T h e o r . Appl. G e n e t . 50, 227-233 (1977)
9 by Springer-Verlag 1977
Intraspecific Unilateral Incompatibility in ViciafabaL. M. M. F . A b d a l l a D e p a r t m e n t of A g r o n o m y , F a c u l t y of A g r i c u l t u r e , C a i r o U n i v e r s i t y , Giza (Egypt)
S u m m a r y . U n i l a t e r a l i n c o m p a t i b i l i t y was d i s c o v e r e d when c r o s s i n g was a t t e m p t e d b e t w e e n d i f f e r e n t s e l f - c o m p a t i b l e types and s u b s p e c i e s of V. faba. C r o s s i n g in the d i r e c t i o n f e m a l e l e s s s e l f - f e r t i l e • m a l e m o r e s e l f - f e r tile f a i l e d , w h e r e a s the r e c i p r o c a l - c r o s s i n g s u c c e e d e d . U n i l a t e r a l i n c o m p a t i b i l i t y developed with the e v o l u t i o n of l e s s f e r t i l e and l a r g e s e e d e d field b e a n t y p e s . How a c r o s s f e r t i l i z e d (and s e l f - i n c o m p a t i b l e ) s y s t e m m a y develop f r o m a s e l f f e r t i l i z e d one is d i s c u s s e d . The u n i l a t e r a l i n c o m p a t i b i l i t y i n V. faba and o t h e r plant s p e c i e s is c o m p a r e d . The t w o - p o w e r c o m p e t i t i o n h y p o t h e s i s can e x p l a i n all k i n d s of u n i l a t e r a l i n c o m p a t i b i l i t y r e p o r t e d so f a r i n the l i t e r a t u r e . B r e e d i n g field b e a n s for i m p r o v e d s e l f - f e r t i l i t y is d i s c u s s e d .
Key w o r d s : Vicia faba - U n i l a t e r a l I n c o m p a t i b i l i t y - S e l f - f e r t i l i t y - S e l f - C o m p a t i b i l i t y - S e l f - I n c o m p a t i b i l i t y
Introduction
4) Consistent occurrence of such p h e n o m e n o n in the s a m e parental combinations is the rule.
The p h e n o m e n o n in which the crossing between two parents succeeds only in one direction has been
Unilateral incompatibility occurs in different
widely referred to as unilateral incompatibility. H o w -
p l a n t s p e c i e s ( s e e r e v i e w of A b d a l l a 1970, 1974a;
ever, other t e r m s have also been used: unilateral
A b d a l l a and H e r m s e n 1972) : in Antirrhinum, Lolium
hybridization, unilateral inhibition, unidirectional
s p e c i e s (Spoor 1976), Lycopersicon ( s e e a l s o de N e t -
crossability, o n e - w a y isolation, unilaterial incon-
t a n c o u r t et al. 1973, 1974), Nicotiana, Pelargonium,
gruity and SI • S C inhibition. The last t e r m was
Petunia, Solarium ( s e e also H e r m s e n et a l . 1974;
used because of the discovery that such hehaviour
H e r m s e n and R a m a n n a 1976), and i n Vicia faba ( A b -
occurs predominantly w h e n crossing is attempted
d a l l a 1974b). U n i l a t e r a l i n c o m p a t i b i l i t y was r e p o r t e d
between self-incompatible (SI) plants as female and
to o c c u r when c r o s s i n g was a t t e m p t e d b e t w e e n s p e -
self compatible (SC) as male. Later, unilatel-al in-
c i e s of the s a m e g e n u s , of d i f f e r e n t g e n e r a and of
compatibility (UI) w a s discovered, with less fre-
d i f f e r e n t f a m i l i e s . In the c a s e of V. faba and in s o m e
quent occurrence, in the direction S C x SC, S C xSI
cases in
and SI X SI.
plants of the s a m e species.
S o m e authors l u m p e d together all kinds of unila-
Lycopersicon, UI w a s detected between
V. faba is a self-compatible species. It is gener-
teral relation ( U R ) as unilateral incompatibility. It
ally accepted that this species is divided into 2 sub-
would be better to reserve the t e r m unilateral in-
species: ssp.
compatibility for those cases of U R
subspecies comprises 3 botanical types differing in
in which:
I) Both parents possess the s a m e c h r o m o s o m e number; 2) C r o s s e s succeed in one direction and hybrids are obtained; 3) Failure of the cross is not due to particular
maternal- or paternal-effects or interactions;
pauciju4a and ssp. eu-faba. The latter
seed size and shape: 'm a j o r ', 'equina ' and 'm i n o r '. Unilateral incompatibility was discovered w h e n crossing - done mainly to broaden the genetic base - w a s attempted between different field bean populations. The question then arose as to whether Ul in
V. faba
could be explained on a similar basis to that reported
228
T h e o r . Appl. G e n e t . 50 (1977)
f o r o t h e r plant s p e c i e s . And i s t h e r e any r e l a t i o n b e tween the o c c u r r e n c e of UI and the e v o l u t i o n of t h i s c r o p ? A n s w e r s to the a b o v e q u e s t i o n s a r e a t t e m p t e d here.
M a t e r i a l s and Methods M a t e r i a l s . The f i e l d bean m a t e r i a l s u s e d in t h e s e s t u d i e s d i f f e r in o r i g i n . In t h i s a r t i c l e m e n t i o n will be m a d e of the r e s u l t s o b t a i n e d f r o m 4 p o p u l a t i o n s : C2, a ' m a j o r ' population o r i g i n a t i n g f r o m E q u a d o r but grown f o r many g e n e r a t i o n s u n d e r E g y p t i a n c o n ditions ; Cs, a ' m a j o r ' stock f r o m the N e t h e r l a n d s ; C8, a paucijuga type f r o m P a k i s t a n that had b e e n handled in Egypt f o r at l e a s t 8 g e n e r a t i o n s ; and an E g y p t i a n l o c a l s t o c k (C9) that l i e s on the b o r d e r b e t w e e n ' e q u i n a ' and ' m i n o r ' . S c i e n t i f i c a l l y it would not m a k e any d i f f e r e n c e if it was a l l o t e d to e i t h e r t y p e . C9 will be r e f e r r e d to as ' e q u i n a ' t y p e . M e t h o d s . A r t i f i c i a l s e l f - p o l l i n a t i o n was a t t e m p t e d on d i f f e r e n t p l a n t s f r o m e a c h s t o c k . F o r c r o s s i n g , buds w e r e e m a s c u l a t e d at a l a t e r s t a g e and w e r e p r o t e c t e d f r o m c o n t a m i n a t i o n . P o l l i n a t i o n took p l a c e a few days l a t e r . C r o s s i n g was m a d e on 26-50 e m a s c u l a t e d f l o w e r s f r o m e a c h f e m a l e p a r e n t . To t e s t p o l len tube g r o w t h in s t y l e s , p o l l i n a t e d p i s t i l s w e r e fixed a f t e r 72 h r s in a m i x t u r e of a c e t i c a c i d - f o r m a l i n - 8 0 % a l c o h o l in a 1 : 1 : 8 p r o p o r t i o n . They w e r e r e f r i g e r a t e d till c h e c k e d a c c o r d i n g to the m e t h o d u s e d by R a m a n n a and M u t s a e r t s ( 1 9 7 1 ) .
F i g . 2. N o r m a l g r o w t h of p o l l e n tubes of ' equina ' C s into s t y l e s of ' m a j o r ' C2
C r o s s i n g . The c r o s s i n g was not d e s i g n e d to t a k e in all p o s s i b l e c o m b i n a t i o n s . F o r b r e e d i n g p u r p o s e s , o u r p r i m a r y i n t e r e s t was to c r o s s d i v e r g e n t p o p u l a t i o n s . The r e c i p r o c a l c r o s s i n g s w e r e a l s o a t t e m p t e d .
Results
The r e s u l t s w e r e as f o l l o w s : S e l f - c o m p a t i b i l i t y . All the p l a n t s s e l f e d f r o m s s p .
paucijuga and the types ' m a j o r ' , 'minor',
'equina',
(and
not i n c l u d e d in this a r t i c l e ) s e t pods c o n -
taining s e e d s . T h e r e f o r e the p r e s e n c e of s e l f - i n c o m p a t i b i l i t y of the type known as the Nicotiana g a m e t o phytic s y s t e m is r u l e d out.
