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UBC Theses and Dissertations

Association of economic characters in rhizoma alfalfa Eek, Catherine J. 1943

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ASSOCIATION of ECONOMIC. CHARACTERS 33T RHIZOMA ALFALFA by C a t h e r i n e J . Eek  A Thesis Submitted i n P a r t i a l  Fulfilment  of t h e Requirements f o r the Degree o f Master o f S c i e n c e i n A g r i c u l t u r e in the Department o f Agronomy*  The U n i v e r s i t y o f B r i t i s h Columbia A p r i l 1943  ACKNOWLEDGMENT  G r a t e f u l acknowledgment I f here made to Dr. V. G. B r i n k 5 Dr. G. G. Moe, and D r . A. H. H u t c h i n s o n , under whose guidance t h i s paper was w r i t t e n *  TABLE OF CONTENTS Page INTRODUCTION  1  REVIEW OF LITERATURE  6  MATERIALS AND METHODS  10  ASSOCIATION OF SEED 'YIELD J n D OTHER CHARACTERS  12  1»  A s s o c i a t i o n o f Pod Shape and Number o f Seeds Per P6d • " (a) S e l f p o l l i n a t e d a l f a l f a  12 12 13  (b)  Open p o l l i n a t e d  alfalfa 14  •• (g,)* _ Seed s e t i n grams 2.  A s s o c i a t i o n o f Flower Abundance and Number o f Seeds  3.  Seed S e t t i n g Compared i n Racemes Which Have Been S e l f e d and Open P o l l i n a t e d  -  16  17  4.  A s s o c i a t i o n o f Flower C o l o r and Seed Y i e l d  20  5.  Comparison o f Seed Y i e l d f o r Two S u c c e s s i v e Years  22  6» 7.  D i s t r i b u t i o n o f Seed Y i e l d C l a s s e s Comparison o f Seed Y i e l d , P l a n t Heights and P l a n t Weights i n F i and F .  22 24  2  8.  Comparison o f Seed Y i e l d ' i n Fj_ p l a n t s & F  2  Progeny  ASSOCIATION OF FACTORS NOT INVOLVING SEED YIELD 1. ,2.  Comparison o f H e i g h t and.Weight Between F^ & F  25 27  2  27  A s s o c i a t i o n o f Y i e l d and Height  29  A s s o c i a t i o n o f L e a f S p o t t i n g Incidence and the Percentage o f Ovules D e v e l o p i n g on t h e Racemes.  30  4.  A s s o c i a t i o n o f L e a f S p o t t i n g and L e a f C o l o r  31  5.  A s s o c i a t i o n o f L e a f S p o t t i n g and Flower Abundance  32  6.  A s s o c i a t i o n o f Stem Thickness and P l a n t Height  32  7.  A s s o c i a t i o n o f H e i g h t and Spread  33  3.  Page 8  9 10  A s s o c i a t i o n o f Flower Abundance and Raceme S u p p o r t i n Ovules  35  A s s o c i a t i o n o f F o l i a g e Colour and Flower Abundance  36  A s s o c i a t i o n o f Flower Abundance andFlower F a l l  37  FLOWER COLOR INHERITANCE  38  DISCUSSION  41  CONCLUSIONS  43  SUMMARY •  "  45  1  ASSOCIATION' CO? ECONOMIC CHARACTERS IN RHIZOMA ALFALFA •' > , A l f a l f a j to-days i s one of the world's l e a d i n g ;  f o r a g e c r o p s , I n the r e g i o n s f a v o r i n g i t s grovvth, a,nd these a r e now many,, no crop.used f o r fodder surpasses i t i n g e n e r a l u t i l i t y and y i e l d .  F o r thousands o f y e a r s  a l f a l f a w a s h i g h l y regarded i n south-western A s i a , i n which a r e a i t was endemic, as forage s i n e qua hon. S l o w l y , s e l e c t e d . s t r a i n s made t h e i r way_into the a g r i cultural  r e g i o n s o f N o r t h A f r i c a , , and southern Europe  u n t i l "by the end o f the' 19th century a l l o f tempera-te  ;  -~  E u r a s i a knew i t as a v a l u a h l e a d d i t i o n t o the f o r a g e resources.  The v a l u e of the crop •was r e c o g n i z e d "by the  e a r l y w h i t e s e t t l e r s i n the Y/estern .hemisphere and, undoubtedly i n many separate o c c a s i o n s the p l a n t was i n t r o d u c e d t o the new a g r i c u l t u r a l a r e a .  However, p r i o r  to 1900 i t i s d o u b t f u l i f the t o t a l acreage i n "both western c o n t i n e n t s , exceeded 3 m i l l i o n "acres. Since^that':, date a t r u l y phenomenal expansion i n acreage has taken p l a c e e s p e c i a l l y i n the U n i t e d S t a t e s , the A r g e n t i n e , Uraguay, Paraguay, Mexico and i n A u s t r a l i a ,  I n the U.S.A.  alone p r e s e n t crop acreage must ..now exceed 20 m i l l i o n acres.  .. •  C.anada has n o t "been excluded i n the "march" of a l f a l f a over the g l o h e .  W i t h the development of w i n t e r  hardy s t r a i n s f o r c o o l e r and more humid areas a l f a l f a acreage spread i n Canada.  O n t a r i o , B r i t i s h Columbia and  the p r a i r i e p r o v i n c e s now m a i n t a i n a combined crop a r e a of ij? m i l l i o n a c r e s .  I n B r i t i s h 'Columbia/ a l f a l f a has  become the standard hay and p a s t u r e crop i n the c a t t l e r a n c h i n g and i r r i g a t e d d i s t r i c t s . A l f a l f a , u n l i k e many other f o r a g e crops which posses, a few commendable c h a r a c t e r i s t i c s , has t o i t s c r e d i t many d e s i r a b l e agronomic f e a t u r e s .  I t i s this  combination or b l e n d i n g of so many d e s i r a b l e agronomic f e a t u r e s which account f o r I t s popularity..  Alfalfa i s  a legume and as such i s a . w e l l known source of p l a n t p r o t e i n and a-'highly regarded s o i l e n r i c h e r .  Few crops  produce p r o t e i n so e f f i c i e n t l y } from t h r e e tons of . a l f a l f a hay (an average crop) 625 pounds of d i g e s t a b l e p r o t e i n are obtained'  A comparable crop of timothy  (1.5 Tons) produces by compai-ison o n l y 90 pounds of d i g e s t a b l e p r o t e i n ; a crop of c l o v e r . (3 Tkns) , 40Q pounds and a b a r l e y crop (50 B u s h e l s ) common w i t h most legumes, . a l f a l f a  5  200 pounds.  In  with associated  FJraobia, f i x e s a p p r e c i a b l e q u a n t i t i e s of atmospheric n i t r o g e n and as such p l a y s an important p a r t i n maint a i n i n g t h e s o i l n i t r o g e n balance on the farm.  The  s i g n i f i c a , n c e of t h i s a t the p r e s e n t time i s w e l l por- . t r a y e d by W i l s o n i n a r e c e n t p u b l i c a t i o n . . . . A l f a l f a has a f u r t h e r marked advantage as a f o r a g e crop i n t h a t i t i s a p e r e n n i a l and a g r e s s i v e .  Once  .•established a stand competes e f f e c t i v e l y w i t h weeds and i n most l o c a l i t i e s w i l l m a i n t a i n i t s e l f w i t h l i t t l e no care f o r a t l e a s t 6 - 7 y e a r s .  or  Then again the deep  r o o t i n g h a b i t of many s t r a i n s of l u c e r n e has e s t a b l i s h e d the crop as a drought t o l e r a n t s p e c i e s .  As such i t i s .  w e l l known i n the subhumid and a r i d r e g i o n s of t h i s continent.  Recent s e l e c t i o n s of w i n t e r hardy s t r a i n s  have f u r t h e r advanced i t s r e p u t a t i o n as a crop f o r c o l d dry c l i m a t e s of the n o r t h and f a r south. Although  the .desirable agronomic f e a t u r e s of a l f a l f a  f a r outweigh . the u n d e s i r a b l e , the crop ..has. c e r t a i n l i m i t a t i o n s which cause the p l a n t breeder concern.  For  one t h i n g s the 'plant, as we know i t i n commerce I s a n o t o r i o u s l y poor seed s e t t e r . high priced.  Seed* as a consequence i s  I n r e c e n t years:, too, a t t e n t i o n has been  drawn to the i n c r e a s i n g . i m p o r t a n c e  of crown injury i n :  standard s t r a i n s and the f a i l u r e of i n j u r e d p l a n t s to overcome a t t a c k s from i n s e r t s and fungus p e s t s .  Then,  a g a i n c o i n c i d e n t , w i t h the expansion of a l f a l f a , acreage i n the world, has come a growing r e a l i z a t i o n of the handicaps i n producti©£l r e s u l t i n g from such d i s e a s e s w i l t , l e a f s p o t and  as  virus.  The a t t e n t i o n o f _ t h e p l a n t breeders,then  has been .  a t t r a c t e d by the r e c o g n i t i o n of these i m p e r f e c t i o n s  and  a l r e a d y many programs f o r a l f a l f a Improvement have been undertaken. One  of the e a r l i e s t consibus attempts a t a l f a l f a  • improvement-' through "breeding and s e l e c t i o n has much of i t s ' h i s t o r y l a i d a t the U n i v e r s i t y of B r i t i s h Columbia from 1918 onwards.  The e a r l y o b j e c t s " o f the program was  to produce through i n t e r s p e c i f i c h y b r i d i z a t i o n a s t r a i n of a l f a l f a w i t h a crown and r o o t system s u i t a b l e f o r subhumid c o n d i t i o n s when a r e l a t i v e l y h i g h water t a b l e p r e v a i l e d over much of 'the y e a r .  The e a r l y work.on t h i s  p r o j e c t has been adequately reviewed by Hoe (23) and only, a, b r i e f r e f e r e n c e w i l l be .made'' to i t .  