y on growth o f the shoot apex and l e a f primordia. J . Expt. Bot. 14: 316-325. Hussey, G. 1965. Growth and development i n the young tomato. I I I . The e f f e c t o f night andlday temperature on vegatative growth. J . Expt. Bot. 16: 373-385.' I r v i n e , J . E. 1967. Photosynthesis i n sugarcahenyarieties f i e l d conditions. Crop S c i . 7_: 297-300".  under  Izhar, S. and Wallace, D. H. 1967. Studies o f the p h y s i o l o g i c a l basis f o r y i e l d d i f f e r e n c e s . I I I . Genetic v a r i a t i o n i n photosynthetic e f f i c i e n c y o f Phaseolus v u l g a r i s L. Crop S c i . 7_: 457-460. " "' s —  Jennings, P. R. and S h i b l e s , R. M. 1968. Genotypical d i f f e r e n c e s i n photosynthetic c o n t r i b u t i o n o f p l a n t parts t o g r a i n y i e l d i n oats. Crop S c i . 8_: 173-175. J i n k s , J . L. 1954. The a n a l y s i s o f continuous v a r i a t i o n i n a d i a l l e l cross o f N i c o t i a n a r u s t i c a v a r i e t i e s . Genetics 39: 769-788. J i n k s , J . L. 1964. Extrachromosomal i n h e r i t a n c e . Inc., Ehg-rew©'©di C l i f f s , N. J . 177 pp.  Prentice-Hall  v  J i n k s , J . L. and Hayman, B. I . 1953. The a n a l y s i s o f d i a l l e l Maize Genet. Coop. News L e t t e r Vol. 27_: 48-54.  crosses.  J i n k s , J . L., Perkins, J . M. and Gregory, S. R. 1972. The a n a l y s i s and i n t e r p r e t a t i o n o f d i f f e r e n c e s between r e c i p r o c a l crosses of iNicot-iaha^:^ .363-377. Johnson, L. P. V. to plant genetics Council,  1963. A p p l i c a t i o n s o f the d i a l l e l cross techniques breeding, i n Hanson and Robinson (eds.) S t a t i s t i c a l and p l a n t breeding. Nat. Acad. S c i . - Nat. Res. Wash., D. C., 623 pp.,  134  Johnson, L. P. V. /-aiid Aksel,"".Rustem. 1959. Inheritance o f y i e l d i n g capacity i n a f i f t e e n parent d i a l l e l cross o f b a r l e y . Can. J . -Genet. C y t o l . 1: 208-265. :  Judkins, W. P. 1940. Time i n v o l v e d i n p o l l e n tube extension through s t y l e and r a t e o f f r u i t growth i n tomato. Proc. Amer. Soc, Hort. S c i . 37_: 891-894. K a l l i o , A. 1968. Research H o r t i c u l t u r i s t i n Alaska Agr. Exp. S t a . Personal communication. Katsuo, K. and Mizushima, U. 1958. Studies on the cytoplasmic d i f ference among r i c e v a r i e t i e s , Oryza s a t i v a L. 1. On the f e r t i l i t y o f hybrids obtained r e c i p r o c a l l y between c u l t i vated and w i l d v a r i e t i e s . Jap. J . P I . Breeding 8_: 1-5. Kemp, G. A. 1968. Low temperature growth responses o f the tomato. Can. J . P I . S c i . 48: 281-286. Kempthorne, 0. 1956. The theory o f the d i a l l e l c r o s s . 41: 451-459.  Genetics  Kerr, E. A. 1955. . Some f a c t o r s a f f e c t i n g e a r l i n e s s i n the tomato. Can. J . Agr. S c i . 35_: 300. K h a l f - A l l a h , A. M. 1970. Studies o f general and s p e c i f i c combining a b i l i t y o f q u a n t i t a t i v e characters i n tomato. Alex. J. Agr. Res. 18: 207-212. K h a l f - A l l a h , A. M. and P e i r c e , L. C. • 1963. A comparison o f -selection t i o n methods f o r improving e a r l i n e s s , f r u i t s i z e and y i e l d i n the tomato. Proc. Amer. Soc. Hort. S c i . '82_: 414-419. K h a l f - A l l a h , A. M. and P e i r c e , L. C. 1964. The e f f e c t o f sibmating on v a r i a t i o n and s e l e c t i o n o f q u a n t i t a t i v e characters i n tomato. Proc. Amer. Soc. Hort. S c i . 85: 471-477. K h e i r a l l a , A. I . 1961. • Genetic a n a l y s i s o f growth i n tomato. M.ScThesis, Univ. Nottingham, England. K h e i r a l l a , A. I . and Whittington, W. J . 1962. Genetic a n a l y s i s o f growth i n tomato: t h e F, generation.. Ann. Bot. 26: 489-504. ' Kidson, E. B. and Stanton, D. J . 1953. Cloud o r vascular" browning i n tomatoes. I I I . Some observations on leaves and- f r u i t o f cloud-susceptible p l a n t s . N. Z. J . S c i . Tech. 35_: 368. K i r k , J . T. 0. and T i l n e y - B a s s e t t , R. A. E. 1967. Genetic c o n t r o l o f formation o f photosynthetic apparatus, i n " P l a s t i d s " , K i r k and Tilney-Bassett' (eds.) p. 349-367.  135  Koopmans, A. 1959. Changes i n sex i n the flowers o f the h y b r i d Solanum r y b i n i i x S. chacoense. I I I . Data about the r e c i p r o c a l cross S.. chacoense x S. r y b i n i i . Genetica 27: 465-471. Koot, I . J . Van. and R a v e s t i j n , W. Van. 1963. The germination o f tomato p o l l e n on the stigma as an a i d t o the study o f f r u i t s e t t i n g problems. Proc. 16th I n t . Hort. Cohgr. 2_: 452-461. Kotowski, F. 1926. Temperature r e l a t i o n s t o germination o f veget a b l e seeds. Proc. Amer. Soc. Hort. S c i . 23_: 176-184. Kramer, P. J . and Kozlowski, T. T. 1960. Physiology o f t r e e s . McGraw-Hill Co. , N.. Y. 642 pp. Kraus, E. J . and K r a y b i l l , H. R. 1918. Vegetation and.reproduction w i t h s p e c i a l reference t o the tomato. Ore. B u l l . 149. K r i s t o f f e r s e n , Trygve 1963. I n t e r a c t i o n s o f photoperiod and temperature i n growth and development o f young tomato p l a n t s . P h y s i o l . P l a n t . Supplement 1: 1-98. Kronstad, W. E. and Foote, W. H. 1964. General and s p e c i f i c comb i n i n g a b i l i t y estimates i n winter wheat. Crop S c i . 