1. ' M a j o r ' C 3 • ' E q u i n a ' and
Paucijuga:
no pod
s e t . The r e c i p r o c a l c r o s s s u c c e e d e d . The F 1 a s well as F 2 w e r e r a i s e d f r o m s o m e of s u c h c r o s s e s ( A b d a l l a 1977). 2. ' M a j o r ' C 2 X P a u e / j u g a : No pod s e t . R e c i p r o cal c r o s s s u c c e e d e d . 3. ' M a j o r ' C 2 •
'Equina': 5gpodset;
recipro-
cal 35 ~. 4. ' E q u i n a ' X
Paucijuga:
both r e c i p r o c a l c r o s s e s
s u c c e e d e d . All the s e e d s e t f r o m the a b o v e mentioned c r o s s e s p r o v e d to be of h y b r i d o r i g i n . P o l l e n tube g r o w t h . In the c r o s s e s which f a i l e d to s e t s e e d , inhibition of p o l l e n tube g r o w t h was o b s e r v e d in the s t y l e s ( F i g . 1). In s u c c e s s f u l c r o s s i n g s , p o l l e n tubes w e r e d e t e c t e d t r a v e r s i n g the s t y l e s ( F i g . 2) and r e a c h i n g v e r y c l o s e to the o v u l e s . F e r t i l i t y . The data on n a t u r a l pod and s e e d s e t p r e s e n t e d in Table 1 h a v e been c o l l e c t e d f r o m 48 p l a n t s f r o m C2, 33 p l a n t s f r o m e a c h of C 3 and C 6 F i g . I . Inhibition of p o l l e n t u b e s of ' equina ' C 9 into s t y l e s of ' m a j o r ' Ca
and 99 p l a n t s f r o m C 9. The v a l u e s a r e g e n e r a l l y h i g h e r than t h o s e found u n d e r l e s s s u i t a b l e e n v i r o n -
M. M. F . A b d a l l a : I n t r a s p e c i f i c U n i l a t e r a l I n c o m p a t i b i l i t y in Vivia faba L.
T ab l e 1. N a t u r a l pod and s e e d s e t in the d i f f e r e n t V. faba s t o c k s ( b e t w e e n p a r e n t h e s e s a r e r e l a t i v e p e r c e n t of C s ) Character
Paucijuga 'Equina I 2vlajor'C2 ' M a j o r ' C s
No. pods/
100(625)
No . s e e d s / plant
298(709)
plant
63(394) 38(237)
16(100)
' major'.
229
What c o u l d happen t h en , when such p o p u l a -
t i o n s m e e t ? The m o s t f e r t i l e t y p e s ( s m a l l - s e e d e d o n e s ) will r e p r o d u c e m o r e and y i e l d m o r e o f f s p r i n g . They will a l s o c r o s s with ' m a j o r ' p o p u l a t i o n s , one r e s u l t b ei n g t h e ' e r o s i o n ' of ' m a j o r ' c h a r a c t e r i s t i c s and i d e n t i t y ( A b d a l l a 1977). On the o t h e r hand,
190(452)
72(171)
42(100)
' m a j o r ' p o p u l at i o n s will p r o d u c e only l i m i t e d n u m b e r s of o f f s p r i n g b e c a u s e they a r e l e s s f e r t i l e (Table 1 ) . They m ay a l s o s u f f e r o t h e r d r a w b a c k s ( l o w e r g e r m i n a t i o n , s l o w e r d e v e l o p m e n t , e s p e c i a l l y at e a r -
m e n t a l c o n d i t i o n s , but the r e l a t i v e c o m p a r i s o n s a r e what i n t e r e s t us h e r e . It is c l e a r f r o m Table 1 that t h e d i f f e r e n t p o p u l a t i o n s v a r i e d widely in f e r t i l i t y . ' M a j o r ' C 2 i s t w i c e as f e r t i l e as ' m a j o r ' C 3. The
ly s t a g e s of g r o w t h , e t c . ). In addition c r o s s i n g with the highly f e r t i l e p o p u l a t i o n s will l e a d to i n b r e e d i n g d e p r e s s i o n of the ' m a j o r ' type b e c a u s e of i t s s e n s i t i v i t y to i n b r e e d i n g ( A b d a l l a 1975). U n de r such c o n -
' e q u i n a ' population i s 4 t i m e s as f e r t i l e and pauei-
ditions,
juga is 6 to 7 t i m e s a s f e r t i l e c o m p a r e d with C 3.
a g a i n s t t h e i n t r o d u c t i o n of g e n e s that affect i t s f e r t i l -
' m a j o r ' p o p u l at i o n s m a y d e v e l o p b a r r i e r s
ity and e n d a n g e r i t s i d e n t i t y and p e r s i s t e n c e . One s u c h b a r r i e r will be s p e c i f i c g e n e s ( u n i l a t e r a l i n c o m p a t i b i l i t y g e n e s = U__II) that r e j e c t f e r t i l i z a t i o n
Discussion
f r o m the m o r e s e l f - f e r t i l e p o p u l a t i o n s . C o n s e q u e n t l y It is b e l i e v e d that the u n i l a t e r a l i n t r a s p e c i f i c i n c o m p a t i b i l i t y in V. faba is a s s o c i a t e d with e v o l u t i o n of t h i s c r o p . The e v o l u t i o n of f i e l d b e a n will be r e p o r t e d e l s e w h e r e . It is a c c e p t e d that th e s m a l l - s e e d e d p o p u l a t i o n s a r e the o l d e s t f o r m s - in t h i s study pauc~juga:
' m a j o r ' would be able to c r o s s a s m a l e with m o r e s e l f - f e r t i l e p o p u l a t i o n s while the r e c i p r o c a l c r o s s e s f a i l . The c r o s s 9 m o r e f e r t i l e • cf l e s s f e r t i l e
succeeds,
9 less fertile
fails.
• d more fertile
i s t h e s m a l l e s t s e e d e d s t o c k - w h e r e a s the l a r g e s t s e e d e d ' m a j o r ' type i s the m o r e r e c e n t l y d e v e l o p e d
That is the b e h a v i o u r known a s u n i l a t e r a l i n c o m p a t i -
one.
b i l i t y . The ' m a j o r '
' M a j o r C3, which i n h i b i t e d p o l l e n tube g r o w t h
- o r o t h e r - p o p u l a t i o n s t h a t did
of ' equina ' and paucijugaj p r o v e d to be the l e a s t f e r -
not p o s s e s s such a b a r r i e r could e i t h e r h a v e n e v e r
t i l e s t o ck ( 1 / 2 to 1/7 t h e f e r t i l i t y of o t h e r s ) .
developed this b a r r i e r ,
'Major'
o r h a v e l o s t the b a r r i e r in
p o p u l a t i o n s a r e known to p o s s e s s b i g g e r s e e d s (100
the a b s e n c e of s e l e c t i o n p r e s s u r e p r e s e r v i n g it, o r
s e e d weight m a y be m o r e than 200 g r ) , w h e r e a s
they m ay r e p r e s e n t r e c e s s i v e s e g r e g a n t s of the UI
' e q u i n a ' p o s s e s s e s i n t e r m e d i a t e seed size, followed
genes (uiui-genotyPes).
by ' m i n o r ' t y p e . The s m a l l e s t s e e d s a r e t h o s e of
The ' m a j o r '
C 2 m a y be one s u c h population with
paucijuga (100 s e e d weight is l e s s than 2 0 g r ) .
r e s p e c t to ' e q u i n a ' C9, but it s t i l l m a i n t a i n s i t s r e -
C o m b i n i n g t h i s and o t h e r i n f o r m a t i o n l e d us to h y -
j e c t i n g u n i l a t e r a l i n c o m p a t i b i l i t y with paucijuga.
p o t h e s i z e on the o r i g i n of UI in t h i s c r o p .
UI in V. f a b a and o t h e r s p e c i e s O r i g i n of u n i l a t e r a l i n c o m p a t i b i l i t y in V. faba In d i s c u s s i n g the h y p o t h e s e s a c c o u n t i n g f o r UI ( A b -
Paucijuga p o p u l a t i o n i s the m o s t a u t o f e r t i l e faba
d a l l a 1970, 1974a; A b d a l l a and H e r m s e n 1972) the
b e a n s t u d i e d by us up to now. ' M i n o r ' and ' e q u i n a
c o n c l u s i o n r e a c h e d was that the " t w o - p o w e r c o m p e -
t y p e s m a y p o s s e s s good s e l f - f e r t i l e p o p u l a t i o n s .
t i t i o n " h y P o t h e s i s co u l d e x p l a i n the o c c u r r e n c e of
F r o m t y p e s s u c h a s paucijuga, 'pliniana ' ( d i s c o v e r -
UI in d i f f e r e n t plant s p e c i e s w h e t h e r the f a i l u r e of
ed in A l g e r i a ) and ' m i n o r ' ,
t h e c r o s s was in the d i r e c t i o n S I X SC, SC • SC,
less self-fertile ones
may have evolved. 'Equina; is m o r e s e l f - f e r t i l e t h a n
SC x S I o r S I x S I .
