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Some studies on the incidence of blothy ripening in greenhouse tomatoes in British Columbia Matsumoto, Tsutomu 1971

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SOME STUDIES ON THE INCIDENCE OF BLOTHY RIPENING IN: GREENHOUSE TOMATOES IN BRITISH COLUMBIA  TSUTOMU MATSUMOTO B.S.A., Chiba  University,1966  A THESIS SUBMITTED IN .PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE  In the Department of Plant  We accept t h i s t h e s i s t o the r e q u i r e d  THE  Science  as conforming  standard  UNIVERSITY OF BRITISH COLUMBIA JUNE 1 9 7 1  ii  In p r e s e n t i n g  t h i s t h e s i s i n p a r t i a l f u l f i l m e n t of  requirements f o r an advanced degree^at the U n i v e r s i t y B r i t i s h Columbia, I agree t h a t the l y a v a i l a b l e f o r reference  and  the  of  l i b r a r y s h a l l make i t f r e e -  study.  I f u r t h e r agree  that  p e r m i s s i o n f o r e x t e n s i v e copying of t h i s t h e s i s f o r scholarly/ purposes may  be  granted by the;head of my  representatives.  Department or b y h i s  I t I s understood t h a t c o p y i n g or  of t h i s t h e s i s f o r f i n a n c i a l gain s h a l l not my  written  permission.  Department of P l a n t  Science  U n i v e r s i t y of B r i t i s h Columbia Vancouver 8,  June  1971  Canada  publications  be allowed without  iii  ABSTRACT  B l o t c h y r i p e n i n g (BR) of tomatoes i s an i r r e g u l a r r i p e n i n g of tomato f r u i t s .  T h i s world-wide d i s o r d e r has been a problem  o f the s p r i n g c r o p , , p a r t i c u l a r l y d u r i n g the l a t e r p a r t of l n greenhouse tomatoes i n B r i t i s h  May,  ;  Columbia.  F o r the i n v e s t i g a t i o n of the f a c t o r s which a f f e c t the occurrence  of BR i n B.C.,-the  f o l l o w i n g were  consideredi=  C o r r e l a t i o n between the hours of b r i g h t sunshine and the i n c i d e n c e of BR, the i n f l u e n c e ' O f weekly a l t e r n a t i o n of l i g h t and temper a t u r e c o n d i t i o n s on the i n c i d e n c e of BR,  and  the a s s o c i a t i o n of the i n c i d e n c e of BR and v i r u s d i s e a s e s . Examination of weather r e c o r d s l e d t o a was t e s t e d i n growth chambers.  hypothesis;_whichi  The l i g h t regimes employed  c o n s i s t e d of a h i g h and a low l i g h t c o n d i t i o n .  Concurrently  two temperature regimes,were used, one w i t h a h i g h maximumtemperature and the other with a low maximum temperature. Both regimes employed  the same minimum temperature.  The r e s u l t s of the s t u d i e s were as f o l l o w s J The c y c l i c  occurrence  of sunny weeks and cloudy weeks  was a s s o c i a t e d with the i n c i d e n c e of BR i n the B.C.  greenhouse  tomatoes. The weekly a l t e r n a t i o n of the l i g h t  c o n d i t i o n s produced  37$ BR f r u i t s when the.-.plants were s u b j e c t e d t o a constant  day-  iv n i g h t temperature c y c l e , but only 11% BR f r u i t s , 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 6% BR i n the c o n t r o l , was  produced  when the temperature c o n d i t i o n s were a l t e r n a t e d s i m u l t a n e o u s l y and d i r e c t l y w i t h l i g h t  regimes  The r o l e of tobacco mosaic v i r u s (TMV)  on the Incidence  of BR i n the B.C. greenhouse.itomatoes d i d not appear t o be important. The e f f e c t of p o t a t o v i r u s (PVX) on the i n c i d e n c e of BR was not c l e a r .  V CONTENTS Page INTRODUCTION.  1  REVIEW OF LITERATURE  3  I n f l u e n c e of l i g h t I n f l u e n c e of temperature I n f l u e n c e of humidity I n f l u e n c e of s o i l moisture I n f l u e n c e of potassium Influence,;of n i t r o g e n I n f l u e n c e of phosphorus I n f l u e n c e of o t h e r m i n e r a l s I n f l u e n c e of d e f o l i a t i o n I n f l u e n c e of v a r i e t y I n f l u e n c e of growth r e g u l a t o r s I n f l u e n c e of seed d e n s i t y I n f l u e n c e of tobacco mosaic v i r u s (TMV) I n f l u e n c e of b a c t e r i a Chemical nature of BR MATERIALS AND  •  b 5 6 7 7 8 9 9 10 11 11 11 12 13 lh  METHODS  1.  C o r r e l a t i o n between hours of b r i g h t sunshine and the i n c i d e n c e of BR 17 Data sources 17 CalculationsftofIlinear regressions 17 S i g n i f i c a n c e of temperature l n r e l a t i o n t o b r i g h t sunshine 20 Comparison of the i n c i d e n c e of BR on Vancouver I s l a n d and Lower Mainland i n 1969 21  2.  The i n f l u e n c e of weekly a l t e r n a t i o n of l i g h t and temperature c o n d i t i o n s on the i n c i d e n c e of BR 21 P l a n t growing 21 Temperatures 22 Light 22 Combination treatments ....... 2k F r u i t harvesting 27  3.  A s s o c i a t i o n of BR of greenhouse tomatoes and tobacco mosaic v i r u s (TMV) i n B r i t i s h Columbia i n 1969 27 A s s o c i a t i o n of BR and t o t a t o v i r u s (PVX)  ..  28  vi  RESULTS 1.  Page C o r r e l a t i o n between hours of b r i g h t sunshine and the i n c i d e n c e of BR L i n e a r r e g r e s s i o n s between the Incidence of BR and the hours of b r i g h t sunshine S i g n i f i c a n c e of temperature i n r e l a t i o n t o b r i g h t sunshine Comparison of the I n c i d e n c e of BR on Vancouver I s l a n d and Lower Mainland  2.  The i n f l u e n c e of weekly a l t e r n a t i o n of l i g h t and temperature c o n d i t i o n s on the i n c i d e n c e of BR ..  3»  Association  Association  30 36 36 43  of BR of greenhouse tomatoes and  tobacco mosaic v i r u s (TMV) i n B r i t i s h Columbia 4.  30  ..  54 54  of BR and p o t a t o v i r u s (PVX)  DISCUSSION 1. C o r r e l a t i o n between hours o f b r i g h t sunshine and the i n c i d e n c e of BR  6l  2.  The i n f l u e n c e of weekly a l t e r n a t i o n of l i g h t and temperature c o n d i t i o n s on the i n c i d e n c e of BR ..  64  3.  A s s o c i a t i o n o f BR of greenhouse tomatoes and tobacco mosaic v i r u s (TMV) i n B r i t i s h Columbia i n 1969  76  Association  78  4.  ofBR and p o t a t o v i r u s  (PVX)  SUMMARY AND CONCLUSION'  ,  80  LITERATURE CITED  ,j  82  APPENDIX  88  vii L I S T OP TABLES Table 1 2 3  4  5  6  7  8  *  Page S e v e r i t y o f BB a s r e c o r d e d i n B r i t i s h f o r s p r i n g greenhouse tomato c r o p s Treatment regimes o f l i g h t combinations  Columbia  and t e m p e r a t u r e  18 26  H o u r s o f b r i g h t s u n s h i n e i n TOTAL* and FLUTO* f o r a g i v e n week o f 12 c a s e s i n T a b l e 1  31  C o e f f i c i e n t of determination (ir ) of l i n e a r r e g r e s s i o n o f t h e i n c i d e n c e o f BR on t o t a l h o u r s o f b r i g h t s u n s h i n e f o r weeks ( T O T A L ) , , o r accumul a t e d d i f f e r e n c e s i n hours o f b r i g h t sunshine b e t w e e n c o n s e c u t i v e d a y s f o r a week (FLUTO)  32  C o e f f i c i e n t of determination ( r ) of l i n e a r r e g r e s s i o n o f t h e i n c i d e n c e o f BR on t o t a l h o u r s o f b r i g h t s u n s h i n e f o r weeks (TOTAL)}, o r on accumul a t e d d i f f e r e n c e s l n hours o f b r i g h t sunshine between c o n s e c u t i v e d a y s f o r weeks (FLUTO)  33  C o e f f i c i e n t of determination ( r ) of l i n e a r r e g r e s s i o n o f t h e i n c i d e n c e o f BR on h o u r s o f b r i g h t s u n s h i n e f o r a c o m b i n a t i o n o f weeks ( T O T A L ) , o r on a c c u m u l a t e d d i f f e r e n c e s l n h o u r s o f b r i g h t sunshine between c o n s e c u t i v e days f o r a c o m b i n a t i o n o f weeks (FLUTO)  Jk  C o e f f i c i e n t of determination ( r ) of l i n e a r r e g r e s s i o n o f t h e i n c i d e n c e o f BR on t o t a l h o u r s o f b r i g h t s u n s h i n e o f t h e week whose v a l u e o f t h a t was amaximum i n t h e weeks o f a g i v e n p e r i o d ( T O T A L ) , o r on t h e a c c u m u l a t e d d i f f e r e n c e s i n h o u r s o f b r i g h t s u n s h i n e between c o n s e c u t i v e days f o r a week whose v a l u e o f t h a t was a maximum i n t h e weeks o f a g i v e n p e r i o d (FLUTO)  35  C o e f f i c i e n t of determination ( r ) of l i n e a r r e g r e s s i o n o f t h e I n c i d e n c e o f BR on t o t a l h o u r s o f b r i g h t s u n s h i n e o f t h e week whose v a l u e o f t h a t was a maximum in>;the weeks o f a g i v e n p e r i o d (TOTAL),, o r on t h e a c c u m u l a t e d d i f f e r e n c e i n h o u r s o f b r i g h t s u n s h i n e b e t w e e n c o n s e c u t i v e d a y s f o r t h e week whose v a l u e o f t h a t was a minimum I n t h e weeks o f a g i v e n p e r i o d (FLUTO)  37?  2  2  2  2  2  See page 20  f o r d e f i n i t i o n s o f TOTAL and FLUTO  viii Table 9  10  11  12  13  14  15  16  Page C o e f f i c i e n t of d e t e r m i n a t i o n ( r ) of l i n e a r r e g r e s s i o n of the i n c i d e n c e of BR and weeklyd i f f e r e n c e s of t o t a l hours of b r i g h t sunshine (TOTAL), or on weekly d i f f e r e n c e s of accumulated d i f f e r e n c e s i n the hours of b r i g h t sunshine between c o n s e c u t i v e days  3"  C o e f f i c i e n t of d e t e r m i n a t i o n ( r ) of l i n e a r r e g r e s s i o n of the Incidence of BR on the maximum of weekly d i f f e r e n c e s of t o t a l hours of b r i g h t sunshine f o r g i v e n weeks (TOTAL), or on the maximum i n the hours of b r i g h t sunshine between cons e c u t i v e days f o r g i v e n weeks (PLUTO)  39  C o e f f i c i e n t of d e t e r m i n a t i o n ( r ) of l i n e a r r e g r e s s i o n of the i n c i d e n c e of BR on the minimum of weekly d i f f e r e n c e s of t o t a l hours of b r i g h t sunshine f o r g i v e n weeks (TOTAL),, or on the m i n i mum of weekly d i f f e r e n c e s of accumulated d i f f e r e n c e i n the hours of b r i g h t sunshine between c o n s e c u t i v e days of g i v e n weeks (FLUTO)  40  The s i g n i f i c a n t l i n e a r r e g r e s s i o n of the s e v e r i t y of the i n c i d e n c e of BR on hours of b r i g h t sunshine  41  C o e f f i c i e n t of d e t e r m i n a t i o n ( r ) of l i n e a r r e g r e s s i o n of the i n c i d e n c e of BR on accumulated maximum or minimum temperatures f o r c e r t a i n comb i n a t i o n s of g i v e n weeks (TOTAL), or on accumulated d i f f e r e n c e s i n maximum o r minimum temperatures f o r c e r t a i n combinations of g i v e n weeks (FLUTO)  42  Comparison of the i n c i d e n c e of BR on Vancouver I s l a n d (ISL) and Lower Mainland (LM) d u r i n g the p e r i o d of May 14-20, 1969  44  C o e f f i c i e n t of d e t e r m i n a t i o n ( r ) of l i n e a r r e g r e s s i o n of the i n c i d e n c e of BR and accumulated l a r g e s t f o u r d i f f e r e n c e s i n .hours of b r i g h t sun•shine between c o n s e c u t i v e days f o r a week, or i t s combinations f o r three weeks  46  The i n f l u e n c e of weekly a l t e r n a t i o n of l i g h t and temperature c o n d i t i o n s on the I n c i d e n c e of BR, expressed as a number of BR f r u i t s over t o t a l f r u i t s harvested  49  2  2  2  2  2  17  The i n f l u e n c e of weekly a l t e r n a t i o n of l i g h t and temperature c o n d i t i o n s on the i n c i d e n c e o f BH I n percentage  18  The I n f l u e n c e of weekly a l t e r n a t i o n of l i g h t and temperature c o n d i t i o n s on t h e y y i e l d s of tomato crops i n grams p e r p l a n t  19  The i n f l u e n c e of weekly a l t e r n a t i o n of l i g h t and temperature c o n d i t i o n s on the f r u i t s i z e i n grams as average f r u i t weight w i t h i n a p l a n t ...  20  The i n f l u e n c e of weekly a l t e r n a t i o n of l i g h t and temperature c o n d i t i o n s on the number of f r u i t s per p l a n t  21  A s s o c i a t i o n of tobacco mosaic v i r u s (TMV) w i t h BR f r u i t s i n commercial crops of greenhouse tomatoes i n 1 9 6 9 ,  22  Results  of t - t e s t on v a r i o u s  comparison of  the d a t a l n Table 2 1 23  Presence of TMV i n f r u i t , l e a f , o r l n both  2k  The i n f l u e n c e of potato v i r u s X (PVX) on the inoidenceo-of BR The i n f l u e n c e of PVX on t o t a l f r u i t weight, p e r plant  25 26  The i n f l u e n c e of PVX on average f r u i t weight within a plant  27  The c y c l i c occurrence of BR with l i g h t a l t e r n a t e d weekly  conditions  X  LIST OF FIGURES F i gure 1  2  3  b 5  Page D a i l y temperature changes i n the growth chambers used f o r the BR experiments: (A) r e p r e s e n t s the temperature changes on sunny-day, and (B) r e p r e sents the cloudy-day  23  D a i l y l i g h t regimes f o r the c o n t r a s t i n g l i g h t treatment used i n the BR experiments» (A) employed the h i g h l i g h t i n t e n s i t y f o r one h a l f of the p h o t o p e r i o d r e p r e s e n t i n g a cloudy day, (B) employed the h i g h l i g h t f o r the e n t i r e photoperiod r e p r e s e n t i n g a sunny day  25  Hours of b r i g h t sunshine on Vancouver I s l a n d and Lower Mainland, B r i t i s h Columbia, f o r the s p r i n g (March 1 t o May 31) 1969  *+5  E x t e r n a l and i n t e r n a l symptoms of BR with v a r i o u s degrees of s e v e r i t y  ^8  fruits  The r e g r e s s i o n e q u a t i o n used f o r d e v e l o p i n g the hypothesis  66  6  Schematic f i g u r e of l i g h t treatment i n TcLa and TaLa c o n d i t i o n s  66  7  Hours of b r i g h t sunshine t o which the p l a n t s were exposed b e f o r e b e i n g put i n chambers and c o r r e s p o n d i n g expected hours of b r i g h t sunshine f o r the p r o d u c t i o n of BR f r u i t s  70  xi ACKNOWLEDGEMENTS The  author wishes t o express h i s s i n c e r e  appreciation:  to Dr. C. A. Hornby f o r s u g g e s t i n g the problem and f o r h i s guidance, c r i t i c i s m , and patience during'.the p r e p a r a t i o n of this thesis. Gratitude  i s a l s o due t o Dr. R. Stace-Smith, Canada  Department o f A g r i c u l t u r e Research S t a t i o n , Vancouver, f o r h i s help i n v i r u s assay. The Dr.  h e l p f u l a d v i c e from the other members of the committee,  G. W. Eaton, Dr. S. Nakai, and Dr. V. C. Runeckles, was  greatly  appreciated.  Gratitude  i s a l s o extended t o Dr. L.N. K o s k i t a l o  t e c h n i c a l help i n o p e r a t i n g  for his  growth chambers, and a l s o f o r h i s  p e r m i s s i o n t o use h i s unpublished experimental r e s u l t s . S p e c i a l thanks are due f o r many h e l p f u l c o n t r i b u t i o n s of the Canada Department of A g r i c u l t u r e Research S t a t i o n , Saanichton, and the B r i t i s h Columbia Department o f A g r i c u l t u r e , e s p e c i a l l y the l a t t e r f o r f i n a n c i n g the r e s e a r c h , the  and a r r a n g i n g  survey of tobacco mosaic v i r u s i n the commercial greenhouse  tomato c r o p s .  1  INTRODUCTION. Blotchy not a l l ,  r i p e n i n g of tomatoes i s a problem i n most, i f  p a r t s of the world where tomatoes.are grown.  This  c o n d i t i o n i s an i r r e g u l a r r i p e n i n g or t i s s u e d i s c o l o r a t i o n of tomato f r u i t s , and many d i f f e r e n t names have been used to d e s i g n a t e the d i s o r d e r ; (Bewley and 194-9),  namely, b l o t c h y  r i p e n i n g or  BR  White 1 9 2 6 ) , i n t e r n a l browning or IB (Haensler  gray w a l l (Lorenz and  Knott 194-1), cloud  (Kldson  and  Stanton 1 9 5 3 ) and. v a s c u l a r browning ( o n o v e r 194-9).  As a l l  these names imply, symptoms of BR may  One  c  be v a r i a b l e .  simi-  l a r i t y i n a l l cases, however, i s t h a t a p a r t or p a r t s of outer f r u i t  w a l l are  the  i s red.  surface  the  green, y e l l o w or gray while the r e s t of There may  a l s o be a breakdown of  pericarp  t i s s u e adjacent to v a s c u l a r bundles which i s r e a d i l y seen when a blotchy  a r e a i s cut t r a n s v e r s e l y .  c l a s s i f i c a t i o n of BR Minges  A distinctive l i s t  symptoms were developed by Sadik  and  and  (1966).  Many f a c t o r s I n c l u d i n g environment, c u l t u r a l methods,  and  pathogens, e s p e c i a l l y tobacco mosaic ^ t r u s , have been shown t o be r e l a t e d to the  incidence  of the d i s o r d e r .  