W i t h the  growing importance of a l f a l f a i n the a g r i c u l t u r a l economy and a 'deeper: r e a l i z a t i o n of i t s problems., i t i s i n c o n f o r m i t y t h a t the a l f a l f a improvement programme should change, should broaden i n I t s scope and purpose.'. F i e l d r e c o r d s , some complete, some incomplete,, are a v a i l a b l e i n t h e programme f o r some twenty y e a r s of i t s history.  Therefore i t seemed a p p r o p r i a t e a t t h i s time t o  survey these r e c o r d s i n the l i g h t of p r e s e n t knowledge. I n a d d i t i o n some r e c o r d s -taken by the author on the l o c a l m a t e r i a l i n the summer of 1941-42 and 1942-43 were s t u d i e d . P r i n c i p a l l y the r e p o r t i s a study of- the a s s o c i a t i o n of economic  c h a r a c t e r s i n the a l f a l f a grown a t the  U n i v e r s i t y of B r i t i s h Columbia.  Charactei-s vvere chosen  such as seed w e i g h t , seed number, p l a n t h e i g h t and t h e l i k e and t h e i r a s s o c i a t i o n w i t h g e n e r a l c h a r a c t e r i s t i c s such as seed s e t t i n g , p l a n t y i e l d and crown c h a r a c t e r i s t i e s s c r u t i n i z e d . F o r p l a n t b r e e d i n g i s n o t the simple s e l e c t i o n of d e s i r a b l e c h a r a c t e r i s t i c s and the mere  i n c o r p o r a t i o n of these i n a s i n g l e d e s i r a b l e s t r a i n .  It  i s a study i n i n t e r a c t i o n and l i n k a g e , complex to a h i g h degree?  the combination o f f e a t u r e s of m e r i t must  i n t i m a t e l y be r e p r e s e n t e d i n many s t r a i n s and not i n one aiohe and the procedure used i n a c c o m p l i s h i n g t h i s are a t once b o t h an a r t and a s c i e n c e . How  s u c c e s s f u l t h i s study i n a s s o c i a t i o n has been,  w i l l be f o r the reader to decide; d i f f i c u l t i e s such as incomplete r e c o r d s , poor seed s e t t i n g and the l i k e , hare upset the study from time to time.  I t i s hoped however  t h a t something has been added to our knowledge of the behaviour of economic c h a r a c t e r s i n the i n t e r s p e c i f i c h y b r i d a l f a l f a such as t h a t a t the U n i v e r s i t y of B r i t i s h Columbia.  REVIEW OE LITERATURE A t p r e s e n t .the most important problem as f a r as 7  a l f a l f a i s concerned i s the improvement of i t s seed set . A l a r g e amount of work on t h i s problem has d e a l t w i t h the e f f e c t of t r i p p i n g on seed s e t .  T r i p p i n g can be brought  about by weather, I n s e c t s or a r t i f i c i a l means.  Ofall  there i n s e c t s s t u d i e s Megachile s p e c i e s have been found the most s a t i s f a c t o r y . Lejeune and Olson (19) found t h a t honeybees brought about very l i t t l e t r i p p i n g . Hay  (13) found t h a t the l a c k of s u i t a b l e i n s e c t s and  •unfavourable weather c o n d i t i o n s f o r t r i p p i n g c o n t r i b u t e d to the low seed y i e l d .  C l a r k and E r y e r ( 7 ) , C a r l s o n ("6).  and Bouthworth (5) conclude t h a t t r i p p i n g i n c r e a s e s yield.  seed  K i r k (17) has developed a s e l f t r i p p i n g (autogamous)  a l f a l f a which g i v e s promise of overcoming t h i s d i f f i c u l t y . Various  s t u d i e s have been done on h y b r i d i z a t i o n s as a  means to i n c r e a s i n g seed y i e l d .  Dwyer s e l e c t e d h i g h  y i e l d i n g s t r a i n s by i n b r e e d i n g , then crossed vigor.  Englebert  them to r e g a i n  (10) found t h a t the seed y i e l d of any  s i n g l e h y b r i d v a r i e d w i t h the environmental c o n d i t i o n s . number of papers have been w r i t t e n on the development  A  of  an i n b r e d s t r a i n - w h i c h w i l l g i v e &, good seed y i e l d K i r k (16) found t h a t . s e e d y i e l d w a s • i n h e r i t e d  to a c e r t a i n degree.  Tysdai and C l a r k ( 2 9 ) , B o l t o n and E r y e r Southworth (25) found t h a t the g e n e r a l  (2) and seed y i e l d went  down on i n b r e e d i n g but a few h i g h y i e l d i n g p l a n t s  segregated which "bred true f o r t h i s q u a l i t y . S e l f s t e r i l i t y i n a l f a l f a has g i v e n r i s e to many studies.  B r i n k and Cooper (3) found t h a t there were  fewer f e r t i l e ovules i n s e l f e d m a t e r i a l and t h a t the lower ovules were r a r e l y f e r t i l e .  B o l t o n and F r y e r (2) working  on p o l l e n s t e r i l i t y d i v i d e d i t i n t o two c l a s s e s : (a) c l e a r empty grains,- (b) normal appearing which d i d not germinate. B r i n k and Cooper (3)- found a f a i l u r e of f e r t i l i z a t i o n even a f t e r t r i p p i n g .  P o l l e n tubes.'were produced and i n  some cases f e r t i l e ovules s t a r t e d to develop but f a i l e d t o mature.  The embryos of low seed y i e l d e r s developed more  s l o w l y and t h e r e was .a'-large percentage of.abor^fesMU o v u l e s . B r i n k and Cooper (3)' found t h a t f e r t i l i z a t i o n was prevented due to abnormal  p o s i t i o n a l r e l a t i o n s h i p between anthers  and' stigma. The p a r t o f • e n v i r o m e n t a l e f f e c t must not be overlooked i n r e l a t i o n - ; to seed s e t . B o l t o n and F r y e r (2) found t h a t . s o i l m o i s t u r e and the .stage.of the seasonal c o n t r i b u t e d a g r e a t d e a l to seed s e t .  development  They found t h a t the  normal appearing p o l l e n , mentioned above, would germinate under f a v o r a b l e c l i m a t i c c o n d i t i o n s . t h a t h e r e d i t a r y f a c t o r s can o n l y show a s u i t a b l e environment.  Preeman (11) c a u t i o n s up to advantage- i n  .-Tysdal and C l a r k (7)  emphasize  the e f f e c t of temperature and l i g h t on seed p r o d u c t i o n . • Southworth (25) s t r e s s e s the e f f e c t of m o i s t u r e , he concludes t h a t there should be s u f f i c i e n t m o i s t u r e to f i l l the seed a f t e r i t has s e t but i n the e a r l y stages of  8 development abundant moisture w i l l s t i m u l a t e the development of l e a v e s and h e i g h t a t the expense of seed; s e t . E n g l e b e r t (10) s u b s t a n t i a t e s Southworth's work $ f i n d i n g , t h a t seed s e t was b e t t e r i n y e a r s when there was  a limited  r a i n f a l l i n J u l y and poor when there was e x c e s s i v e r a i n f a l l f o r t h i s month. H y b r i d i z a t i o n has been used as another method o f improving a l f a l f a .  Among the c h a r a c t e r i s t i c s which have  been g i v e n s p e c i a l emphasis are d i s e a s e r e s i s t a n c e , r o o t types, winter h a r d i n e s s s e e d  y i e l d and weight of p l a n t s .  The c y t o l o g y of these h y b r i d s has . y i e l d e d a g r e a t d e a l •of i n f o r m a t i o n of i n t e r e s t g e n e t i c a l l y .  The c r o s s i n  a l l cases was only s u c c e s s f u l i f H. f a l a c a t a as the p i s t i l l a t e parent.  was used  I)wyer (9) found t h a t a c r o s s  between M. s a t i v a and M. L u p u l i n a gave a poor forage yield.  Southworth (23) i n t r y i n g to develop a s e l f  t r i p p i n g v a r i e t y used Iffi. l u p i l i n a , as the p i s t i l l a t e parent because of i t s s e l f g r i p p i n g c h a r a c t e r i s t i c s . The F l and E2 gave a g r e a t v a r i e t y o f types b u t a very poor seed y i e l d . p l a n t s appear,.  I n the E3 a few good _seed producing A few, s e l f t r i p p i n g v a r i e t i e s appeared i n  the E4 b u t were not s e l f f e r t i l e .  I t was not u n t i l the  3?6 t h a t one s e l f t r i p p i n g ^ s e l f f e r t i l e p l a n t appeared. The f l o w e r c o l o r i n these i n t e r s p e c i f i c c r o s s has provoked c o n s i d e r a b l e i n t e r e s t . '  The Iff., f a l a c a t a i s pure  breeding y e l l o w and the M. s a t i v a b l u e . - The E l and , succeeding g e n e r a t i o n s g i v e a wide v a r i e t y of c o l o r from  white to y e l l o w and deep p u r p l e s .  Burton  (5) found t h a t  f l o w e r c o l o r had no p o s i t i v e c o r r e l a t i o n s w i t h any of a number of other c h a r a c t e r i s t i c s .  Hay  (13) found t h a t  c o l o r had no e f f e c t on seed s e t , w h i l e M o e ( 2 3 ) on the other hand suggested t h a t w h i t e f l o w e r e d p l a n t s v/ere poor seed y i e l d e r s .  Lepper and Odland (20) conclude t h a t  f l o w e r c o l o r i n a l f a l f a was  due  to three f a c t o r s .  •'During the many breeding experiments i n v o l v i n g a l f a l f a , a number of abnormal t i e s have come to l i g h t . Lepper and Odland (19) mention a c r i n k l y . l e a f  mutation.  Stewart (24) mentions a p e c u l i a r v e g i t a t i v e p r o l i f e r a t i o n , which r e p l a c e s the a l f a l f a f l o w e r s . w h i t e seeds were due  MeVicar (22) found  to a homozygous r e c e s s i v e f a c t o r as  a r e s u l t of the absence of a f a c t o r f o r y e l l o w . B l a c k seed r e q u i r e d a t l e a s t three f a c t o r p a i r s and arose  originally  as a s i n g l e gene mutation. T h i s only v e r y s u p e r f i c i a l l y touches on a few of the l i n e s of i n v e s t i g a t i o n being c a r r i e d on w i t h a l f a l f a . Winter h a r d i n e s s and d i s e a s e r e s i s t a n c e are problems which are r e c e i v i n g a g r e a t deal.; of a t t e n t i o n i n other p a r t s of the c o n t i n e n t .  I n t h i s v a s t improvement Work w i t h a l f a l f a  many i n t e r e s t i n g ' f a c t s are being brought to l i g h t which are c o n t r i b u t i n g g r e a t l y to the improvement -of. a l f a l f a , and p l a n t improvement work i n g e n e r a l .  10  MATERIALS AED METHODS. The m a t e r i a l s used i n these s t u d i e s were the h i g h l y heterozygous p o p u l a t i o n which r e s u l t e d from s i x h y b r i d s of a c r o s s M. f a l a c a t a ( $ ) X M. s a t i v a ( <jp ) .  Details  of the h y b r i d i z a t i o n and subsequent treatment of the progeny are g i v e n by Moe ( 2 3 ) . "A few o f the more important f e a t u r e s o f t h i s p l a n t m a t e r i a l might be b r i e f l y emphasized.  I t should be noted  t h a t t h e ' p i s t i l l a t e parent-.in the c r o s s was u s u a l l y the low growing y e l l o w f l o w e r e dffi.f a l a c a t a Y a r . Don. and t h a t the p o l l e n parent was a t a l l p u r p l e f l o w e r e d v a r i e t y of Grimm one o f the O n t a r i o "Variegated type.  Seed obtained  from the h y b r i d s was grown out and s i x t a l l growing hybrids' were d i f f e r e n t i a t e d from the low growing h y b r i d s . , The h y b r i d s proved to be c o n s i d e r a b l y f e r t i l e and produced some seed i n good seed y e a r s both from s e l f e d and open p o l l i n a t e d racemes. .  The f l o w e r c o l o r of the h y b r i d s was v a r i e g a t e d but  showed a preponderance of y e l l o w pigment. The h y b r i d s were s e l f e d and the seed thus produced was s u b j e c t e d to progeny -row t e s t s .  The seed was then  taken from these, s e l e c t e d p l a n t s -and- i t s e l f s e t out i n progeny rows.  A t t h i s time l i t t l e or no attempt was  made to c o n t r o l p o l l i n a t i o n but there was no o p p o r t u n i t y for  admixture of p o l l e n from other s t r a i n s or v a r i e t i e s . The progeny from the F2 and subsequent g e n e r a t i o n s  11 showed an enormous degree of s e g r e g a t i o n .  Many of the  s e l e c t e d p l a n t s showed a g r e a t v a r i a t i o n as to type of growth, v i g o r and degree of s t e r i l i t y .  ;  .  C a r e f u l s e l e c t i o n of i n d i v i d u a l p l a n t progeny was c a r r i e d on f o r f i v e g e n e r a t i o n s "but a t the end of t h a t time t h e r e was s t i l l a h i g h degree of s e g r e g a t i o n ; I.e. no s t a b i l i t y of type had, as y e t "been e s t a b l i s h e d . From the F2 arid succeeding g e n e r a t i o n s the p p p u l a t i o n s Yirere the s u b j e c t of a mass s e l e c t i o n program.  In' t h i s  work emphasis was placed, on seeking a h i g h e r y i e l d i n g a l f a l f a w i t h , t h e spread c h a r a c t e r i s t i c s of the M. f a l a c a t a parent and the q u a l i t y c h a r a c t e r i s t i c s of the M. s a t i v a . Records were taken by the Department of Agronony on many m o r p h o l i g i c a l c h a r a c t e r i s t i c s of b o t h the h y b r i d s arid p l a n t s of. subsequent g e n e r a t i o n s .  From these r e c o r d s •  d a t a on spread, h e i g h t , seed y i e l d , pod shape and f l o w e r c o l o r were used. D u r i n g the summer of 1941 p l a n t s were s e l e c t e d a t f random from the f i f t h g e n e r a t i o n m a t e r i a l and Roger's a l f a l f a . ' From there p l a n t s data on pod slaape, number of seeds per pod, seed s e t , f o l i a g e c o l o r , f l o w e r c o l o r , flower f a l l ,  stem t h i c k n e s s , p l a n t h e i g h t and degree of  l e a f s p o t t i n g , were taken. The f o l l o w i n g s t a t i s t i c a l a n a l y s i s was used as the b e s t method of o r g a n i z i n g and i n t e r p r e t i n g t h i s data.  EXPERIMENTAL WORK I  A s s o c i a t i o n o f Pod Shape and Number o f Seeds Per Pod, (a)  Self pollinated alfalfa  It,was thought t h e r e might be some a s s o c i a t i o n between the seed y e i l d and t h e s i z e o f t h e pod, i . e . the number o f twists i n i t . Cooper and B r i n k (3) have found t h a t s t r a i n s which produce a l a r g e number o f seeds c o n t i n u e t o do so and s t r a i n s g i v i n g a s m a l l amount o f seed t e n d t o c o n t i n u e t h i s low seed y e i l d i n f u t u r e g e n e r a t i o n s . Bo^toE* and F r y e r (2) are o f t h e o p i n i o n t h a t t h e number o f seeds p e r pod i s a b e t t e r i n d e x o f i n h e r e n t f e r t i l i t y than t h e percentage o f f l o w e r s which g i v e r i s e t o f u l l y developed pods*  They a l s o s t a t e t h a t seed s e t i s due  t o g e n e t i c f a c t o r s and the number o f seeds p e r pod i s a good i n d i c a t i o n of t h i s inherent capacity,  A good seed s e t t i n g  s t r a i n w i l l t e n d t o c o n t i n u e t h i s abundant seed s e t t i n g capa c i t y , even o f s e l f i n g . Table I g i v e s the d i s t r i b u t i o n o f the number oj seeds per pod a g a i n s t the number o f t w i s t s per pod. The number dh b r a c k e t s i n each case i s t h e expected number the number above t h e the a c t u a l number,  The number o f t w i s t s  per pod were d i v i d e d i n t o t h r e e c a t a g o r i e s curved ( s e m i - c i r c l e ) , one c i r c l e , and more t h a n one c i r c l e .  The number o f seeds per  pod were a l s o d i v i d e d i n t o t h r e e c a t e g o r i e s , 2, 4, and 6 seeds per pod; M a t e r i a l used f o r t h i s s t u d y was d a t a t a k e n by the author  from  Rogers (24) a l f a l f a . The t o t a l number o f samples t a k e n here i s fifty-nine<>  A  l a r g e r number might y e i l d somewhat d i f f e r e n t r e s u l t s . The c h i square f o r 4 degrees o f freedom a t t h e 1% l e v e l i s only;13.28| t h e c h i square f o r e x p e c t a t i o n  i s 28.10. I n -  dependence i s t h e r e f o r e u n l i k e l y and a s t r o n g a s s o c i a t i o n o f h i g h l y - c u r l e d seeds and a l a r g e number o f seeds p e r pod i s likely. Table I 2  6  i  Total l  1-  vL • -  1.  16  i- 0 . i t 23  7  a (9.4)  (9.1)  8  14  (9.4)  (9.1)  (3.5) 1 1  1  23  b  •''/ 5  0  (3.5) 1  /  8  : 13  c (5.3) (5.8) Total  ; 24  26  (2.9) 9  / . 59  •:  a —  curved  b —  one c i r c l e  c —  more t h a n one circle.  •, (b) Open p o l l i n a t e d This s t u d y i s t h e same as t h e p r e v i o u s one i n a l l r e s p e c t s except t h a t t h e m a t e r i a l was open p o l l i n a t e d i n s t e a d o f s e l f e d . Table 2"gives t h e d i s t r i b u t i o n o f t h e seeds and the shape o f • t h e pods.  The' c a t e g o r i e s are t h e same as Table 1.  Table 2 2  4 .  e  Total  9  2  0  11  a (2*5)  (4.3)  (2.5)  3  16  0  (2.6)  (7.5)  (7.1)  !  19  b 0  3  20  c (5.3) Total  12  (8.6)  (7.1) 21  53  20 •  The c h i square f o r 4 degrees o f freedom a t the 1% l e v e l of s i g n i f i c e n c e i s 13.28 which shows an a s s o c i a t i o n between the the number o f seeds per pods and the number o f t w i s t s per pod. K i r k (17) found t h a t t h e seed y i e l d upon open p o l l i n a t i o n was g r e a t e r t h a n upon s e l f i n g but h i g h y e i l d i n g s t r a i n s tended to remain good seed producers whether open or s e l f e d . As i n the p r e v i o u s case the number o f samples are s m a l l , making these r e s u l t s f a r from conclusive,, (c)  Seed s e t i n grams  L a r g e r number were a v a i l a b l e f o r t h i s s t u d y . 