230
T h e o r . A p p l . G e n e t . 50 (1977) The t w o - p o w e r c o m p e t i t i o n h y p o t h e s i s was w o r k e d
out ( A b d a l l a 1970) to e x p la in the UI that f r e q u e n t l y
s o m e medium-seeded stocks. Another change could have happened leading to low fertility populations
o c c u r s when c r o s s i n g i s t r i e d b e t w e e n SI s p e c i e s a s
(SLF), comparable to s o m e 'major' stocks. A third
f e m a l e s and SC r e l a t i v e s as m a l e s . It was a s s u m e d
change could have occurred, leading to cross-ferti-
that the h y b r i d i z a t i o n b e t w e e n SI and SC p o w e r s , r e -
lized p o p u i a t i o n s (SC) but m a i n t a i n i n g s e l f - c o m p a t i -
s u l t i n g in a d v e r s e e f f e c t s of i n t r o d u c i n g s e l f - c o m -
b i l i t y . A fourth c h a n g e might o c c u r - n e v e r p r o v e d
p a t i b i l i t y into the h e t e r o z y g o u s SI p o p u l a t i o n s , l e d
till now - r e s u l t i n g in s e l f - i n c o m p a t i b l e popul a t i ons
to the e v o l u t i o n of the U_.~Ig e n e s on the s i d e of SI
( S I ) . A s e l f - c o m p a t i b l e plant m a y d e v e l o p into a
p l a n t s . The U._~Ig e n e s p r e v e n t f e r t i l i z a t i o n by s p e c i f -
s e l f - i n c o m p a t i b l e one t h r o u g h a c h a n g e of S s p e c i f i -
i c S ( s e l f - c o m p a t i b i l i t y ) a l l e l e s of the SC s p e c i e s ,
c i t y f r o m S ( s e l f - c o m p a t i b i l i t y a l l e l e ) to S ( s e l f - i n -
not only l e a d i n g to UI, but a l s o r e n d e r i n g the r e c i p -
c o m p a t i b i l i t y a l l e l e ) o r t h r o u g h the d e v e l o p m e n t of
r o c a l F 1 p l a n t s (SC • SI) s e l f - i n c o m p a t i b l e and c o n -
U_.!Ir e j e c t i n g g e n e s a g a i n s t i t s S a l l e l e s (S i S 1 UI 1 UI 1
s e q u e n t l y p r e v e n t i n g the " s e l f - c o m p a t i b i l i t y d i s e a s e "
is a s e l f - i n c o m p a t i b l e p l a n t ) .
f r o m t h r e a t e n i n g the SI p o p u l a t i o n s . The e v o l u t i o n S of a U I - g e n e s - g e n e s y s t e m as a r e s u l t of the c h a l -
a l r e a d y at the s t a g e of the t h i r d change ( p e r c e n t a g e s
l e n g e of h y b r i d i z a t i o n b e t w e e n SI and SC p o w e r s
of c r o s s f e r t i l i z a t i o n r e a c h i n g m o r e than 60 7~ h a v e
( c o m p a r a b l e to the g e n e - f o r - g e n e s y s t e m of h o s t -
been r e p o r t e d in fild b e a n s by s o m e a u t h o r s ) .
p a r a s i t e r e l a t i o n s ) was p u b l i s h e d in detail in 1972 by A b d a l l a and H e r m s e n . U n i l a t e r a l i n c o m p a t i b i l i t y in Y. faba is t h e f i r s t
It i s p o s s i b l e that s o m e V. faba p o p u l a t i ons a r e
The h y p o t h e s i z e d s t e p s e x p r e s s the p o s s i b i l i t y of the e v o l u t i o n of a c r o s s - f e r t i l i z e d s y s t e m f r o m a s e l f - f e r t i l i z e d one ( s e e a l s o A b d al l a and H e r m s e n
r e p o r t e d o c c u r r e n c e of this p h e n o m e n o n a m o n g d i f f e r -
1972). It is a l s o p o s s i b l e that s e l f - i n c o m p a t i b l e s p e -
ent s e l f - c o m p a t i b l e p o p u l a t io n s of the s a m e s p e c i e s
cies have evolved from s e l f - c o m p a t i b l e ones follow-
l a c k i n g SI r e l a t i v e s . It can be e x p l a i n e d on the s i m i -
ing s o m e o r all of the following s t e p s l e a d i n g to the
l a r b a s i s of the e v o l u t i o n of u n i l a t e r a l i n c o m p a t i b i l i t y ,
different changes :
a s o u t l i n e d in the t w o - p o w e r c o m p e t i t i o n h y p o t h e s i s . The U__~Ig e n e s p r e s e n t on the s i d e of low s e l f - f e r t i l e p o p u l a t i o n s will p r o t e c t t h e m f r o m the d r a w b a c k s of
S H F -* SF -* SLF -* SC -* Sl (Scl SCl --UI I --UI 1 or
t h e " s e l f - f e r t i l i t y d i s e a s e " . The " s e l f - f e r t i l i t y d i s si
e a s e " e x p e c t e d to o c c u r in p r o g e n i e s of l o w e r s e l f -
si).
f e r t i l e when c r o s s e d with h i g h e r s e l f - f e r t i l e p o p u l a t i o n s is c o m p a r a b l e to the " s e l f - c o m p a t i b i l i t y d i s e a s e " that o c c u r s a f t e r c r o s s i n g s e l f - i n c o m p a t i b l e with s e l f - c o m p a t i b l e s p e c i e s .
The UI in V. faba o r any o t h e r s p e c i e s will d e v e l op on the s i d e of p o p u l at i o n s that a r e t h r e a t e n e d and e n d a n g e r e d in t h e i r e v o l u t i o n a r y pathways o r in t h e i r p e r s i s t e n c e . In V. ]'aba the U._~I-genes will d e v e l o p f a v o u r i n g low f e r t i l i t y p o p u l a t i o n s a g a i n s t highly f e r -
E v o l u t i o n of s e l f - i n c o m p a t i b i l i t y f r o m s e l f - c o m p a t i -
t i l e o n e s . In SI s p e c i e s , U_~Ig e n e s will d e v e l o p
bility
favouring s e l f - i n c o m p a t i b l e populations against s e l f compatible relatives.
It m a y be a r g u e d that V. f a b a e v o l v e d f r o m an a u t o -
The s c h e m e ab o v e r u l e s out t h e p o s s i b i l i t y of the
g a m o u s a n c e s t o r , o r f r o m an a l l o g a m o u s o n e - n e v e r
dual function of s e l f - i n c o m p a t i b i l i t y a l l e l e s (Lewis
found - that was f o r c e d to i n b r e e d and has u n d e r g o n e
and C r o w e 1958 and o t h e r s ) . It a l s o i m p l i e s that SI
a c h a n g e l e a d i n g to a t u o g a m i c n a t u r e . W h a t e v e r the
s p e c i e s should p o s s e s s U._~tg e n e s a g a i n s t SC r e l a -
a n c e s t o r w a s , the c u l t i v a t e d V. faba i s a s s u m e d to
t i v e s , e s p e c i a l l y ' o l d ' o n e s ; and that UI g e n e s ma y
h a v e d e v e l o p e d f r o m highly s e l f - f e r t i l e p o p u l a t i o n s
be p r e s e n t f a v o u r i n g d i f f e r e n t SC p o p u l a t i o n s a g a i n s t
that p o s s e s s g e n e s s p e c i f i c f o r high f e r t i l i t y ( S H F ) .
o t h e r SC o n e s , in p a r t i c u l a r on the s i d e of low s e l f -
A c h a n g e co u ld h a v e happend l e a d i n g to s e l f - f e r t i l e
f e r t i l i t y a g a i n s t high s e l f - f e r t i l i t y and c r o s s - f e r t i -
p o p u l a t i o n s ( S F ) , s i m i l a r to s o m e s m a l l - s e e d e d and
lized against self-fertilized.