Frequently  experimental r e s u l t s have been c o n t r a d i c t o r y . The  occurrence of BR  i n B r i t i s h Columbia has  been a  problem f o r greenhouse tomato growers f o r the l a s t ten T h i s BR  i s u s u a l l y accompanied with n e c r o t i c t i s s u e I n t h e -  s p r i n g grop, and,mos.tly i n the  l a t t e r p a r t of May.  a l s o annual f l u c t u a t i o n i n the BR c u l t u r a l p r a c t i c e s used i n B?.C. the past  years.  several  years.  incidencej  There Is  however, the  have been very s i m i l a r f o r  The BB s i t u a t i o n In B r i t i s h Columbia  warranted the study  o f , 1 ) the i n f l u e n c e of weather, p a r t i c u l a r l y l i g h t , i n terms of hours of b r i g h t sunshine, on i n c i d e n c e of BR,  and 2) the  r e l a t i o n s h i p of TMV  t o the i n c i d e n c e oof BR i n the p r o v i n c e .  The f i r s t  intended t o be a s y s t e m a t i c examination  study was  of m e t e o r o l o g i c a l d a t a t o develop a h y p o t h e s i s which i n t u r n could be t e s t e d i n c o n t r o l l e d environment second study was  chambers.  intended t o a s c e r t a i n the importance  as a component of the BR problem  in British  Columbia.  The of  TMV  3  REVIEW 0? LITERATURE A l a r g e "body o f l l t e r a t u r e has r e p o r t >on b l o t c h y r i p e n i n g (BR) the d i f f i c u l t i e s In reviewing the terminology employed. t o c l a r i f y the v a r i o u s  accumulated s i n c e the  of tomatoes i n 1921.  Initial  One  of  the l i t e r a t u r e on the d i s o r d e r  Sadlk and  observations  (1966)  Mlnges  and  defined  Included, l n the b l o t c h y r i p e n i n g d i s o r d e r .  the  Is  attempted symptoms  They presented  the f o l l o w i n g c l a s s i f i c a t i o n s } A.  I n t e r n a l symptoms  1.  White t i s s u e  c h a r a c t e r i z e d by the presence of  areas which were o f f - c o l o u r e d , l l g n i f l e d , hardened, and s t a r c h , and gas 2.  a l s o contained  (Sadlk and  Mlnges  1966).  r e s u l t e d from the  parenchyma c e l l w a l l s and  B.  an abundance of  what Is r e f e r r e d to as an unknown  Brown t i s s u e  and  and  lignification  t h e i r ultimate  of  breakdown  browning.  E x t e r n a l symptoms 1.  B l o t c h , with or without brown t i s s u e .  2.  Y e l l o w or green  3.  Subsurface y e l l o w i n g  shoulder. or s t r e a k s or l a r g e d i s c o l o r e d  patches. 4. The  Yellowing  around the a b s c i s s i o n zone.  above l i s t  excludes I n t e r n a l browning (IB) which i s  induced by s t r a i n s of tabacco mosaic v i r u s (TMV). browning both i n BR  and  IB i s very s i m i l a r and  to make a d i s t i n c t i o n between the two Sadik and.Minges I 9 6 6 ) .  The  tissue  i t is difficult  cases (Murakishl  I960,  P r i o r to the work of Boyle and  Wharton  ( 1 9 5 6 ) , who f i r s t r e p o r t e d the r e p r o d u c t i o n of IB symptoms by l a t e I n o c u l a t i o n of p l a n t s w i t h TMV, there i s no mention of the presence of TMV i n p l a n t s producing BR f r u i t .  Thus i n  much of the l i t e r a t u r e i t i s i m p o s s i b l e t o know whether the d i s o r d e r was caused by TMV i n f e c t i o n or by p h y s i o l o g i c a l or non-pathogenic  causes.  In the f o l l o w i n g review the d i s o r d e r w i l l be c a l l e d by the names which appeared i n the l i t e r a t u r e under  review.  Although IB i s t r e a t e d as a d i f f e r e n t d i s e a s e i n some of the l i t e r a t u r e , i t i s i n c l u d e d i n the present review because the I F symptoms are very s i m i l a r t o those of BR;  hence IB i s  regarded as p a r t of the BR problem. I n f l u e n c e of l i g h t Observations of annual v a r i a t i o n i n the i n c i d e n c e of BR from 1921-5 i n B r i t a i n , l e d Bewley and White (1926) t o suggest c l i m a t e , e s p e c i a l l y s u n l i g h t , as the c a u s a l agent.  White  (1938) r e p o r t e d a c o r r e l a t i o n c o e f f i c i e n t of - 0 . 8 0 3 (p=0.03) between the i n c i d e n c e of BR and the accumulated of b r i g h t s u n l i g h t over a five^month p e r i o d .  t o t a l of hours D u r i n g the same  p e r i o d the c o r r e l a t i o n o f maximum temperature and BR.vwas only 0.3^6.  C l a r k e (19^4) noted i n a comparison of two seasons,  t h a t the lower Incidence of BR was a s s o c i a t e d w i t h the season having the g r e a t e r t o t a l sunshine.  Kidson and Stanton (1953')-  r e p o r t e d t h a t the i n c i d e n c e of " c l o u d " v a r i e d c o n s i d e r a b l y from season t o season under s i m i l a r c u l t u r a l  conditions.  Cooper (1956) s t a t e d i n h i s review of l i t e r a t u r e t h a t there was g e n e r a l agreement t h a t BR had a pronounced  seasonal v a r i a t i o n  5 and suggested that more d e t a i l e d i n v e s t i g a t i o n o f the cause of the s e a s o n a l e f f e c t would be of c o n s i d e r a b l e v a l u e . Kldson (1956) suggested t h a t shade and h i g h humidity were " c l o u d " inducingj'f a c t o r s , although h i g h humidity might not be harmful p r o v i d e d there was adequate Dennlson  (1955)  light.  H a l l and.  r e p o r t e d shading t o be a c o n t r i b u t i n g f a c t o r Murakishi (1959i  i n the occurrence of v a s c u l a r browning.  1960a) r e p o r t e d t h a t the e f f e c t of low l i g h t i n t e n s i t y , was t o Increase the i n c i d e n c e of "gray w a l l " . In  c o n t r a s t t o the above, Woods (1963b) o b t a i n e d l i m i t e d  evidence t h a t shading was e f f e c t i v e i n r e d u c i n g BR. a l (1964) experimenting with l i g h t , temperature  Cooper e t  and water  supply, concluded t h a t "shading the glasshouses reduced the p r o p o r t i o n of non-unlformly c o l o r e d f r u i t a t the h i g h temper a t u r e ( 2 6 . 5 C;).  At the low temperature  (18.3 C ) , shading  reduced the p r o p o r t i o n i n i 9 6 0 but t h e r e was no e f f e c t Irr 1959". for  C o l l i n e t a l (1965) manipulated  t e n day p e r i o d s from f l o w e r i n g t i l l  l i g h t and temperature fruit  r i p e n i n g , but  none of the treatments was e f f e c t i v e i n changing the i n c i d e n c e of  BR.  I n f l u e n c e of temperature Seaton  (1933) determined  the weekly accumulated  degree  hours over a base of ?0 C a n d compared these v a l u e s with the weekly percentage o f b l o t c h y f r u i t . tage of b l o t c h y f r u i t  He found t h a t the p e r c e n -  f o l l o w e d c l o s e l y the v a r i a t i o n s l n the  weekly excess temperature,  but there was a l a g o f approximately  one week between the i n f l u e n c e of temperature ance of b l o t c h y f r u i t .  and the appear-  Lorenz and Knott (1941) r e p o r t e d  6 t h a t "gray  w a l l " was due t o the p a r t i a l d e s i c c a t i o n of the  f r u i t w a l l caused by the high temperature r e s u l t i n g from direct  sunshine. Jones and Alexander ( 1 9 5 6 ) r e p o r t e d t h a t the number of  b l o t c h y f r u i t s decreased  w h e n p l a n t s were subjected t o low  temperature f o l l o w e d by high temperature.  Under o r d i n a r y  temperature c o n d i t i o n s t h i s c o r r e l a t i o n d i d not h o l d . Woods (I965)  reported  t h a t there was no c o n s i s t e n t - e f f e c t 1  of temperature on g r e e n - b l o t c h , u n a f f e c t e d by temperature.  and that y e l l o w b l o t c h was  C o l l i n e_t a l (I965)  subjected  tomato p l a n t s t o t e n day p e r i o d s a t 50 P o r ?0 F from the f l o w e r i n g stage u n t i l f r u i t r i p e n i n g , but none of these  treat-  ments sug&eeded i n changing the i n c i d e n c e of BB o r IB.  Lingle  et a l (I965)  r e p o r t e d a h i g h i n c i d e n c e i n a growth chamber  where n i g h t temperatures were low and n i t r o g e n l e v e l normals  was  whereas only one or two BR f r u i t appeared on low  n i t r o g e n p l a n t s r e g a r d l e s s of n i g h t  temperature.  I n f l u e n c e of humidity H a l l and Dennlson (1955) i n an experiment with shade, m i s t and s o i l compaction,, found t h a t the h i g h humidity  produced  by m i s t i n g i s one of the f a c t o r s c o n t r i b u t i n g t o the p r o d u c t i o n of " v a s c u l a r browning".  S i m i l a r l y P r o c t o r (I958) r e p o r t e d  t h a t severe  by c o n d i t i o n of high humidity  BR was induced  assoc-  i a t e d with h i g h l e v e l s of watering. C o l l i n and. C l i n e ( I 9 6 5 ) d i d not f i n d any e f f e c t of h i g h humidity  on BR i n t h e i r experiments done i n c o n t r o l l e d e n v i r o n -  ment chambers.  7  I n f l u e n c e of s o l i moisture Kldson and Stanton (1953')  r e p o r t e d that: heavy watering  i n c r e a s e d the number of " c l o u d " f r u i t  considerably.  et a l (1958) found the s i m i l a r e f f e c t s f o r IB. Alexander (1962) observed t h a t TMV- i n o c u l a t e d  Taylor  Jones and plants pro;  duced more BR f r u i t s when p l a n t s were grown s u c c u l e n t l y with h i g h s o i l moisture and h i g h n i t r o g e n .  Bergman and Boyle  (1966) noted an exaggerated e f f e c t o f TMV i n f e c t i o n on the i n c i d e n c e o f IB under a h i g h s o i l moisture regime.  They  found h i g h s o i l moisture i n c r e a s e d y i e l d with l a r g e r  fruit  B e r r y (1966) s t a t e d t h a t BR appeared more f r e q u e n t l y  size.  under c o n d i t i o n s of low moisture  stress.  Woods (1963b) r e p o r t e d no s i g n i f i c a n t e f f e c t of s o i l moisture l e v e l on the d i s o r d e r . I n f l u e n c e of potassium Bewley and White (1926) i n t h e i r c l a s s i c a l study of the effects  o f m i n e r a l elements on the i n c i d e n c e of BR i n tomatoes  s t a t e d among many f i n d i n g s t h a t "BR of tomato f r u i t s Is the result  of m a l n u t r i t i o n i n r e s p e c t of potash and n i t r o g e n ,  especially  the former."  t h a t "under c e r t a i n  Kldson and Stanton (1953.)* found  c o n d i t i o n s potassium i n excess o f the  standard has reduced the s u s c e p t i b i l i t y t o c l o u d , " and t h a t " l n the e a r l y stages of the experiment the e x t r a potassium was without apparent e f f e c t on c l o u d . "  Jones and Alexander  (1956) s t a t e d t h a t "the number of d i s e a s e d f r u i t s i n c r e a s e d as the potassium l e v e l decreaseduwhen p l a n t s were s u b j e c t e d to low temperatures.  When p l a n t s were s u b j e c t e d t o normal  temperatures t h i s c o r r e l a t i o n  d i d not h o l d . "  R i c h (1958),..  8  K i d s o n and Stanton ( 1 9 6 3 ) . and Winsor and Long (1967) reported  also  the b e n e f i c i a l e f f e c t of h i g h potassium on r e d u c i n g  the i n c i d e n c e  of the d i s o r d e r .  Ozbun e t a l (1967)  stated  t h a t "the occurrence of white t i s s u e i n tomato f r u i t was Induced i n sand c u l t u r e by low l e v e l s of K." reported  Tompkins ( I 9 6 3 )  t h a t s o i l treatment with potassium s u l p h a t e and  potassium c h l o r i d e d i d not i n f l u e n c e IB i n c i d e n c e .  Collin  and C l i n e (1966) concluded from s o l u t i o n c u l t u r e s t u d i e s  that  BR d i d not r e s u l t d i r e c t l y from the potassium d e f i c i e n c y but r a t h e r from the replacement Influence  of potassium by c a l c i u m  or sodium.  of n i t r o g e n  Bewley and White (1926) s t a t e d among many f i n d i n g s t h a t BR of tomato f r u i t s i s the r e s u l t of m a l n u t r i t i o n l n r e s p e c t of potash and n i t r o g e n .  There i s some evidence t h a t h i g h  n i t r o g e n n u t r i t i o n l e v e l s reduce BR.  Kidson and Stanton  (1953 ) found t h a t " c l o u d " was reduced by the f r e q u e n t app!  l i c a t i o n of nltrogeneous f e r t i l i z e r . study of d i f f e r e n t sources of n i t r o g e n , NH4NO3,  ( N H 4 ) S 0 ^ , Ca ( N 0 ^ ) , and 2  2  Geraldson (1964) i n h i s i n c l u d i n g NaNO^,  KNOj, observed no r e l a t i o n  of prevalence of "gray w a l l " t o p a r t i c u l a r source m a t e r i a l s . L i n g l e et. a l ( I 9 6 5 )  s t a t e d t h a t BR o r "gray w a l l " was  almost always r e s t r i c t e d t o those p l a n t s r e c e i v i n g n i t r o g e n i n the n u t r i e n t s o l u t i o n .  Only one o r two BR f r u i t  among those from low n i t r o g e n p l a n t s , r e g a r d l e s s  were noted  of n i g h t  temperature. Cotter  (1961) s t u d i e d the I n f l u e n c e  potassium, boron,.and TMV on the i n c i d e n c e  of n i t r o g e n , of I E and found  t h a t no treatment o r treatment combinations, a f f e c t e d the  9  i n c i d e n c e of IB. I n f l u e n c e of phosphorus R i c h ( 1 9 5 8 ) r e p o r t e d on the e f f e c t s of combinations of phosphorus and potassium l e v e l s and TMV, a s c e r t a i n any pronounced  and he c o u l d  e f f e c t s of phosphorus.  Stanton  (1961) r e p o r t e d the i n c i d e n c e of " c l o u d " or BR was Increased by a heavy a p p l i c a t i o n of c o n c e n t r a t e d phate t o the s o i l .  He f u r t h e r r e p o r t e d ( I 9 6 6 )  i n c r e a s e d s u s c e p t i b i l i t y to BR was by adequate phosphate to  fairly  potassium and n i t r o g e n .  not  greatly superphos-  that  readily  this  suppressed  He suggested t h a t h i g h  probably tends to Increase BR through i t s tendency  induce a v i g o r o u s r o o t system and consequently a r a p i d  growing,  heavy-cropping p l a n t .  Winsor and Long ( 1 9 6 7 ) noted  t h a t h i g h e r l e v e l s of phosphorus Increased the p r o p o r t i o n of unevenly r i p e n e d f r u i t ,  and the combination of low  and h i g h phosphorus had a p a r t i c u l a r l y adverse  potassium  effect.  I n f l u e n c e of other m i n e r a l s Kldson and Stanton ( 1 9 5 3 ) ) r e p o r t e d that the a p p l i c a t i o n of  c a l c i u m c h l o r i d e t o the s o i l decreased the amount of  BR.  Subsequently Stanton (I96I) showed t h a t the a p p l i c a t i o n of lime to the s o i l i n c r e a s e d the number of " c l o u d " f r u i t plant. 1965,  H i s r e p e t i t i o n of a s i m i l a r experiment and confirmed h i s p r e v i o u s r e s u l t s ( 1 9 6 6 ) .  Bbutonnet  per  continued  till  Mlnges and  ( 1 9 6 6 ) r e p o r t e d no s i g n i f i c a n t d i f f e r e n c e s i n  occurrence of BR between h i g h a p p l i c a t i o n of c a l c i u m and application i n a f i e l d  experiment.  no  10 Wlnsor and h i s coworkers  (1965b,  1967)  observed  that  magnesium a p p l i c a t i o n t o the s o i l reduced the amount of BR  fruit  v e r y s l i g h t l y , e s p e c i a l l y when compared with the e f f e c t of potassium and magnesium i n combination. T a y l o r ( 1 9 5 7 ) used boron as a p o s s i b l e treatment t o prevent IB and obtained f a v o r a b l e r e s u l t s i n one but not i n another.  Cotter  (1961)  from s o i l a p p l i c a t i o n of boron.  experiment  a l s o r e p o r t e d no  effect  Maynard e t a l ( 1 9 5 9 )  observed  a marked decrease of i n c i d e n c e of IB as the amount of boron l n c r e a s e d i i n sand c u l t u r e .  Tomkins ( I 9 6 3 )  decrease i n the amount of BR when boron was  was  reported a s l i g h t a p p l i e d t o the  soil.  He a l s o t r i e d f o l i a r sprays of z i n c sulphate and manganese sulphate which f a i l e d t o reduce the number of f r u i t s with IB s i g n i f i c a n t l y from the c o n t r o l .  On the o t h e r hand, f e r r o u s  sulphate spray tended t o reduce the i n c i d e n c e of  BR.  I n f l u e n c e of d e f o l i a t i o n Kidson and Stanton (1953')/ found t h a t heavy and p r u n i n g were a s s o c i a t e d with an i n c r e a s e i n " c l o u d " .  