4_: • 616-619. Lake, J . V.  1965. P l a n t and temperature.  S c i . Hort. 17_: 161-166.  Lake, J . V. 1967. The temperature response o f s i n g l e t r u s s tomatoes. J . Hort. S c i . 42: 1-12. Larson, R. E. and Paur, S. 1948. The d e s c r i p t i o n and i n h e r i t a n c e o f a f u n c t i o n a l l y s t e r i l e mutant i n tomato and i t s probable value i n h y b r i d tomato seed production. Proc. Amer. Soc. Hort. S c i . 52_: 355-364. Lawes, D. A. and Treharne, K. J . 1971. V a r i a t i o n i n photosynthetic a c t i v i t y i n c e r e a l s and i t s i m p l i c a t i o n s i n a p l a n t breedi n g programme. I . V a r i a t i o n i n s e e d l i n g leaves and f l a g _ leaves. Euphytica 20_: 86-92. Learner, E. N. and Wittwer, S. H. 1953. Some e f f e c t s o f photoperi o d i c i t y and t h e r m o p e r i o d i c i t y on vegetative growth, floweri n g and f r u i t i n g o f the tomato. Proc. Amer. Soc; Hort. S c i . 61: 373-380. Legg, P. D., C o l l i n s , G. B. and L i t t o n , C. C. 1970. Heterosis and * combining a b i l i t y i n d i a l l e l crosses o f b u r l e y tobacco, N i c o t i a n a tabacum L. Crop S c i . 10: 705-507.  136  Leopold, A. C. and S c o t t , F. I . 1952. P h y s i o l o g i c a l f a c t o r s i n tom.. ato f r u i t set. Amer. J . Bot. 39_: 310-317. :  Levine, R. P. • 1969. The a n a l y s i s o f photosynthesis using mutant s t r a i n s o f algae and high p l a n t s . Ann. Rev. P I . P h y s i o l . 20_: 523-540. Lewis, D.  1953. Some f a c t o r s a f f e c t i n g flower production i n the tomato. J . Hort. S c i . 23_: 207-219.  Lewis, D.  1959. Gene c o n t r o l o f s p e c i f i c i t y and activity:', l o s s by mutation and r e s t o r a t i o n by complementation. Nature 182: 1620-1621.  Lewis J . 1970. Reproductive growth i n Lolium. 1. Evaluation o f genetic d i f f e r e n c e s w i t h i n an'esrablished v a r i e t y by means o f . a d i a l l e l cross. Euphytica 19: 470-479. L i , S. C. and Hornby, C. A. 1972. E f f e c t s o f two temperature r e gimes on v a r i a b i l i t y o f growth staged components i n two tomato c u l t i v a r s and t h e i r F, hybrids. Can. J . P I . S c i . 52: 835-836. 1  Lonquist, J . H. and M c G i l l , D. P. 1959. Performance o f corn synt h e t i c s i n advanced generations of synthesis and a f t e r two c y c l e s o f recurrent s e l e c t i o n . Agron. J . 48: 249-253. L u c k w i l l , L. C. 1939. • Studies i n the i n h e r i t a n c e o f p h y s i o l o g i c a l characters. IV. Hybrid v i g o r i n the tomato. Part 2. Mani f e s t a t i o n s o f h y b r i d v i g o r during the flowering period. Ann. Bot. 1: 379-407. McGinnis, R. C. and Taylor, D. K. 1961. The a s s o c i a t i o n o f a gene f o r c h l o r o p h y l l production i n Avena s a t i v a . Can. J . Genet. C y t o l . 3_: 436-443. . • . '"" MacArther, J . W. and B u t l e r , L. 1938. Size i n h e r i t a n c e and geometric growth processes i n the tomato f r u i t . Genetics 23: 253-268. Machold, 0. 1969. Relations between temperature, i r o n metabolism and c h l o r o p h y l l content i n a mutant o f L. esculentum M i l l . Biologisches Z e n t r a l b a t t . 88_: 681-693. ( c i t e d i n Hort Abst. 40: 6535.) Mallah, G. S., Sahrigy, M. A. and S h e r i f , M. I . 1970, I n t e r s p e c i f i c h y b r i d i z a t i o n i n the Lycopersicon. 1. C o m p a t i b i l i t y r e l a t i o n s and c y t o l o g i c a l behaviour. Alex. J . Agr. Res. 18:- 161-166. Mather, K.  1949. 158 pp.  B i o m e t r i c a l genetics.  137  Dover P u b l i c a t i o n s . N. Y.  Mather, K. 1953. The g e n e t i c a l s t r u c t u r e o f populations. Soc. Exp. B i o l . No. 7, -EvolutioriVp.r66-95• "  Symp.  Mather, K. 1960. Genetics pure and a p p l i e d , ( l e c t u r e s d e l i v e r e d at the John Innes I n s t . ) , P r i n t e d by East Yorkshire P r i n t e r . 15 pp. Mather, K. and J i n k s , J . L. 1971. B i o m e t r i c a l g e n e t i c s . Univ. Press. I t h a c a , N. Y. 382.pp.  Cornell  D. F., Wernsman, E. A. and Ross, H. F. 1971. D i a l l e l -> crosses among bur l e y v a r i e t i e s <&fljggaag^teB&c^ L." in. the £Bpf^:il^gene^aiicSfeV. £&&'&&J^f. 275-279. ''  Matzinger,  J  Meyer, A. and Peacock, N. D. 194-1. Heterosis i n t h e tomato determined by y i e l d . Proc. Amer. Soc. Hort. S c i . 38_:- 576-590. M i c h a e l i s , P. 1954. Cytoplasmic i n h e r i t a n c e i n Epilobium and i t s t h e o r e t i c a l s i g n i f i c a n c e . Adv. Genet. 6_: 287-401. Moore, J . F. and Currence, T. M. 1950. Combining a b i l i t y i n tomato. Minn. Agr. Exp. Sta. Tech. B u l l . 188. MossipoD? ,NH. ,I3:69ketJjabo^ - syntheticeeffdciencyareim photosynthetic p r o d u c t i v i t y " . Trebon. p. 323-330.  photo-' ahdtmeastirement o f . Proc. IBP/OP Tech. Meeting,  Muramoto, H., Hesketh, J . and El-Sharkawy, M. 1965. R e l a t i o n s h i p s among r a t e s o f l e a f area development, photosynthetic r a t e and r a t e o f dry matter production among American c u l t i v a t e d cottons and other species. Crop S c i . 