M . M . F . A b d a l l a : I n t r a s p e c i f i c U n i l a t e r a l I n c o m p a t i b i l i t y in Vicia faba L. U n i l a t e r a l i n t r a s p e c i f i c i n c o m p a t i b i l i t y in
d e p r e s s i o n was c l e a r l y d e m o n s t r a t e d also in
Lycopersicon
persicon
231
Lyco-
i n b r e d s (Hogenboom 1972a) ; (3) r e j e c t e d
the r o l e of evolution and n a t u r a l s e l e c t i o n in b u i l d i n g C a s e s of u n i l a t e r a l i n t r a s p e c i f i c i n c o m p a t i b i l i t y w e r e
up a U._~.I-gene-S-gene s y s t e m ( A b d a l l a and H e r m s e n
reported in Lycopersicon by M a r t i n (1961, 1963,
1972).
1964). These i n v o l v e d SI and SC p o p u l a t i o n s . The
C o m p a r e d with the t w o - p o w e r c o m p e t i t i o n hypo-
r e s u l t s r e p o r t e d by M a r t i n (1964) on the l i n e s Banjos
t h e s i s , the i n c o n g r u i t y model cannot f u r n i s h an a c -
and S u r c o of the b o t a n i c a l t y p e s ' g l a b r a t u m ' and
c e p t a b l e e x p l a n a t i o n for the d i f f e r i n g r e s u l t s r e p o r t e d
'hirsutum'
of L. hirsutum a r e i n t e r e s t i n g . The two
i n the l i t e r a t u r e , such a s : b e h a v i o u r of h y b r i d s b e -
l i n e s a r e SC but d i f f e r e d in t h e i r f e r t i l i t y . B a n o s
tween SC and SI p a r e n t s and t h e i r s e g r e g a t i n g p r o -
b e i n g m o r e f e r t i l e (40 9 3 s e e d s p e r f r u i t ) , a n d Surco
g e n i e s in c o n n e c t i o n with s e l f - c o m p a t i b i l i t y and s e l f -
l e s s f e r t i l e (18 9 9 s e e d s p e r f r u i t ) . Surco r e j e c t e d
i n c o m p a t i b i l i t y ; the a s s o c i a t i o n of s e l f - i n c o m p a t i b i l i -
f e r t i l i z a t i o n by p o l l e n f r o m B a n o s ; the r e c i p r o c a l -
ty and u n i l a t e r a l i n c o m p a t i b i l i t y in h y b r i d s b e t w e e n
c r o s s s u c c e e d e d . The f a i l u r e of the c r o s s was in the
SC and SI p a r e n t s ; the o c c u r r e n c e of SC p r o g e n i e s
d i r e c t i o n of f e m a l e l e s s f e r t i l e • m a l e m o r e f e r t i l e ,
a m o n g S I x SI h y b r i d s and SI p r o g e n i e s in SC • SC
a g r e e i n g with the p r e s e n t m o d e l . The SI l i n e ( C a j a -
h y b r i d s . Also the r e s u l t s of G r u n and A u b e r t i n
m a r c a ) r e j e c t e d f e r t i l i z a t i o n f r o m both SC l i n e s
( 1 9 6 6 ) , Hogenboom (1972d), H e r m s e n et a l . (1974)
which also a g r e e s with the model p r e s e n t e d a b o v e .
and Spoor ( 1 9 7 6 ) , and the b e h a v i o u r of ' m a j o r ' C 2
The fact that UI o c c u r s b e t w e e n p l a n t s of the s a m e s p e c i e s ( V i c i a and
Lycopersicon)
is i n t e r e s t -
in o u r r e s u l t s , a r e a n t a g o n i s t i c to the i n c o n g r u i t y m o d e l . These r e s u l t s dealt with the s u c c e s s f u l r e -
i n g . This j u s t i f i e s the a r g u m e n t that this p h e n o m e -
c i p r o c a l c r o s s i n g b e t w e e n p l a n t s that accept and those
non evolved due to the c h a l l e n g e of h y b r i d i z a t i o n b e tween d i f f e r e n t p l a n t s , and c o n t r o l l e d by s p e c i f i c U._~I
that r e j e c t S - c a r r y i n g p o l l e n . All the r e s u l t s r e p o r t c ed c a n be s{-mply explained on the b a s i s of the two-
g e n e s . It a l s o shows that UI o c c u r s b e f o r e s p e c i a -
power competition hypothesis.
tion t a k e s p l a c e . UI (and s e l f - and c r o s s - i n c o m p a t i b i l i t y ) f u n c t i o n s e q u a l l y well a m o n g p l a n t s of the s a m e s p e c i e s and b e t w e e n p l a n t s of d i f f e r e n t s p e c i e s . This c o n t r a d i c t s the r e p o r t s that UI f u n c t i o n s only b e t w e e n p o p u l a t i o n s (Hogenboom 1973 and o t h e r s ) .
D r . H o g e n b o o m ' s (1972b, c) r e s u l t s c a n be e x p l a i n e d on the b a s i s of the t w o - p o w e r c o m p e t i t i o n h y p o t h e s i s as follows: the SC i n b r e d s o b t a i n e d through m u t a t i o n , i n b r e e d i n g and s e l e c t i o n may p o s s e s s diff e r e n t S s t r u c t u r e s ; s o m e differ f r o m those u n a b l e to f e r t i i i z e U__~Igenotypes p r e s e n t in Lycopersicon
peruvianum, and will c r o s s r e c i p r o c a l l y with s i s t e r The i n c o n g r u i t y model
SI p l a n t s ; m u t a t i o n and i n b r e e d i n g may have r e s u l t e d
Hogenboom (1973) p r e s e n t e d what he c a l l e d the i n -
ones a g a i n s t L. esculentum p o l l e n ( m u t a t i o n of UI
in d i f f e r e n t U..~Ig e n o t y p e s , i n b r e e d i n g l e a d i n g to uiui c o n g r u i t y model to a c c o u n t for u n i l a t e r a l r e l a t i o n s .
g e n e s is not r u l e d o u t ) , and c o n s e q u e n t l y s o m e m a y
The model i s e s s e n t i a l l y M a r t i n ' s (1963) h y p o t h e s i s
also c r o s s r e c i p r o c a l l y with L. esculentum. The s e g -
of the p o l y g e n i c a l l y c o n t r o l l e d b a l a n c e of s u b s t a n c e s
r e g a t i o n of U__~I-genesin H o g e n b o o m ' s m a t e r i a l may
affecting p o l l e n tube growth and s t y l a r i n h i b i t i o n
e x p l a i n all his r e s u l t s . The e x p l a n a t i o n of Hogenboom
( s e e a l s o P a n d e y 1969). In addition to a r g u m e n t s
(1973) of the model of Lewis and C r o w e (1958) of the
p r e s e n t e d e a r l i e r a g a i n s t such i d e a s ( A b d a l l a 1970,
g r a d u a l m u t a t i o n f r o m SI s p e c i e s t h r o u g h Sc and S~
1974a; A b d a l l a and H e r m s e n 1972; de N e t t a n c o u r t
to SC o n e s is b a s e d on d i s p u t a b l e s u p p o s i t i o n s : "low-
et a l . 1974) it is o b s e r v e d that the i n c o n g r u i t y m o d e l :
e r i n g c a p a c i t i e s of m a n y b a r r i e r g e n e s " and " m a i n -
(1) failed to d i f f e r e n t i a t e b e t w e e n w i d e s p r e a d o c c u r -
r a i n i n g p e n e t r a t i o n c a p a c i t y " and " a d j u s t i n g p e n e t r a -
r e n c e of c e r t a i n b e h a v i o u r (SI • SC i n h i b i t i o n ) and
tion c a p a c i t y " a r e too m a n y a s s u m p t i o n s without
f i n d i n g s of r a r e e v e n t s ; (2) i g n o r e d the i m p o r t a n c e
p r o o f . The m u t a n t s a s s u m e d in the model of Lewis
of i n b r e e d i n g d e p r e s s i o n o c c u r r i n g i n SI p o p u l a t i o n s
and Crowe (1958) a r e e a s i l y e x p l a i n e d as a o n e - g e n e
following the i n t r o d u c t i o n of S a l l e l e s , although such
m u t a t i o n step in S o r U_.II-genes. On the b a s i s of the
232
Theor. Appl. G e n e t , 50 (1977)
t w o - p o w e r c o m p e t i t i o n h y p o t h e s i s the m u t a n t s m a y
the ' m a j o r ' c h a r a c t e r i s t i c . C 2 i s a ' m a j o r ' type
be given such genotypes as the following to a c c o u n t
with b e t t e r f e r t i l i t y c o m p a r e d with C 3.