light Davis  et a l ( 1 9 5 9 ) s t a t e d t h a t severe I d e f o l i a t i o n r e s u l t e d i n b e t t e r grade f r u i t and reduced the p r o p o r t i o n of i r r e g u l a r l y  colored  f r u i t , but a t ;the expense of a marked r e d u c t i o n l n y i e l d . Cooper et a l ( 1 9 6 4 ) observed t h a t d e l e a f l n g had l i t t l e on f r u i t c o l o r except i n one experiment all  effect  where the r e t e n t i o n of  leaves i n June and J u l y i n c r e a s e d the p r o p o r t i o n of u n i f o r m l y  colored  fruit.  11  Influence of v a r i e t y V a r i e t y differences  l n s u s c e p t i b i l i t y to the d i s o r d e r  have been reported by many workers (Bewley and White 1926, Seaton 1 9 3 6 , Lorenz and Knott 1942, Jones and Alexander 1957, Muraklshi I 9 6 0 , C o l l i n and Wlebe i 9 6 0 , Tomkins I 9 6 3 , Cooper et a l i960,,Woods 1964a, 1965b, Fogleman 1 9 6 6 , Winsor and Long 1 9 6 7 ) .  Boyle and Wharton (1957) and Cox and Weaver  (1950) reported no d i f f e r e n c e among v a r i e t i e s i n the incidence of I B .  No v a r i e t i e s t r i e d so f a r have been completely  r e s i s t a n t to the d i s o r d e r . Using F i r e b a l l as a s u s c e p t i b l e parent and P l a n t I n t r o d u c t i o n 235673 as a r e s i s t a n t parent, P h i l l i p (1964) reported that IB i s c o n t r o l l e d by two genes-showing c o m p l i mentary recessive e p i s t a s i s , w i t h l e v e l s of penetrance  governed  by the genotype of the p l a n t . Influence of growth r e g u l a t o r s Tompkins (1963) found that CCC ( 2 - c h l o r o e t h y l t r i m e t h y l ammonium c h l o r i d e , a growth retardant) reduced the incidence of IB and. g i b b e r e l l i c a c i d tended" to increase i t . Influence of seed density Berry (1964) found that the outer w a l l t i s s u e e x h i b i t i n g BR i s l o c a l i z e d over areas of low seed d e n s i t y .  He a l s o  observed that poor p o l l i n a t i o n produced a higher  percentage  of BR f r u i t , and these f r u i t s had a lower seed d e n s i t y under the blotched area.  12 Influence  of tobacco mosaic v i r u s  Bexfley and White which i s a s t r a i n of TMV  (TMV)  (1926) found that acuba mosaic v i r u s , (Bawden  r i p e n i n g of tomato, d e s c r i b e d  1964), caused  irregular  as " f l e c k s of b r i l l i a n t red  or orange s c a t t e r e d over a s i l v e r y white background".  They  thought t h i s c o n d i t i o n d i f f e r e d from the common BR which they described reported  as green b l o t c h on a r e d background. t h a t he thought TMV  incidence  would be a s s o c i a t e d w i t h the  of IB, but h i s experiments f a i l e d Then Boyle (1956) r e p o r t e d  symptoms.  (1949)  Holmes  to induce IB  the c o n s i s t e n t  repro-  d u c t i o n of IB by i n o c u l a t i o n of tomato p l a n t s w i t h s t r a i n s of TMV  i s o l a t e d from IB: f r u i t s .  The i n o c u l a t i o n of the <-;healthy  p l a n t s was done when f r u i t s were b e g i n n i n g to r i p e n . Interpreted  the e x p r e s s i o n  He  of IB: symptoms as a "shock" r e a c t i o n  r e s u l t i n g from v i r u s I n v a s i o n .  Boyle and Wharton  (1957a)  reported  t h a t I F symptoms were not o b t a i n e d when i n o c u l a t e d  w i t h TMV  soon a f t e r t r a n s p l a n t i n g to the f i e l d .  Their further  i n v e s t i g a t i o n (1957b)  i n d i c a t e d t h a t no o t h e r kind of tomato  f r u i t abnormality was  produced by i n o c u l a t i o n w i t h TMV,  different  s t r a i n s of TMV  number of b l o t c h y f r u i t .  may  d i f f e r i n s e v e r i t y as shown by the 1  Boyle (1959) s t u d i e d TMV,  tobacco  r l n g s p o t v i r u s , and cucumber mosaic v i r u s , and r e p o r t e d TMV  was  and  that  the only one which produced s i g n i f i c a n t l y more IB than  the c o n t r o l p l a n t s .  Lewis and T a y l o r  ( I 9 6 7 ) demonstrated  n e c r o t i c and white t i s s u e were induced by TMV late plant  growth.  that  i n o c u l a t i o n at  13  R i c h (1958) used TMV as one v a r i a b l e l n a m i n e r a l n u t r i t i o n experiment with potassium and phosphorus. TMV gave the h i g h e r i n c i d e n c e  of IB, but t h e v a r i a b i l i t y i n  occurrence o f IB over the e n t i r e h a r v e s t i n g doubt t h a t  Presence of  period  "shock" r e a c t i o n was the cause.  l e d him t o  Cotter  (I96I)  u s i n g e a r l y and l a t e stage i n o c u l a t i o n with TMV, showed no e f f e c t of TMV. on the s e v e r i t y and i n c i d e n c e Alexander (1962) r e p o r t e d an i n c r e a s e  of BR.  t h a t l a t e i n o c u l a t i o n with TMV showed  l n s e v e r i t y and Incidence of BR.  BR v a r i e d . i W i t h d i f f e r e n t s t r a i n s o f TMV. high incidence  and s e v e r i t y of BR on p l a n t s  Thus they b e l i e v e d  Jones and  The amount of  They a l s o found a which were TMV-free.  t h a t there were two d i s t i n c t d i s e a s e s ,  namely  "gray w a l l " o r BR Induced without presence of TMV and IB induced by TMV i n f e c t i o n . I n f l u e n c e of b a c t e r i a When Conover (19^9) reported causal and  "gray w a l l " d i s e a s e , a  organism was not I s o l a t e d from d i s e a s e d t i s s u e .  Hogan (1950) a l s o concluded t h a t the d i s o r d e r  i n c i t e d by a t r a n s m i s s i b l e ( 1 9 6 7 a , 1967b) r e p o r t e d  pathogen.  was not  R e c e n t l y H a l l and S t a l l  the a s s o c i a t i o n i o f  "gray w a l l " with  b a c t e r i a , and S t a l l and H a l l (1969) I s o l a t e d t h i r t y from "gray w a l l " t i s s u e .  Stoner  bacteria  When t h o s e l i s o l a t e s were i n j e c t e d  i n t o h e a l t h y tomato f r u i t s , "gray w a l l " symptoms were induced. Twenty three of the I s o l a t e d s p e c i e s Erwlnla  o r Aerobacter.  were e i t h e r B a c i l l u s .  However, constant a s s o c i a t i o n of b a c t e -  r i a with f i e l d occurrence of "gray w a l l " wasirinot  established.  14 Chemical nature of BR T a y l o r (1957) r e p o r t e d t h a t IB f r u i t s Induced  by  lower  n i t r o g e n and boron were lower i n r e d u c i n g sugar c o n t e n t . Similarly E l l s  (I96D  observed lower r e d u c i n g sugar content i n  BR f r u i t caused by TMV.  They b e l i e v e d t h a t impaired t r a n s -  l o c a t i o n of sugars caused abnormal t i s s u e . b l o t c h y areas was  T o t a l sugar l n  a l s o found t o be lower than i n normal a r e a s ,  but v a r i a b l e r e s u l t s were o b t a i n e d with f r u i t s from h e a l t h y and diseased  plants.  Winsor and h i s coworkers  (1958, 1959.  1962c) analyzed b l o t c h y and normal f r u i t s . 1)  1962a,  1962b,  T h e i r f i n d i n g s werei  B l o t c h y f r u i t s were lower i n dry matter, t o t a l s o l i d s i n sap,  r e d u c i n g sugars, t i t r a t a b l e a c i d i t y , nitrogenous compounds, potassium and e l e c t r i c a l c o n d u c t i v i t y of sap, but h i g h e r i n pH 2) B l o t c h y t i s s u e was  than normal f r u i t s ?  lower i n t o t a l  solids  in;;sap, t i t r a t a b l e a c i d i t y , sugars, immersion r e f r a c t o m e t e r r e a d i n g and f r e e a c i d , but h i g h e r l n pH and a l c o h o l i n s o l u b l e s o l i d s than normal  t i s s u e from the same f r u i t s .  Values f o r  these a n a l y s e s f o r green b l o t c h y t i s s u e s were between those f o r normal t i s s u e and waxy b l o t c h t i s s u e , s u g g e s t i n g t h a t waxy b l o t c h y i s the advanced  form of green b l o t c h *  3) B l o t c h y t i s s u e was  er i n the amount of glutamic a c i d , a s p a r t i c a c i d ,  pyrrolldone-  c a r b o x y l i c a c i d and c i t r i c a c i d , but h i g h e r l n m a l i c a c i d phosphoric a c i d .  low-  and  Prom t h e i r f r u i t a n a l y s i s , they suggested  that  the b l o t c h y area should be regarded as abnormal r a t h e r than merely delayed i n r i p e n i n g .  Davies (1966) making a s i m i l a r study,  r e p o r t e d t h a t both the green and red areas of b l o t c h y tomatoes should be regarded as e x c e p t i o n a l i n chemical c h a r a c t e r i s t i c s .  15 Hobson (1963)  found that the a c t i v i t y of p e c t i n e s t e r a s e ,  which i s assumed to be r e s p o n s i b l e f o r s o l u b i l i z a t i o n and e s t e r i f i c a t i o n of p e c t i n , r o s e , and there was  a decrease i n  content of p e c t i c substances of the f r u i t w a l l s as the matured normally. areas was  de-  fruit  However the enzyme a c t i v i t y l n b l o t c h y  lower than i n the normal f r u i t j  to the e a r l y h a l f - r i p e stage.  l n f a c t I t was  close  The a c t i v i t y of p o l y g a l a c t u r o -  nase ( r e s p o n s i b l e f o r the d e g r a d a t i o n of p e c t i c substances thus the s o f t e n i n g of f r u i t s ) was  and  found t o Increase d u r i n g normal  r i p e n i n g , but the i n c r e a s e was  r e t a r d e d i n b l o t c h y areas  (Hobson 1 9 6 4 ) ,  s t a t e d that polyphenoloxldase,  Kidson (1958)  an enzyme well-known f o r producing browning of f r u i t s ,  appeared  to be r e s p o n s i b l e f o r the browning of " c l o u d " t i s s u e s .  Healthy  f r u i t - w a l l t i s s u e when added t o b l o t c h y t i s s u e i n v i t r o p o l y p h e n o l oxidase browning of d i s i n t e g r a t e d A s c o r b i c a c i d was  inhibited  "cloud" t i s s u e .  very e f f e c t i v e l n p r e v e n t i n g browning i n sus-  pensions of b l o t c h e d t i s s u e . some i n h i b i t i n g e f f e c t . a s u f f i c i e n t amount.  C i t r i c and m a l i c a c i d s a l s o  Glucose was  had  e f f e c t i v e i f p r e s e n t in-  High a c t i v i t y of p o l y p h e n o l oxidase  was  observed i n green f r u i t s but the a c t i v i t y d i m i n i s h e d with i n c r e a s i n g m a t u r i t y , and there was at the c o l o u r i n g stages.  no a c t i v i t y shown by normal f r u i t s B l o t c h e d areas r e t a i n e d  a c t i v i t y while r e d p a r t s of the same f r u i t  their  lost i t .  The  was most a c t i v e near the s k i n and i n the v a s c u l a r system walls. areas was who  enzyme of the  Higher a c t i v i t y of p o l y p h e n o l oxidase i n the a f f e c t e d a l s o r e p o r t e d by Hobson (1967)  and Tompkins  (1963)  found a s i m i l a r t r e n d w i t h peroxidase and cytochrome c  oxidase as w e l l .  16  Four p h e n o l i c a c i d s l n tomato f r u i t f i e d "by Walker  ( 1 9 6 2 )  chlorogenlc acids.  w a l l s were i d e n t i -  as p-coumaric, c a f f e l c , f e r u l i c and  Except f o r p-coumaric a c i d , these  acids  were lower i n t i s s u e from " c l o u d " than from-normal f r u i t same stage  of m a t u r a t i o n .  was s i m i l a r I n both f r u i t  a t the  The p-coumaric a c i d c o n c e n t r a t i o n types.  The d e p o s i t s l n white t i s s u e  i n b l o t c h y areas of the f r u i t were i d e n t i f i e d as l i g n i n i m nature  by Sadik and Minges  ( 1 9 6 6 )  b i l i t y and s t a i n i n g r e a c t i o n s .  on the b a s i s of t h e i r s o l u -  They s t a t e d t h a t  lignificatiom  of c e l l w a l l s occurred d u r i n g e a r l y stages of f r u i t and  hence might be considered  r i p e n i n g and c o l o r a t i o n .  development  as a cause of a b n o r m a l i t i e s  during  17  MATERIALS AND 1):  C o r r e l a t i o n between hours of b r i g h t sunshine Incidence of  Data  METHODS and  the  BR.  sources M e t e o r o l o g i c a l r e c o r d s were obtained from the U n i v e r s i t y  of B r i t i s h Columbia to r e p r e s e n t the Lower Mainland  climate f o r  the greenhouse tomato p r o d u c i n g a r e a , and from the Canada Department of A g r i c u l t u r e Research S t a t i o n at Saanichton  to  r e p r e s e n t the Vancouver I s l a n d greenhouse tomato producing r e g i o n . ( D a i l y A g r o m e t e o r o l o g l c a l Data, Department of T r a n s p o r t , M e t e o r o l o g i c a l Branch).  Records were obtained f o r the  1962  The  was  to 1969  Inclusive.  years  i n c i d e n c e of BR d u r i n g t h a t p e r i o d  obtained from the r e p o r t s contained l n the B r i t i s h Columbia  Department of A g r i c u l t u r e " H o r t i c u l t u r a l News L e t t e r s " . r a t i n g system was  A  d e v i s e d t o give a q u a n t i t a t i v e e x p r e s s i o n t o  d e s c r i b e d i n the weekly r e p o r t s .  The  r a t i n g s c a l e employed  BR  was  as f o l l o w s * Oi  "no  BR"  1»  "a s m a l l amount of  21  "some  3«  "severe  BR"  BR" BR"  The  n e w s l e t t e r s only contained 12  was  c l e a r l y s t a t e d and they are shown i n Table  items where the BR  incidence  1.  C a l c u l a t i o n of the l i n e a r r e g r e s s i o n s of the Incidence of BR hours of b r i g h t The  on  sunshine  s e l e c t e d weeks l i s t e d i n Table 1 w i l l be  designated  h e r e a f t e r as WO,.meaning the week of harvest when the  occurrence  18  Table 1 S e v e r i t y of BR as recorded i n B r i t i s h Columbia f o r s p r i n g greenhouse tomato c r o p s .  Order  Severity of BR incidence  Week  , 1962  Location  2  Lower Mainland  1963  2  Lower Mainland  May  1 9 - 2 5 . 1966  3  Vancouver I s l a n d  4.  May  2 5 - 3 1 , 1967  3  Vancouver I s l a n d  5.  May  1968  0  Vancouver I s l a n d  6.  May  1 4 - 2 0 , 1968  1  Vancouver I s l a n d  7.  May  1969  1  Vancouver I s l a n d  8.  May  1 4 - 2 0 , 1969  3  Vancouver I s l a n d  9.  May  1 4 - 2 0 , 1969  1  Lower Mainland  10.  May  24-30, 1969  3  Vancouver I s l a n d  11.  June 1 0 - 1 6 , 1969  1  Vancouver I s l a n d  12.  June 1 7 - 2 3 ,  1  Vancouver I s l a n d  1.  June  2.  May  17-23,  3.  1-7  7-13,  6-12,  1969  19  of BR was r e p o r t e d .  The week before WO w l l l - b e designated as  Wl which means one week before h a r v e s t i n g .  The week before  Wl; w i l l be W2, and t h i s sequence continues t o W? which i s the seventh week before the;-harvesting week.  I t was supposed t h a t  tomatoes harvested a t WO would have been a t o r b e f o r e the stage of  fruit  s e t a t W7. .Hours of b r i g h t sunshine  Wl,  W2, W3, W4, W5, W6,  b r i g h t sunshine  and W7.  were summed weekly f o r WO, The value of t o t a l hours of  f o r each week ( i . e . WO through t o W7) was  p l o t t e d a g a i n s t s e v e r i t y of the i n c i d e n c e of BR which w i l l be d e s i g n a t e d as Y h e r e a f t e r . Y I s between 0 and 3.  As a l r e a d y d e s c r i b e d , the value o f  At the same time, l i n e a r r e g r e s s i o n ,  F - R a t i o , r 2 , and standard e r r o r of estimate were c a l c u l a t e d f o r each p l o t .  Many combinations  of g i v e n weeks were t e s t e d f o r  c o r r e l a t i o n between hours of b r i g h t sunshine of BR.  I n making these combinations,  and the i n c i d e n c e  the f o l l o w i n g items were  t e s t e d f o r a s s o c i a t i o n with the i n c i d e n c e of BR. A.  Hours of b r i g h t sunshine  accumulated f o r s e v e r a l weeks  i n a sequence. B.  Hour's of b r i g h t sunshine and  C.  f o r a l t e r n a t e weeks of sunny  cloudy c o n d i t i o n s .  Hours of b r i g h t sunshine  f o r one p a r t i c u l a r week of a  g i v e n p e r i o d , which had a maximum or minimum of hours of D.  The d i f f e r e n c e i n the hours of b r i g h t sunshine two  E.  b r i g h t sunshine. between  c o n s e c u t i v e weeks.  Maximum or minimum of the d i f f e r e n c e i n the hours of b r i g h t sunshine period.  between two c o n s e c u t i v e weeks of a g i v e n  20 There were 180 combinations used i n t h i s study. "TOTAL" w i l l be used i n the t a b l e s t o t a l hours o f b r i g h t listed.  The term  o f r e s u l t s t o mean "the  sunshine" f o r the models u s i n g weeks as  F o r example, TOTAL f o r a week which has hours of b r i g h t  sunshine o f 7, 8, 9, 10, 9, 6, and y i s 52 c a l c u l a t e d t  as 7+8+9+  10+9+6+3=52. Additionally of b r i g h t  the e f f e c t o f d a l l y f l u c t u a t i o n i n hours  sunshine on the s e v e r i t y o f the i n c i d e n c e of BR was  c o n s i d e r e d and the d a i l y d i f f e r e n c e s W2, W3, W4, W5, W6, and W7. of hours o f b r i g h t or FLUTO.  