5_: 163-166. Murneek, A. E. 1937. A separation o f c e r t a i n types o f response o f p l a n t s t o photoperiod. Proc. Amer. Soc. Hort. S c i . 34: 507-509. NogutikjYA. iI9411.931nvestigations on photosynthesis o f leaves o f r i c e p l a n t s . Jap. J . Bot. 11: 167-191. Osborne, D. J . and Went, F. W. 1953. C l i m a t i c f a c t o r s i n f l u e n c i n g parthenocarpy and normal f r u i t - s e t i n tomatoes. Bot. Gaz: 114-312-322.; Patterson, Max E.  1970. The r o l e o f r i p e n i n g i n the a f f a i r s o f man.  • BHortSsiencJ;: 5_f:0;3Q-33.  Pearce, R. B., Carlsow, G. E., Barner, D. K., Hart, R. H. and Hanson, C. H. 1969. S p e c i f i c l e a f weight and photosynthesis i n a l f a l f a . Crop S c i . 9: 423-426.  138  Peat, W. E. 196ft'.' An i n v e s t i g a t i o n i n t o the i n h e r i t a n c e o f growth r a t e s i n tomatoes. Ph. D. Thesis, Univ. o f Nottingham, England. Peat, W. E. 1970. Relationships between photosynthesis and l i g h t i n t e n s i t y i n the tomato. Ann. Bot. 34_: 319-328. Peat, W. E. and Whittington, W. J . 1963. Genetic a n a l y s i s o f growth i n tomato;: segregating generation. Ann. Bot. 29:. 725-238. . P e i r c e , L. C. 1968. S e l e c t i o n and s t a b i l i t y o f phenotype i n p l a n t breeding. fS^s^e\ic^^|:5C25 (P2'51. 7  P e i r c e , L. C. and Currence,-T. M. 1959. The e f f i c i e n c y o f s e l e c t i n g f o r e a r l i n e s s , y i e l d and f r u i t s i z e i n a tomato cross. Proc. Amer. Soc. Hort. S c i . 73_: 294-304. Pharr, D. M. and Kattan, A. A. 1971. E f f e c t s o f a i r flow r a t e , storage temperature harvest maturity on r e s p i r a t i o n and r i p e n i n g o f tomato f r u i t s . P I . P h y s i o l . 48:- 53-55. Phatak, S. C. 1966. flowering.  Top and root temperature e f f e c t s o f tomato Proc. Amer. Soc. Hort. S c i . 88_: 527-531.  P i r c h n e r , Franz; 1969. Population genetics i n animal breeding. W. H. Freeman Co., San Francisco. 274 pp. P o l l a c k , B. L. and Larson, R. E. 1956. Factors a f f e c t i n g embryo s i z e , and the i n f l u e n c e o f embryo s i z e on germination, time t o m a t u r i t y , and p r o d u c t i v i t y i n F^ generation tomatoes. Pa. A g r i c . Exp. S t a . B u l l . 606. P o n e l e i t , C. G. and Bauman, L. F. 1970. D i a l l e l a n a l y s i s o f f a t t y acids i n corn o i l . Crop S c i . 10_: 338-341. P o r t e r , A. M. 1937. E f f e c t o f l i g h t i n t e n s i t y on the photosynthetic e f f i c i e n c y o f tomato p l a n t s . P I . P h y s i o l . 12_: 225-251. P p v i l a i t i s , ^ B. 1966. D i a l l e l cross a n a l y s i s .''of''quantitative characters i n tobacco. Can.. 7J. Genet. C y t o l . 8_: 336-346. :  Powers, L., Locke, L. F. and Garret, J . C. 1950. P a r t i t i o n i n g method o f genetic a n a l y s i s a p p l i e d t o q u a n t i t a t i v e characters o f tomato crosses. U. S. Dept. Agr. Tech. Bull. 998. Powers, L. and Lyon, B. 1941. Inheritance studies on d u r a t i o n o f developmental stages i n crosses w i t h i n the genus Lyccpersicon. J . Agr. Res. 63: 129-148. P r e i l , W. and Reimann-Philip, R. 1969. I n v e s t i g a t i o n s on the e f f e c t o f d i f f e r e n t environmental f a c t o r s on the p o l l e n v i a b i l i t y o f tomatoes, e s p e c i a l l y those w i t h h e r e d i t a r y tendencies towards parthenocarpy. . Angewc-s Bot. 4 3 : 175-193. ( c i t e d i n Hort. Abst. 40: 4014).  139  Reynard, G. B.  1968.  (Horticulturist).  Personal communication.  Richardson, G. L. . 1967. Development of photosynthesis i n cotton seedlings (jGossypium hirsutum L. Crop S c i . 7: 6-8. Rick, C. M. 1946. The development of s t e r i l e ovules i n Lycopersicon esculentum M i l l . Amer. J . Bot. 33: 250-256. Robinson, H. F., Comstock, R. E. and Harvey, P. H. 1949. Estimates o f h e r i t a b i l i t y and the degree o f dominance i n corn. Agron. J . 4: 353-359. Robinson, R. W., Mishanec, W. and Shannon, S. 1965. F r u i t s e t t i n g a b i l i t y i n r e l a t i o n t o extreme temperature. Farm Res. 31: 13. Roseribrood, R. W. and Andrew, R. H. 1971. D i a l l e l a n a l y s i s of k e r n e l •'carbohydrate i n sweet corn. Crop S c i . 11: 536-638. Sager, R.  1965. 70-79.  Genes outside the chromosomes.  S c i . Amer. 212(1):  Sando, C. E. 1920. The process of r i p e n i n g i n the tomato considered e s p e c i a l l y from the commercial standpoint. U. S. Dept. Agr. B u l l . 859. Schaible, C. W. 1962. F r u i t s e t t i n g response of tomatoes t o h i g h night temperature. Campbell Soup Co. P I . S c i . Sym. Proc. p. 89-98. Scott, D., Menalda, P. H. and Rowley, J . A. 1970. C0 exhange of p l a n t s . L. Technique and response of seven species t o l i g h t i n t e n s i t y . N. Z. J . Bot. 8: 82-90. 2  Shan|'gina, Z. I . 1961. Causes of y i e l d r e d u c t i o n i n tomato p l a n t s i n s u f f i c i e n t l y i l l u m i n a t e d i n the f o u r t h stage of development. Soviet P I . P h y s i o l . 7: 254-256. Shehata, A. H. and Comstock, V. E. 1971. Heterosis and combining a b i l i t y estimates i n F]_ f l a x populations as i n f l u e n c e d by p l a n t density. Crop S c i . 