for t h e i r a s s u m e d b e h a v i o u r [ s e e also A b d a l l a and
H y b r i d s a r e good y i e l d e r s and e x p r e s s high f e r t i l i -
H e r m s e n (1972) and A b d a l l a (1974a) for m o r e d e -
ty, but they s t i l l a r e difficult to p r o d u c e c o m m e r c i a l -
tails ] :
l y . Some i n b r e d s with high s e l f - f e r t i l i t y and which a r e l e a s t affected by e n v i r o n m e n t a l c o n d i t i o n s may be
Lewis and Crowe (1958) s p e c i e s
E x p e c t e d genotype a c c o r d i n g to the t w o - p o w e r c o m p e t i t i o n hypothesis
e q u a l l y good as h y b r i d s . H y b r i d i z a t i o n b e t w e e n ' m a j o r ' and o t h e r v a r i e t a l types is p o s s i b l e . R e c i p r o c a l c r o s s i n g and f a c i l i t a t -
SI
= SiS i U I l . . u i 2 u i 2 u i 3 u i 3
Sc
= Sc3Sc3UIiUIlUi2ui2ui3ui3
$6
= S c 2 S c 2 U i l u i l u i 2 u i 2 u i 3 u i3
ing the r e c o v e r y of useful s e g r e g a n t s n e c e s s i t a t e s u s i n g uiui gentoypes ( s e e A b d a l l a and H e r m s e n 1972). However, the p r a c t i c a b i l i t y of r e c o v e r i n g the o r i g i n a l typical ' m a j o r ' with f e r t i l i t y s i m i l a r to
SC
= S c l S c l U i l U i l u i 2 u i 2 u i 3 u i3
So f a r a s it has b e e n t e s t e d , the t w o - p o w e r c o m p e t i tion h y p o t h e s i s can s a t i s f a c t o r i l y and s i m p l y f u r n i s h a b a s i s to e x p l a i n the r e s u l t s of u n i l a t e r a l i n t e r s p e cific and i n t r a s p e c i f i c i n c o m p a t i b i l i t y p u b l i s h e d up to now. F r o m the p r a c t i c a l point of view uiui g e n o types a r e b e i n g used in r e s e a r c h in d i f f e r e n t plant s p e c ! e s . The s t u d i e s of m u t a t i o n , i n c o m p a t i b i l i t y and i n t r a - and i n t e r s p e c i f i c c r o s s i n g s a r e expected to r e v e a l i n t e r e s t i n g d i s c o v e r i e s in the p o t e n t i a l i t i e s of S Sc and UI genes and t h e i r i n t e r a c t i o n s . C o m p a r e d
q th
alleles, ~_ a l l e l e s have been given l e s s a t t e n -
tion.
paucijuga o r ' m i n o r ' types may be q u e s t i o n e d . It is being e x p e r i m e n t a l l y t e s t e d . Handling ' e q u i n a ' p o p u l a t i o n s may be p r o m i s i n g in different a s p e c t s . It would be i n t e r e s t i n g to t h r o w m o r e light on the r e l a t i o n s h i p and the p r o d u c t s of r e c o m b i n a t i o n of the d i f f e r e n t Sc a l l e l e s in V. faba ( s e e A b d a l l a 1977). The d i s c o v e r y of the p r e s e n c e of u n i l a t e r a l i n c o m p a t i b i l i t y in V. faba c a l l s for r e - a s s e s s m e n t of the d e g r e e of n a t u r a l c r o s s - f e r t i l i z a t i o n r e p o r t e d in this c r o p . If s o m e of the p l a n t s u s e d in the e a r l i e r s t u d i e s happened to be c a r r y i n g U I r e j e c t i n g g e n e s , such p l a n t s would fail to c r o s s as f e m a l e s l t h e r e f o r e , it is p o s s i b l e that e a r l i e r r e s u l t s may need to be r e checked.
F e r t i l i t y and field b e a n b r e e d i n g
Literature With r e s p e c t to the f e r t i l i t y c h a r a c t e r i s t i c , differing s p e c i f i c i t i e s a r e known i n V. faba, d i f f e r e n t ones of which m a y be p r e s e n t in s i m i l a r o r d i f f e r e n t b o t a n i cal t y p e s . The n a t u r e of the Sc a l l e l e s r e m a i n s to be thoroughly i n v e s t i g a t e d . An i n t e r e s t i n g d i s c o v e r y by A b d a l l a and H u s s e i n (1977) is the m u t a t i o n of an ' e q u i n a ' to a ' m a j o r ' type. 'Major',
' e q u i n a ' and ' m i n o r ' t y p e s p o s s e s s
s t o c k s with different f e r t i l i t i e s , paucijuga is highly ' a u t o f e r t i l e ' but a v e r y low y i e l d e r . I m p r o v i n g f e r t i l ity t h r o u g h i n d i v i d u a l - p l a n t s e l e c t i o n may be a c h i e v e d in c e r t a i n s t o c k s but not in o t h e r s ( A b d a l l a 1976). S m a l l - s e e d e d populations a r e g e n e r a l l y m o r e s e l f f e r t i l e . ' M a j o r ' stocks a r e m o s t l y low in f e r t i l i t y . In o r d e r to i m p r o v e the f e r t i l i t y of such p o p u l a t i o n s , one may t r y to change the
_S-specificity
towards bet-
t e r f e r t i l i t y but at the s a m e t i m e g r e a t l y i n a f f e c t i n g
Abdalla, M . M . F . : Inbreeding, heterosis, fertility, p l a s m o n d i f f e r e n t i a t i o n and PhF~ophthoz~ r e s i s t a n c e in Solarium ver~cosum Schlechtd., and s o m e interspecific crosses in Solarium.Agric. ires. Rep. Wageningen (the Netherlands) 748, 1-213 (1970) Abdalla, M . M . F. : Unilateral incompatibility in plant species: analysis and implications. Egypt. J. G e n e t . Cytol. 3, 133-154 (1974a) A b d a l l a , M . M . F . : U n i l a t e r a l i n c o m p a t i b i l i t y in field b e a n s , Vicia faba L. I n c o m p a t i b i l i t y N e w s l e t t e r 4, 16 (1974b) Abdalla, M.M.F. : Inbreeding, selection and hybridization in field beans, Vicia faba L. Egypt. J. Genet. tyrol. 4_, 473 (Abst.) (1975) Abdalla, M . M . F. : Natural variability and selection in s o m e local and exotic populations of field beans, Vicia faba L. Z. Pflanzenz(ichtg. 76, 332341 (1976) A b d a l l a , M . M . F . : P e r f o r m a n c e of Fr and F2 h y b r i d s of Vicia faba L. Egypt. J. Genet. Cytol. 6_, 108-121 (1977) Abdalla, M . M . F . ; Hermsen, J.G.Th. : Unilateral incompatibility: hypotheses, debate and its implications for plant breeding. Euphyfica 21, 32-47 (1972)
M.M.F.
A b d a l l a : I n t r a s p e c i f i c U n i l a t e r a l I n c o m p a t i b i l i t y in Vicia faba L.