26 progeny rows (open p o l l i n a t e d ) from a l l o f the  There were hybrids  (1928), g i v i n g a t o t a l o f 770 p l a n t s . Table 3 g i v e s the d i s t r i b u t i o n o f seed y i e l d i n grams compared w i t h the shape o f the pod. l a r g e d i n both c a s e s . Table 3  The c a t e g o r i e s have been en-  15 Table 3 Seed -weight i n ' grams  1  Ho.of t w i s t s 0-2 12 (7.7)  2-4  |4-6'  144' ! 22 8 ,110.3) (25.9) (4.4) '<  ".  •  1-|~2  -  „  4 (9.8)  10-12  total 1  1 (6.4)  2 (6.2)  13  4 "T (12;.  /  24 . 13' 14 25 18 52 190 336 (23.1) (11.3) (11.?:) (24.8) (17.9) 199,8) (47.1) 8 14 10 17 98 30 116.5) (27.5) :(14.5) (10.4) (6.8) (6.6) 14 4 23.7) (5.1)  Total  i 6-8 i 18-10 1 (.4)  458  108  7 (2.9) 57  5 (2.1) 41  19 : 196 (13,5)  -'"1. '- 3 (1,4) (1.1)  6 (2.7)  27  53  ;  26  40 770  1  The number o f t w i s t s bears no s t a t i s t i c a l r e l a t i o n t o the weight o f seed s e t p e r p l a n t .  This however does n o t imply  t h a t t h e r e i s no c o r r e l a t i o n between t h e number o f t w i s t s per pod and the number or weight o f seed s e t per pod.  I n t a b l e 4 t h e c a t e g o r i e s have been reduced t o 3 f o r y i e l d and 3 f o r number o f t w i s t s p e r pod.  16 Table 4 1 1 811 JTo. of t w i s t s | . 0-1 l ,• 1 1 - 2  1  1  Amount o f Seed Set (Grams) 0 .- 4 4 -8 • 8 - 14  2 - 3  Total  178 (145.5)  12 (25.2)  370 (391)  74 (67.7)  88 (73.23)  532  18 (29.4)  12 (5.09)  10 (5.5)  40  98  106  770  Total  566  8 (27.25)  198  The c h i square f o r 4 degrees: o f freedom a t the 1% l e v e l of p r o b a b i l i t y is' 13 28. 0  One might conclude t h a t t h e r e i s a s i g n i f i c a n t a s s o c i a t i o n between low y i e l d o f seed and t h e s m a l l amount o f t w i s t i n g i n the pod. In t h i s connection  B r i n k and Cooper (3) found t h a t the  lower ovules i n the c a r p e l d i d n o t develop i n t o mature due t o  (a) f a i l u r e o f . f e r t i l i z a t i o n (b) ovule a b o r t i o n  seeds or  (c) i n f e r t i l i t y o f the o v u l e . 2.  A s s o c i a t i o n of Flower Abundance and Number o f Seeds The F^ p l a n t s d i f f e r e d g r e a t l y i n the number of f l o w e r s  produced.  A c h i square was r u n on t h i s c h a r a c t e r i s t i c t o see  i f i t had any b e a r i n g on the seed y i e l d . The f l o w e r abundance was put i n 3 c a t e g o r i e s , poor, f a i r and good.  The i n d i v i d a u l seeds produced were counted and d i v i d e d  into 3 categories  0 - 3 0 , 30 - 60,  Table 5 g i v e s t h e d i s t r i b u t i o n .  60 and more.  17 Table 5 Flower Abundance  Poor  Number of Seeds 0-30 30 -SO "1 : 1 • 10 1. s ; (7.9) (4.8) i  14  .  !  j- 60 +  Total  1  16  (3.2) 2  11  27  Fair (13.3)  (8.2)  (5.4) 11  10  |  26 . -  Good  Total  (12.8)  •(7.9)  34  21  C5*5) 69  14,  The c h i square a t the 5% l e v e l of p r o b a b i l i t y and degrees o f freedom i s  4  9.49.  An a s s o c i a t i o n i s i n d i c a t e d , however, d a t a are too to p l a c e much confidence  i n these r e s u l t s .  few  A d d i t i o n a l work  u s i n g l a r g e r numbers might y i e l d d i f f e r e n t r e s u l t s . B o l t o n and F r y e r (2) are 6f t h e o p i n i o n t h a t f l o w e r abundance i s no i n d i c a t i o n o f seed y i e l d .  And Cooper and  B r i n k (3) found t h a t t r i p p i n g i n c r e a s e s the number of f l o w e r s forming seed.  3.  Seed S e t t i n g (expressed as seeds per pod per p l a n t ) Com-  pared i n Racemes Which Have Been S e l f e d and Open P o l l i n a t e d . Rogers (24) a l f a l f a was  used f o r t h i s c o r r e l a t i o n .  were s e l e c t e d on the b a s i s of f l o w e r c o l o u r . i g n a t i o n s were g i v e n , w h i t e , paJLe y e l l o w  9  Plants  S i x c o l o u r des-  yellow, variegated  18 purple yellow, dark purple, pale purple.  Open p o l l i n a t e d  racemes were tagged, w h i l e s e l f p o l l i n a t e d ones were r o l l e d i n the f i n g e r s and tagged. Table 6 g i v e s t h e seed y i e l d per raceme i n number o f seeds.  There too few seeds t o weigh. Table 6  Seed S e t t i n g (expressed as seeds per pod per p l a n t ) Compared .in-Racemes'-Which Have Been S e l f e d and Open P o l l i n a t e d .  PLANT  No. Seeds p e r Raceme (average)  No •  Selfed (x)  Open (y) .  1  1 2  6  2  2  15  4  1  3  16  3  5  •  3  2.  4  17  4  1  4  3  3  18  3  1  5  4  19  2  2  6 i •  q  4  20  2  2  7  2  2  21  5  5  8  4  3 " .*  22.  '5  3  9  6  23  7  3  10  4  2  24  9  •2 -  11  3  3  25  7 .•  12  ; 4'  3  26  6  ®  13  4  3  27  3  1  28  6  14  i  6  '•  4  ;  •" • 8  A  j  :  ,  3  19 29  4  ".  '  4  43  2  4  4  44  6  6  30  4  31  4  4  45  2  2  4  2  46  5  2  2  47  4  4  1  2  33  6  34  5  5  48  35  6  2 \'-:  49  36  2  37  : 4  V  4  '."2; •  50  4  '  3  :  .4 :  51  6  5  38  5  6  52  '4  2  39  3  2  53  2  2  40  4  3  54  6  3  41  6  2  55  5  4  42  •5.  1  >  —  One may s a f e l y conclude t h a t t h e open p o l l i n a t e d racemes s e t more seed p e r pod than d i d t h e s e l f p o l l i n a t e d racemes. The d i f f e r e n c e , however, i s not" l a r g e and would i n d i c a t e t h a t t h e degree o f s e l f s t e r i l i t y  I n t h e F5 p l a n t s used i s n o t h i g h .  S e l f i n c o m p a t a b i l i t y f a c t o r s e t c e t e r a might be s e t f o r t h and t h e i n f l u e n c e o f t a g g i n g andjJaandiiHg might have been deleterious. the .  AhnormaX p o l l e n Is - as abundant i n the open as i n  s e l f ed.plant m a t e r i a l . for  -It 'could n o t t h e r e f o r e be a reason  the lower y i e l d i n t h e f i r s t c a s e .  However, p l a n t s which  tend t o s e t seed abundantly I n t h e open p o l l i n a t e d m a t e r i a l t a n d t o s e t seed w e l l i n the s e l f e d .  20 The a s s o c i a t i o n i s n o t s t r o n g b i o l o g i c a l l y s t a t i s t i c a l l y i t i shighly significant.  although  I t would seem t h e r e ~  f o r e t h a t t h e r e i s some evidence t o support t h e i n d i c a t i o n s o f s e l f incompatability factors. Kirk. (17)  on comparing s e l f and open p o l l i n a t e d m a t e r i a l  found a g e n e r a l decrease i n y i e l d - w i t h s e l f i n g , however, a fewe s t r a i n s segregated which gave c o n s i s t e n t l y good y i e l d .  Tysdal  and C l a r k (28) and C l a r k and F r y e r (7) s u b s t a n t i a t e s K i r k ' s work. 4.  A s s o c i a t i o n o f Flower C o l o r and Seed Y i e l d M a t e r i a l s used here were t h e 1928 r e c o r d s o f t h e F  4  progeny.  There were a g r e a t many f l o w e r c o l o r types e x h i b i t e d i n t h e f i e l d and i t was thought t h a t t h e seed y i e l d might be a s s o c i a t e d w i t h flower^ color.  Although  t h e r e were about 15 d i f f e r e n t c o l o r  d e s i g n a t i o n s they were e i t h e r predominantly  p u r p l e or y e l l o w .  The f l o w e r c o l o r was t h e r e f o r e d i v i d e d i n t o 4 c l a s s e s on t h e b a s i s , p u r p l e , v a r i e g a t e d p u r p l e , y e l l o w , and v a r i e g a t e d y e l l o w . The seed y i e l d was t a k e n i n grams per p l a n t and d i v i d e d i n t o 4 c a t e g o r i e s as shown i n Table 7' Table 7 F FlowerColor  ' t'Seed s 0-1  .  Y i e l d i n grams per p l a n t 1-6  6-10  Total  10 -  Purple.  15  Var.. P u r p l e  23  •8  29  12  76  25  170  38 52  Yellow V a r . Yellow  29  Total  61  1  69  15  21 Many r a t i o s w e r e t r i e d to determine the g e n e t i c s of f l o w e r c o l o r i n h e r i t a n c e hut none f i t t e d .  No doubt these c o u l d  be. worked out w i t h c o n t r o l l e d p o l l i n a t i o n .  Two  f a c t o r s (a)  f a i l u r e of c o n t r o l l e d p o l l i n a t i o n ( s e l f i n g ) and (b) the proba b i l i t y of complex p o l y p l o i d r a t i o s c o m p l i c a t e d t h i n g s . Lepper and Odland (20) s e t f o r t h a 3 f a c t o r b a s i s f o r f l o w e r c o l o r i n h e r i t a n c e i n a l f a l f a . , They o n l y t o o k t h e i r work t o the F , p  but had they c a r r i e d t h e i r i n v e s t i g a t i o n s on to  the Fg they might have found f l o w e r c o l o r i n h e r i t a n c e more complex, i . e . p o l y p l o i d y was  involved*  In connection w i t h f l o w e r c o l o r n&  seed y i e l d , Moe  a  (23)  found t h a t w h i t e f l o w e r e d p l a n t s tended to g i v e a low seed y i e l d w h i l e Hay  (14) e?n the other hand, found no a s s o c i a t i o n  between f l o w e r c o l o r and seed y i e l d . Table 8 g i v e s the d i s t r i b u t i o n of seed y i e l d ( i n grams) and f l o w e r c o l o r u s i n g more c o l o r d e s i g n a t i o n s than Table 7. Table 8 Seed y i e l d (Grams per p l a n t ) Flower Color  ;o-i  1-6  6-10  10-  Total  12  5  2  13  15  4  6  38  V a r i a g a t e d 51  59  11  20  141  Green  7  9  Yellow  2  2  Purple  Total  :  80  98  30 4 1  1  1  White: . ;  :. 