were summed f o r WO, Wl,  This t o t a l of d a i l y  fluctuations  sunshine i s a b b r e v i a t e d t o F l u c t u a t i o n  Total  Thus FLUTO ( f o r the week g i v e n as an example o f the  c a l c u l a t i o n o f TOTAL) w i l l be |7-H|+10, d e r i v e d  from  f7-H|+  |8-7| + |9-8|+|10-9|+ |9-10|+|6-9| + |3-6| = |?-H|+ 10, where H i s the hours of b r i g h t  sunshine o f the l a s t day o f the p r e c e d i n g week.  The combinations o f weeks used i n c a l c u l a t i n g TOTAL were a l s o used t o c a l c u l a t e FLUTO. sented i n the same t a b l e s Significance  Thus TOTAL and FLUTO v a l u e s are p r e of r e s u l t s .  of temperatures l n r e l a t i o n t o b r i g h t  sunshine  The combinations of weeks which were s i g n i f i c a n t l y c o r r e l a t e d w i t h the i n c i d e n c e of BR i n terms o f hours o f b r i g h t shine were a l s o used t o a s c e r t a i n  sun-  the c o r r e l a t i o n with r e s p e c t  to maximum o r minimum temperatures f o r those same time p e r i o d s . The a b b r e v i a t i o n s TOTAL and FLUTO I n t h i s case are used f o r t o t a l s of maximum o r minimum temperature and f l u c t u a t i o n t o t a l s of maximum o r minimum temperature  respectively.  21  Comparison of the i n c i d e n c e of BR  on Vancouver I s l a n d and  In  the Lower Mainland In 1969» The of BR  y e a r 1969  showed a marked c o n t r a s t i n the  on Vancouver I s l a n d and  of May  very  little  on the Mainland.  sunshine at both p l a c e s were compared. obtained  The  week  on Vancouver I s l a n d showed about 3 0 - 5 0 $ BR  14-20  there was  on Lower Mainland.  incidence  whereas  D a i l y hours of b r i g h t The  regression  equations  from m e t e o r o l o g i c a l d a t a were used l n e v a l u a t i n g  the  comparison. The  d a l l y hours of b r i g h t sunshine f o r t h a t p e r i o d i n  both r e g i o n s  were p l o t t e d .  Since there were more f l u c t u a t i o n s  i n the hours of b r i g h t sunshine i n the Lower Mainland r e c o r d 8-12,-i  than i n the I s l a n d r e c o r d d u r i n g the f o u r days from May I969,  the p o s s i b i l i t y of the e f f e c t of the f o u r l a r g e s t d i f f e r -  ences i n hours of b r i g h t sunshine w i t h i n a week on the of BR 2)c  was  incidence  investigated.  The  e f f e c t of temperatures and  The  s t u d i e s of c l i m a t i c d a t a p l u s some o b s e r v a t i o n s  greenhouse c o n d i t i o n s l o c a l l y  l i g h t on the i n c i d e n c e of  l e d t o a program which was  on tested  i n growth chambers. P l a n t growing The  tomato p l a n t s f o r the experiment were grown and  handled i n : t h e f o l l o w i n g manner. v a r i e t y was  sown on February 1 0 ,  Seed of the E a r l y Red 1970  Chief  i n the greenhouse.  month l a t e r , the s e e d l i n g s were t r a n s p l a n t e d to p l a s t i c pots c o n t a i n i n g s t e a m - s t e r i l i z e d s o i l .  9•6-litre The  plants  One  BR.  22 were t r a i n e d Hoagland's  t o two  stems.  standard n u t r i e n t  Koskitalo 1970).  P l a n t s were watered d a i l y w i t h solution  (macro n u t r i e n t s  A s u r p l u s of s o l u t i o n was  added  only,  beyond  field  c a p a c i t y l n o r d e r t o have the excess d r a i n out o f the pot, and thus p r e c l u d e s a l t a c c u m u l a t i o n .  On May  8,  1970,  p l a n t s were  moved t o growth chambers ( P e r c i v a l Model PGC-78 w i t h a d i u r n a l temperature  programmer ) w i t h fou:? p l a n t s i n each of f o u r  chambers.  The programmers i n the chamber employed  different  temperature and l i g h t c o n d i t i o n regimes. Temperatures The c h o i c e of temperatures was r e c o r d s from f o u r o f the tomato houses on the Lower Mainland, B.C. employed.  Two  based on  thermograph  of commercial  greenhouses  temperature t r e a t m e n t s were  Both regimes had the same minimum o f 1 1 . 7  Maximum temperatures were 2 6 . 7  or 2 1 . 1  C.  C.  The two p a t t e r n s of  d i u r n a l f l u c t u a t i o n s are shown l n F i g u r e 1.  P a t t e r n A or  day temperatures w i t h the h i g h l e v e l of maximum  sunny-  temperature  (26.7C) r e p r e s e n t s the c o n d i t i o n s of a sunny day.  Pattern B  o r cloudy-day temperature, w i t h a low l e v e l of maximum  tempera-  t u r e r e p r e s e n t s the c o n d i t i o n of a c l o u d y day. Thus the two temperature regimes were: (11.7  C / 2 6 . 7 C, n i g h t / d a y )  A.  Sunny-day temperature  B.  A l t e r n a t e weeks o f sunny-day and cloudy-day temperature  temperature  (11.7  (11.7  C/26.7  C)  C/21.1 C).  L l crht Two  l e v e l s of l i g h t  l i g h t regimes.  i n t e n s i t y were employed  The h i g h l e v e l of l i g h t  t o produce  intensity, 1,700  two  f-c  23  12 Time of Day  18  24  Figure 1 D a i l y temperature changes i n the growth chambers used f o r the BR experiments: (A) r e p r e s e n t s the temperature changes on sunny-day* and (B) r e p r e s e n t s the cloudy-day.  24 ( f o o t c a n d l e s ) or 4 2 , 0 0 0 erg/cm /sec was 2  obtained with s i x t e e n  20-watt c o o l white f l u o r e s c e n t tubes and t e n 40-watt tungsten F o r the low l e v e l of l i g h t , 990 f - c or 2 4 , 0 0 0  lamps.  erg/cm / 2  sec,, e i g h t f l u o r e s c e n t tubes and ten tungsten lamps were used. A t h i n c l e a r cellophane f i l m was  used as a b a r r i e r i n the growth  chambers to o b t a i n h i g h e r l i g h t I n t e n s i t y , i n s t e a d of the o r d i n a r y t h i c k p l a s t i c sheet which g i v e s d i f f u s e d l i g h t with lower A p h o t o p e r i o d of 15 hours was  intensity.  used f o r both  light  As shown i n F i g u r e 2 , . sunny-day c o n d i t i o n s were  regimes.  obtained by u s i n g 15 hours of h i g h i n t e n s i t y l i g h t whereas cloudy-day c o n d i t i o n s were o b t a i n e d by u s i n g 7 . 5 i n t e n s i t y l i g h t preceded and f o l l o w e d by 3 . 7 5 Thus the two  hours of h i g h  hours of low  light.  l i g h t treatments were*  A.  Sunny-day l i g h t or 15 hours of h i g h l i g h t  B.  A l t e r n a t e weeks of sunny-day l i g h t and  intensity.  cloudy-day  light. A l l measurements of l i g h t i n the experiment  were obtained w i t h  a s p e c t r o r a d i o m e t e r (ISCO) which measured the l i g h t energy a t the c o n t a i n e r height without p l a n t s . between 400 nm and 700 nm.  L i g h t energy was  calculated  These v a l u e s were a l s o converted  to f o o t c a n d l e s a c c o r d i n g to the S o l a r C e l l and P h o t o c e l l Handbook ( 1 9 6 6 ) . Combination Two  treatments temperature  treatments and two  employed i n a f a c t o r i a l manner.  l i g h t treatments were  Thus a t o t a l of f o u r  were used, and they are shown l n Table  2.  treatments  85 erg/cm /sec 42,000 2  r  foot candles 1,700  Cloudy-day l i g h t  (A)  •7.5 hrs-  24,000 - 900  -15 h r s —  0  foot erg/cm2/sec candles 42,0001-1,700  12 Time o f Day  18  Sunny-day l i g h t  24  (B)  -15 h r s  12 Time o f Day  18  24  Figure 2 D a i l y l i g h t regimes f o r the. c o n t r a s t i n g l i g h t treatment used i n the BR experiments: (A) employed the h i g h l i g h t i n t e n s i t y f o r one h a l f o f the p h o t o p e r i o d r e p r e s e n t i n g a cloudy day, (B) employed the h i g h l i g h t f o r the e n t i r e photoperiod r e p r e s e n t i n g a sunny day.  26 Table 2  Treatment regimes of l i g h t and temperature combinations.  Treatment regime  Temperature  Light  TcLc  Sunny-day temperature  Sunny-day l i g h t  TcLa  Sunny-day temperature  A l t e r n a t e weeks of sunny-day l i g h t and cloudy-day l i g h t  TaLc  A l t e r n a t e weeks of sunny-day temperature and cloudy-day temperature  Sunny-day l i g h t  TaLa  A l t e r n a t e weeks of sunny-day temperature and cloudy-day temperature  A l t e r n a t e weeks of Sunny-day l i g h t and cloudy-day l i g h t  In treatment TaLa, sunny-day temperature was coupled w i t h sunny-day l i g h t , and cloudy-day temperature w i t h c l o u d y day l i g h t .  27  F r u i t Harvesting P l a n t s were examined d a i l y and each f r u i t  was  dated a t  the time of r e a c h i n g the breaker p o i n t or when any r e d d i s h c o l o r was  n o t i c e d on f r u i t .  First  harvested on June 4 ,  f r u i t was  1970.  Then p i c k i n g s were made each week a t the end of weekly treatments. F r u i t was point.  harvested when f o u r or more days past the breaker I t was  judged t h a t f r u i t  had developed enough c o l o r a t  t h a t stage t o show BR i f the f r u i t was The f r u i t s  were weighed i n d i v i d u a l l y .  a f f e c t e d f r u i t was fruits  d e s t i n e d t o be  BR.  N e c r o t i c t i s s u e i n the  r e c o g n i z e d e x t e r n a l l y i n most cases, however  were cut t r a n s v e r s e l y and examined f o r the symptoms i n  a l l d o u b t f u l cases. 3)  A s s o c i a t i o n of BR of greenhouse tomatoes and tobacco mosaic  v i r u s (TMV)  in British  Columbia  A survey of the TMV house tomatoes was  i n I969.  i n f e c t i o n i n commercial  c a r r i e d out i n 1969  crops of green-  i n some e s t a b l i s h m e n t s i n  the Saanichton area of Vancouver I s l a n d and Surrey i n the Lower Mainland  region.  The primary purpose  a s c e r t a i n whether BR f r u i t with  l n the B.C.  of the survey was crops was  to  always i n f e c t e d  TMV. T h i s survey i n c l u d e d samples from the crop of s i x growers  on Vancouver I s l a n d and two sampled on May latter  was  20,  1969  growers i n Surrey.  when severe BR was  sampled on May  The former  apparent, and  25 and repeated on J u l y 4 ,  the  1969.  was  28  A f r u i t and kept i n the  a l e a f were taken from the same p l a n t  same p l a s t i c bag u n t i l they were used f o r TMV  N i c o t i a n a g l u t I n o s a was The  used as the TMV  tomato f r u i t s and  followsi  placed i n a depression  spot p l a t e with f o r c e p s which had been dipped i n 95% and. then s t e r i l i z e d I n s t a n t l y over a flame before  of a  alcohol  handling  A g l a s s rod, which had both ends f l a t t e n e d and  roughened, was of the p l a t e .  used to c r u s h the m a t e r i a l i n the The  assay.  assay p l a n t .  l e a v e s were handled as  A p i e c e of sampled m a t e r i a l was  sample.  and  g l a s s rod c a r r y i n g the  each  then  depression  j u i c e was  gently  rubbed over the surface of a l e a f of a p l a n t of N^_ g l u t l n o s a . The  s o i l e d g l a s s rods and  they had been washed and The nine  spot p l a t e s were not used again  until  then s t e r i l i z e d i n a heated oven.  NJt g l u t l n o s a p l a n t s used f o r a s s a y i n g had  seven to  l e a v e s , and f o u r of the middle aged leaves xvere used.  i n f e c t e d f r u i t s which had l e a f which was I f TMV  been p r e v i o u s l y assayed and a tobacco  f r e e from TMV was  the leaves l n two  TMV-  present,  were used as a c o n t r o l .  the t y p i c a l l o c a l l e s i o n appeared  to three days a f t e r i n o c u l a t i o n .  on  The r e s u l t s  of the assay were noted a week or more a f t e r I n o c u l a t i o n . 4)  A s s o c i a t i o n of BE and potato Seeds of E a r l y Bed  v i r u s X (PVX).  C h i e f v a r i e t y were sown i m bands i n the  greenhouse on September 2%.  1969.  I n f e c t e d with the v i r u s by rubbing from an i n f e c t e d p l a n t . the c o n t r o l s .  The  The  H a l f of the s e e d l i n g s were a young l e a f with a l e a f l e t  remaining untreated  p l a n t s were  i n o c u l a t e d and c o n t r o l p l a n t s were moved  29  i n t o 9 . 6 - l i t r e p l a s t i c containers The  i n f e c t e d p l a n t s and  houses.  filled  with s t e r i l i z e d  soil.  the c o n t r o l s were kept i n separate green-  A f t e r November 17.  the p l a n t s were watered d a i l y w i t h  Hoagland's standard n u t r i e n t s o l u t i o n (macro n u t r i e n t s only).P l a n t s were moved i n t o the growth chambers ( P e r c i v a l PG-85 w i t h a d i u r n a l temperature programmer) when the three  f r u i t s of the  first  group s t a r t e d c o l o r i n g i . e . the end  January f o r the c o n t r o l s and  of  the b e g i n n i n g of February f o r  the  infected plants.  Seven P V X - i n f e c t e d p l a n t s were placed  growth chamber and  seven c o n t r o l or v i r u s - f r e e p l a n t s were put  another chamber.  Seven p l a n t s of I n f e c t e d  p l a n t s were l e f t The Koskitalo minimum. at  the  i n the  The  height  f - c and  17.8'  described  index p l a n t s f o r PVX  The  twice- a f t e r  assay procedure  f o r the TMV  C  19,800 e r g / c m 2 / s e c  done once before and  i n the chambers.  the same as t h a t a l r e a d y  840  by  without p l a n t s .  V i r u s assay was  p l a n t s were placed  t h a t the  s i m i l a r to t h a t used :  l i g h t c o n d i t i o n was  container  in  a l s o of c o n t r o l  Temperatures were 2 5 . 6 C maximum and  (1970).  one  greenhouse.  growth chamber regime was  The  and  in  was  assay, except  were Gomphrena globosa.  30 RESULTS Do  C o r r e l a t i o n between hours of b r i g h t sunshine and the i n c i d e n c e of BR.  L i n e a r r e g r e s s i o n of the Incidence of BR on hours of b r i g h t sunshine. Hours of b r i g h t sunshine l n TOTAL and FLUTO f o r a given week of 12 cases i n Table 1 are presented i n Table 3» The c o e f f i c i e n t o f d e t e r m i n a t i o n of the l i n e a r r e g r e s s i o n s of the i n c i d e n c e of BR on the hours of b r i g h t sunshine l n B r i t i s h Columbia greenhouse tomatoes are summarized i n Tables 4 t o 11.  Each t a b l e p r e s e n t s groups of r e g r e s s i o n s as f o l l o w s .  Table 4 presents s i n g l e weeks f o r TOTAL and FLUTO. were no s i g n i f i c a n t  There  correlations.  Table 5 p r e s e n t s accumulations  o f the e i g h t weeks i n t h e i r  proper sequence f o r TOTAL and FLUTO.  There were no s i g n i f i c a n t  correlations. Table 6 presents many p o s s i b l e combination  of e i g h t weeks,  p a r t i c u l a r l y a l t e r n a t i n g weeks, u s i n g accumulations, cases s u b t r a c t i o n s f o r TOTAL and FLUTO. f i c a n t c o r r e l a t i o n s with the s i g n i f i c a n t r 0.54.  and l n some  There were some 2  signi-  r a n g i n g from 0.3^ t o  I t can be seen t h a t the h i g h e s t c o r r e l a t i o n was found  with the model W0+W2+W4+ W6-(W1+W3+W5+W7). Table 7 presents the models i n which one p a r t i c u l a r week of a.;given p e r i o d was chosen because i t had the maximum value f o r TOTAL. models.  There were no s i g n i f i c a n t c o r r e l a t i o n s : i n these  Table 3 Hours o f b r i g h t sunshine i n TOTAL and FLUTO f o r a g i v e n week o f 12 cases i n T a b l e 1.  Week  TOTAL or FLUTO  WO  TOTAL FLUTO  1 61.4 29. 7  2 38.3 20. 2  3 52. 7 32.0  4 42.3 29.9  5 69.9 20. 5  6 82. 7 17. 8  7 87.4 3.0  8 88. 6 14.4  9 59. 3 23. 8  10 82.9 13.9  11 50. 2 14. 2  12 32. 6 21. 2  Wl  TOTAL FLUTO  47. 7 19.0  47.5 24.0  57.3 25.0  67. 8 15.4  49. 3 25. 2  88. 4 2.6  40. 2 17. 8  79.0 14.5  69.9 20. 5  75. 8 24. 7  82.9 13.9  85. 6 16.0  W2  TOTAL FLUTO  31.4 29.9  26. 6 23.0  65.3 26. 6  40.3 26.5  50.3 44.4  50.9 16.9  33. 2 20.0  44. 5 20. 1  49.3 25. 2  45. 8 24.5  75. 8 24. 7  83. 1 8. 8  W3  TOTAL FLUTO  40.2 28.4  34.5 33.9  68. 6 19. 6  41.0 43.4  51. 1 29.2  33.0 19.4  23. 7 24. 8  31.3 27. 7  50.3 44.4  65.0 9.9  45. 8 24. 5  81. 1 8.9  W4  TOTAL FLUTO  51.0 27.1  8. 8 13.0  32. 2 26.1  34. 8 28.0  30.4 33. 7  15. 6 23.9  46.0 34. 7  6.4 16.7  51. 1 29. 2  82.9 18.0  65.0 9.9  19.0 19. 8  W5  TOTAL FLUTO  30.1 28.4  25.4 13. 6  56.3 23.5  46.5 23. 7  39.2 32.3  47.4 36.6  19. 2 11.6  42.6 36. 8  30.4 33. 7  87. 4 3.0  82.9 18.0  34. 2 20. 2  W6  TOTAL FLUTO  21. 7 31.5  13.9 25.6  26.5 16.9  18.0 14.2  25.3 25. 5  27. 7 11.9  45. 7 10.2  21. 2 9.3  39.2 32.3  40. 2 17.8  87. 4 3.0  30.0 29.4  W7  TOTAL FLUTO  43.2 56.2  16.2 20.3  62.3 7.0  45. 