233
A b d a l l a , M . M . F . ; H u s s e i n , H . A . S . : E f f e c t s of s i n g l e and c o m b i n e d t r e a t m e n t s of g a m m a - r a y s and EMS on M ~ - q u a n t i t a t i v e v a r i a t i o n in Vicia faba L. Z . P f l a n z e n z f i c h t g . 78, 57-64 (1977) G r u n , P . ; A u b e r t i n , M. : The i n h e r i t a n c e and e x p r e s s i o n of u n i l a t e r a l i n c o m p a t i b i l i t y in Solarium. H e r e d i t y 21, 131-138 (1966) H e r m s e n , J . G . T h . ; O l d s d e r , J . ; J a n s e n , P . ; Hov i n g , E . : A c c e p t a n c e of s e l f - c o m p a t i b l e p o l l e n f r o m So~num verrucosum in d i h a p l o i d s f r o m S. tuberosum. In: Fertilization in higher plants (ed. Linskens, H.F. ) 37-40. A m s t e r d a m : NorthHolland Publ. Co. 1974 Hermsen, J.G.Th. ; Ramanna, M.S. : Barriers to hybridization of Solanum bulbocastanum Dun. and S. verrucosum Schlechtd. and structural hybridity in their F~ plants. Euphytica 25, I-I0 (1976) Hogenboom, N.G. : Breaking breeding barriers in Lycopersicon. 2. Breakdown of self-incompatibility in n. peruvianum (L.) Mill. Euphytica 21, 228243 (1972a) Hogenboom, N.G. : Breaking breeding barriers in Lycopersicon. 3. Inheritance of self-compatibility in L. peruvianwn (L.) Mill. Euphytica 2_.!1 , 244256 (1972b) H o g e n b o o m , N . G . : B r e a k i n g b r e e d i n g b a r r i e r s in Lyeopersieon. 4. B r e a k d o w n of u n i l a t e r a l i n c o m p a t i b i l i t y b e t w e e n L. peruvianwn ( L . ) M i l l . and L. esculentwn M i l l . E u p h y t i c a 2_1, 397-404 (1972c) H o g e n b o o m , N . G . : B r e a k i n g b r e e d i n g b a r r i e r s in Lyeopersicon. 5. The i n h e r i t a n c e of the u n i l a t e r a l i n c o m p a t i b i l i t y b e t w e e n L. peruvianum ( L . ) M i l l . and L. eseulentum M i l l . and t h e g e n e t i c s of its b r e a k d o w n . E u p h y t i c a 2_!1, 405-414 (1972d)
H o g e n b o o m , N . G . : A m o d e l f o r i n c o n g r u i t y in i n t i m a t e p a r t n e r r e l a t i o n s h i p s . E u p h y t i c a 2_22, 219233 (1973) L e w i s , D. ; C r o w e , L . K . : U n i l a t e r a l i n t e r s p e c i f i c i n c o m p a t i b i l i t y in f l o w e r i n g p l a n t s . H e r e d i t y 12, 233-256 (1958) Martin, F . W . : Complex unilateral hybridization in Lycopersicon hirsutum. Proc. Nat. Acad. Sci. (USA) 47, 855-857 (1961) M a r t i n , F . W . : D i s t r i b u t i o n and i n t e r r e l a t i o n s h i p s of i n c o m p a t i b i l i t y b a r r i e r s in the Lycopersicon h i t suture Humb. and B o n p l . c o m p l e x . E v o l u t i o n 1._~7, 519-528 (1963) M a r t i n , F . W . : The i n h e r i t a n c e of u n i l a t e r a l i n c o m p a t i b i l i t y in Lycopersieon hirsutum. G e n e t i c s 50, 459-469 (1964) de Nettancourt, D. ~ Devreux, M. ~ Laneri, U. ; Pacin i , E . ; C r e s t i , M. ; S a r f a t t i , G. : U l t r a s t r u c t u r a l a s p e c t s of u n i l a t e r a l i n t e r s p e c i f i c i n c o m p a t i b i l i t y b e t w e e n Lycopersicon peruvianum and L. esculentum. C a r y o l o g i a 255, Suppl. 207-217 (1973) de N e t t a n c o u r t , D. ; D e v r e u x , M. ; L a n e r i , U. ; C r e s t i , M. ; P a c i n i , E . ; S a r f a t t i , G. : G e n e t i c a l and u l t r a s t r u c t u r a l a s p e c t s of s e l f and c r o s s i n c o m p a t i b i l i t y in i n t e r s p e c i f i c h y b r i d s b e t w e e n s e l f c o m p a t i b l e Lycopersicon esculentum and s e l f - i n c o m p a t i b l e L. peruvianwm T h e o r . A p p l . G e n e t . 4_.~4, 278-288 (1974) Pandey, K . K . : Elements of the S-gene complex V. Interspecific cross-compatibility relationships and t h e o r y of the e v o l u t i o n of the S - c o m p l e x . G e n e t i c a 40, 447-474 (1969) R a m a n n a , M . S . ~ M u t s a e r t s , M . C . A . : Unusual b e h a v i o u r of g r o w i n g p o l l e n t u b e s in the s t y l e s and o v u l e s of Spinacia oleracea L. E u p h y t i c a 20, 145-151 (1971) S p o o r , W. : I n t e r s p e c i f i c i n c o m p a t i b i l i t y in Lolium s s p . I n c o m p a t i b i l i t y N e w s l e t t e r 7--, 62-64 (1976)
A c c e p t e d D e c e m b e r 15, 1976/ M a r c h 15, 1977 C o m m u n i c a t e d by H . F . L i n s k e n s
Dr. M.M.F. Abdalla Associate Professor D e p a r t m e n t of A g r o n o m y F a c u l t y of A g r i c u l t u r e Cairo University Giza (Egypt)
Note Added in Proof The d i s c u s s i o n in t h i s and in p r e v i o u s p a p e r s a s s u m e d the r e j e c t i n g U_[I g e n e s to b e d o m i n a n t . P r e l i m i n a r y r e s u l t s in V. f a b a s h o w e d that t h i s m a y not b e a r u l e .
9 by Springer-Verlag 1977
Intraspecific Unilateral Incompatibility in ViciafabaL. M. M. F . A b d a l l a D e p a r t m e n t of A g r o n o m y , F a c u l t y of A g r i c u l t u r e , C a i r o U n i v e r s i t y , Giza (Egypt)
S u m m a r y . U n i l a t e r a l i n c o m p a t i b i l i t y was d i s c o v e r e d when c r o s s i n g was a t t e m p t e d b e t w e e n d i f f e r e n t s e l f - c o m p a t i b l e types and s u b s p e c i e s of V. faba. C r o s s i n g in the d i r e c t i o n f e m a l e l e s s s e l f - f e r t i l e • m a l e m o r e s e l f - f e r tile f a i l e d , w h e r e a s the r e c i p r o c a l - c r o s s i n g s u c c e e d e d . U n i l a t e r a l i n c o m p a t i b i l i t y developed with the e v o l u t i o n of l e s s f e r t i l e and l a r g e s e e d e d field b e a n t y p e s . How a c r o s s f e r t i l i z e d (and s e l f - i n c o m p a t i b l e ) s y s t e m m a y develop f r o m a s e l f f e r t i l i z e d one is d i s c u s s e d . The u n i l a t e r a l i n c o m p a t i b i l i t y i n V. faba and o t h e r plant s p e c i e s is c o m p a r e d . The t w o - p o w e r c o m p e t i t i o n h y p o t h e s i s can e x p l a i n all k i n d s of u n i l a t e r a l i n c o m p a t i b i l i t y r e p o r t e d so f a r i n the l i t e r a t u r e . B r e e d i n g field b e a n s for i m p r o v e d s e l f - f e r t i l i t y is d i s c u s s e d .
Key w o r d s : Vicia faba - U n i l a t e r a l I n c o m p a t i b i l i t y - S e l f - f e r t i l i t y - S e l f - C o m p a t i b i l i t y - S e l f - I n c o m p a t i b i l i t y
Introduction
4) Consistent occurrence of such p h e n o m e n o n in the s a m e parental combinations is the rule.
The p h e n o m e n o n in which the crossing between two parents succeeds only in one direction has been
Unilateral incompatibility occurs in different
widely referred to as unilateral incompatibility. H o w -
p l a n t s p e c i e s ( s e e r e v i e w of A b d a l l a 1970, 1974a;
ever, other t e r m s have also been used: unilateral
A b d a l l a and H e r m s e n 1972) : in Antirrhinum, Lolium
hybridization, unilateral inhibition, unidirectional
s p e c i e s (Spoor 1976), Lycopersicon ( s e e a l s o de N e t -
crossability, o n e - w a y isolation, unilaterial incon-
t a n c o u r t et al. 1973, 1974), Nicotiana, Pelargonium,
gruity and SI • S C inhibition. The last t e r m was
Petunia, Solarium ( s e e also H e r m s e n et a l . 1974;
used because of the discovery that such hehaviour
H e r m s e n and R a m a n n a 1976), and i n Vicia faba ( A b -
occurs predominantly w h e n crossing is attempted
d a l l a 1974b). U n i l a t e r a l i n c o m p a t i b i l i t y was r e p o r t e d
between self-incompatible (SI) plants as female and
to o c c u r when c r o s s i n g was a t t e m p t e d b e t w e e n s p e -
self compatible (SC) as male. Later, unilatel-al in-
c i e s of the s a m e g e n u s , of d i f f e r e n t g e n e r a and of
compatibility (UI) w a s discovered, with less fre-
d i f f e r e n t f a m i l i e s . In the c a s e of V. faba and in s o m e
quent occurrence, in the direction S C x SC, S C xSI
cases in
and SI X SI.
plants of the s a m e species.