11: 534-536. Shumaker, J . R., Davis, D. W. and Currence, T. M. 1970. Maternal and genie cytoplasmic d i f f e r e n c e s i n r e c i p r o c a l l y crossed tomatoes. Can. J . Genet. C y t o l . 12: 795-805. Singh, L. and Hadley, H. H. 1972. Mafcernal and cytoplasmic e f f e c t s on seed p r o t e i n content i n soybeans. Crop S c i . 12:'583-585. Singh, M.  1965. Cytoplasmic e f f e c t s on seme agronomic characters i n backcross maize h y b r i d s . Indian J . Genet. 25: 198-207.  140  Singh, M.  1 9 6 6 . Cytoplasmic e f f e c t s on::':, agronomic characters i n maize. Indian J . Genet. 2 6 : 3 8 6 - 3 9 0 .  Smith, 0 .  1 9 3 5 . P o l l i n a t i o n and l i f e h i s t o r y studies of the tomato. C o r n e l l Agr. Exp. Sta. Memoir 18H.  Smith, 0 . and Cochran, H. L. 1 9 3 5 . E f f e c t of temperature on p o l l e n germination and tube growth i n the tomato. C o r n e l l Agr. Exp:;- Sta. Memoir 1 7 5 . Smith, P. G. and M i l l e t t , A. H. 1 9 6 4 . Germinating and sprouting responses o f the tomato a t low temperatures. Proc. Amer. Soc. Hort. S c i . 8 4 : 4 8 0 - 4 8 4 . Sprague, G. F., B r i m h a l l , B. and M i l l e r , PP. AA. 1 9 5 2 . A d d i t i o n a l " , studies o f the r e l a t i v e e f f e c t i v e n e s s of two systems o f s e l e c t i o n f o r o i l content o f the corn k e r n e l . Agronr. J . 44:  329-33.  Sprague, G. F. and Tatum, L. A. 1 9 4 2 . General v s . s p e c i f i c combini n g a b i l i t y i n s i n g l e crosses i n corn. ' J . Amer. Soc. Agron. 34v  923-932.  Stambera, J . and P e t r i c k o v a , R. 1 9 7 0 . The r e s u l t s w i t h studies o f photosynthesis i n the tomato. Acta U n i v e r s i t a t i s Agr. 3rn6,' ' A. 1 8 : 6 3 5 - 6 4 4 . ( c i t e d i n Hort. Abst. 42_: 4 0 9 6 . ) S t e e l , R. G. and T o r r i e , J . H. 1 9 6 0 . P r i n c i p l e s and procedures o f s t a t i s t i c s . McGraw-Hill Book Co. Inc., N. Y. Stoner, K.- and Thompson, A. E. 1 9 6 6 . A d i a l l e l a n a l y s i s o f s o l i d s "in tomatoes. Euphytica 1 5 : 3 7 7 - 3 8 2 . Sweet',,- G. B. and Wareing, P. F. 1 9 6 6 . Role o f p l a n t growth; i n r e g u l a t i n g photosynthesis. Nature 2 1 0 : 7 7 - 7 9 . T a i l i n g , J . L. 1 9 6 1 . Photosynthesis under n a t u r a l c o n d i t i o n s . Ann. Rev. P I . P h y s i o l . 1 2 : 1 3 5 - 1 5 4 . Tomes, M. L. 1 9 6 2 . Temperature i n h i b i t i o n o f carotene synthesis i n tomato.  Bot. Gaz. 1 2 4 : 1 8 0 - 1 8 5 .  Treharne, K. J . and Eagles, C. F. 1 9 7 0 . E f f e c t o f temperature on photosynthetic a c t i v i t y o f cLLmatic races o f D a c t y l i s glomerata L. Photosynthetica 4 : 107-117.. Varhalen, L. M., Morrison, W. C., Al-Rawi, B. A., Fun Kwee-Chong and Murray, J . C. 1 9 7 1 . A d i a l l e l a n a l y s i s o f s e v e r a l agronomic t r a i t s i n upland cotton. Crop. S c i . 1 1 : 9 2 - 9 6 . Verkerk, K. The i n f l u e n c e o f temperature and l i g h t on the tomato. Meded. Div. Tuinb. 1 7 : 6 3 7 - 6 4 7 . ( c i t e d i n Hort.' Abst. 25:  656).  —  141  Walker, J . T. 1969. S e l e c t i o n and q u a n t i t a t i v e characters i n f i e l d crops. B i o l . Rev. 44: 207-243. Walkof, C. 1962. Environmental pressures and e a r l i n e s s o f tomatoes. Report o f 18th Ann. Meeting W. Can. Soc. Hort. p. 49-51. Wallace, D. H. and Munger, H. M. 1966. Studies o f the p h y s i o l o g i c a l b a s i s f o r y i e l d d i f f e r e n c e s . I I . V a r i a t i o n i n dry.^ matter d i s t r i b u t i o n among a e r i a l organs f o r s e v e r a l dry bean v a r i e t i e s . Crop S c i . 6_: 503-507. Wassink, Ev IS. aiL9.45. Experiments oh photosynthesis o f h o r t i c u l t u r a l p l a n t s , w i t h the a i d o f the Warburg method. Enzymologia'-; 12: 33-55. Wedding, R. T. and Vines, H. M. 1959. Temperature e f f e c t s on tomato. C a l i f . Agr. 13: 13-14. Wellington, R. 1922. Comparison o f f i r s t generation tomato crosses and t h e i r parents. Minn. Agr. Sta?: Tech. B u l l . 6. Went, F. W. 1944. P l a n t growth under c o n t r o l l e d conditions. I I I . C o r r e l a t i o n between various p h y s i o l o g i c a l processes and growth i n the tomato p l a n t . Amer. J . Bot. i'3l: 597-618. Went, F. W. 1945. P l a n t growth under c o n t r o l l e d c o n d i t i o n s . IV. Response o f C a l i f o r n i a annuals t o photoperiod and temperature. Amer. J . Bot. _32j 1-12. Went, F. W. 1957. The experimental c o n t r o l o f p l a n t growth. Botanica, Waltham, Mass. 343 pp.  Chronica  Whaley, W. G., 1939a. A developmental a n a l y s i s o f h e t e r o s i s i n Lycopersicon. I . The r e l a t i o n o f growth r a t e t o h e t e r o s i s . .Amer. J . Bot. 26: 609-616. White, H. L. 1930. Carbon dioxide i n r e l a t i o n t o glasshouse crops. V. An a n a l y s i s o f the response o f the tomato crop t o an atmosphere enriched w i t h carbon d i o x i d e . Ann. Appl.BBiol. 17: 755-766. White, T. H. 1918. The p o l l i n a t i o n o f greenhouse tomatoes. Agr. Exp. Sta'. B u l l . 222.  Md.  Whittington, W. J . and F i e r l i n g e r , P. 1972. The genetic c o n t r o l o f time t o germination i n tomato. Amer. Bot. -36: 873-880. Whittington, W. J . , C h i l d s , J . D., H a r t r i d g e , J . M. and How, J . 