7  •7 " ;  '  26  7  Blue  21  35  240  22 In both Tables 7 and 8 no a s s o c i a t i o n was found between seed y i e l d and f l o w e r c o l o r .  I n t h e above s t u d i e s f o r m a t i o n  of c l a s s e s f o r f l o w e r c o l o r w>as d i f f i c u l t due t o v a r i o u s f i e l d workers i d e a o f c o l o r .  The f l o w e r s tended t o change c o l o r  d u r i n g t h e blooming p e r i o d w h i c h made an a c c u r a t e c o l o r designation d i f f i c u l t .  I n t h i s c o n n e c t i o n i t was noted t h a t t h e  darker c o l o r s - b l u e s and p u r p l e s tended t o  predominate,Whether  t h i s i s due t o dominance o r a g r e a t e r gene frequency i s unknown*  5,  Comparison o f Seed Y i e l d f o r Two S u c c e s s i v e Y e a r s , A comparison o f t h e seed y i e l d o f t h e progeny o f t h e h y b r i d s  f o r two d i f f e r e n t years was made. The mean y i e l d f o r t h e f i r s t year was 1,52 grams and f o r the  second ,60 grams. This lower seed y i e l d i s p r o b a b l y due t o e n v i r o n m e n t a l  causes and bears out t h e work o f Hay ( 1 4 ) , B o l t o n & F r y e r (2) Freeman ( 1 1 ) , Southw#t*F^23) arid E n g l e b e r t (10) In both years though, good seed y i e l d e r s t e n d t o y i e l d seed w e l l and poor seed y i e l d e r s t o g i v e poor seed y i e l d s . This c o n s i s t a n c y o f seed y i e l d suggests t h e o p e r a t i o n o f heredity factors, 6,  D i s t r i b u t i o n o f Seed Y i e l d C l a s s e s . The accompanying  as t o seed y i e l d .  graph shows t h e d i s t r i b u t i o n o f p l a n t s  Plants  38 36 34  \  O Ordinarily  CO <D  1  01 ~3 CD FO O O €>  i t would be expected t o f i n d t h e seed y i e l d  f a l l i n g i n a normal d i s t r i b u t i o n c u r v e .  This d i s t r i b u t i o n i s  h i g h l y skewed, t h e r e are d i s t i n c t l y more h i g h y i e l d i n g p l a n t s than expected  i n a normal d i s t r i b u t i o n .  This would seem t o  i n d i c a t e the operation of h e r e d i t a r y f a c t o r s .  24 7  Comparison o f Seed Y i e l d , P l a n t H e i g h t s and P l a n t Weights i n F]_ and F- ' The m a t e r i a l s used f o r t h i s . s t u d y were t h e o r i g i n a l 7 h y b r i d s  and t h e i r F^ and S*2 progeny.  The seed y i e l d and p l a n t weight  were ..taken i n grams . and t h e h e i g h t i n i n c h e s . Table 9 g i v e s t h e seed y i e l d , p l a n t w e i g h t , and p l a n t h e i g h t for the,7•hybrids -also  the average seed y i e l d , p l a n t weight  f  and p l a n t h e i g h t f o r the Fg progeny o f t h e h y b r i d s . Table .9 Designation of P l a n t s  Seed P l a n t Wt. 'Plant Ht. (") Y i e l d (g) •  H y b r i d -7  F  "  -56  »  -68  "  -71  • V7.0  172  28  • .1.4. :  148  24  123  20  136  23  0.9  r :  ; ;0-,3 ; >  »' -156  2.4  100  24  "  3.5  263  30  -190 o f H-7  1.5 (ave.  11  " H-56  1,6  it  ti _  0.8  » '~  "  " H-71  0.4  "  0.8  " -.3  "  2  H  6 8  "H-190 ••.••,1.7.,;  )tj  92.4(Ave] ••25.4 (ave.)  •»»•"/.; 57 © 2 ti  20,3  ii'..  it  19.7  it  L  55,7  •: 24,-9 It • 13,5  \\  32.7  H'  14,8  II  48.9  11  14.9  H.  i  1 Kirk- (17) found a r e d u c t i o n o f v a r i a b i l i t y i n the F selfing.  2  with  The above f i g u r e s would i n d i c a t e h y b r i d v i g o r .  Comparisons  of previous t a b l e s on seed y i e l d s i n d i c a t e t h a t t h e seed y i e l d and p l a n t v i g o r are c o r r e l a t e d , I . e . t h e same f a c t o r s which are r e s p o n s i b l e f o r low seed y i e l d are i n a l l p r o b a b i l i t y r e s p o n s i b l e for a lessening of vigor.  From Table 9 can be seen t h e s t r i k i n g  r e d u c t i o n i n h e i g h t and w e i g h t o.f t h e Fg over t h e F i b u t a few plants i n the F  gave an i n c r e a s e d y i e l d over t h e F-,, Ct.  Throughout there seems t o be a s m a l l c o r r e l a t i o n i n y i e l d o f t h e Ft and t h e y i e l d o f t h e i r progeny.  This may be a s i g -  n i f i c a t n o b s e r v a t i o n i n terms o f t h e i r chromosome number. 8.  Comparison of. Seed Y i e l d i n F. P l a n t s and F2 Progeny (Open  pollinated  prevaling)  The Fj_ here used were t h e o r i g i n a l J T h y b r i d s . T  ;<. The weight i n each case was t a k e n i n grams.  The seed  y i e l d o f the progeny i s l i s t e d i n 2 columns, t h e average seed y i e l d and t h e maximum seed y i e l d . Table 10 g i v e s t h e s e seed y i e l d s .  .•  Table 10 ' "1  H y b r i d No. •H y b r i d Seed Y i e l d (grams) # 7  *  56 1  68 71 168 j • 190 Average  ,  Progeny Sample Seed Y i e l d Average gms.. Maximum- gms • per p l a n t per p l a n t .  7.0  1.5  ,4.7 ;  1.4  1.6  11.5  0.8  6.0  0.3  0.4  6.2  2.4  0.8  3.5 2.56  1.7' ;  .  • .  0.9  0.9  4,0 7.0 6.6  ,  26  The progeny on the average tended t o r e p e a t t h e seed y i e l d i n g a b i l i t i e s of the p a r e n t a l  hybrids.  -The maximum seed y i e l d e d by any one i n d i v i d u a l i n progeny b e a r s l i t t l e r e l a t i o n s h i p t o the c o n s t i t u t i o n of i t s h y b r i d . The d a t a were too few f o r I f x y but t h e j f x y — ^".45 was s i g n i f i c a n t f o r columns a and b.  which  ASSOCIATION' OF FACTORS NOT 1.  Comparison  INVOLVING SEED YIELD.  o f Height and Weight Between F ^ and Fg.  • M a t e r i a l s used f o r t h i s s t u d y were the weights and h e i g h t s o f the h y b r i d s and the average h e i g h t s and weights of random samplings o f t h e i r  progeny.  Both K i r k ( 1 7 ) , Stewart ( 2 6 ) , T y s d a l & C l a r k ( 2 8 ) and Southworth  ( 2 5 ) found a r e d u c t i o n o f v a r i a b i l i t y on s u c c e e d i n g  generations. Table 1 2 g i v e s the d i s t r i b u t i o n of h e i g h t and w e i g h t f o r the F-^ and Fg« The lower number f o r t h e Fg would p o i n t t o t h e a c t i o n o f hybrid vigor.  The F]_ c e r t a i n l y g i v e s h i g h f i g u r e s than the  p a r e n t M. f a l a c a t a p l a n t which i s low gown and low y i e l d i n g . Table 1 2 i n d i c a t e s t h a t the v i g o r o f t h e p l a n t s decreases on s e l f i n g , which i s shown by the s t r i k i n g decrease i n h e i g h t and w e i g h t of t h e F  over t h e Fq_.  28 Table 12A ; 1  Hybrid  4  Wt. Comparisons  !  Wt. o f h y b r i d , Av, Wt. o f [ i n grams) progeny number f (samples i n grams) Fg i P l a n t s F. .5 r 172  208  ! . 92..4. ' . -57.2  j  167  j  9 1  148  68  123  55 » 7  71  136  24.9  100  - ; ; 32.7  1  • 76  263  48.9  1  79.  157  52 © 1  j  Average  -  Maximum Wt. f o r progeny j sample fI F 2  56  190  j  --  ;  1  41  L  120.3 _  _  .  .,' _|: J  Table 12B Ht. Comp ar i s ons Ht. o f h y b r i d Av. H t . f o r ! , progeny sample, ^in inches)  . Hybrid  t  number  (in inch )  .Plants  e s  25 «> 4.  28 ' 56. ''' 68  .  190 Average  32  20.3  ' 29 "  20  19.7  27  13.5 .  24 !  .... i  j24  • 23.:  156  !  Maximum Ht J f o r progenjsample ( i n : inches)  30  1  24.8  j  14.8  2.L-  14,9  22  i s . i  25.1  1  29 2.  Y i e l d and  Pleight  A g r e a t amount o f d a t a was The m a t e r i a l used was o r i g i n a l 7 hybrids.  available for this correlation.  the f o u r t h g e n e r a t i o n p l a n t s from the P l a n t s were s e l e c t e d at random from t h i s  l a r g e group and c o r r e l a t i o n s r u n on them. was  o n l y a v a i l a b l e the d a t a f o r 1928  U n f o r t u n a t e l y there  making i m p o s s i b l e to make  a year to s t u d y . The r e s u l t s are g i v e n i n Table I Table I Correlation Numbers  The to -f- 0.88.  No.  of P l a n t s  Field Designation  Correlation Coefficients  c o r r e l a t i o n s are a l l p o s i t i v e and range from -/- 0.35 By f a r the l a r g e r number have a h i g h c o r r e l a t i o n  which would seem to i n d i c a t e t h a t t h e r e i s 3. h i g h c o r r e l a t i o n between h e i g h t o f p l a n t and y i e l d of p l a n t .  The  same r e s u l t s  were o b t a i n e d by Hacbarth and U f e r ( 2 9 ) , Burton (5) and  Kirk  (17). This c o r r e l a t i o n , however, i s not a b s o l u t e as seen i n the  30 two v a l u e s which g i v e -h 0,35 and -f- 0.45, 3»  A s s o c i a t i o n Leaf S p o t t i n g Incidence and % Ovules Developing  on Racemes* L e a f s p o t t i n g i s v e r y p r e v a l e n t and i s due t o a d i s e a s e ffeeudopeziea m e d i c a g i n i s .  