S o m e authors l u m p e d together all kinds of unila-
Lycopersicon, UI w a s detected between
V. faba is a self-compatible species. It is gener-
teral relation ( U R ) as unilateral incompatibility. It
ally accepted that this species is divided into 2 sub-
would be better to reserve the t e r m unilateral in-
species: ssp.
compatibility for those cases of U R
subspecies comprises 3 botanical types differing in
in which:
I) Both parents possess the s a m e c h r o m o s o m e number; 2) C r o s s e s succeed in one direction and hybrids are obtained; 3) Failure of the cross is not due to particular
maternal- or paternal-effects or interactions;
pauciju4a and ssp. eu-faba. The latter
seed size and shape: 'm a j o r ', 'equina ' and 'm i n o r '. Unilateral incompatibility was discovered w h e n crossing - done mainly to broaden the genetic base - w a s attempted between different field bean populations. The question then arose as to whether Ul in
V. faba
could be explained on a similar basis to that reported
228
T h e o r . Appl. G e n e t . 50 (1977)
f o r o t h e r plant s p e c i e s . And i s t h e r e any r e l a t i o n b e tween the o c c u r r e n c e of UI and the e v o l u t i o n of t h i s c r o p ? A n s w e r s to the a b o v e q u e s t i o n s a r e a t t e m p t e d here.
M a t e r i a l s and Methods M a t e r i a l s . The f i e l d bean m a t e r i a l s u s e d in t h e s e s t u d i e s d i f f e r in o r i g i n . In t h i s a r t i c l e m e n t i o n will be m a d e of the r e s u l t s o b t a i n e d f r o m 4 p o p u l a t i o n s : C2, a ' m a j o r ' population o r i g i n a t i n g f r o m E q u a d o r but grown f o r many g e n e r a t i o n s u n d e r E g y p t i a n c o n ditions ; Cs, a ' m a j o r ' stock f r o m the N e t h e r l a n d s ; C8, a paucijuga type f r o m P a k i s t a n that had b e e n handled in Egypt f o r at l e a s t 8 g e n e r a t i o n s ; and an E g y p t i a n l o c a l s t o c k (C9) that l i e s on the b o r d e r b e t w e e n ' e q u i n a ' and ' m i n o r ' . S c i e n t i f i c a l l y it would not m a k e any d i f f e r e n c e if it was a l l o t e d to e i t h e r t y p e . C9 will be r e f e r r e d to as ' e q u i n a ' t y p e . M e t h o d s . A r t i f i c i a l s e l f - p o l l i n a t i o n was a t t e m p t e d on d i f f e r e n t p l a n t s f r o m e a c h s t o c k . F o r c r o s s i n g , buds w e r e e m a s c u l a t e d at a l a t e r s t a g e and w e r e p r o t e c t e d f r o m c o n t a m i n a t i o n . P o l l i n a t i o n took p l a c e a few days l a t e r . C r o s s i n g was m a d e on 26-50 e m a s c u l a t e d f l o w e r s f r o m e a c h f e m a l e p a r e n t . To t e s t p o l len tube g r o w t h in s t y l e s , p o l l i n a t e d p i s t i l s w e r e fixed a f t e r 72 h r s in a m i x t u r e of a c e t i c a c i d - f o r m a l i n - 8 0 % a l c o h o l in a 1 : 1 : 8 p r o p o r t i o n . They w e r e r e f r i g e r a t e d till c h e c k e d a c c o r d i n g to the m e t h o d u s e d by R a m a n n a and M u t s a e r t s ( 1 9 7 1 ) .
F i g . 2. N o r m a l g r o w t h of p o l l e n tubes of ' equina ' C s into s t y l e s of ' m a j o r ' C2
C r o s s i n g . The c r o s s i n g was not d e s i g n e d to t a k e in all p o s s i b l e c o m b i n a t i o n s . F o r b r e e d i n g p u r p o s e s , o u r p r i m a r y i n t e r e s t was to c r o s s d i v e r g e n t p o p u l a t i o n s . The r e c i p r o c a l c r o s s i n g s w e r e a l s o a t t e m p t e d .
Results
The r e s u l t s w e r e as f o l l o w s : S e l f - c o m p a t i b i l i t y . All the p l a n t s s e l f e d f r o m s s p .
paucijuga and the types ' m a j o r ' , 'minor',
'equina',
(and
not i n c l u d e d in this a r t i c l e ) s e t pods c o n -
taining s e e d s . T h e r e f o r e the p r e s e n c e of s e l f - i n c o m p a t i b i l i t y of the type known as the Nicotiana g a m e t o phytic s y s t e m is r u l e d out.
1. ' M a j o r ' C 3 • ' E q u i n a ' and
Paucijuga:
no pod
s e t . The r e c i p r o c a l c r o s s s u c c e e d e d . The F 1 a s well as F 2 w e r e r a i s e d f r o m s o m e of s u c h c r o s s e s ( A b d a l l a 1977). 2. ' M a j o r ' C 2 X P a u e / j u g a : No pod s e t . R e c i p r o cal c r o s s s u c c e e d e d . 3. ' M a j o r ' C 2 •
'Equina': 5gpodset;
recipro-
cal 35 ~. 4. ' E q u i n a ' X
Paucijuga:
both r e c i p r o c a l c r o s s e s
s u c c e e d e d . All the s e e d s e t f r o m the a b o v e mentioned c r o s s e s p r o v e d to be of h y b r i d o r i g i n . P o l l e n tube g r o w t h . In the c r o s s e s which f a i l e d to s e t s e e d , inhibition of p o l l e n tube g r o w t h was o b s e r v e d in the s t y l e s ( F i g . 1). In s u c c e s s f u l c r o s s i n g s , p o l l e n tubes w e r e d e t e c t e d t r a v e r s i n g the s t y l e s ( F i g . 2) and r e a c h i n g v e r y c l o s e to the o v u l e s . F e r t i l i t y . The data on n a t u r a l pod and s e e d s e t p r e s e n t e d in Table 1 h a v e been c o l l e c t e d f r o m 48 p l a n t s f r o m C2, 33 p l a n t s f r o m e a c h of C 3 and C 6 F i g . I . Inhibition of p o l l e n t u b e s of ' equina ' C 9 into s t y l e s of ' m a j o r ' Ca
and 99 p l a n t s f r o m C 9. The v a l u e s a r e g e n e r a l l y h i g h e r than t h o s e found u n d e r l e s s s u i t a b l e e n v i r o n -
M. M. F . A b d a l l a : I n t r a s p e c i f i c U n i l a t e r a l I n c o m p a t i b i l i t y in Vivia faba L.
T ab l e 1. N a t u r a l pod and s e e d s e t in the d i f f e r e n t V. faba s t o c k s ( b e t w e e n p a r e n t h e s e s a r e r e l a t i v e p e r c e n t of C s ) Character
Paucijuga 'Equina I 2vlajor'C2 ' M a j o r ' C s
No. pods/
100(625)
No . s e e d s / plant
298(709)
plant
63(394) 38(237)
16(100)
' major'.
229
What c o u l d happen t h en , when such p o p u l a -
t i o n s m e e t ? The m o s t f e r t i l e t y p e s ( s m a l l - s e e d e d o n e s ) will r e p r o d u c e m o r e and y i e l d m o r e o f f s p r i n g . They will a l s o c r o s s with ' m a j o r ' p o p u l a t i o n s , one r e s u l t b ei n g t h e ' e r o s i o n ' of ' m a j o r ' c h a r a c t e r i s t i c s and i d e n t i t y ( A b d a l l a 1977). On the o t h e r hand,
190(452)
72(171)
42(100)
' m a j o r ' p o p u l at i o n s will p r o d u c e only l i m i t e d n u m b e r s of o f f s p r i n g b e c a u s e they a r e l e s s f e r t i l e (Table 1 ) . They m ay a l s o s u f f e r o t h e r d r a w b a c k s ( l o w e r g e r m i n a t i o n , s l o w e r d e v e l o p m e n t , e s p e c i a l l y at e a r -
m e n t a l c o n d i t i o n s , but the r e l a t i v e c o m p a r i s o n s a r e what i n t e r e s t us h e r e . It is c l e a r f r o m Table 1 that t h e d i f f e r e n t p o p u l a t i o n s v a r i e d widely in f e r t i l i t y . ' M a j o r ' C 2 i s t w i c e as f e r t i l e as ' m a j o r ' C 3. The
ly s t a g e s of g r o w t h , e t c . ). In addition c r o s s i n g with the highly f e r t i l e p o p u l a t i o n s will l e a d to i n b r e e d i n g d e p r e s s i o n of the ' m a j o r ' type b e c a u s e of i t s s e n s i t i v i t y to i n b r e e d i n g ( A b d a l l a 1975). U n de r such c o n -
' e q u i n a ' population i s 4 t i m e s as f e r t i l e and pauei-
ditions,
juga is 6 to 7 t i m e s a s f e r t i l e c o m p a r e d with C 3.