1965. A n a l y s i s o f v a r i a t i o n i n the r a t e s o f germination:, and";early s e e d l i n g ^ gseedOnng grxawfh>in tomato. Ann. Bot. 29: 59-71.  142  W i l l i a m s , E. J . 1962. The a n a l y s i s f o r competition experiments. Aust. J . B i o l . S c i ; 15: 509-524. W i l l i a m s , W. 1959. Heterosis and genetics o f complex characters. Nature 184: 527-530. Wittwer, S. H. and Aung, L. H. 1969. Lycopersicon esculentum M i l l . i n L.T. Evans (ed.), The i n d u c t i o n o f f l o w e r i n g some case h i s t o r i e s . C o r n e l l Univ. Press. I t h a c a , N. Y. p. 409-423. Yeager, A. F. and Meader, E. 1937. Short cuts i n tomato breeding. Proc. Amer. Soc. Hort. S c i . 35_: 539-540. Young, P. A. 1963. Two way v a r i e t i e s f o r hot o r c o l d c l i m a t e s . Amer. Veg. Grower 11(5): 13. Young, W. A. 1966. A study o f f a c t o r s a f f e c t i n g e a r l i n e s s and mode o f i n h e r i t a n c e o f t h i s character i n the tomato. Lycopers i c o n esculentum. Diss. Abst. 26B: 4159-4160.. Z e l i t c h , I . and Day, P. R. 1973. The e f f e c t o f net photosynthesis on pedigree s e l e c t i o n f o r low and h i g h r a t e s o f photoresp i r a t i o n o f tobacco. P I . P h y s i o l . 52_: 33-37. Z i e l i n s k i , Q. B. 1948. F a s c i a t i o n i n Lycopersicon. • I . Genetic'' a n a l y s i s o f dominance m o d i f i c a t i o n . Genetics 33_: 404-428.  143  APPENDIX  L i s t o f Appendix Tables  Table  Page  1.  Experimental design f o r the greenhouse e x p e r i ment I .  146  2.  Temperature record during the greenhouse e x p e r i ment I . -  146  3.  Experimental design f o r the greenhouse experiment II.  147  4.  Temperature record during the greenhouse e x p e r i ment I I .  147  5.  Experimental design f o r the greenhouse experiment III.  148  6.  Temperature record during the greenhouse e x p e r i ment I I I .  148  7. ;llf©isinplandesigri f o r the f i e l d experiment I .  149  8.  149  :  Experimental design f o r the f i e l d experiment I I . ment I I J . •  1  150  10.  Days required f o r the 7 stages i n the greenhouse experiment I i n the warm regime.  151  11.  Days required f o r the 7 stages i n the greenhouse experiment I i n the c o o l regime.  152  12.  Days required f o r stages 5 and 6 i n the greenhouse experiment I I i n the warm regime.  153  13.  Days r e q u i r e d f o r stages 5 and 6 i n the greenhouse experiment I I i n the c o o l regime.  153  14.  Days required per plastochron i n the greenhouse experiment I I i n the warm regime. .  154  15.  Days required per plastochron i n the greenhouse experiment I I i n the c o o l regime.  154  144  Page  16. 17. 18.  F r u i t weight (g) and f r u i t diameter (mm) i n the greenhouse experiment I I under two temperature regimes.  155  Days required f o r stages i n the greenhouse experiment I I I i n the warm'regime.  156  Days r e q u i r e d f o r stages i n the greenhouse experiment I I I i n the c o o l regime.  157  2 Net photosynthesis r a t e (mg CC^/ dm /hr) i n the growth chamber experiment I I i n the warm regime. 2 20. • Leaf area (cm ) i n the growth chamber experiment I I i n the warm regime. 2 21. Net photosynthesis r a t e (mg CC^/dm /hr) i n the growth chamber experiment I I i n the cool regime. 2 22. Leaf area (cm ) m the growth chamber experiment I I i n the c o o l regime. 23. Days required f o r stages A and C i n the f i e l d e x p e r i ment I , part 1.  19.  24.  Days required f o r stages A and C i n the f i e l d experiment I I .  145  158 158 159 159 160 161  Table 1.  E x p e r i m e n t a l d e s i g n f o r the greenhouse experiment I . Block Block Block Block  T a b l e 2.  1 2 3 4  CB BC B C  BC I CI BC  I IC BC CB  IB CI CB I  C B IB BI  B~ BI I CI  CI C BI B  BI IB IC IB  IC CB C IC  Temperature r e c o r d d u r i n g the greenhouse experiment I . date Oct.26-Nov.3 Nov.3-Nov.10 Nov.10-Nov.17 Nov.17-Nov.24 Nov.24-Dec.l Dec.l-Dec.8 Dec.8-Dec.15 Dec.15-Dec.22 Dec.22-Dec.29 Dec.29-Jan.5 Jan.5-Jan.12 Jan.12-Jan.19 Jan.19-Jan.26 Jan.26-Feb.2 Feb.2-Feb.9 Feb.9-Feb.16 Feb.16-Feb.23 Feb.23-Mar.2 Mar.2-Mar.9 Mar.9-Mar.16 Mar.16-Mar.23 Mar.23-Mar.30 Mar.30-Apr.6 Apr.6-Apr.13 Apr.13-Apr.20 Apr.20-Apr.27  warm  cool  17.2 18.3 17.8 17.2 17.2 17.2 17.2 17.8 17.2 17.2 17.8 17.2 17.2 16.7 16.1 16.1 16.1 16.7 16.7  10.0 10.6 13.3 13.9 13.9 12.8 12.8 12.8 12.8 13.9 13.3 12.8 13.3 12.8 11.7 11.7 11.7 12.8 12.2 12.8 12.8 12.8 12.8 12.8 12.8 12.8  average temperature d a i l y ,  146  C.  T a b l e 3.  E x p e r i m e n t a l d e s i g n f o r the greenhouse experiment I I . Block Block Block Block  T a b l e 4.  1 2 3 4  CI C C CB  B IB •B C  IC I BC I  IB BI CI IB  C B BI BC  CB CB IC B  BI IC I CI  BC BC CB BI  I CI IB IC  Temperature r e c o r d d u r i n g the greenhouse experiment I I . cool 12.8 12.8 12.2 12.2 12.8 12.8 14.4 11.1 13.3 12.2 12.2 12.2 12.2 13.3 12.2 12.2 11.7 11.1 12.2 11.7 13.3 12.8 12.8 12.8  warm 16.7 17.2 17.8 17.8 17.8 17.8 20.0 18.3 17.8 18.9 17.8 18.9 17.8 17.2 17.8 17.2 17.8 17.8 17.8 16.7  date Nov.l-Nov.8 Nov.8-Nov.15 Nov.15-Nov.22 Nov.22-Nov.29 Nov.29-Dec.7 Dec.7-Dec.14 Dec, 14-Dec. 21 Dec. 21-Dec.28 Dec.28-Jan.4 Jan.4-Jan.ll Jan.11-Jan.18 Jan.18-Jan.25 Jan.25-Feb.l Feb.1-Feb.8 Feb.8-Feb.15 Feb.15-Feb.22 Feb.22-Mar.l Mar.1-Mar.8 Mar.8-Mar.15 Mar.15-Mar.22 Mar.22-Mar.29 Mar.29-Apr.5 Apr.5-Apr.12 Apr.12-Apr.19  average temperature d a i l y ,  147  C.  