I t was thought t h a t t h e r e might be  an impairment o f p h y s i o l o g i c a l a c t i v i t y due t o l e a f s p o t t i n g . I f t h e r e i s any i t does n o t m a n i f e s t i t s e l f i n t h e number o f ovules d e v e l o p i n g on t h e racemes.  Table 2 shows the l e a f s p o t t i n g  i n c i d e n c e p l o t t e d a g a i n s t t h e % ovule development. Table 2  %  Leaf Spot •'•Incidence  0 -50%  •• 1 •  3 (4.2)  ' '21V' (19.6)  11 (11.2)  35  2  6 (4.8)  21 (22.4).  13 (12.8)  40  Dotal  9  50% -80%  80% - 100%  .,. 42  Mo, 1 denotes h i g h i n c i d e n c e and 2. low.  24  '"75 ' '.  The t o p v a l u e . i s  the a c t u a l number w h i l e the lower i s the t h e o r e t i c a l . The c h i square f o r 2 degrees o f freedom a t t h e 5% l e v e l o f s i g n i f i c a n c e i s 5.99 wMehh I n d i c a t e s t h a t t h e r e i s no a s s o c i a t i o n 9  between t h e degree o f l e a f spot p r e s e n t and the number o f ovules developing.  31 4»  A s s o c i a t i o n of Leaf S p o t t i n g and L e a f C o l o r . L i t t l e i s mentioned i n the l i t e r a t u r e r e g a r d i n g the e f f e c t  t h a t l e a f s p o t may  have on a l f a l f a .  Present i n d i c a t i o n s are  that i t i s increasing. Table 3 g i v e s the d i s t r i b u t i o n f o r the i n c i d e n c e of l e a f s p o t and l e a f c o l o r . Table 3 • Leaf .Spot  Incidence  51  •1 .  2  Dark 23 (24.1)  Foliage Color  26 (15.4)  49  13 (14.1)  28  Light 15 (13.8) - 38 / m  Leaf Spotting?  39 1 2  77  high incidence med» .& low i n c i d e n c e  The m a t e r i a l s used here were 77 p l a n t s s e l e c t e d at random f r o m t h e F^ progeny. The  c h i square f o r 1 degree o f freedom at the 5% l e v e l of  p r o b a b i l i t y was  3.84  .  This i n d i c a t e s t h e r e i s no s p e c i a l s i g -  n i f i c a n c e between f o l i a g e c o l o r and the amount of l e a f s p o t t i n g . I t s h o u l d be n o t e d i n t h i s c o n n e c t i o n w i l l aften give a paler l e a f .  t h a t a boron d e f i c i e n c y  However, i n t h i s ease the d i f f e r e n t  c o l o r s of l e a v e s c o u l d h a r d l y be a t t r i b u t e d to n u t r i t i o n a l factors.  32 5,  A s s o c i a t i o n l e a f s p o t and Flower Abundance. Instead o f a f f e c t i n g the seed y i e l d d i r e c t l y the l e a f spot  might have reduced the number o f f l o w e r s , t h e r e b y seed y i e l d .  decreasing  the  -A comparison o f f l o w e r abundance and l e a f s p o t t i n g  i s g i v e n i n Table 4. Random s e l e c t i o n s from the F^ progeny were used f o r these studies. Table 4  Poor 13  Fair  Good  13  13  1  38 (918) 7  (14.3) 16  (13.8) 16  2  39 (10.1)  Total  20  (14.7)  29  (14.2)  28  The l e a f s p o t i n c i d e n c e was d i v i d e d i n t o 2  77  categories  Xdenoting h i g h degree o f l e a f s p o t t i n g and 2 low.  The  flower  abundance was d i v i d e d i n t o 3 c l a s s e s , poor, f a i r , and good. The c h i square a t 2 degrees o f freedom a t t h e 5% o f p r o b a b i l i t y was 5.99, which would i n d i c a t e t h a t l e a f s p o t t i n g has n o t s e r i o u s l y i n f l u e n c e d the number o f f l o w e r s .  The number^  o f samples used was s m a l l and a d i f f e r e n t a s s o c i a t i o n might be o b t a i n e d u s i n g l a r g e r numbers.  33 6.  A s s o c i a t i o n o f Stem Thickness and P l a n t H e i g h t . The m a t e r i a l s used f o r t h i s a s s o c i a t i o n were s e l e c t i o n s  from Rogers (24) a l f a l f a .  75 p l a n t s were s e l e c t e d at random  and a e h i square r u n on t h e s e .  The stem t h i c k n e s s was  given  3 d e s i g n a t i o n s , t h i n , medium, and t h i c k f the h e i g h t was  also  d i v i d e d i n t o 3 c a t e g o r i e s , 25 inches and l e s s , 25-30 i n c h e s , and 30 inches and more.  Table 5 g i v e s the d i s t r i b u t i o n .  Table 5 P l a n t He i g h t ( I n c h e s ) 0-25 18  25- 30  30 & over  3  Total  0  Thin  21 (8.9)  (7.5)  (4.48)  Stem. thickn  13  18  4  Medium  35 (14.9)  (12.6)  1  6 -  (8.1)  (6.8)  (7.4) 12  Thick  19  Total  32  27  (4)  16  The c h i square a t the 5% l e v e l o f p r o b a b i l i t y o f freedom was  9.49  75 and 4 degrees  which would i n d i c a t e avery s t r o n g a s s o c i a t i o n  between t h i c k n e s s o f stem and p l a n t h e i g h t .  However, i t might  be p o s s i b l e t o s e l e c t a t a l l growing p l a n t w i t h a t h i n g stems Burton (5) found a s t r o n g a s s o c i a t i o n between'height and number o f stemso  3 4  7.  A s s o c i a t i o n o f H e i g h t and Spread, M a t e r i a l s used were random s e l e c t i o n s from the progengy  i n v o l v i n g 5 0 0 plants. were taken by the Department o f Agronomy i n A  the e a r l y summer. K i r k ( 1 7 ) and Armstrong and White ( 1 ) found a p o s i t i v e c o r r e l a t i o n between these 2 c h a r a c t e r s . Table 6 g i v e s the d i s t r i b u t i o n . Table 6  2t*15  • » • • • • • • . • • • • » a  •  3** 1 3  • » ft 1 3  * • » • • • • • « « • • . . .  f . 0 3  4.** 3  • . .  "^,30  5™^1  . . . . / » » 1 6  7  » . . .  •  • * . •  7**^  •  2 4  - , 0 7  • • .  11**15  e » * 9 « * * 9 0 V . . .  12*"*11*  ™*2yL,  14~*23  ^ . 3 5  . . . .  10*^19 •  1 3  1 5  • •• •  ^ , 2 3  f  . 2 6  •  2 3  * • • • » • • • « » - • » • • • * ^ » 2 4  The c o r r e l a t i o n i s p o s i t i v e b u t low though i n some l i n e s the a s s o c i a t i o n i s q u i t e s t r o n g .  I t s h o u l d t h e r e f o r e be  p o s s i b l e t o s e l e c t "tatfe growing p l a n t s which are s p r e a d i n g .  35 The stage o f growth a t which these c o r r e l a t i o n s are t a k e n i s i m p o r t a n t . The above mentioned p l a n t s were r e l a t i v e l y mature, e a r l i e r c o r r e l a t i o n s may have been b e t t e r , 8.  A s s o c i a t i o n o f Flower Abundance and Raceme S u p p o r t i n g  Ovules. I t was thought t h a t the f l o w e r abundance would have a c o n s i d e r a b l e e f f e c t on seed.development.  The f o l l o w i n g  s t u d i e s d e a l w i t h the e f f e c t o f f l o w e r abundance on v a r i o u s c h a r a c t e r i s t i c s a f f e c t i n g seed y i e l d . Table 7. FLower Abundance  Racemes % Remaining, 0-50  50-80  80-100 i  13  '  Poor  i  i  Total' *  1 20  (2.63)  (11- 37)  (6.1)  !  3  -15  12  (3.4)  (16.9)  (9.1)  Fair  J  30  7  |.  4  15  Qbod  26 (3.4)  .Total.  10  I 1 i  (14.2)  ]  •' 43 '  1(7.8) ! 23  76  i  The f l o w e r abundance was d i v i d e d i n t o 3 c a t e g o r i e s , poor f a i r , andgood and t h e percentage o f f l o w e r s r e m a i n i n g were  36 divided into 3 classes 80-100%.  a c c o r d i n g t o percentage 0-50%, 50-80%,  There i s no a s s o c i a t i o n "between the f l o w e r abundance,  and the number o f racemes r e m a i n i n g .  The c h i square a t t h e 5 %  l e v e l o f s i g n i f i c a n c e i s 9.49 which i n d i c a t e s ho r e l a t i o n s h i p .  9.  Association  of Foliage  Color and Flower Abundance.  Rogers a l f a l f a (24) was used f o r t h i s c o r r e l a t i o n .  The  f o l i a g e c o l o r was d i v i d e d i n t o l i g h t and dark and the f l o w e r abundance i n t o 3 c l a s s e s poor, f a i r and good. Table 8  Foliage Color Dark Green  F l o wer Abunclance | Fair Good Poor 18  10  (17.7)  9  10  (  17.1) 8 27  (6.9)  Total  19 47  ' (12.0) Light Green  Total  (10.2)  19  28  (9.8)  27 :  74 .:  As would be expected t h e r e was no r e l a t i o n s h i p i n t h i s association.  The c h i square f o r 2 degrees o f freedom a t the ;  5% l e v e l o f p r o b a b i l i t y i s 5 »99"  e  Here a g a i n the p o s s i b i l i t y o f the e f f e c t o f a boron d e f i c i e n c y must not be o v e r l o o k e d .  37 10.  A s s o c i a t i o n o f Flower Abundance and Flower F a l l . \ I n some cases t h e r e were a l a r g e number o f f l o w e r s  f e l l e a r l y i n development form.  that  I.e. l o n g b e f o r e pods had begun to  I n Table 9 the f l o w e r abundance i s d i v i d e d i n t o 3 c l a s s e s  poor, f a i r and good, and t h e amount o f f l o w e r f a l l i n t o 3 c l a s s e s 0-50,50-80 and 80 and o v e r . Table 9 Slower ibundance  Amount o f Flower 1? a l l 0- 50  50-80 13  Total  -80- . 7  Poor  20 (2.63) 3  (11.3) 15  (6.1) 12  Fair  36 (31.9)  7  (16.9) 15  (9.1) 4  3ood  26 (3.4)  10  Total  (14.7) ' £7.8)  43  ,23  76  M a t e r i a l s used were random s e l e c t i o n s from the -F4  progeny.' The c h i square a t the 5% o f p r o b a b i l i t y and 4  degrees o f freedom i s 5.81 which would i n d i c a t e no a s s o c i a t i o n .  