6 40. 6  27. 6 22. 5  35. 6 10.5  48. 6 36.3  31. 6 10. 2  25.3 25.5  33.2 25.4  40.2 17.8  47. 7 29. 8  Y  2  2  3  3  1  1  1  3  12  0  3  cases  1  3  Table 4  C o e f f i c i e n t of d e t e n n i n a M n n  SMIML sunshine between a  r  2  c  c  (*2\  n  ^ e d d i f f e r e n c e s i n hours "of brtSt c o n s e c u t i v e days f o r a week (PLUTO). u  m  u  l  for  Week  TOTAL  FLUTO  WO  .23  .28  Wl  .06  .13  W2  .23  .28  W3  .05  .02  W4  .13  .00  W5  .00  .00  W6  •!3  .00  W7  .24  .00  No r 2 was s i g n i f i c a n t a t 5 * l e v e l .  33 Table 6 C o e f f i c i e n t o f d e t e r m i n a t i o n ( r ) o f l i n e a r r e g r e s s i o n of the Incidence of BR on t o t a l hours of b r i g h t sunshine f o r weeks (TOTAL), o r on accumulated d i f f e r e n c e s l n hours o f b r i g h t sunshine between c o n s e c u t i v e days f o r weeks (FLUTO). 2  Accumulated  weeks  W0+W1 W0+W1+W2 WO+W1+W2+W3 W0+W1+W2+W3+W4  wo+wi+w2+W3+w4+W5  W0+W1*W2+W3+W4+W.5+W6.' W0+W1+W2+W3+W4+W5+W6+W77 W1+W2 W1+W2+W3 W1+W2+W3+W4 W1+W2+W3+W4+W5 W1+W2+W3+W4+W5+W6 wi+W2+¥3+w4+W5+w6+W7? W2+W3 W2+W3+W4 W2+W3+W4+W5 W2+W3+W4+W5+W6 W2+W3+W4+W5+W6+W7 W3+W4  W3+W4+W5  W3+W4+W5+W6 W3+W4+W5+W6+W7 W4+W5 w4+W5+w6c' W4+W5+W6+W7  W5+W6 W5+W6+W7 W6+W7 No r  2  r^ for TOTAL FLUTO .04 .00 .00 .01 .01 .03 .01 .06 .07 .00 .00 .00 .00 .05 .00 .00 .01 .00 .02 .01 .04 .01 .06 .10 .03 ..06 .00 .00  was s i g n i f i c a n t a t 5% l e v e l .  .02 .02 .03 .03 .01 .01 .00 .27 .19 .15 .09 .06 .04 .14 .10 .05 .03 .02 .02 .00 .00 .00 .00 .00 .00 .00 .00 .00  34  Table 6  C o e f f i c i e n t o f d e t e r m i n a t i o n ( r ) o f l i n e a r r e g r e s s i o n of- the i n c i d e n c e o f BR on hours of b r i g h t sunshine f o r a combination of weeks (TOTAL), o r on accumulated d i f f e r e n c e s i n hours of b r i g h t sunshine between c o n s e c u t i v e days f o r a combination o f weeks (FLUTO). 2  Combinations.of weeks  r  2  TOTAL W0+W2 W0+W2+W4 WO+W2+W4+W6:'  W1+W3 W1+W3+W5  WI+W3+W5+W7 W2+W4 W2+W4+W6.'  W3+W5  W3+W5+W7 W4+W6  W5+W7  W0-W1 W0+W2-W1 W0+W2-(W1+W3)  W0+W2+W4-.(W1+W"3)  W0+W2+W4-(W1+W3+W5) W0+W2+W4+W6-(W1+W3+W5)  wo+W2+w4+w6-(WI+W3+W5+W7) W1-W2 W1+W3-W2 W1+W3-(W2+W4) Wi+W3+W5-(W2+W4) Wl+W3+W5-(W2+W4+W6) wi+W3+w5+W7-(W2+W4+W6) W2-W3 W2+W4-W3  W2+w4-(W3+W5)  W2+w4+w6-(W3+W5)  W2+w4+w6-(W3+W5+W7) W3-W4 W3+W5-W4  W"3+W5-(w4+w6) W3+W5+W7-(w4+w6) w4-W5 W4+W6-W5 W4+W6-(W5+W7) W5-W6  W5+W7-W6 W6-W7 *i **i  S i g n i f i c a n t a t 5% l e v e l . S i g n i f i c a n t a t 1% l e v e l .  .08 .18 .19 .09 .02 .07 .03 .07 .00 .05 .16 .02 .27 .28 .28 .40 .31 .38 .54 .00 .09 .26 .15 .23 .40 .00 .14 .12 .17 .34 .24 .14 .04 .38 .10 .21 .40 .07 .24 .37  #  «  «  * « #  f  OT  FLUTO .00 .00 .00 .09 .03 .01 .14 .06 .00 .00 .00 .00 .52 * * .03 .11 .05 .03 .03 .02 .07 .00 .00 .01 .00 .00 .06 .06 .06 .02 .03 .00 .00 .02 .00 .01 .00 .00 .00 .00 ..00  35  Table 7 C o e f f i c i e n t of d e t e r m i n a t i o n ( r ) of l i n e a r r e g r e s s i o n of the i n c i d e n c e of BR on hours of b r i g h t sunshine of the week whose value of t h a t was a maximum i n the weeks of a given p e r i o d (TOTAL), o r on the accumulated d i f f e r e n c e s l n hours o f b r i g h t sunshine between consecutive days f o r a week whose value o f t h a t was a maximum i n the weeks of a given p e r i o d (FLUTO). 2  Weeks from which max. was chosen  WO, Wl WO, W l „ WO, Wl, WO, Wl, W0;,.W1, W0, Wl,  W2 W2, W2, W2, W2,  wo, w i , W2, W3,,w4, W5, W6..W7 Wl, W2 Wl, W2, Wl, W2, Wl, W2, Wl, W2, Wl, W2, W2, W3 W2, W3, W2, W3, W2, W3, W2..W3, W3, W4 W3, W4, W3, W4, W3, w4, W4, W5 W4, W5. W4, W5, W5, W6 W5, w6, W6, W7  No r  2  W3 W3, W3, W3, W3,  d  TOTAL  .03 W3 W3. W4 W3, W4, W5 W3, W4, W'5,,W6  W4 W4, W5 W4, W5, w6 W4..W5, W6, W7  W4 W4, W5 W4, W5, W6 W4, W5 W6,,W7 (i  W5  W5, W6 W5, w6,  W7  W6 W6, W7 W7  w a s ; s i g n i f i c a n t at 5% l e v e l .  r for  FLUTO .12  .01 .01 .01 .01 .02  .08 .06  .02 .09  .00  .10 .08 .06  .05  .05 .02 .00 .00 .00 .00 .00 .00 .00  .08 .04 .01 .24 .12  .13 .08  .03 .00  .15 .13 .07 .03 .00 .02 .00 .00  .00  .00  .01 .00  .01  .06 .06 .02 .04  .02 .00 .01 .01  .00  36  S i m i l a r l y Table 8 presents models l n which the minimum value f o r TOTAL and PLUTO f o r the same models used l n Table and again there were no s i g n i f i c a n t  7,  correlations.  Table 9 shows the systematic c o n s i d e r a t i o n of the d i f f e r e n c e between two c o n s e c u t i v e weeks f o r TOTAL and FLUTO. were no s i g n i f i c a n t  Again there  correlations.  Table 10 shows the systematic c o n s i d e r a t i o n of the d i f f e r ences of two c o n s e c u t i v e weeks of a given p e r i o d , which had the maximum value f o r TOTAL and FLUTO.  There were two s i g n i f i c a n t  c o r r e l a t i o n s as can be seen i n the t a b l e . S i m i l a r l y the maximum values were c o n s i d e r e d , but there were no s i g n i f i c a n t c o r r e l a t i o n s as shown l n Table 11. l i n e a r r e g r e s s i o n s which had s i g n i f i c a n t r  2  The  are brought  together  i n Table 12. S i g n i f i c a n c e of temperature l n r e l a t i o n t o b r i g h t sunshine. Maximum and minimum a i r temperatures r e c o r d s , f o r the important hours of b r i g h t sunshine  combinations  from m e t e o r o l o g i c a l  of the weeks i n which  were s i g n i f i c a n t l y c o r r e l a t e d with the  i n c i d n e c e of BR, were not s i g n i f i c a n t l y c o r r e l a t e d w i t h the BR i n c i d e n c e (Table 13). Comparison of the i n c i d e n c e of BR on Vancouver I s l a n d and Lower  Mainland. The  severe BR present l n Vancouver I s l a n d greenhouse con-  t r a s t e d with very low i n c i d e n c e on the Lower Mainland study of the hours of b r i g h t sunshine  l e d t o the  a t these two l o c a t i o n s t o  t r y t o e l u c i d a t e the reason f o r t h i s d i f f e r e n c e .  37 Table 8 C o e f f i c i e n t of d e t e r m i n a t i o n ( r ) of l i n e a r r e g r e s s i o n of the i n c i d e n c e of BR on t o t a l hours of b r i g h t sunshine of the week whose value of t h a t was a minimum i n the weeks of a given p e r i o d (TOTAL),.or on the accumulated d i f f e r e n c e s l n hours o f b r i g h t sunshine between c o n s e c u t i v e days f o r the week whose value o f t h a t was a minimum i n the weeks of a g i v e n p e r i o d (FLUTO). 2  T  C  Weeks from which min. was chosen WO, , Wl WO, . Wl, W2 wo, Wl, W2, wo, Wl, W2, wo, Wl, W2, wo, Wl, W2, wo, Wl, W2, Wl, W2 Wl, W2, W3 Wl, W2, W3, Wl, W2, W3, Wl, W2, W3, Wl, W2, W3, W2, W3 W2, W3, W4 W2, W3, W4,, W2, W3, W4, W2, W3, W4, W3, W4 W3, W4, W5 W3, W4, W5, W3, W4, W5, W4, W5 W4, W5. w6 W4, W5, W6, W5,  w6  W6,  W7  No v  W3 W3, W3, W3, W3.  W4 W4, W5 W4, W5. W6 W4, W5. w6, W7  W4 W4, W5 W4, W5, w6 W4, W5, w6. W7 W5 W5, W5,  w6  w6, W7  w6 w6, W7 W7  w6, W7  d  w a s > s i g n i f i c a n t a t 5% l e v e l .  TOTAL  .02 .03 .03 .07 .03 .01 .07 .02 .06 .07 .03 .01 .07 .07 .07 .03 .10 .07 .00 .04  .01 .07 .07 .10 .07 .06 .02  .09  for FLUTO  .00 .01 .03 .03 .00 .00 .03 .21 .19 .20 .08 .04  .09 .09 .02 .00 .00 .03 .02 .00 .01 .03 .01 .00  .00 .00 .00  .00  38 Table 9 C o e f f i c i e n t of d e t e r m i n a t i o n ( r ) of l i n e a r r e g r e s s i o n of the i n c i d e n c e o f BR and weekly d i f f e r e n c e s o f t o t a l hours of b r i g h t sunshine (TOTAL), o r on weekly d i f f e r e n c e s of accumulated d i f f e r ences i n the hours of b r i g h t sunshine between c o n s e c u t i v e days. 2  Combinations of weeks  Abbreviations t o be used i n other tables  TOTAL  r  2  for FLUTO  W0-W1  Al  .00  .16  W1-W2  A2  .03  .00  W2-W3  A3  .04  .10  W3-W4  A4  .11  .00  W4-W5  A5  .02  .10  W5-W6  A6::  .00  .00  W6-W7  A7  .09  .00  No r  2  was s i g n i f i c a n t  a t 5% l e v e l .  See the appendix f o r the a c t u a l value of A l , A2, A3, A4,. A5. A6,. and A7 f o r the 12 cases l i s t e d l n Table 1.  39 Table 10 C o e f f i c i e n t of d e t e r m i n a t i o n ( r ) o f l i n e a r r e g r e s s i o n of the i n c i d e n c e of BR on the maximum of weekly d i f f e r e n c e s of t o t a l hours of b r i g h t sunshine f o r given weeks (TOTAL), o r on weekly d i f f e r e n c e s of accumulated d i f f e r e n c e s i n the hours of b r i g h t sunshine between consecutive days. 2  Weekly d i f f e r e n c e s from which the max. was chosen Al, Al, Al, Al, Al, Al, A2, A2, A2, A2, A2, A3,  A2 A2, A2, A2, A2, A2, A3  A3 A3, A3, A3, A3,  A4 A4, A4, A3, A4, A4 A4, A3, A5 A3, A4, A5, A3, A4, A5, A4, A5 A4, A5. A4, A5, A3, A3, A3.  A6 A6,  A5. A6 A5, A6, A7  A6, A7  r for TOTAL FLUTO 2  .00 .00 .14 .14 .08 .04 .00 .29 .29 .17 .10 .08 .12 .14 .07 .16 .17 .07 .00 .00 .00  .03 .16 .15 .33 * .13 .01 .06 .10 .35 * .13 .01 .12 .18 .06 .00 .02 .00 .03 .00 .03 .03  *i S i g n i f i c a n t at 5% l e v e l . A l , A2, A3, A4, A5, A6 and A7 are t h e a b b r e v i a t i o n s l n Table 9 .  shown  40  Table 11 C o e f f i c i e n t of d e t e r m i n a t i o n ( r ) o f l i n e a r r e g r e s s i o n of the i n c i d e n c e of BR on the minimum of weekly d i f f e r e n c e s of t o t a l hours of b r i g h t sunshine f o r g i v e n weeks (TOTAL),, or on the minimum of weekly d i f f e r e n c e s of accumulated d i f f e r e n c e s i n the hours of b r i g h t sunshine between c o n s e c u t i v e days of g i v e n weeks (PLUTO).. 2  Weekly d i f f e r e n c e s from which the min. was chosen Al, Al, Al, Al, Al, Al, A2, A2, A2, A2, A2, A3, A3, A3, A3,  A2 A2, A2, A2, A2, A2,  A3 A3, A3, A3, A3,  A3 A3, A3, A3, A3,  A4 A4, A5 A4, A 5 , A6 A4, A 5 , A6, A7  A4 A4, A 5 A4, A 5 , A6 A4, A 5 , A6, A7  A4 A4, A5 A4, A 5 , A6 A4, A 5 , A6, A7  A4, A 5 A4, A 5 , A6 A4, A 5 , A6, A7 A 5 , A6 A 5 , A6, A7 A6, A7  r for TOTAL FLUTO 2  .07 .02 .02 .01 .00 .00 .00 .00 .01 .02 .00 .02 .00 .01 .00 .03 .02 .22 .02 .24  .31  .28  .03  .04  .06 .19 .12 .08  .00 .00 .01 .10 ,00 .08 .01 .00 .18  .05 .03 .02 .03 .00  No r was s i g n i f i c a n t a t 5% l e v e l . A l , A2, A 3 , A4, A 5 , A6 and A7 are the a b b r e v i a t i o n s shown i n Table 9. 2  41 Table 12 The s i g n i f i c a n t l i n e a r r e g r e s s i o n o f the Incidence o f BE on~ hours of b r i g h t sunshine.  Combinations of weeks  TOTAL or r FLUTO  W0-W1  FLUTO .52  W0+W2+W4-(W1+W3)  Coefficient (b)  Standard e r r o r of estimate  1.62  .0809  .765  TOTAL .40  2.43  -.0184  .854  W0+W2+W4+W6r(W1+W3+W5)  TOTAL .38  2.09  -.0143  .867  W0+W2+W4+W6(W1+W3+W5+W?)  TOTAL .54  1.51  -.016?  .744  W1+W3+W5+W7-(W2+W4+W6)  TOTAL .40  .0170  .854  W2+w4+Wot-( W3+W5+W7)  TOTAL .3*  .0174  .897  W3+w5+W7-(w4+w6)  TOTAL .38  .0170  .864  W6-W7  TOTAL .37  1.60  -.0298  .874  Max.* (A1,A2,A3,A4,A5)  FLUTO  3.82  -.1291  .900  Max.** (A2,A3,A4,A5)  FLUTO .35  3.86  -.1324  .885  TOTALt  FLUTO«  2  .33  Constant (a)  .446 1.56 .720  Accumulated hours o f b r i g h t sunshine f o r a week. Accumulated d i f f e r e n c e s i n the hours o f b r i g h t sunshine between c o n s e c u t i v e days f o r a weeks. A maximum of A l , A2, A3, A4 and A5. A maximum of A2, A3, A4 and A5. A l , A2, A4 and A5 are a b b r e v i a t i o n s shown i n Table 9.  4B Table 13 C o e f f i c i e n t of d e t e r m i n a t i o n ( r ) of l i n e a r r e g r e s s i o n s of the i n c i d e n c e o f BR on accumulated maximum o r minimum temperatures f o r c e r t a i n combinations of g i v e n weeks (TOTAL), o r on accumul a t e d d i f f e r e n c e s I n maximum o r minimum temperatures f o r c e r t a i n combinations of g i v e n weeks (PLUTO). 2  Combinations of weeks W0-W1. W0+W2+W4-(W1+W3)  wo+w2+w4+w6-(WI+W3+W5)  W1+W3+W5+W7-(W2+W4+W6) W3+W5+W?-(w4+w6) W6-W7 Max.* (A1,A2,A3,A4,A5) Max.** (A2,A3,A4,A5)  TOTAL or FLUTO FLUTO TOTAL TOTAL TOTAL TOTAL TOTAL FLUTO FLUTO  r2 f o r maximum minimum temperature temperature .15 .20 .20 .08  .14 .12 .03 .09  .00 .01 .00 .00 .00 .00 .12 .14  * Maximum o f A1,A2,A3,A4, and A5. ** Maximum o f A2,A3,A4 and A5. A l , A2, A3, A4 and A5 are a b b r e v i a t i o n s shown i n Table 9 .  43 I t can be seen i n Table 14 t h a t the r e g r e s s i o n of  BR  Incidence (Y) on the v a r i o u s t e n models (X^....X^Q) f o r l i g h t e f f e c t s gave c a l c u l a t e d values  f o r Y which i n only the case of  the Xx model c l o s e l y approached the a c t u a l or known value which was The  the BR  incidence  reported  the f l u c t u a t i o n value  of the p r e c e d i n g  harvest  and  harvest  between the two Figure  t  Y=l.62+0.0809X, combination!  week (W0-W1) showed the Lower Mainland,  great d i f f e r e n c e i n the s e v e r i t y of  and  BR  regions. 3 shows t h a t the p a t t e r n s  sunshine f o r the I s l a n d and were s i m i l a r .  was  o r PLUTO f o r the  l a r g e s t Y d i f f e r e n c e between the I s l a n d and t h a t week showed the  Y.  from commercial greenhouses.  X i model used i n the r e g r e s s i o n equation  where the X was  of  of d a i l y hours of b r i g h t  Lower Mainland d u r i n g March to  May  A marked decrease l n hours of b r i g h t sunshine  can be noted f o r three days from May  9 to 11 i n the Lower  Mainland r e c o r d whereas the same p e r i o d f o r the I s l a n d was a l most  constant. S i g n i f i c a n c e of the l i n e a r r e g r e s s i o n of the  of BR and WO,  Wl,  the accumulated f o u r l a r g e s t d i f f e r e n c e s i n a week f o r  or W2  Only the W0-W1 equation of 2.03  and  t h e i r combinations i s summarized i n Table  model was  significant  The  (r ~.42). 2  The  f o r the I s l a n d and  1.54  f o r the Mainland, and a c t u a l l y reported  ture conditions  on the i n c i d e n c e  of  BR.  values  these  f o r BR  i n f l u e n c e of weekly a l t e r n a t i o n of l i g h t and  15.  regression  f o r t h a t model i s Y=l.59+0.0887X which g i v e s Y  c l o s e l y approximate the values 2)  incidence  incidence.  tempera-  44 Table 1 4 , Comparison o f the i n c i d e n c e o f BR on Vancouver I s l a n d (ISL) and Lower Mainland (LM) d u r i n g the p e r i o d of May 14-20, 1 9 6 9 .  Regression equation  X v a l u e f o r Corresponding ISL LM v a l u e of Y f o r ISL LM"  Y=l.62+.0809Xi  15.2  Y=2.43-.0I84X  2  Y=2.09-.OI43X3  A c t u a l value of Y f o r ISL LM'  2.84  1..61  3  r  27.8 29.2  1.91  I.89  3  1  8.10  7.80  1.97  1.98  3  1  -.10  Y = l . 51-.,0167X4  -27.5  ^23.8  1.97  1.90  3  1  Y=.446+,0170X3  110  112  2.31  2.35  3  1  Y=1.56+.0174X  -21.8  -33.4  1.13  3  1  72.7  77.9  1.95  2.04  3  1  -7.9  -10.4  I.83  1.90  3  1  Y=.720+.0170X  6  ?  Y=l.60-.0298X  8  .982  Y=3.82-.I29IX9  15.2  20.1  1.86  1.23  3  1  Y:=3.86-.1324X  14.3  20.1  1.97  1.20  3  1  Yt Xl,  1 0  S e v e r i t y o f the i n c i d e n c e of BR. 0 Y 3 FLUTO f o r (W0-W1) TOTAL f o r (W0=W2+W4-(W1+W3)) Xy TOTAL f o r (W0+W2+W4+W6-(W1+W3+W5)) *4: TOTAL f o r (W0=W2+W4+W6-(W1+W3+W5+W7)) TOTAL f o r (W1+W3+W5+W7-(W2+W4+W6)) TOTAL f o r (W2+w4+w6-(W3+W5+W7)) TOTAL f o r (W3+W5+W7-(W4+W6)) TOTAL f o r (W6-W7) 8 FLUTO f o r the the maximum of ( A l , A2, A3, A4 and A5) X9i o * FLUTO f o r the the maximum of (A2, A3, A4 and A5) TOTAL: T o t a l hours of b r i g h t sunshine, FLUTO: T o t a l of d a l l y f l u c t u a t i o n s i n hours of b r i g h t sunshine. A l , A2 A3, A4 and A5 are a b b r e v i a t i o n s shown l n Table 9 . x  x  Hours  45  Figure 5 iiours o f b r i g h t sunshine on Vancouver I s l a n d and Lower Mainland, B r i t i s h Columbia, f o r the s p r i n g (March 1 t o Kay 31) 1969.  46 Table 15 C o e f f i c i e n t of d e t e r m i n a t i o n ( r ) o f l i n e a r r e g r e s s i o n o f the i n c i d e n c e of BR and accumulated l a r g e s t f o u r d i f f e r e n c e s i n hours of b r i g h t sunshine between c o n s e c u t i v e days f o r a week, o r i t s combinations f o r three weeks. 2  Combinations of weeks WO Wl W2 WO-Wl W1-W2 WO-Wl W2  Iwo-wil IW1-W2I..  |W0-W1'|+|W1-W2| Max (W0.W1) Max (W0.W1.W2) Max (W1.W2) Min (W0.W1) Min (W0.W1.W2) Min (W1.W2)  r .24  .10 .10  .42*  .00  .14 .2?  .00  .14  .20 .03 .09 .00 .00 .12  *i S i g n i f i c a n t a t 5% l e v e l . Max (W0.W1) means the:_inaxlmum o f W0 and Wl. Min (W0.W1) means the minimum o f W0 and Wl.  47 The number o f BR f r u i t s produced experiment  v a r i e d w i t h the treatments.  