T a b l e 5.  T a b l e 6.  E x p e r i m e n t a l d e s i g n f o r the greenhouse experiment I I I .  Block 1 I B Bl IB  Block 2 I IB Bl B  Block 3 Bl I B IB  Block 4 B Bl I IB  Block 5 IB B I Bl  Block 6 B Bl I IB  Block 7 Bl IB I B  Block 8 I B Bl IB  Block 9 IB I Bl B  Block 10 I Bl B IB  Temperature r e c o r d d u r i n g the greenhouse experiment I I I . date Oct.29-Nov.8 Nov.8-Nov,15 Nov.15-Nov.22 Nov.22-Nov.29 Nov.29-Dec.6 Dec.6-Dec.13 Dec.13-Dec.20 Dec.20-Dec.27 Dec.27-Jan,3 Jan. 3-Jan..10 Jan.10-Jan.17 Jan.17-Jan.24 Jan.24-Jail. 31 Jan.3lTFeb.7 Feb.7-Feb.14 Feb.14-Feb.21 Feb.21-Feb.28 Feb.28-Mar.6 Mar.6-Mar.13 Mar.13-Msr,20 Mar.20-Mar.27 Mar.27-Apr.3 Apr.3-Apr.10 Apr.lO-Apr.17 Apr.17-Apr.24 Apr.24-May.l May 1-May 6  warm 21.1 21.7 20.0 18.3 17.8, 17.8 17.8 17.2 17.2 17.2 17.8 17.2 16.7. 17.2 17.8 17.2 16.1 16.7 16.7  average temperature d a i l y ,  148  cool 15.6 15.6 16.1 12.8 14.4 12.2 13.9 12.2 12.2 12.2 11.7 13.9 11.7 11.1 11.7 12/2 12.2 11.1 12.8 13.9 12.2 13.3 13.3 13.3 12.8 12.8 16.7 C.  Table 7.  Planting plan f o r the f i e l d experiment I.  B  BIF  BIxI  BIxB  Every Table 8. Block  represents one plant  Experimental design for the f i e l d experiment I I .  plant  1 2 3 4 5 1 2 3 4 5  plot 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 O O LO CM rH CO rH rH CM LO VD 1 rH 1 pq 1 LO 1 rH 1 CM M 1 M PM H 1 H 1 H 1 M H M H rH H H rH M pq M  LO CN | H H  OS rH 1 H M  CM CM 1 H H  CO CO 1 H H  CO CO 1 H  VO <M | H  i H H  CO o> CO rH 00 1 1 H rH i rH M M pq  CM CN 1 H H  CO CO 1 H  CO LO 1 M M  O rH 1 H H  CO CO Csl vO LO LO CN CM oo CO VD CM <f rH H 1 1 1 rH 1 1 1 <t 1 CM H H H I H 1 M H H 1 H H H M M H H H H M  O rH 1 H H  O LO 1 rH H  rH LO 1 M  LO CO 1 H M  CO LO CO 00 CM VO 1 CM 1 H 1 rH 1 H H H H  LO CO 1 H M  VD rH 1 H M  CM rH 1 M  rH 1 H M  rH LO 1 M  pq  CO CO OS O LO vO CO U0 00 rH CN CN <f rH CO CN 1 1 1 rH 1 1 1 CO pq i M 1 M H 1 H H H 1 H H H H H H M H H M M  CN | H rH  rH LO 1 M  CN CN 1 H H  LO CO 1 H H  rH rH 1 H  VD rH 1 H H  O LO CO CN LO CM 1 rH 1 1 H 1 rH HH H H M H  LO CN 1 H rH  OOco CD LOinW-iH I I - I I, H H H H - . H  r-i  mpQLn H H H  i  2 3 4 5 1 2 3 4 5 1 2 3 4 5  CO LO 1 H H  O O CO LO rH rH 1 rH 1 pq CO H 1 H PH 1 H H H H H  'I' from IBF ; ' I I ' from BIF 3  149  3  as  CO  PQ H  CM rH 1 H  co,r-H CO . I H  I  PQp'H  CM CMpviCN I I H ',H H i ; H  H  .  zt I H H  O *• CD LO " rH I I H H  H H  CQ  Table 9.  P l a n t i n g plan f o r the f i e l d experiment III.' Line  Rep.  IB;^F  r  every  PM  pq pq  Bl F  H CM n -o-m vor--oo i l l I I l i t  r  L O L O L O L O L O L O L O L O  represents one plant  150  T a b l e 10.  Male parent  B  I  Days r e q u i r e d f o r the 7 stages i n the greenhouse experiment I i n the warm regime.  H4-r  Female p a r e n t I Replicate-  L> C O  B  C  45.6 6.8  1 7.0 8.3 22.6 21.0 6.4 37.0 5.4  2 6.3 8.6 22.3 21.0 6.2 38.1 4.8  3 6.4 8.5 23.4 20.0 6.5 37.2 5.2  4 6.3 8.5 21.4 23.0 6.6 38.4 5.5  3 7.1 11.5 19.0 16.0 711 43.7 5.6  4 6.4 11.5 18.0 19.0 6.5 44.2 5.3 6.0 9.9 18.5 19.0 6.6 38.9 5.0  2 1 3 1 9.5 8.8 8.7 2 • 9.2 9.4 9.1 3 33.8 34.6 31.9 4 21.0 23.0 23.0 5 9.1 9.0 9.3 6 44.8 45.0 43.7 7/2 6.0 •"7,0" 7  4 7.9 9.0 30.0 20.0  1 2 3 4 5 6 7  8.6.  1 7.0 11.7 20.8 19.0 8.5 45.5 5.0  2 6.9 11.5 23.0 17.0 6.7 43.3 5.1  6.5 9.4 22.5 20.0 5.7 41.1 5.3  6.6 9.4 19.5 21.0 6.4 41.0 5.0  7.4 9.0 23.9 23.0 5.2 42.4 5.2  7.6 9.0 18.0 19.0 6.4 37.0 4.7  7.3 8.7 17.3 17.0 6.8 34.2 5.2  6.8 9.2 15.8 19.0 6.0 36.1 4.9  7.5 6.3 6.3 6.7 9.0 L0.2 LO.O 10.1 18.0 19.6 18.8 17.7 19.0 17.0 18.0 17.0 6-:.8 6.8 6.8 6.4 35.9 40.5 40.0 39.8 5.0 4.9 4.9 5.2  1 8.0 6.3 2 9.0 8.5 3 24.2 22.7 4 25.0 20.0 5 8.4 7.5 6 45.5 46.3 7 . 5.0 •5.8  7.6 8.6 20.6 18.0 8.5 46.0 5.3  7.0 8.5 20.0 20.0 7.8 45.7 6.2  6.0 9.8 21.8 17.0 5.6 37.8 4.4  6.4 9.8 19.7 17.0 6.3 39.8 5.1  6.3 11.3 19.2 17.0 6.4 41.2 5.4  7.0 9.9 19.7 17.0 6.5 40.5 4.9  7.3 8.7 20.2 17.0 6.6 38.3 4.8  151  7.8 9.2 22.8 27.0 8.6 45.7 5.1  7.0 9.3 21.7 20.0 6.3 48.3 5.3  7.3 9.1 21.9 23.0 6.7 49.8 5.7  7.5 9.2 21.8 21.0 8.0 48.1 5.4  Table 11. Days required f o r the 7 stages i n the greenhouse experiment I i n the cool regime. Female parent age 1 2 3 4 5 6 7  I  C  1 2 3 4  1 17.9 9.5 38.5 72.0 23.2 62.7 10.0  . Replicate 2 )3 -A 1 •: 2 19.0 18.3 18.7 14.4 15.0 9.2 9.6 9.8 7.6 7.9 37.8 35.4 35.0 25.4 24.1 71.0 70.0 70.0 60.0 58.0 22.6 22.9 23.0 17.3 18.9 64.5 64.7 63.8 46.2 44.5 9.8 9.6 9.9 6.8 7,2  3 (• "4 Ilk ?2*J.'