38 FLOWER COLOR,OTHERITANCES!32UDIES. Flower C o l o r I n h e r i t a n c e S t u d i e s i n A l f a l f a . The f l o w e r c o l o r s have been p l a c e d i n 15 c a t e g o r i e s A l though t h e v a r i e g a t l s j % c o l o r s are predominately  blue or purple  t h e r e appeared v a r i e g a t e d f l o w e r s which wens b a s i c a l l y y e l l o w or g r e e n o r a m i x t u r e o f t h i s w i t h blue and purple»  :  The m a t e r i a l used was t h e F  o f the o r i g i n a l 7 h y b r i d s .  Q  Table 1 g i v e s t h e i r d i s t r i b u t i o n .  T h e ' f i r s t column i n d i c a t e s  the h y b r i d from which t h e p l a n t s were d e r i v e d . Table 1  CD  0) 0)  H  m  H ft  CD HCD H ft ,Q Sh I Q) P4 H  ft  3  PM  I  CD  CD  cd  CO  H  PM  ft  H PM  >  CD  ft 1h 13 O HI  d) »r!  H  0)  o  I P» o H H  H  ft ft  o H H  iS I ci CD  H  4-3  o i—l  H  cis a)  •H  •a  >  >  13  3  # 56  3  6  1  20  # 68  3  2  2  2  3  1  3  6  4  1  2  13  1  8  12  18  3  # 156  1  # 190  1  8  &  12  2  1  0)  H ft  P-t  # 7  # 71  -d CD -P cS hQ CD •rt  1  1  5  '  The d e s i g n a t i o n o f a c t u a l c o l o r s p r e s e n t e d a g r e a t d i f f i c u l t y . Some p l a n t s weas-different c o l o r s d u r i n g the v a r i o u s stages o f  39 t h e i r blooming p e r i o d . > A l a r g e number o f r a t i o s were t r i e d b u t none f i t t e d , , C o l o r i n h e r i t a n c e I s p r o b a b l y f u r t h e r complicated the p o l y p l o i d n a t u r e o f the m a t e r i a l .  due t o  .  In t a b l e 2 t h e c o l o r classeswere c u t down t o 3.  The  f l o w e r s wer b a s i c a l l y p u r p l e , green or y e l l o w and were c l a s s i f i e d on t h a t b a s i s . Table 2 —  Parent Plant  —  —  ,  f — — 1 Pnrple & 1 Green Blue i '•  Yellow.  •  #7  21  #56  30  #68  0 '  17  12  I 8  •  7  #71 #156  10  #190  .• is.;.!^ 12  8 ;  20  •. .3 ,  Lepper and Qdlqnd^ (20) p u t f l o w e r c o l o r I n h e r i t a n c e i n a l f a l f a on a 3 f a c t o r b a s i s .  T h e i r hypothesis  was not d i s -  proved. However, "pure y e l l o w " occurs much l e s s f r e q u e n t l y than expected.  Out o f 185 Fg p l a n t s , w h i t e s and y e l l o w s are n o t  recovered a t a l l .  They are r e c o v e r e d f a i r l y f r e q u e n t l y i n  l a t e r generations.  P o l l i n a t i o n c o n t r o l may n o t have been  s a t i s f a c t o r y . E i t h e r some c r o s s i n g may have taken p l a c e o r t h e  40 numbers o f progeny r e c e i v e d were n o t s u f f i c i e n t f o r accurate conclusions.  The h y b r i d s are p o l y p l o i d and t h e r e f o r e not  l i k e l y t o y i e l d many y e l l o w s and w h i t e s t i l l l a t e r g e n e r a t i o n s . The g e n e r a l s e g r a t i o n d i s t r i b u t i o n , however, suggests an i n h e r i t a n c e p a t t e r n i n v o l v i n g s e v e r a l p r i n c i p a l mendelian factors', w i t h f a c t o r s f o r p u r p l e s and blues e p i s t a t i c t o those f o r y e l l o w and w h i t e .  41 DISCUSSION The r e s u l t s obtained from t h i s work are o f i n t e r e s t i n r e l a t i o n t o t h e p r a c t i c a l bearing, which they may have on t h e problem o f a l f a l f a improvement.  When s e l e c t i o n i s d e s i r e d  for. a c e r t a i n , c h a r a c t e r j i t i s o f t e n d e s i r a b l e t o determine, i f p o s s i b l e , which other c h a r a c t e r s o f the. p l a n t , i f any, are a s s o c i a t e d w i t h i t .  By s e l e c t i n g f o r o n e ; f t may be, r  p o s s i b l e t o secure t h e other a l s o .  However, i n crop improvement  work a b r e e d i n g program must go hand i n hand w i t h c o r r e l a t i o n studies. I t i s p o s s i b l e t o g e n e r a l i z e On the p o s s i b i l i t i e s o f i n b r e e d i n g and h y b r i d y k t l o n as a means o f improving  alfalfa.  As i n most n o r m a l l y c r o s s f e r t i l i z e d crops t h e r e i s a r e d u c t i o n o f v i g o r upon I n b r e e d i n g .  However, some l i n e s showed no l e s s -  ening o f v i g o r upon s e l f - f e r t i l i z a t i o n , which seems t o i n d i c a t e t h a t t h e d i f f e r e n t i a l e f f e c t o f s e l f - f e r t i l i z a t i o n i s due t o the g e n e t i c c o n s t i t u t i o n . In t h i s i n v e s t i g a t i o n emphasis has been p l a c e d upon seed production.  At p r e s e n t t h e major problem i s t o develop a  v i g o r o u s p l a n t which i s a l s o a good seed y - i e l d e r . An abundance of f l o w e r s would appear t o have some b e a r i n g on t h e f i n a l seed p r o d u c t i o n .  Many f a c t o r s both g e n e t i c and environmental  a f f e c t these c h a r a c t e r i s t i c s o f t h e p l a n t .  High and low  f e r t i l i t y and v i g o r are a p p a r e n t l y inherited,, environmental  However,  c o n d i t i o n s must be s a t i s f a c t o r y before a p l a n t  w i l l f u n c t i o n t o i t s optimum.  I t i s hoped t h a t t h e c o r r e l a t i o n  e s t a b l i s h e d , b o t h p o s i t i v e and n e g a t i v e , between seed y i e l d  42 and other c h a r a c t e r i s t i c s w i l l prove o f h e l p i n f u t u r e a l f a l f a improvement work. Pigmentation does n o t appear t o have any e f f e c t on any of the characters s t u d i e d .  Both f l o w e r c o l o r and t h e degree  o f p i g m e n t a t i o n o f the leaves y i e l d e d no d e f i n i t e a s s o c i a t i o n s . L e a f spot was t h e o n l y d i s e a s e o f w h i c h there was any evidence*Other  than its•appearance on the l e a v e s i t d i d n o t  appear t o have any e f f e c t e i t h e r m o r p h o l o g i c a l l y or p h y s i o logically. In some o f these s t u d i e s s u f f i c i e n t numbers were a v a i l able b u t i n o t h e r s due t o t h e l a c k o f time and f a c i l i t i e s , the number o f samples t a k e n were few.  I t should therefore  be c a u t i o n e d t h a t i n these "cases where l i m i t e d numbers were used c o n c l u s i v e r e s u l t s are i m p o s s i b l e . y i e l d different conclusions.  F u r t h e r work may  CONCLUSIONS • S e l e c t i o n w i t h i n s e l f f e r t i l i z e d l i n e s appears t o p r o v i d e a primary' mode o f a t t a c k f o r t h e b r e e d i n g o f improved v a r i e t i e s of a l f a l f a .  As i n d i c a t e d ' i n  these and other s t u d i e s t h e r e i s  a g e n e r a l r e d u c t i o n o f v i g o r lipon s e l f p o l l i n a t i o n .  However,  a few p l a n t s r e t a i n t h e i r good c h a r a c t e r i s t i c s even upon s e l f ing.  When s u p e r i o r i n b r e d s t r a i n s . h a v e been o b t a i n e d which are  v i g o r o u s enough t o r e p l a c e t h e heterogenous v a r i e t y now grown, the b r e e d i n g program beSmes r e l a t i v e l y simple,,  These s t u d i e s  show t h a t t h e r e i s a g e n e r a l r e d u c t i o n o f seed y i e l d , p l a n t y i e l d and p l a n t h e i g h t between t h e F^ and F2.  But a few  p l a n t s tend t o r e t a i n the good q u a l i t i e s o f the p a r e n t . Seed y i e l d was s t u d i e d i n some d e t a i l and i t was shown t h a t h i g h y i e l d i n g p l a n t s had a g r e a t e r number o f t w i s t s p e r pod.  Open p o l l i n a t i o n and good weather had a b e n e f i c i a l e f f e c t  on the amount o f seed s e t .  The abundance o f f l o w e r s seemed t o  be an i n d i c a t i o n o f f i n a l seed y i e l d i . e . an abundance o f f l o w e r s would g i v e a good seed-set.  However, due t o t h e s m a l l  number o f samples i n v o l v e d and some d i f f i c u l t i e s  encountered  i n the f i e l d , t h i s r e s u l t can by no means be taken as a b s o l u t e . Leaf spot and f l o w e r c o l o r , on t h e other hand, gave no associ a t i o n w i t h seed y i e l d a t a l l . decrease t h e seed y i e l d . the processes  S e l f f e r t i l i z a t i o n tended t o  Whether h a n d l i n g o f the racemes i n  e f f e c t i n g f e r t i l i z a t i o n i n c r e a s e d or decreased  the f i n a l seed y i e l d , i s u n c e r t a i n . These r e s u l t s i n d i c a t e t h a t flov/er abundance i s no i n d i c a t i o n o f alisuperiorcplan'ti'il.Associations of t h i s c h a r a c t e r w i t h  44 f o l i a g e color.  ?  