n e c r o t i c t i s s u e i n the a f f e c t e d f r u i t symptoms was a l s o v a r i a b l e treatment  (Fig.4).  i n t h i s growth chamber A l l the BR f r u i t s had  wall.  The s e v e r i t y of t h e  The symptoms i n the c o n t r o l  (TcLc^) were very m i l d except f o r two of seven BR f r u l t s , -  i . e . e x t e r n a l l y the a f f e c t e d a r e a on the f r u i t d i d not exceed one oi  ,.and i n t e r n a l l y , o n l y v a s c u l a r bundle I n the a f f e c t e d a r e a  had a n e c r o t i c appearance. h i g h e s t BR i n c i d e n c e produced  The TcLa treatment which  gave the  the most severe symptoms.  a f f e c t e d areas of the m a j o r i t y of the BR f r u i t s i n t h a t 1 0 cmS  exceeded  i n some c a s e s .  The treatment  The e n t i r e f r u i t was a f f e c t e d with the d i s o r d e r F r u i t with severe BR had l a r g e i r r e g u l a r  strips  of n e c r o t i c t i s s u e , and the b l o t c h y a r e a o f t e n had c o l l a p s e d  cells  i n the subsurface l a y e r s r e s u l t i n g i n s m a l l hollow spaces o r cavities.  The s e v e r i t y of the BR symptoms of most f r u i t s  from  TaLc and TaLa treatments was somewhat i n t e r m e d i a t e between TcLc and  TcLa. The i n c i d e n c e of BR, w i t h degrees of s e v e r i t y as des-  c r i b e d above, i s shown i n Table 1 6 .  I n s p e c t i o n of the data  showed t h a t the TcLa treatment had the h i g h e s t i n c i d e n c e of BR which was 3 7 * 2 # of the t o t a l number of f r u i t s . had a low Incidence of 6 . 1 $ BR. and i s a l s o markedly TcLa.  TcLc treatment  The Incidence l n TaLa was 1 0 . 9 #  lower i n BR i n c i d e n c e than e i t h e r TaLc o r  I t i s t o be noted t h a t the lower amounts of BR occur l n  the chambers where both temperature  and l i g h t c o n d i t i o n s were  e i t h e r consistent or alternated simultaneously.  Figure  4  E x t e r n a l and I n t e r n a l symptoms of s e v e r i t y .  o f BR f r u i t s  with various  degrees  The f i r s t p i c t u r e shows t h e e x t e r n a l symptoms; the second, the i n t e r n a l symptoms o f t h e same f r u i t s . The c r o s s - s e c t i o n s o f t h e f r u i t s were a r r a n g e d so t h a t t h e f r o n t p a r t o f t h e f r u i t I n t h e f i r s t p i c t u r e i s p o i n t i n g t o w a r d t h e t o p o f t h e page i n t h e second p i c t u r e .  49 Table  16  The I n f l u e n c e of weekly a l t e r n a t i o n of l i g h t and temperature c o n d i t i o n s on the i n c i d e n c e of BR, expressed as a number of BR f r u i t s over the t o t a l number o f f r u i t s h a r v e s t e d .  Length of treatment  Treatment TcLc  TcLa  TaLc  -  TaLa  (weeks) 4  1/9  -  5  1/13  1/1  0 /4  0/5  6  0/21  2/7  1/7  2/13  7  0/10  7/15  4/17  2/15  8  3/24  4/19  1/20  1/15  9  0/13  12/29  3/28  2/20  10  2/9  12/25  10/32  3/15  11  0/6  6/19  6/1?  1/7  12  0/6  1/4  3/H  0/7  13  0/4  0/2  -  0/2  Total {% BR f r u i t )  7/H5 (6.1)  45/121 (37.2)  28/136 (20.6)  0/2  11/101 (10.9)  50  When the data i n Table 1 6 was s u b j e c t e d t o s t a t i s t i c a l a n a l y s i s , d i f f i c u l t i e s were encountered. samples and the v a r i a b i l i t y  The s m a l l s i z e of some  i n number of f r u i t s harvested d u r i n g  t e n weeks p r e c l u d e d the a n a l y s i s of d a t a as a b i n o m i a l d i s t r i b u tion.  The u s u a l recommendation of e x p r e s s i n g such data i n - p e r -  centages a l s o had t o be r e j e c t e d . were c o n s i d e r e d as a commercial  When the d a t a i n Table 16  h o r t i c u l t u r a l crop, y i e l d s c o u l d  be c o n s o l i d a t e d i n t o the f o u r harvest groups, namelyj 1)  e a r l y crops  2)  second e a r l y crops  3)  main crops  y i e l d f o r weeks 9 and 10  4)  l a t e crops  y i e l d f o r weeks 1 1 t o 1 3 .  Y i e l d f o r weeks k t o 6 —  y i e l d f o r weeks 7 and 8  The data of Table 1 6 are shown l n t h i s manner i n Table 1 7 , expressed as percentages.  S t a t i s t i c a l a n a l y s i s showed t h a t  the i n t e r a c t i o n of l i g h t and temperature component o f v a r i a n c e . ment produced  was the only s i g n i f i c a n t  Duncan's t e s t shows that the TcLa  a s i g n i f i c a n t l y h i g h e r percentage  and TaLa treatment.  treat-  of BR than TcLc  The o t h e r d i f f e r e n c e s i n the occurrence of  BR were not s i g n i f i c a n t . Total yield, f r u i t  s i z e , and f r u i t number p e r p l a n t were  a l s o recorded (Tables 18, 19 and 2 0 ) .  The treatments TcLa and  TaLc,. which r e s u l t e d i n the g r e a t e r percentage tended t o have the l a r g e r f r u i t  of BR f r u i t s ,  s i z e , g r e a t e r number of f r u i t s  per p l a n t and t h e r e f o r e , g r e a t e r t o t a l y i e l d .  The d i f f e r e n c e s  are not s i g n i f i c a n t with the e x c e p t i o n of the TaLc y i e l d to the other treatments.  relative  Table 17 The I n f l u e n c e of weekly a l t e r n a t i o n of l i g h t and temperature c o n d i t i o n s on the i n c i d e n c e of BR i n percentage.  Crops TcLc  %  Treatment TcLa TaLc  #'  %  TaLa <  9.1  10.1  32.4  13.5  10.1  9.1  44.4  21.7  14.:  Late  0.0  28.0  32.1  6.:  Mean  5 . 6 b:•  35.6 a  1 9 . 1 ab i o . :  Early  4.7  37.5  2nd  8.8  Main  early  Treatment means w i t h common l e t t e r s a r e not s i g n i f i c a n t l y d i f f e r e n t a t 5% l e v e l .  Table 18 The I n f l u e n c e of weekly a l t e r n a t i o n of l i g h t and temperature c o n d i t i o n s on the y i e l d of tomato crops l n grams of f r u i t . Treatment  Plant  Mean  TcLc  4900  5050  3701  3143  4198. 5b-  TcLa  4654  4698  4942  3850  4536.0b  TaLc  4764  6339  6090  5461  5663.5a  TaLa  3529  4318  3161  2674  3420.5b  Treatment means with a common l e t t e r are not s i g i f i c a n t l y d i f f e r e n t a t 5% l e v e l . Table 19 The I n f l u e n c e of weekly a l t e r n a t i o n of l i g h t and temperature c o n d i t i o n s on the f r u i t s i z e i n grams as average f r u i t weight within a plant.  Plant  Treatment  Mean:  TcLc  148.5  148.5  154.2  131.0 145.6a  TcLa  179.0  134.2  164.7  128.3 151.6a  TaLc  158.2  171,3  164.6  170.7  TaLa  196.1  110.7  121.6  148.6 144.3a  l6.6.1 a ?  Treatment means with a common l e t t e r are not. s i g n i f i c a n t l y d i f f e r e n t a t 5% l e v e l .  53 Table 20 The I n f l u e n c e of weekly a l t e r n a t i o n of l i g h t and temperature c o n d i t i o n s on the number of f r u i t s per p l a n t .  Treatment  Plant.  Mean  TcLc  33  34  24  24  28.5 a  TcLa  26  35  30  30  30.3  a  TaLc  30  3?  3?  32  34.0  a  TaLa  18  39  26  18  25-3 a  Treatment means with a common l e t t e r are not s i g n i f i c a n t l y d i f f e r e n t at 5% l e v e l .  54 3)  A s s o c i a t i o n of BR o f greenhouse tomatoes and tobacco mosaic virus  (TMV) i n B r i t i s h Columbia I n  I969.  The data i n Table 21 show t h a t some BR f r u i t s from commerc i a l greenhouses were f r e e from TMV.  Although BR was present  l n the greenhouse of grower No.3» the p l a n t s were f r e e from  TMV.  The d a t a i n Table 21 were analyzed f o r v a r i o u s aspects and r e s u l t s are l i s t e d i n Table 2 2 . The prevalence of TMV" both i n BR f r u i t s and non-BR i n the two l o c a t i o n s d i d not d i f f e r s i g n i f i c a n t l y .  A l s o the  prevalence of TMV among non-BR f r u i t s d i d not d i f f e r between Vancouver I s l a n d and the Lower Mainland.  fruits  significantly  Furthermore,  the prevalence of TMV among non-BR f r u i t s l n May on the Lower Mainland  d i d not d i f f e r s i g n i f i c a n t l y  were s i g n i f i c a n t l y the  from t h a t i n J u l y .  There  more BR f r u i t s w i t h TMV on the I s l a n d than on)  Mainland. The assays of TMV i n a f r u i t and a l e a f from the same  p l a n t , as shown i n Table 2 3 , i n d i c a t e t h a t the presence  of the  TMV. was not always demonstrated i n both the f r u i t and l e a f of a given p l a n t .  One extreme case I s noted f o r grower NO.8  where 33 p l a n t s were sampled, and 26 of the f r u i t showed  TMV  with c o r r e s p o n d i n g leaves a p p a r e n t l y f r e e from the v i r u s . 4)  A s s o c i a t i o n of BR and potato v i r u s X  (PVX).  V i r u s assays showed t h a t c o n t r o l p l a n t s were f r e e TMV and PVX throughout  the experiment.  were i n f e c t e d by PVX only and not by TMV. of  PVX i n f e c t i o n appeared  inoculation.  from  The PVX-lnfected p l a n t s The mosaic  symptoms  on the p l a n t s two months a f t e r the  55 Table  21  A s s o c i a t i o n of tobacco mosaic v i r u s (TMV.) with BR f r u i t s l n commercial crops of greenhouse tomatoes i n 1969.  P l a c e Grower  F r u i t s w i t h BR Infected Total number with TMV assayed  F r u i t s without BR Total Infected number with TMV assayed  N0.1  10  8  2  2  NO. 2  -  -  6C  2  NO. 3  7  0  8  0  NO. 4  2  2  1  0  NO. 5  5  5  5  5  NO. 6  6  6  k  k  Subtotal  30  21  NO. 7  6  5  k  3  NO.8  28  28  5  5  Subtotal  3*  33  ~9  "8"  NO. 7  -  -  2k  NO.8  -  -  23  36  34  60  57  ISL  Date of sampling  May 25/69  13  ray 20/69  LM  Subtotal  ISLJ LMI  Vancouver I s l a n d Lower Mainland  J u l y 14/69  56  Table 22 R e s u l t s of t - t e s t  on v a r i o u s comparisons of the d a t a i n Table  D i f f e r e n c e s i n frequency of TMV between; BR (21/30) and non--BR f r u i t s  (13/26)  BR (33/34) and non--BR f r u i t s  (8/9) on LM' i n May..  on ISL.  ISL  (13/26)  and. LM. (8/9)  ISL  (21/30)  and LM~ (33/34) B R ' f r u i t s i n May.  May ( 8 / 9 ) : and.  Significance  non-BR f r u i t s i n May.  J u l y (57/60) i n non-BR f r u i t s on LM.  N.S. N.S. N.S. « N.S.  Numbers i n a p a r e n t h e s i s show the number of f r u i t s TMV."over t o t a l number of f r u i t s surveyed. ISLi LM'i N.S.i *t  Vancouver I s l a n d . Lower Mainland. Not s i g n i f i c a n t .at 5fo l e v e l . S i g n i f i c a n t a t 5% l e v e l .  with  21.  57 Table  23  P r e s e n c e o f TMV  Place  ISL  or i n both.  TMV p r e s e n t l n leaf fruit only only neither  Total number of fruits assayed  both fruit and leaf  N0.1  13  61  5  l ;•;  NO.2  6  2  0  0  NO.3  16  0  0  0  16  NO.4  3  2  0  l  0  Grower  5  10  10  0  0  0  NO.  6  10  10  0  0  0  58"  30  7  10  4  4  NO.8  33  7  26:  NO.  Date of sampling  l  NO.  Subtotal  LM  In f r u i t , - l e a f ,  May 25/69?  21  1 1 ' 0  0  May 20/69  58  One  p l a n t only l n the experiment produced BR  n e c r o t i c t i s s u e i n the f r u i t statistically two  wall.  chamber s e r i e s , that i s 3.3% Y i e l d per p l a n t and shown i n Tables 25 and grown i n the  This observation  s i g n i f i c a n t because the BR was  out of e i g h t f r u i t s on one  of the  which  present  was on  had not only  14 p l a n t s i n t h a t growth  BR f r u i t as;.shown i n Table  24.  average f r u i t weight per p l a n t  are  26 r e s p e c t i v e l y .  The  control plants  greenhouse -gave a h i g h e r y i e l d than p l a n t s i n the  growth chambers.  The  average f r u i t  under greenhouse c o n d i t i o n s , but s i g n i f i c a n t e f f e c t on f r u i t  size.  weight per p l a n t was  the presence of PVX  had  greater no  59 Table The  24  Influence  of potato  virus  X(PVX)  on t h e i n c i d e n c e  of  BR.  P e r c e n t a g e o f f r u i t w i t h BR Growth chambers Greenhouses  PVXr-infected  3.3  .0  .0  .0  PVX;free  Table The  25  influence  Plant  NO.  o f PVX  on t o t a l  fruit  weight per p l a n t .  Weight of f r u i t p e r p l a n t (grams) PVX-infected PVX f r e e Greenhouse Chamber Greenhouse  1 2 3  1075-5  5 6 7  962.5 832.3  k  Mean  T r e a t m e n t means different.  610.7 987.5 630.7  838.7  513.6  672.2 979.5 1093.0  816.9  500.1 930.6  845.2b-  789.7b  with  a common  letter  932.8 755.8 814.7 509.1 1147.0 970.3 1263.5 995.2a  are not  Chamber  1011.8  725.8  706.4 1116.9 380.2 862.4 638.0  777.4b  significantly  60 Table 26 The  I n f l u e n c e of PVX on average  f r u i t weight w i t h i n a p l a n t .  • A v e r a g e f r u i t weight (grams) P l a n t NO. PVX-lnfected PVX f r e e Greenhouse Chamber Greenhouse Chamber  1 2 3 4 5 6 7 Mean  119.5  122.1 157.7 96.3 92.5 98.8 90.8  111.0a  93.2 85.6 74.7 81.6  109.3 83.4 116.3 92.0a  116.6 94.5 90.5 72.7  114.7  97.0  140.4  103.7a  101.2 103-7 88.3 101.5 63.4 106.3 95.8 94.3a  Treatment means with a common l e t t e r are not s i g n i f i c a n t l y d i f f e r ent. The a n a l y s i s of v a r i a n c e showed t h a t the primary e f f e c t of l o c a t i o n was s i g n i f i c a n t a t 5% l e v e l .  61 DISCUSSION 1).  C o r r e l a t i o n .between hours o f b r i g h t sunshine and the i n c i d e n c e o f BR. White (1938) observed a n e g a t i v e c o r r e l a t i o n between BR  i n c i d e n c e and t o t a l hours of b r i g h t sunshine d u r i n g f i v e of the season.  He a t t r i b u t e d the annual d i f f e r e n c e s i n the  i n c i d e n c e o f BR t o the t o t a l hours o f b r i g h t sunshine vary a n n u a l l y . the  months  which  Data used I n t h i s present study suggest t h a t  hours of b r i g h t sunshine may a l s o be a s s o c i a t e d w i t h the  f l u c t u a t i o n of the i n c i d e n c e o f BR w i t h i n a season.  Although  hours of b r i g h t sunshine f o r any p a r t i c u l a r week were not significantly  c o r r e l a t e d with the s e v e r i t y o f the BR i n c i d e n c e  (Table 4 ) , the hours o f b r i g h t sunshine f o r some combinations of weeks were c o r r e l a t e d s i g n i f i c a n t l y  (Table 6 ) .  Such  combi-  n a t i o n s , as summarized i n Table 12, suggested that weekly a t i o n of t o t a l hours of b r i g h t sunshine i s the Important  fluctuinflu-  ence o f the l i g h t f a c t o r on the i n c i d e n c e o f BR, r a t h e r than the t o t a l hours of b r i g h t sunshine of the season as emphasized by White (1938).  The r e g r e s s i o n of the i n c i d e n c e of BR on t o t a l  hours of b r i g h t sunshine was most s i g n i f i c a n t  when the time  p e r i o d was extended t o seven weeks b e f o r e h a r v e s t (W0*W2+W4+W6(W1+W3+W5+W7))» s u g g e s t i n g t h a t the i n f l u e n c e of b r i g h t  sunshine  on BR i n c i d e n c e may be cumulative. The maximum and minimum temperatures recorded a t the weather s t a t i o n s d i d not appear t o be r e l a t e d with BR i n c i d e n c e , thus g i v i n g support t o the i d e a that l i g h t i s the important f a c t o r i n the models d i s c u s s e d .-.-above.  62 In a d d i t i o n t o the t o t a l s of hours of b r i g h t  sunshine,  there are t h r e e f l u c t u a t i o n o r PLUTO values t a b u l a t e d i n Table 1 2 . The use of the maxima of the "A" values which are d i f f e r e n c e s between c o n s e c u t i v e weeks l n terms of f l u c t u a t i o n s i n hours of b r i g h t sunshine from day t o day l n a given week, showed a negative relationship.  .1291X  One of the two examples I s the equation Y=3.82-0  (Table 1 2 ) , where X I s the maximum of PLUTO v a l u e s which  are A l , A2, A3, A4, and A5. t  T h i s equation means t h a t , w i t h l m  a p e r i o d of f i v e weeks before h a r v e s t , the maximum value i n d i f f e r ences between c o n s e c u t i v e weeks i n terms of t o t a l d a i l y ences i n hours of b r i g h t sunshine w i t h the i n c i d e n c e of BR.  was c o r r e l a t e d  differ-  significantly  The negative c o e f f i c i e n t (-0.1291)  i n d i c a t e s t h a t the g r e a t e r the maximum of FLUTO v a l u e , the s m a l l e r the Incidence of BR.  In other words, an occurrence of a week  w i t h r e l a t i v e l y uniform weather, f o l l o w e d o r preceded of very v a r i a b l e weather i n terms o f hours of b r i g h t w i t h i n a p e r i o d of f i v e weeks, should decrease BR.  T h i s type of environmental  by a week sunshine,  the i n c i d e n c e of  e f f e c t c o n f l i c t s w i t h the known  BR i n c i d e n c e i n B r i t i s h Columbia i n 1 9 6 9 .  