?3., 15.0 15.5 15.9 15.0 14.1 8.6 9.3 10.0 10.0 10.4 23.4 20.7 31.0 29.0 27.6 60.0 59.0 50.0 53.0 54.0 17.2 17.0 18.0 1*8.0 18.2 45.2 44.0 63.8 64.9 65.0 6.7 6.8 7.3 7.0 7.5  'A  14.3 12.1 26.9 54.0 18.1 64.7 7.5  7  15.0 14.7 15.5 15.3 16.7 16.0 16.3 16.3 16.9 16.4 15.1 14.4 9.4 8.5 8.5 8.0 10.0 9.4 9.3 9.3 10.7 11.1 10.7 10.6 23.3 25.1 20.1 24.6 19.5 19.7 21.2 19.8 20.1 19.8 18.9 19.4 49.0 52.0 53.0 51.0 58.0 59.0 58.0 57.0 46.0 50.0 47.0 47.0 18.6 19.0 18.9 18.7 21.0 20.0 20.8 18.119.3 18.9 19.0 18.8 43.2 40.8 42.6 42.9 48.2 48.7 49.5 49.2 59.2 57.6 58.7 56.9 7.6 7.2 7.9 7.5 7.0 6.8 8.2 8.0 9.6 10.0 8.9 10.0  1 2 3 4 5 6 7  17.7 9.4 29.4 52.0 17.8 64.1 7.2  5 6  17.3 7.0 20.8 53.0 18.0 65.0 6.9  15.5 9.6 27.2 52.0 18.1 64.7 7.0  15.0 9.7 27.1 54.0 17.9 65.2 7.3  152  15.9 12.0 19.0 58.0 71.0 58.0 8.6  16.3 11.2 19.1 60.0 18.6 62.0 9.2  15.0 10.9 18.9 57.0 17.8 56.2 8.2  16.0 15.7 10.6 12.2 18.2 28.1 62.0 50.0 18.0117.9 57.8 52.7 9.0 8.1  16.0 12.4 26.9 52.0 18.0 53.2 8.6  14.9 12.4 26.8 54.0 18.6 52.6 8.0  16.4 12.5 24.9 51.0 18.7 53.4 8.4  Table 12.  Male parent  B Stage  "R a  T X  n  Table 13.  Male parent B T  J_  r  Days required for stages 5 and 6 i n the greenhouse experiment I I i n the warm regime.  1  2  3  4  Female parent I Replicate  1  2  3  C  4  1  2  3  4  5 6  8.0 8.0 8.0 8.0 7.0 6.0 6.0 6.0 6.5 6.5 7.0 7.0. 37.0 39.0 40.0 44.0 34.5 33.5 37.0 36.0 41.0 44.5 41.5 43.0  5 6 5 6  6.0 7.0 5.5 6.0 7.0 6.0 6.5 5.5 6.0 7.0 6.0 7.0 33.5 35.0 33.0 36.0 31.0 35.0 32.0 28.0 37.0 35.0 35.0 38.5 8.0 8.5 8.0 7.5 5.5 6.5 7.0 7.0 5.5 7.0 6.0 6.0 41.0 36.5 38.0 39.5 34.5 35.5 39.0 39.0 44.5 42.5 40.5 46.0  Days required f o r stages 5 and 6 i n the greenhouse experiment I I i n the cool regime. Female parent  Stage  5 6 5 6 5 6  I  B  2 1 4 3 7.0 7.0 6.5 6.0 60.0 58.0 56. 5 60. 0 8.0 7.0 8.0 7.0 54.0 54.0 54. 0 55. 0 7.5 9.0 7.0 7.0 63.5 63.0 68. 0 65. 0  Replicate  1 2 8.0 9.0 53.0 48.5 9.0 10.0 51.0 50.5 11.0 10.0 58.0 57.0  153  3 7.5 49.5 9.0 55.5 9.5 59.5  C 1 4 2 3 4 7.0 7.5 9.0 8 .0 7.0 60.062.5 62.0 64 .0 63.0 9.0 11.0 8.5 7.0 8.0 53.056.0 50.0 59 .5 56.0 9.5 7.5 7.5 8.0 7.0 58.555.5 57.0 58 .5 60.0  T a b i e 14.  Male parent  Days r e q u i r e d per p l a s t o c h r o n i n the greenhouse experiment I I i n the warm regime.  Female p a r e n t I Replicate  B Stage  C  1  2  31  4  1  2  3  4  1  2A  4.5  4.4  4.4  4.3  3.7  3.7  3.8  3.7  4.0  4.0  4.1 4.2  I  3.5  3.7  3.7  3.7  3.7  3.8  3.8  3.8  4.1  4.0  4.1 4.1  C  4.0  3.7  4.0  3.8  3.9 .3.7  4.0  4.0  4.0  4.0  4.1 4.2  B  1  T a b l e 15.  3  4  Days r e q u i r e d p e r . p l a s t o c h r o n i n the greenhouse experiment I I i n the c o o l regime.  Female Male parent  parent  Replicate  2;:  B  5.9  5.9  6.0  6.1  5.4  5.9  6.1  6.1  5.4  5.3  5.5 5.6  I  5.4  5.4  5.1  5.3  6.0  5.9  5.9  5.9  5.9  5.9  5.6 5.5  C  5.8  5.7  6.2  6.1  5.9  5.8  5.5  5.7  6.5  6.4  6.0  154  6.1  T a b l e 16,.  F r u i t weight (g) and f r u i t diameter (mm), i n the experiment I I under two temperature regimes.  greenhouse  Temperature warm Line  Block fruit weight  B  I  BI  IB  C  BC  CB  IC  CI  1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4  89.5 102.5 93.5 85.6 22.1 28.4 18.2 18.0 33.3 47.2 43.1 33.5 21.7 37.3 52.9 39.0 47.4 72.6 67.0 120.0 il2.. 1 91.0 100.0 95.3 94.3 111.5 50.3 65.2 25.0 44.3 33.7 48.0 34.2 47.5 31.9 48.5  cool Characteristic s fruit fruit weight diameter  53.5 58.0 56.0 56.0 34.0 36.5 31.5 33.5 40.0 44.5 44.0 39.5 34.0 41.0 48.0 41.0 45.5 51.5 48.5 63.0 59.5 55.0 57.0 57.0 58.0 65.0 44.0 50.0 36.5 42.5 38.0 45.0 40.5 45.0 39.0 45.0  155  195.3 200.2 186.7 227.8 27.0 27.9 26.2 32.8 72.9 44.9 45.6 46.0 57.6 57.5 59.9 75.0 80.5 c 78.5 80.0 78.5 92.6 90.3 , 96.7 86.5 95.0 100.2 101.0 97.3 58.7 49.4 58.0 39.9 63.0 44.9 60.2 52.9  fruit diameter  70.0 76.0 68.0 78.0 37.0 37.5 35.5 40.0 46.0 44.0 45.0 46.8 47.0 48.0 48.0 52.5 53.5 53.0 53.0 52.0 57.0 55.0 58.0 55.0 53.0 58.0 58.0 54.0 49.0 45.0 49.0 41.5 48.0 48.0 49.0 46.0  Table \1.  Days required f o r stages i n the greenhouse experiment I I I i n the warm regime.  Line  B  Stage 1 2 3 4 5 6 7  1 9 8 31 36 7 31 9  2 8 8 32 34 6 32 8  1 2 3 4 5 6 7  8 6 21 25 5 25 6  7 7 20 25  1 2 3 4. 5 6 7 1 2 3 4 5 6 7  I  Bl  Replicate 4 5 3 8 8 8 8 8 8 32 32 33 36 34 326 7 7 31 31 38 9 . 10 8  6 9 8 34 33 8 41 17  7 8 7 33 31 8 35 9  8 8 8 32 31 : 8 35 10  9 8 8 31 31 8 42 7  10 8 8 31 30 7 40 7  6"'.  8 7 19 27 6 29 5  7 7 19 22 8 28 5  7 • 6 18 22 6 29 5  7 6 18 23 7 35 5  7 6 18 22 7 27 7  7 6 19 24 7 38 5  7 7 19 22 7 27 6  7 6 19 31 5 36 6  8 6 25 25 6 41 7  7 7 24 25 8 27 6  8 7 23 26 8 28 5  7 6 25 26 7 30 5  7 7 22 25 7 32 4  7 7 25 24 10 40 7  7 7 24 24 7 32 6  7 7 25 25 6 27 5  7 6 25 24 5 39 5  7 7 25 25 6 30 5  7 7 27 23 6 29' s:  8 8 6 7 27 29 23 24 8 5 27 32 4 44  7 7 27 24 5 30 5  7 7 24 25 6 29 6  7 7 23 24 7 36 5  7 8 28 24 6 28 6  7 7 26 24 7 29 6  7 7 24 24 6 32 6  7 7 25 24 7 30 6  •6  30  c  156  I  Table 18.  Days r e q u i r e d f o r s t a g e s i n the greenhouse experiment I I I i n the c o o l regime.  . Line T  Stage  z  -  Replicates, = v  1 2 3 4 5 6 7  19 •-. 9 28 65 8 59 11  21 9 30 65 10 60 9  20 9 29 66 7 59 11  21 10 30 63 8 59 12  20 11 32 64 11 60 9  20 10 30 64 10 61 8  20 10 34 64 10 61 7  8 20 10 31 66 9 60 9  9 20 9 34 67 11 59 11  10 20 10 34 66 11 59 8  1 2 3 4 5 6 7  18 10 20 49  18 9 18 51 8 53 8  16 9 19 51 11 53 11  16 9 19 50 10 51 10  17 9 20 53 8 53 8  17 8 19 47 10 54 8  17 10 19 47 10 54  17 10 19 55 12 52  17 9 22 51 12 48 13  17 9 18 44 12 47 14  18 9 26 49 8 40 8  18 16 17 8 8 8 9 25 26 24 52 50 51 8 41 41 43 8 9 15  17 8 26 50 10 42 9  17 9 24 50 9 40  17  BI  1 2 3 4 5 6 7  25 49 8 42  17 10 26 50 11 43  17 9 25 56 10 41  17 8 27 50 9 40 10  19  17 8 28 59  18  IB  1 2 3 4 5 6 7  188 28 30 56* 56 8 10 41 38 8 7  18 7 27 57 9 42 9  18 7 29 58 9 42 9 T.  18 8 28 57 10 41 9  18 9 29 57 10 40 10  52  30 58 8 50 7  44 9  18 8 28 58 8 44 7  157  19 28 57 7 49 10  Table 19.  