l e a f spot and percentage o f ovules d e v e l o p i n g  on t h e raceme gave no p o s i t i v e results» The stem, on t h e other hand,' i s a f a i r l y r e l i a b l e ation of a superior plant.  indic-  C o r r e l a t i o n s between the h e i g h t  o f t h e stem and stem w i d t h , p l a n t y i e l d and spread a l l gave positive results. L e a f spot d i d n o t appear t o h i n d e r the a c t i v i t y of the plant at a l l .  There was no a s s o c i a t i o n between l e a f spot  and f l o w e r abundance, l e a f c o l o r o r percentage o f ovules developing.on t h e raceme. S e v e r a l uns-uccessful attempts were made t o r e a c h some c o n c l u s i o n r e g a r d i n g t h e mode o f f l o w e r c o l o r i n h e r i t a n c e . V a r i o u s workers have suggested h y p o t h e s i s f o r f l o w e r c o l o r i n h e r i t a n c e o f a l f a l f a but t h e author was unable to f i t any o f these t o h e r r e s u l t s . I t i s hoped t h a t t h i s work w i l l c o n t r i b u t e something t o f u t u r e a l f a l f a improvement work. some cases d a t a was v e r y l i m i t e d . be used as i n d i c a t i o n s .  I t was u n f o r t u n a t e t h a t i n These r e s u l t s can o n l y  However, f u r t h e r i n v e s t i g a t i o n u s i n g  l a r g e r numbers may c o n t r i b u t e some d e f i n i t e c o n c l u s i o n .  45  SUMMARY I  There was a s i g n i f i c a n t a s s o c i a t i o n between pod shape and number o f seeds per pod f o r s e l f p o l l i n a t i o n m a t e r i a l ,  2.  There was a h i g h l y s i g n i f i c a n t c o r r e l a t i o n between number of seeds per pod and pod shape i n the open p o l l i n a t e d material,  3  Low seed y i e l d i n g p l a n t s tend t o have s t r a i g h t podsf h i g h seed y i e l d i n g p l a n t s tend t o have t w i s t e d pods,  4  There i s p r o b a b l y some a s s o c i a t i o n between many f l o w e r s w i t h a l a r g e seed s e t but d a t a are too s c a n t y t o put much r e l i a n c e on i t ,  5  There i s a. s i g n i f i c a n t d i f f e r e n c e i n seeds (a)  per pod between s e l f and open p o l l i n a t e d racfmes,  (b)  t h e r e i s a s i g n i f i c a n t c o r r e l a t i o n between pods w i t h abundant seed i n b o t h open p o l l i n a t e d and s e l f p o l l i n ated,  6  There i s no a s s o c i a t i o n between f l o w e r c o l o r and seed y i e l d ,  7  Comparisons between seed y i e l d o f s u c c e s s i v e years showed a decline.  However, a good seed y i e l d e r tended t o remain  good seed y i e l d e r s , 8  There are d i s t i n c t l y more h i g h y i e l d i n g p l a n t s than exp e c t e d i n a normal d i s t r i b u t i o n c u r v e ,  9  Comparisons o f seed y i e l d , p l a n t y i e l d and p l a n t h e i g h t between the F-j_ and Fr, showed a r e d u c t i o n i n g e n e r a l ,  10  There i s no a s s o c i a t i o n o f f l o w e r abundance and floxver color.  46  11  There i s no a s s o c i a t i o n between, l e a f s p o t t i n g and f l o w e r  12  incidence  abundance,  There i s no a s s o c i a t i o n between f l o w e r abundance and the percentage o f ovules d e v e l o p i n g on t h e racemes,  13  There i s no a s s o c i a t i o n between f l o w e r abundance and f l o w e r fall,  14  There i s no a s s o c i a t i o n between f l o w e r abundance and l e a f dolor*  15  There i s a s t r o n g c o r r e l a t i o n between stem t h i c k n e s s  and  stem h e i g h t , 16  There i s a p o s i t i v e c o r r e l a t i o n between p l a n t h e i g h t and plant y i e l d .  The p o s i t i v e c o r r e l a t i o n i s h i g h but n o t  absolute, 17  There i s a c o r r e l a t i o n between p l a n t h e i g h t and s p r e a d .  18  There I s no a s s o c i a t i o n between l e a f s p o t t i n g  incidence  and l e a f c o l o r , 19  There i s no a s s o c i a t i o n between l e a f s p o t t i n g  incidence  and the percentage o f ovules d e v e l o p i n g on t h e racemes, 20  Ho c o n c l u s i o n s color  were a r r i v e d a t r e g a r d i n g  inheritance.  the mode o f f l o w e r  46 1,  Armstrong, J.M.' and White, W. J . F a c t o r s A f f e c t i n g Seed S e t t i n g i n A l f a l f a : A g r i c . S c i e n c e , V o l , 25 - 1935,  Jour o f  2,  B o l t o n , J.L. and F r y e r , J.M. I n t e r p l a n t V a r i a t i o n s i n C e r t a i n Seed S e t t i n g Processes in Alfalfas Sex. A g r i c , V o l , 18 - 1937,  3,  B r i n k , R.A, and Cooper, D.D. S o m a t o p l a s t i c S t e r i l i t y i n M, s a t i v a : S e r v i c e , V o l , 90,  S c i , News  4,  B r i n k , R..A. and Cooper, D.C. P a r t i a l and S e l f I n c o m p a t a b i l i t y and the C o l l a p s e o f F e r t i l e Ovules as F a c t o r s A f f e c t i n g Seed Formation i n A l f a l f a : J o u r , A g r i c , Research, Vol,.60 - 1940  5,  B u r t o n , G.W. ' A l f a l f a I n h e r i t a n c e S t u d i e s i n New Agroa. J o u r , , V o l , 27 - 1935  J e r s e y : Am,  Soc.  6,  C a r l s o n , J,W. A r t i f i c i a l T r i p p i n g of Flowers i n A l f a l f a i n R e l a t i o n to Seed Production? J o u r , o f Am. Soc, Agroa,, V o l , 22 1930.  7,  C l a r k e , A.E. and F r y e r , J.M, Seed S e t t i n g i n A l f a l f a :  8,  9^  s S c i . A g r i c . , V o l . 11 -  Cooper, D.C. ' Embryo M o r t a l i t y i n R e l a t i o n to Seed Formation Alfalfas Am, J o u r , o f Bot., V o l . 24, 1937.  1930  in  Dwyer, R.E.P, Lucerne Breeding Technique - A New System o f Close B r e e d i n g : Herbage Reviews, V o l . 4- 1936  10,  E n g l e b e r t , V. A Study o f V a r i o u s F a c t o r s I n f l u e n c i n g Seed P r o d u c t i o n in Alfalfas S c i . A g r i c . , V o l . 12 - 1931.  11,  F a r l e y , H. A C y t o l o g i c a l Study of U. B. C. A l f a l f a s 1936 - u n p u b l i s h e d .  M.S.A. Thesis  12,  Freeman, G.F. P h y s i o l o g i c a l C o r r e l a t i o n s and C l i m a t i c R e a c t i o n s i n A l f a l f a Breedings Am. Nat., V o l . 48 - 1941,  13,  G r i z z a r d , A.L. and Matthews, E. M. E f f e c t s o f Boron on Seed P r o d u c t i o n o f A l f a l f a s J o u r . Am. Soc. Agron., V o l . 34 -1942  14..  Hay, W.D. D o e s . . A r t i f i c i a l T r i p p i n g of- A l f a l f a Blossoms Increase Seed S e t t i n g ! S c i . A g r i c , V o l . 5,  1924,  .15.  Hut c h i n s on A. H, and Farley., H. • ' Seed Development i n Medicago H y b r i d s | Normal Ovule Canadian J o u r . Research, V o l , 19, 1941,  16.  Jones, F.R. Evidence o f R e s i s t a n c e i n A l f a l f a , Red Clover and Sweet C l o v e r to C e r t a i n Fungus P a r a s i t e s ? Phyt., V o l . 31- 1941.  17*  K i r k , L.E. S e l f F r t i l i t y i n R e l a t i o n to Forage Crop Improvement! Sc. A g r i c , V o l , 8 - 1927  ?  e  18,  Ledingham, G. F. G y t o l o g i c a l and Developmental S t r u c t u r e s of Hybrids Between M. s a t i v a and a D i p l o i d M. F a l a c a t a : Genetics, V o l . 25- 1040.  19.  Lejeune, C.J. and Olson, P.J. Seed S e t t i n g i n A l f a l f a 5 Sc. A g r i c , V o l . 20 -  20.  21,  '22.  23.  24.  Lepper, R. and Odland, T.E. L e a f M u t a t i o n i n A l f a l f a : J o u r n . Am. V o l . 31 - 1937.  Soc. A g r o n .  Lepper, R and Odland, T.E. I n h e r i t a n c e o f Flower C o l o r i n a l f a l f a : J o u r n . .Soc Agron., V o l . 31- 1937. McVicar, R. F. ' I n h e r i t a n c e o f Seed Colour i n A l f a l f a : V o l , 15 - 1934. Moe, G.G. • Inherantance S t u d i e s o f A l f a l f a s Unpublished. Rogers, C.B. W. Rhizome S t u d i e s o f A l f a l f a s M.S.. Unpublished.  1928  1939.  Sc  9  Am.  Agric  Thesis -  A. Thesis -  1941  25.  Southworth, W» I n f l u e n c e s Which Tend t o A f f e c t Seed P r o d u c t i o n i n A l f a l f a and an Attempt to R a i s e High Seed Producing S t r a i n s by H y b r i d i z a t i o n s S c A g r i c . , V o l . 9 - 1928.  26.  S t e w a r t , G. A b n o r m a l i t i e s i n Inbred A l f a l f a and Surgar Beets 1 J o u r , o f H e r e d i t a r y , V o l . 25, 1934.  27.  Stewart, G« The E f f e c t s o f I n b r e e d i n g on V a r i a b i l i t y i n A l f a l f a s J o u r . A g r i c . Reasearch, V o l . 49- 1934 s  28.  T y s d a l , H. M. Is T r i p p i n g Necessary f o r Seed S e t t i n g i n A l f a l f a s J o u r . Am. Soc. Agron., V o l . 32s 1940.  29.  T y s d a l , HvR. and C l a r k , I . ' = Improvement o f A l f a l f a Seed P r o d u c t i o n by J o u r . Am. Soc. Agron., V o l . 26-1934.  30.  Inbreedings  T y s d a l , H.R. And Westover. A l f a l f a Improvements U. S. A g r i c . Year Book - 1937.  

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