There was very h i g h  i n c i d e n c e of BR on Vancouver I s l a n d d u r i n g May 1 4 - 2 0 , there was a week with no f l u c t u a t i o n preceded  I 9 6 9 when  by the week with a  c o n s i d e r a b l e f l u c t u a t i o n i n terms of hours of b r i g h t  sunshine;  but there was a very low Incidence of BR on the Lower Mainland d u r i n g the same p e r i o d when a l l weeks had f l u c t u a t i n g weather. T h i s c o n t r a d i c t i o n warranted The  r e j e c t i o n of the e q u a t i o n .  f o r e g o i n g i s a l s o t r u e f o r the other equation Y=3.86-0  . 1324X: (Table 12) where X i s the maximum of PLUTO v a l u e s which  63  are A2, A3, A4, and A5t t h e r e f o r e ,  t h i s model was  rejected.  A l a r g e r d a l l y f l u c t u a t i o n of hours of b r i g h t sunshine during harvesting weeks was associated with a higher  Incidence  of BR, I f the preceding week had a smaller f l u c t u a t i o n of hours of b r i g h t sunshine as Indicated by the p o s i t i v e  coefficient  (0.0809) f o r the combination of W0-W1 f o r FLUTO i n Table 12, which was h i g h l y s i g n i f i c a n t .  This r e g r e s s i o n , Y=l.62+0.0809X  was most suited to e x p l a i n i n g the difference  of the incidence of  BR i n 1969 between the Vancouver I s l a n d and the Lower Mainland commercial houses, when the former had a high incidence of BR i n contrast to the very low incidence on the Mainland.  This  r e l a t i o n s h i p may be seen i n Figure 3 as a marked decrease i n the hours of b r i g h t sunshine during the week of May 6-11 i n the Lox<rer Mainland r e c o r d . incidence).  (That week was Wl f o r the difference  i n the BR  These records suggested that a four day period  instead of a seven day period was worth c o n s i d e r a t i o n , and the several patterns or models are l i s t e d i n Table 15.  Again the  W0-W1 combination was the only one to show a s i g n i f i c a n t  regres-  sion of BR on the f l u c t u a t i o n i n the hours of b r i g h t sunshine.. The r  2  f o r that regression was 0.4-2 which i s smaller than, or l e s s  s i g n i f i c a n t than the r  2  of 0 . 5 2 f o r the combination of W0-W1 f o r  FLUTO i n Table 6, suggesting that the d a i l y f l u c t u a t i o n  accumulated  f o r seven days was more r e v e a l i n g than accumulating the l a r g e s t four days of a week i n order to e x p l a i n 1 the Incidence of BR. The examination of the weather data i n general the f o l l o w i n g two points»  Indicates  64 A.  BR i n c i d e n c e i n B.C. greenhouse tomatoes appears  to be a s s o c i a t e d with the c y c l i c  occurrence  o f a sunny week and  a cloudy week. B.  The low i n c i d e n c e o f BR d u r i n g May 14-20 i n 1 9 6 9  on the Lower Mainland may be a t t r i b u t e d t o the marked d a i l y f l u c t u a t i o n of hours o f b r i g h t sunshine d u r i n g May 6 - 1 3 . whereas the h i g h BR Incidence virtually 2)  on Vancouver I s l a n d was a s s o c i a t e d  with  no f l u c t u a t i o n .  The i n f l u e n c e o f weekly a l t e r n a t i o n of l i g h t and temperature  c o n d i t i o n s on the i n c i d e n c e o f BR. The  primary purpose of the growth chamber experiments  was t o t e s t the hypothesis study  which was d e r i v e d from the p r e v i o u s  of the a s s o c i a t i o n of hours of b r i g h t sunshine and the  i n c i d e n c e of BR.  The hypothesis  proposed t h a t there i s a l i n e a r  a s s o c i a t i o n between the BR i n c i d e n c e and the combination of t o t a l hours of b r i g h t sunshine.  The l i n e a r r e g r e s s i o n proposed was  Y=1.51-0.0167X, where Y I s the s e v e r i t y of the Incidence  of BR  d u r i n g a g i v e n week, and X i s the t o t a l hours of b r i g h t sunshine for  the combination of e i g h t weeks, W0-W1+W2-W3+W4-W5+W6-W?. The  The  first  r e g r e s s i o n equation  and the most important  implies three p r e d i c t i o n s . p r e d i c t i o n i s t h a t the weekly  a l t e r n a t i o n of l i g h t c o n d i t i o n s , sunny-day l i g h t and cloudy-day light  ( F i g . 2 ) w i l l produce BR, s i n c e Y can be 3 when X = - 8 9 . 2 .  S i m i l a r l y , Y can be 0 when i n Figure  5«  X=90.4.  T h i s r e l a t i o n s h i p i s seen  The s m a l l e r the X v a l u e , the l a r g e r the Y value  ( i . e . the s e v e r i t y of the i n c i d e n c e of BR)..  Figure  6 shows how  65 the  liRht  condition was employed l n TcLc and TaLa treatments.  Supposing f r u i t s were harvested during the 9 t h week a f t e r the i n i t i a l treatment, as shown i n Figure 6, then the crops w i l l be high i n the incidence of BR as X (which i s a TOTAL of W0+W2+W4+W6-(W1+W3+W5+W7)) becomes - 2 1 0 (derived from 5 2 . 5 * + 5 2 . 5 +52.5+52.5-(105**+105+105+lO5+105)).  The X values i n TcLa and TaLa  were exaggerated i n the present experiment to ensure that contrasting effects of the l i g h t treatments.  The X value of -210 corres-  ponds to a Y value of 3 (any Y value over 3 was regarded as 3 ) . But, i f the harvest was done i n the 1 0 t h week, the X value w i l l become 210 which corresponds to a Y value of 0 (any Y value smaller than 0 was regarded as 0 ) « therefore, there w i l l be l i t t l e incidence of BR,  Thus the incidence of BR w i l l depend  on the week designated as WO i n the use o f the model.  Therefore,  the second prediction i s that the incidence of BR produced by the weekly alternation of l i g h t conditions w i l l occur as a weekly cycle. The regression equation i s based on eight weeks of treatment period because X i n the equation i s a combination of l i g h t records over eight weeks.  Thus the t h i r d prediction  i s that eight weeks of the treatment period may be needed to produce BR. The f i r s t prediction appeared to be realized because the TcLa treatment, where daily temperature conditions were alternated weekly, produced a s i g n i f i c a n t l y *i **i  greater percentage  ( 7 . 5 hours/day)x(7 days/week)=52.5 hours/week ( 1 5 hours/day)x(7 days/week)=105 hours/week  Figure 5 The regression equation used f o r developing the hypothesis. Y: Severity of the incidence of BR. X: TOTAL of W0+W2+W4+W6- (Wlf W 3 + W 5 + W 7 ) .  W7  W5 '  > > 4J CO  r-l  a)  Pi  W6  I-I  W3 W4  Wl W2  -U  M •  1 2  •  3  4 5 6 7 8 9 weeks of treatments  10  11  12  Figure 6 Schematic figure of l i g h t treatment i n TcLa and TaLa conditions,  67 of BR f r u i t s than. ToLc, where temperature and were h e l d c o n s i s t e n t .  light  However, the TaLa treatment where the  l i g h t c o n d i t i o n s were a l t e r n a t e d , but  temperatures were a l s o  a l t e r n a t e d , d i d not give a s i g n i f i c a n t l y higher BR  than the c o n t r o l , TcLc.  conditions ture  conditions  The  incidence  of  e f f e c t of a l t e r n a t i o n of  light  seemed to be n u l l i f i e d by the a l t e r n a t i o n of tempera-  conditions. The  second p r e d i c t i o n proposes t h a t f r u i t  harvested  d u r i n g even weeks w i l l have absence or low Incidence of T h i s p r e d i c t i o n i s based on the f a c t that the f i r s t treatments began with cloudy-day l i g h t . shows no  such r e l a t i o n s h i p !  The  BR.  c y c l e of 27  d a t a i n Table  t h e r e f o r e the p r e d i c t i o n was  not  v a l i d i n t h i s case. There Is no doubt that many environmental f a c t o r s are i n v o l v e d i n the occurrence of BR.  I t i s a l s o w e l l known that  environmental c o n d i t i o n s w i t h i n a greenhouse d i f f e r from those in  a growth chamber.  in  the present  study and  greenhouses may responses may  growth chambers  the p l a n t s grown i n the  have responded d i f f e r e n t l y .  The  p e r i o d of one  commercial  Such d i f f e r e n t  e x p l a i n the f a c t t h a t the i n c i d e n c e  on a weekly c y c l e . been  Thus the p l a n t s l n the  of BR was  week per harvest may  not have  inappropriate. When c o n s i d e r i n g the t h i r d p r e d i c t i o n the d a t a i n Table  16  should  be handled w i t h s p e c i a l c a r e .  The  first  harvest  began  f o u r weeks a f t e r the p l a n t s were put l n the growth chambers. Thus f r u i t s were exposed to greenhouse c o n d i t i o n s f o r some weeks p r i o r to b e i n g placed  i n the chambers.  S i m i l a r l y other  fruits  68  Table 27 The c y c l i c occurrence of BR with l i g h t conditions alternated weekly. Treatment Plant  TcLa  TaLa  Mean  Odd weeks  40.0 2 3 . 1 47.4 2 3 . 1 36.4 0  8.3 12.5  23.9 a  even weeks  43.8 40.9 54.5 17.6 28.6 0  2 3 . 1 18.4  28.4 a  Means with a common l e t t e r are not s i g n i f i c a n t l y different.  69  which were harvested later were s t i l l subjected to possible influences of greenhouse conditions.  These pre-chambering  conditions may have had some influence on the production of BR fruits.  The regression equation i s based on eight weeks of  exposure to the laternating l i g h t conditions, suggesting that the influence of l i g h t conditions on the Incidence of BR may be cumulative.  Thus i t should be recognized that pre-exposure  conditions may be important because some influence may have accumulated before the plants were put into chambers.  Thus  the l i g h t conditions or hours of bright sunshine, to which the plants were exposed during the pre-exposure periods, were examined and are shown i n Figure 7.  It can be seen that  t o t a l hours of bright sunshine during A p r i l 24-30,, and May 1-7 are very close to the expected values derived from the regression-! equation.  Plants were put into chambers on May 8.  Thus two  such weeks should be considered as a possible part of the treatment intended to produce BR.  Hence, the length of the time of  the treatments as shown i n Table l6 may be extended to Include ;  the pre-exposure two weeks.  Thus i n Table 16 the 4th week of  treatment might be considered the 6th xveek, and similarly 5th would be considered as 7th weeks.  The 6th weeks of treatment  length i n Table 16 could, be regarded as 8th weeks and that i s the week when f r u i t s i n TcLa and TaLa commenced to be harvested i n volume. The weeks of A p r i l 10-16 and 17-24 had the t o t a l hours of bright sunshine very different from the expected values accordingly to the regression equation.  The influence of these two  weeks on the incidence of BR i s unknown.  However, one of the  70  May 1970  T  J  T o t a l hours o f 75.9 b r i g h t sunshine (Expected) (37.8) Difference (Expected)  7 V  V  47.6 (-22.4)  28.3 (60.2) l  V_  y  r 44.0 -15.7 (37.8) -17.4 / \ (-22.4) (22.4).  61.4 (60.2) /  Figure 7 Hours o f b r i g h t s u n s h i n e t o w h i c h t h e p l a n t s were exposed b e f o r e b e i n g p u t i n chambers, and c o r r e s p o n d i n g expected h o u r s o f b r i g h t s u n s h i n e f o r t h e p r o d u c t i o n o f BR f r u i t s .  71  s i g n i f i c a n t regressions l i s t e d  i n Table 12  i s based  on f i v e  weeks of hours of b r i g h t sunshine before h a r v e s t , i m p l y i n g t h a t only f i v e weeks of treatment may BR,  t h e r e f o r e weeks of A p r i l 10-16  important  i n producing  be enough to produce  and 17-24  may  not have been  BR.  F r u i t s harvested d u r i n g the 4th b e i n g put i n t o chambers (Table 16)  5th  and  week a f t e r  were exposed t o greenhouse  c o n d i t i o n s , the i n f l u e n c e of which on the i n c i d e n c e of BR i s u n c e r t a i n , f o r two  weeks and  one week r e s p e c t i v e l y .  The  number of f r u i t s harvested d u r i n g those two weeks i s too s m a l l t o compare w i t h the number of f r u i t s h a r v e s t e d f o r the r e s t of weeks f o r the e f f e c t of treatment  lengths;  therefore  the t h i r d p r e d i c t i o n from the r e g r e s s i o n e q u a t i o n - c o u l d not be t e s t e d w i t h the data i n Table  16.  Apart from the f i t n e s s of the experimental r e s u l t s to the h y p o t h e s i s , the d a t a . i n Table 16  suggested  a compensatory e f f e c t of l i g h t and temperatures  t h a t there Is i n BR i n c i d e n c e .  The h i g h e r i n c i d e n c e of BR r e s u l t i n g from the a l t e r n a t i o n of e i t h e r l i g h t or temperature and temperature (Table 16). of BR may  c o n d i t i o n s , was  reduced when l i g h t  c o n d i t i o n s were a l t e r n a t e d s i m u l t a n e o u s l y  In other words the d a t a suggests t h a t the  Incidence  be reduced by keeping the greenhouse temperature  e r d u r i n g cloudy days, and even warmer on sunny¥days.  cool-  It i s  b e l i e v e d t h a t growers u s u a l l y c o n t r o l v e n t i l a t i o n i n j u s t the opposite  way.  72  Abnormality In the affected tissue i s associated with early l i g n l f i c a t i o n of c e l l walls, which i n turn results i n a decrease l n permeability of c e l l walls, and hence renders the c e l l more vulnerable to injury caused by physiological or mechanical stress (Sadik and Mlnges 1966).  The metabolic  pathway for l i g n l f i c a t i o n i s summarized by Shubert  (I965).  These two sources can be used to develop a hypothetical scheme for tissue browning as follows.. polyphenoloxldase., sugars  ^ phenolic lignin ce^Ll^T' acids + * formation ^breakdown ~ r I stimuli 1! stress  ssue ^browning 11  I  fruit J maturation'1  f r u i t ripening  In this scheme, a certain kind of stimulus or stimuli are needed to i n i t i a t e l i g n l f i c a t i o n and deposit enough Hgnlm i n the c e l l wall so that the c e l l becomes vulnerable to Injury which i s a result of stress during f r u i t ripening.  That a  stress must be applied during f r u i t ripening matches the "shock" reaction theory of TMV i n f e c t i o n , which i s shown when a TMV-free plant i s inoculated with the virus when f r u i t s are about to ripen. Lignin formation may maturation and may ripening.  start during the period of f r u i t  continue i n the affected tissue during  When c e l l s are injured and the tissue broken down,  phenolic acids may be used to form polyphenols, catalyzed the polyphenoloxldase, which makes the tissue brown.  by  The  high a c t i v i t y of polyphenoloxldase i n the affected areas has  73  been reported (Kidson 1958, Then Walker  (I962)  Tompkins 1963,  Hobson 1967).  reported that f e r u l i c and caffeic acid  were lower i n the affected tissue than i n the normal f r u i t , leads to the deduction that i t i s the rate of conversion of phenolic acids into polyphenols and/or l i g n l n that i s abnormal rather than the synthesis of phenolic acids. A Kind of stimulus by which early l i g n i f i c a t i o n i s i n i t i a t e d and. continues to accumulate may vary with different situations.  Environmental factors Influencing l i g n l n formation  were reviewed by Brown (1966), but no definite effects of environmental factors i s known.  I t seems probable, from  the present study, that weekly alternation of l i g h t and temperature conditions may promote l i g n i f I c a t i o n .  The degree of c e l l  wall l i g n i f i c a t i o n could be Increased during Wl - W7 period so that the tissue becomes vulnerable to an injury caused by a stress.  Such a stress could result from a high temperature  with a low l i g h t l e v e l during a period of the WO which followed the high temperature with the high l i g h t level of the Wl. The higher temperature could allow a higher rate of respiration which demands more photosynthate  to be supplied,  whereas the low l i g h t level w i l l decrease the rate of photosynthesis.  Thus under these conditions there would be a shorts  age of the photosynthate.  The shortage would be greater when  the c e l l wall i s excessively l i g n i f i e d because i t would impede the rate of translocation.  Taylor (1957) and E l l s (I96D  suggested that the translocation of sugars was impaired i n the affected areas.  This l o c a l shortage of materials may disturb  the normal metabolism, and l n turn may cause a stress.  If a  low l i g h t level was coupled with a lower temperature, the stress  74 may not occur as the respiration rate would also be decreased. A stimulus f o r lignin- formation may be provided by weekly alternation of l i g h t or temperature as indicated i n the present study;  but, the actual stimulus i s not known.  