Net photosynthesis rate (ingCC^/dm /Kr) i n the growth, chamber experiment I I i n the warm regime.  Line  11.07 11.09  14.57 15.51 16.23 17.23  11.31 10.94 11.08 10.20  11.88 10.50 11.27 8.78  8 8.40 7.69 8.12 8.97  1 2 3 4  11.61 13.41 12.89 12.96  14.08 15.36 14.20 15.02  5.65 5.91 5.12 7.73  19.15 18.38 20.79 23.47  9.67 8.71 9.88 9.49  1 2 3 4  18.59 16.19 17.54 16.31  15.50 17.30 14.60 18.59  11.71 10.78 11.02 11.24  10.46 12.76 9.13 10.28  8.22 7.94 8.96 8.33  1 2 3 4  17.61 15.59 14.51 17.65  13.97 13.38 14.41 14.21  10.44 8.55 8.74 9.97  6.07 6.99 7.49 9.25  6.75 5.65 6.87 6.56  1 2 3 4  T  i  IB  Bl  Plastochron  Rep.  9.91  10V38  2 Table 20. Leaf area (cm ) i n the growth chamber experiment I I i n the warm regime. Plastochron Rep. Line 8 157 85 161 236 356 1 68 91 151 233 375 2 54 101 142 252 382 3 70 105 162- 249 380 4 51 64 89 152 286 1 50 64 97 174 289 2 52 75 96 175 271 3 49 60 106 155 290 4 46 85 140 247 383 1 39 90 152 226 389 2 144 101 157 249 395 3 IB 43 97 140 238 400 4 49 88 128 259 414 1 43 98 133 250 404 2 51 91 150 239 401 3 Bl 46 .198 148 260 396 4  158  Table  21.  N e t p h o t o s y n t h e s i s r a t e (mgCG^/dm experiment II i n the c o o l regime.  Line  B  I  IB  Bl,  Table  22.  Rep.  1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4  Leaf cool  a r e a (cm ) regime.  Line  Rep.  4  5  9.82 8.93 10.21 10.50 9.40 10.19 8.29 8.29 10.91 11.11. 9.89 12.57 10.13 11.23 9.76 10.10  i n the  /hr)  i n the  Plastochron 6  7.20 8.62 8.93 10.10 9.47 8.51 8.81 9.80 13.60 13.17 12.97 14.11 10.33 9.82 8.02 10.58  growth  growth  7  8  6.32 11.64 5.82 4.42 10.31 6.90 6.75 10.02 4.21 5.28 9.82 5.69 12.50 6.12 9.06 10.84 5.49 8.38 12.17 4.05 6.73 12.07 5.77 7.46 10.25 8.67 4.44 13.02 7.75 3.71 11.43 7.01 5.67 10.50 6.12 5.53 9.56 7.91. 3.02 10.80 6.69 3.72 11.25 9.82 .3.15 11.91 8.30 3.52  chamber  experiment  Plastochron  1 B  I  IB  Bl  3 4 1 2 3 4 1 2 3 4 1 2 3 4  4 64 56 58 52 34 36 33 44 50 46 55 58 69 65 52 54  5 114 116 112 115 88 75 82?. 109 92 95 90 89 88 96 104 106  159  chamber  6 159 176 170 162 112 120 115 116 159 169 140 153 157 13.7 160 168  7 188 186 183 190 153 170 173 165 205 200 195 190 216 218 232 230  8 220 215 209 211 184 192 189 190 246 237 240 245 272 269 275 280  II  in  the  T a b l e 23.  Days r e q u i r e d p a r t 1.  f o r stages A and C i n the f i e l d experiment I ,  Line Stage  A  C  Rep. I  1 2 3 4 5 6 7 8 9 10 11 12  72 70 70 70 70 71 67 69 65 71 64 68  1 2 3 4 5 6 7 8 9 10 11 12  47 46 45 41 41 47 47 52 53 48 50 50  mc air  B  82 82 79 77 81 82 80 80 80 82 82 82 56 56 58 60 58 57 59 62 62 63 63 62  IB)F  74 74 74 74 75 80 74 71 73 73 77 74  53 46 52 54 54 50 54 53 53 53 53 52  1  1  IBxB  BIxB  BI)F  IBxI BIxI  70 69 68 71 68 72 67 71 71 66 69 70  72 77 78 73 73 70 76 71 71 . 77 76 71 77 71 82 72 76 71 76 73 75 74 78 68  82 81 72 79 86 79 79 80 80 83 76 78  51 51 52 50 51 49 52 52 51 50 51 52  47 47 51 47 48 48 48 46 48 49 53 48  50 47 47 50 50 51 52 53 52 49 52 53  52 52 56 56 57 53 59 45 50 54 52 53  55 51 51 59 55 •55 60 54 56 57 57 54  77 75 74 75 76 77 72 74 73 74 71 75  68. 9  160  Table 24.  Days required for stages A and C i n the f i e l d experiment I I .  „. Stage  T  . Line  B I  A  BI  Line  ^ ^^  C  2  3  4  5  74.4  71.8  72.6  a  e  a  n  :  22.2-72.4  1-11 1-12  69.8 72.8 63.6 63.8 73.4 68.2 62.8 68.8 63.8 71.3 63.4 ' " 64.2 68.6 67.6 64.8 64.8 63.4  71.4 69.6 61.8 70.3 62.8 64.4 64.0 67.6 68.6 57.4 67.2 67.4 64.4 66.2 66.0 66.6 69.6 66.2 73.2 72.0 66.0 „ 67.3 67.2 *63.2 66.8 67.4 68.6 68.0 65.8 66.0 66.4 74.2 61.8 62.4  69. 4 70. 4 63. 4 64. 8 64. 2 68. 6 72. 3 64. 8 64. 8 75. 0 v,,.~8 67. " 2 73. 64. 8 68. 6 67. 2 65. 8 58. 6  71. 6 63. 0 62. 4 66. 2 61. 6 68. 2 65. 8 67. 0 62. 6 70. 4 66. 2 " • 0 66.8±6.8 69. 69.0 68. 6 66.0 65. 2 61. 0  54.0 44.8  56.0 47.0  57.8 45.4  55.6 46.8  I- 48 1-51 II-2 II-4 11-10 11-16 11-19 11-22 .11-25 11-33 11-35 11-50 11-53  B _I  IB F  Block 1  N q >  1-11 1-12 T—9 fi  63.6  r  52.2 43.6 48.0 -46.6 T" ' 52.8 50.0 51.6 45.4 51.4 43.8 52.0 '"' ° 41.8 40.6 52.7 43.2 41.2 43.2  63.2  n  63.0  r  49. 8 47. 0 51. 0 . 53. - w 6 ^ 52. 2 55. 0 48. 8 54. 2 54. 4 47. 2 42. w -r-.~0 45.°8 49. 6 45. 6 45. 8 42. 2 46. 2  n  56.4 48.0  51.2 48.4 46.8 -rw.w 47.8 ' "* ° 49.2 54.6 50.4 47.6 51.8 51.2 -.ww 48.6 -rw.w '44.6 ' ^ 42.2 49.0 49.6 49.0 46.6  63.4  51.4 51.8 45.2 -r^.~ 48.8 ' 46.2 47.2 48.9 48.2 46.2 46.4 -r 46.4 -rw.-r /48.0 r» /\ 50.6 46.4 47.4 41.6 43.4  63.4  /  161  r  r n  / r  n  n  63.3+0.5  56.0±3.1 46.4+2.9  49.4 46.6 48.6 -rw.v, ,„ _ - , 47.0 I -I r\ *t —J 48.8 53.4 50.0 45.4 57.4 50.0 -r^. 45.2 -r^.*.^ ,-j - , rn 50.0 47.0 53.0 44.6 44.4 42.8  1—33 1-48 1-51 II-2 II-4 11-10 11-16 11-19 BI F A 11 — 22 11-25 11-33 11-35 11-50 11-53 each datum i s the mean of the 5 plants. r  72.7+1.7  +  +  • *t  7  

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
http://iiif.library.ubc.ca/presentation/dsp.831.1-0093715/manifest

Comment

Related Items