In  the TaLa conditions, the stimulus f o r l i g n l n formation may have been exerted during the period of ¥1 - W7, but the stress does not appear to be as great as i n the case of TcLa and TaLc cond i t i o n s , as indicated by the production of more BB f r u i t s than TcLc but mueh less than TcLa and TaLc conditions (Table 16). In the proposed hypothetical scheme for tissue browning, a stress i s needed to damage the c e l l which had become suscept i b l e to an injury because of the excess l i g n i f I c a t i o n .  It  i s obvious that the more the c e l l i s l i g n i f l e d , the more the c e l l w i l l lose p l a s t i c i t y and w i l l become vulnerable to the injury.  Probably, the greater the stress, the less l i g n i -  f i c a t i o n required to permit injury.  This Idea could be  applied to the regression equation Y=1.62+0.0809X (Table 14),. where X Is the FLUTO value f o r the combination of WO - Wl. That equation was used to explain the difference l n the i n c i dence of BR on Vancouver Island and the Lower Mainland i n 1969,. during the period of May 14 - 20.  The equation indicates that  the greater the FLUTO value i n WO than i n Wl, the more BR w i l l occur.  In other words, when the dally fluctuations i n the  hours of bright sunshine are greater during the harvest period (WO) after the week (Wl) which had less fluctuations, the incidence of BR w i l l be greater.  In the case of the weather  pattern of May, 1969 (Fig. 3) on Vancouver Island where the  75  week (WO)  with.much d a i l y f l u c t u a t i o n i n the hours of b r i g h t  sunshine f o l l o w e d the week (Wl) w i t h v i r t u a l l y no  fluctuation,  the s t r e s s which was produced by t h i s f l u c t u a t i o n may  have been  much g r e a t e r than the case f o r the Lower Mainland where both WO and Wl had much the same f l u c t u a t i o n as shown by the X v a l u e (FLUTO f o r WO-Wl) of - . 1 0  i n Table 14.  Jones and Alexander (1962) r e p o r t e d the e f f e c t of changing temperature c o n d i t i o n s d u r i n g p l a n t development. i n c r e a s e d the i n c i d e n c e of BR i n the greenhouse 32.1^  or 10.9  t o 25.1$  They  from 2 0 . 0 t o  on p l a n t s w i t h low l e v e l s of potassium  by s u b j e c t i n g p l a n t s t o room temperature  (65-70 F/58-6O F,  day/night) f o r f i v e days, and then to low temperatures ('55  F/  50 F,. d a y / n i g h t ) f o r two months f o l l o w e d by h i g h temperature (80 F, day and n i g h t ) f o r the remainder of the season. the temperature c o n d i t i o n s were changed b e g i n n i n g a t the e a r l y stage of p l a n t  Thus  t h r e e times i n the study  growth.  G l o s s (1958) r e p o r t e d t h a t low l i g h t i n t e n s i t i e s or two weeks p r i o r t o r i p e n i n g r e s u l t e d i n BR.  one  Agalni the  change i n l i g h t c o n d i t i o n s was not a l o n g term c y c l e as l n the present study. a few changes  However, i t i s i n t e r e s t i n g to note that  Just  i n temperature or l i g h t c o n d i t i o n s are r e p o r t e d  to I n f l u e n c e the i n c i d e n c e of BR whereas the present study i n d i c a t e d t h a t more f r e q u e n t changes could be needed BR.  t o produce  There are no r e p o r t s on the e f f e c t of c y c l i c changes i n  temperature or l i g h t c o n d i t i o n s on the occurrence of Thus f u r t h e r work i s needed  to decide how much and how  those c o n d i t i o n s should be changed eliminate  BR.  BR. often  i n o r d e r t o produce or  76  3);  A s s o c i a t i o n of BR mosaic v i r u s (TMV) Since Boyle and  of greenhouse tomatoes and  tobacco  i n B r i t i s h Columbia i n 1 9 6 9 Wharton ( 1 9 5 6 ) r e p o r t e d the shock r e -  a c t i o n of tomatoes t o TMV,  the r o l e of the v i r u s i n the  of IB'seems to be w e l l e s t a b l i s h e d .  BR  incidence  of greenhouse tomatoes  i n B r i t i s h Columbia i s c h a r a c t e r i z e d by presence of n e c r o t i c t i s s u e such as t h a t d e s c r i b e d f o r IB; arose:  i s BR  survey  i n B.C.  The  a r e s u l t of TMV  r e v e a l e d the r o l e of TMV  i n BR  obvious  infection? of B.C.  question The  TMV  greenhouse  tomatoes. As seen In Table with TMV.  2 1 , not a l l the BR f r u i t s were i n f e c t e d  Furthermore the prevalence  of TMV  non-BR f r u i t s d i d not d i f f e r s i g n i f i c a n t l y !  i n BR f r u i t s  and  t h e r e f o r e i t does  not appear t h a t the TMV" i s the only f a c t o r c a u s i n g BR i n the B;.C.  crop.  The  extreme example i s seen i n the case of grower  NO.3  (Table 2 1 ) where the crop was  the time of sampling and yet BR When a f r u i t and  apparently  was  f r e e from TMV  at  present.  a l e a f from the same p l a n t were assayed  f o r the v i r u s on N i g l u t l n o s a i t was  noted i n a few  cases  that  e i t h e r the f r u i t or the l e a f from the same p l a n t , but not both, showed TMV  symptoms i n the assay.  T h i s phenomenon may  be  e x p l a i n e d by Bawden's ( 1 9 6 4 ) review of v i r u s behaviour i n p l a n t d i s e a s e s , and  can be  summarized as f o l l o w s .  The movement of  v i r u s over a r e l a t i v e l y long d i s t a n c e w i t h i n a p l a n t may  largely  be determined by the d i r e c t i o n i n which the main food stream i s moving.  Developing  f r u i t t r u s s e s of tomatoes o f t e n became  i n f e c t e d a t the same time as r o o t s and young l e a v e s , whereas mature leaves adjacent weeks.  to t r u s s e s remained freevfrom v i r u s f o r  I t takes l e s s time f o r v i r u s to i n f e c t a l l p a r t s of  77  young p l a n t s than l n the case of o l d p l a n t s . of small tomato p l a n t s became I n f e c t e d ones, but stage.  A l l the  leaves  soon a f t e r the youngest  three weeks were needed f o r p l a n t s i n the  fruiting  In l a r g e p l a n t s , i n f e c t i o n of mature leaves  was  u s u a l l y r e s t r i c t e d to l i m i t e d areas around the main v e i n s even three months a f t e r the i n i t i a l i n o c u l a t i o n . A very n o t i c e a b l e case was  t h a t of grower  where 26 f r u i t s out of 33 TMV-infected f r u i t s d i d not i n the c o r r e s p o n d i n g l e a f samples.  NO.8 show  Those f a c t s suggest t h a t  the I n f e c t i o n of those p l a n t s w i t h TMV  occurred  at a r e l a t i v e l y  l a t e stage of p l a n t development, which i n d i c a t e d t h a t BR toms i n t h a t greenhouse could, be a r e s u l t of the r e a c t i o n " a f t e r the i n f e c t i o n of The speculations. f r u i t s and stage.  leaves  "shock  5 and  NO.6  leads to the same  presence of TMV. i n a l l the samples both i n  suggests t h a t i n f e c t i o n occurred  I f t h i s were s c  at an e a r l y  then p l a n t s were w e l l beyond  the  "shock r e a c t i o n " stage at the time of f r u i t r i p e n i n g and should  be f r e e of v i r u s - i n d u c e d  evidence that the r o l e of TMV causing  BR  in this  symp-  TMV.  case of growers NO. The  IB.  i s not  T h i s may  be  hence  further  the Important f a c t o r i n  region.  Table 23 shows t h a t a f r u i t Is a more r e l i a b l e source f o r v i r u s assay than a mature l e a f , suggesting f r u i t s should  that  always be used f o r the v i r u s assay i f one;*s  i n t e r e s t i s l n TMV  TMV  in fruits.  78 k),  A s s o c i a t i o n of BR  and  potato v i r u s X (PVX),  Some tomato p l a n t s grown by K o s k i t a l o l n the Department of P l a n t Science  at the U n i v e r s i t y of  Columbia produced severe BR  symptoms i n the c o n t r o l l e d growth  chambers.  The  p l a n t s were o b v i o u s l y I n f e c t e d with a v i r u s  desease,,and I t was  noted t h i t the i n f e c t i o n had  the e a r l y growth stage of p l a n t s . v i r u s were f r e e from BR. TMV  globosa  was  v i r u s X, PVX  results;  only BR  reported  TMV  assay gave  i d e n t i f i e d as The  potato  e f f e c t of t h i s  further studied.  r e s u l t s of the experiment  T h i s BR  as. shown i n Table  Koskitalo's observation.  Admittedly,,  24 the  on one p l a n t i n f e c t e d by  i n c i d e n c e c o u l d be e i t h e r by chance only  or  infection. The  The  as PVX.  i n the experiment occurred  by the PVX  The  the v i r u s was  i n c i d e n c e was  f a i l e d to confirm  PVX.  These p l a n t s were i n c l u d e d i n the  h e r e a f t e r designated  The  in  t h e r e f o r e a f u r t h e r assay u s i n g Gomphrena  employed and  on the BR  occurred  A l s o , p l a n t s f r e e from  studies previously described.  negative  British  discrepancy  here may  be due  between K o s k i t a l o ' s r e s u l t s and  those  to d i f f e r e n t growing c o n d i t i o n s .  p l a n t s grown by K o s k i t a l o and  those f o r the  experiment  r e p o r t e d here, were kept i n the greenhouse u n t i l some f r u i t s reached m a t u r i t y .  Thus these p l a n t s were grown d u r i n g  ent times of the year as w e l l as i n d i f f e r e n t y e a r s . d i f f e r e n t pre-chamber c o n d i t i o n s may  account f o r the  differThe  different  i n c i d e n c e of BR i n s p i t e of the s i m i l a r procedure i n the same greenhouses and  growth chambers.  The  growing c o n d i t i o n s f o r  79  the control plants l n the PVX experiment may be such that BR did not develop.  A l l the plants which remained i n the  greenhouse, whether infected or not with PVX, had no BR. These apparently favourable growing conditions i n the greenhouse may have been s u f f i c i e n t to counteract the adverse effect of PVX, i f there i s any. I t i s known that PVX usually causes only mild mosaic symptoms on tomato plants.  However, a very severe necrotic  disease, known as "streak" w i l l occur, I f tomato plants are infected with both PVX and TMV' (Bawden  1964).  In B.C. green-  houses, l n spite of the wide spread occurrence of TMV, streak disease i s very rare, suggesting that PVX i s not a problem for commercial growers. The non-significant difference between f r u i t weight of PVX  infected plants and control plants may be a mani-  festation of the mild effext which PVX i s reported to have on host tomato plants.  The higher average f r u i t weights and  t o t a l yields per plant are no doubt a result of the difference i n the greater amount of radiant energy available i n the greenhouse compared to the lower l i g h t intensity of the growth chambers.  80 SUMMARY AND CONCLUSION! In a study which was concerned with BR i n the greenhouse tomato i n B r i t i s h Columbia, the p o s s i b l e f a c t o r s which ence the i n c i d e n c e  influ-  of t h i s d i s o r d e r were sought i n the hours of  b r i g h t sunshine and i n the v i r u s e s .  By f i n d i n g some s i g n i -  f i c a n t l i n e a r r e g r e s s i o n s of the i n c i d e n c e of BR on the combinations  of hours of b r i g h t sunshine, a p a t t e r n o f hours of b r i g h t  sunshine was p o s t u l a t e d t o produce BR, and t h i s p a t t e r n was subsequently  t e s t e d i n the growth chambers.  Two l e v e l s of maximum temperature and two l e v e l s of the d u r a t i o n of h i g h l i g h t c o n d i t i o n s were employed,  i n a factorial  combination, t o make f o u r treatments f o r the experiment i m the growth chambers. Conclusions 1) .  from these s t u d i e s were as f o l l o w s :  The i n c i d e n c e of BR l n the B.C. greenhouse  tomatoes  appeared t o be a s s o c i a t e d w i t h the c y c l i c occurrence of sunny weeks and cloudy 2) .  weeks.  When the temperature c o n d i t i o n s were h e l d c o n s i s t e n t  the weekly a l t e r n a t i o n of l i g h t c o n d i t i o n s c o u l d produce a s i g n i f i c a n t l y g r e a t e r percentage of BR fruits/thanrs i n the cont r o l treatment, i n which the l i g h t and temperature were kept c o n s i s t e n t .  conditions  However, t h i s e f f e c t of weekly  alter-  n a t i o n of l i g h t c o n d i t i o n s was n u l l i f i e d by the simultaneous a l t e r n a t i o n of temperature c o n d i t i o n s , suggesting s a t o r y e f f e c t of temperature and l i g h t 3).  some compen-  conditions.  The r o l e of TMV. on the Incidence of BR i n the B.C.  greenhouse tomatoes d i d not appear t o be the important f a c t o r  81  In the spring crops i n 1969. 4).  The effect of PVX on the incidence of BR was not clear.  82 LITERATURE CITED Bawden, F.C. 1964. P l a n t v i r u s e s and v i r u s d i s e a s e s . Ronald P r e s s Company. 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Gray-wall symptom development i n tomato f r u i t a f t e r i n f e c t i o n of e x t r a c t s of g r a y - w a l l a f f e c t e d t i s s u e . Phytopath. 57« 1276-1277. Hobson, G.E. 1963. P e c t i n e s t e r a s e l n normal and abnormal tomato f r u i t . Biochem.J. 86« 358-365. . 1964. P o l y g a l a c t u r o n a s e i n normal and abnormal tomato f r u i t . Biochem.J. 92« 324-332. . 1967. Phenolase a c t i v i t y i n tomato f r u i t i n r e l a t i o n to growth and to v a r i o u s r i p e n i n g d i s o r d e r s . J.Scl.Fd.Agrl., I81 523-526. Holmes, F.O. 19*4-9, A s s o c i a t i o n of s t r a i n s of tobacco mosaic v i r u s with i n t e r n a l browning l n tomatoes. P l a n t D i s . Reptr. 3 3 ' 338-339. . 1950. I n t e r n a l browning d i s e a s e of tomato caused by s t r a i n s of tobacco mosaic v i r u s from P l a n t a g o . Phytopath. 40J 487-492. Jones, J.P. and Alexander, L . J . 1 9 5 6 . 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E f f e c t s of sub-optimal r i p e n i n g temperat u r e s on tomato f r u i t q u a l i t y as determined by o b j e c t i v e measurement. Ph.D. T h e s i s , Univ. of B.C. Lewis, G.D. and T a y l o r , G.A. 1967. A s s o c i a t i o n of tomato f r u i t a b n o r m a l i t i e s with tobacco mosaic v i r u s i n f e c t i o n . Hort.Sci. 2J 163-164.  85 L i n g l e , J . C , Yamaguchi, M., Luh, B.S. and U l r l c h , A. 1 9 6 5 . The e f f e c t of h i g h temperature and n i t r o g e n n u t r i e n t on y i e l d , time of maturing and q u a l i t y of tomato f r u i t s . Veg. Crops Ser. Univ. C a l . Davis 1 3 9 « pp.8. L o r e n t z , O.A. and Knott, J . E . 1941. S t u d i e s of g r a y - w a l l of tomato. Proc.Amer.Soc.Hort.Sci. 40i 445-454. Maynard, D.N., Gersten, B". and M i c h e l s o n , L.F. 1 9 5 9 . The e f f e c t s of boron n u t r i t i o n on the occurrence of c e r t a i n tomato f r u i t d i s o r d e r s . Proc.Amer.Soc.Hort.Sci. ?4t  500-505.  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The e f f e c t s of some n u t r i t i o n a l and e n v i r o n mental f a c t o r s on f r u i t q u a l i t y i n tomatoes. Symposiunr 1966. pp.313-323.  APPENDIX The v a l u e s o f TOTAL and FLUTO f o r the c o m b i n a t i o r s e l e c t e d weeks l i s t e d i n Table 1. Week  o f two weeks f o r 12 cases o f  12  TOTAL or FLUTO  1  Al  TOTAL FLUTO  13.7 10.3  9.2 3.8  25.5 7.0  4.6 14.5  20. 6 4.7  5. 7 15.2  A2  TOTAL FLUTO  16.3 10.9  20.9 1.0  27.5 1.6  8.0 11.1  1.0 19,2  37.5 14.3  A3  TOTAL FLUTO  8,8 1,5  7.9 10,9  0.7 7,0  3.3 16.9  0,8 15.2  A4  TOTAL FLUTO  10.8 1.3  25. 7 20.9  6.2 6.5  36.4 15.4  A5  TOTAL FLUTO  20.9 1.3  16.6 0.6  11.7 2.6  A6  TOTAL FLUTO  8.4 3.1  11.5 12.0  A7  TOTAL FLUTO  21.5 24.7  2.3 2.7  2  3  4  5  cases  6  7  8  9  10  11  12  9.6 0.1  10.6 3.3  7.1 10.8  32.7 0.3  53.0 5.2  7.0 2.2  34.5 5.6  20.6 4.7  30.0 0.2  7.1 10.8  2.5 7.2  17.9 2.5  9.5 4.8  13.2 7.6  1.0 19.2  19.2 14.6  30.0 0.2  2.0 0.1  20.7 4.5  17.4 4.5  22.3 9.9  24.9 11.0  0.8 15.2  17.9 8.1  19.2 14.6  62.1 10.9  24.1 4.3  8.8 1.4  31.8 12.7  26.8 23.1  36.2 20.1  20.7 4.5  4.5 15.0  17.9 8.1  15.2 0.4  28. 5 6. 6  39.8 9.5  13.9 6.8  19.7 24.7  26. 5 1.4  21.4 27.5  8.8 1.4  47.2 14.8  4.5 15.6  4.2 9.2  27.6 9.9  35.8 26.4  2.3 3.0  7.9 1.4  2.9 26.1  10.4 0.9  13.9 6.8  7.0 7.6  47.2 14.8  17.7 0.4  0  3  1  1  1  1  3  47.2 14.8  1  For A l , A2,A3, A4, A5, A6 and A7, see T a b l e 9. 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