a g a i n s t t h e i n t r o d u c t i o n of g e n e s that affect i t s f e r t i l -
' m a j o r ' p o p u l at i o n s m a y d e v e l o p b a r r i e r s
ity and e n d a n g e r i t s i d e n t i t y and p e r s i s t e n c e . One s u c h b a r r i e r will be s p e c i f i c g e n e s ( u n i l a t e r a l i n c o m p a t i b i l i t y g e n e s = U__II) that r e j e c t f e r t i l i z a t i o n
Discussion
f r o m the m o r e s e l f - f e r t i l e p o p u l a t i o n s . C o n s e q u e n t l y It is b e l i e v e d that the u n i l a t e r a l i n t r a s p e c i f i c i n c o m p a t i b i l i t y in V. faba is a s s o c i a t e d with e v o l u t i o n of t h i s c r o p . The e v o l u t i o n of f i e l d b e a n will be r e p o r t e d e l s e w h e r e . It is a c c e p t e d that th e s m a l l - s e e d e d p o p u l a t i o n s a r e the o l d e s t f o r m s - in t h i s study pauc~juga:
' m a j o r ' would be able to c r o s s a s m a l e with m o r e s e l f - f e r t i l e p o p u l a t i o n s while the r e c i p r o c a l c r o s s e s f a i l . The c r o s s 9 m o r e f e r t i l e • cf l e s s f e r t i l e
succeeds,
9 less fertile
fails.
• d more fertile
i s t h e s m a l l e s t s e e d e d s t o c k - w h e r e a s the l a r g e s t s e e d e d ' m a j o r ' type i s the m o r e r e c e n t l y d e v e l o p e d
That is the b e h a v i o u r known a s u n i l a t e r a l i n c o m p a t i -
one.
b i l i t y . The ' m a j o r '
' M a j o r C3, which i n h i b i t e d p o l l e n tube g r o w t h
- o r o t h e r - p o p u l a t i o n s t h a t did
of ' equina ' and paucijugaj p r o v e d to be the l e a s t f e r -
not p o s s e s s such a b a r r i e r could e i t h e r h a v e n e v e r
t i l e s t o ck ( 1 / 2 to 1/7 t h e f e r t i l i t y of o t h e r s ) .
developed this b a r r i e r ,
'Major'
o r h a v e l o s t the b a r r i e r in
p o p u l a t i o n s a r e known to p o s s e s s b i g g e r s e e d s (100
the a b s e n c e of s e l e c t i o n p r e s s u r e p r e s e r v i n g it, o r
s e e d weight m a y be m o r e than 200 g r ) , w h e r e a s
they m ay r e p r e s e n t r e c e s s i v e s e g r e g a n t s of the UI
' e q u i n a ' p o s s e s s e s i n t e r m e d i a t e seed size, followed
genes (uiui-genotyPes).
by ' m i n o r ' t y p e . The s m a l l e s t s e e d s a r e t h o s e of
The ' m a j o r '
C 2 m a y be one s u c h population with
paucijuga (100 s e e d weight is l e s s than 2 0 g r ) .
r e s p e c t to ' e q u i n a ' C9, but it s t i l l m a i n t a i n s i t s r e -
C o m b i n i n g t h i s and o t h e r i n f o r m a t i o n l e d us to h y -
j e c t i n g u n i l a t e r a l i n c o m p a t i b i l i t y with paucijuga.
p o t h e s i z e on the o r i g i n of UI in t h i s c r o p .
UI in V. f a b a and o t h e r s p e c i e s O r i g i n of u n i l a t e r a l i n c o m p a t i b i l i t y in V. faba In d i s c u s s i n g the h y p o t h e s e s a c c o u n t i n g f o r UI ( A b -
Paucijuga p o p u l a t i o n i s the m o s t a u t o f e r t i l e faba
d a l l a 1970, 1974a; A b d a l l a and H e r m s e n 1972) the
b e a n s t u d i e d by us up to now. ' M i n o r ' and ' e q u i n a
c o n c l u s i o n r e a c h e d was that the " t w o - p o w e r c o m p e -
t y p e s m a y p o s s e s s good s e l f - f e r t i l e p o p u l a t i o n s .
t i t i o n " h y P o t h e s i s co u l d e x p l a i n the o c c u r r e n c e of
F r o m t y p e s s u c h a s paucijuga, 'pliniana ' ( d i s c o v e r -
UI in d i f f e r e n t plant s p e c i e s w h e t h e r the f a i l u r e of
ed in A l g e r i a ) and ' m i n o r ' ,
t h e c r o s s was in the d i r e c t i o n S I X SC, SC • SC,
less self-fertile ones
may have evolved. 'Equina; is m o r e s e l f - f e r t i l e t h a n
SC x S I o r S I x S I .
230
T h e o r . A p p l . G e n e t . 50 (1977) The t w o - p o w e r c o m p e t i t i o n h y p o t h e s i s was w o r k e d
out ( A b d a l l a 1970) to e x p la in the UI that f r e q u e n t l y
s o m e medium-seeded stocks. Another change could have happened leading to low fertility populations
o c c u r s when c r o s s i n g i s t r i e d b e t w e e n SI s p e c i e s a s
(SLF), comparable to s o m e 'major' stocks. A third
f e m a l e s and SC r e l a t i v e s as m a l e s . It was a s s u m e d
change could have occurred, leading to cross-ferti-
that the h y b r i d i z a t i o n b e t w e e n SI and SC p o w e r s , r e -
lized p o p u i a t i o n s (SC) but m a i n t a i n i n g s e l f - c o m p a t i -
s u l t i n g in a d v e r s e e f f e c t s of i n t r o d u c i n g s e l f - c o m -
b i l i t y . A fourth c h a n g e might o c c u r - n e v e r p r o v e d
p a t i b i l i t y into the h e t e r o z y g o u s SI p o p u l a t i o n s , l e d
till now - r e s u l t i n g in s e l f - i n c o m p a t i b l e popul a t i ons
to the e v o l u t i o n of the U_.~Ig e n e s on the s i d e of SI
( S I ) . A s e l f - c o m p a t i b l e plant m a y d e v e l o p into a
p l a n t s . The U._~Ig e n e s p r e v e n t f e r t i l i z a t i o n by s p e c i f -
s e l f - i n c o m p a t i b l e one t h r o u g h a c h a n g e of S s p e c i f i -
i c S ( s e l f - c o m p a t i b i l i t y ) a l l e l e s of the SC s p e c i e s ,
c i t y f r o m S ( s e l f - c o m p a t i b i l i t y a l l e l e ) to S ( s e l f - i n -
not only l e a d i n g to UI, but a l s o r e n d e r i n g the r e c i p -
c o m p a t i b i l i t y a l l e l e ) o r t h r o u g h the d e v e l o p m e n t of
r o c a l F 1 p l a n t s (SC • SI) s e l f - i n c o m p a t i b l e and c o n -
U_.!Ir e j e c t i n g g e n e s a g a i n s t i t s S a l l e l e s (S i S 1 UI 1 UI 1
s e q u e n t l y p r e v e n t i n g the " s e l f - c o m p a t i b i l i t y d i s e a s e "
is a s e l f - i n c o m p a t i b l e p l a n t ) .
f r o m t h r e a t e n i n g the SI p o p u l a t i o n s . The e v o l u t i o n S of a U I - g e n e s - g e n e s y s t e m as a r e s u l t of the c h a l -
a l r e a d y at the s t a g e of the t h i r d change ( p e r c e n t a g e s
l e n g e of h y b r i d i z a t i o n b e t w e e n SI and SC p o w e r s
of c r o s s f e r t i l i z a t i o n r e a c h i n g m o r e than 60 7~ h a v e
( c o m p a r a b l e to the g e n e - f o r - g e n e s y s t e m of h o s t -
been r e p o r t e d in fild b e a n s by s o m e a u t h o r s ) .
p a r a s i t e r e l a t i o n s ) was p u b l i s h e d in detail in 1972 by A b d a l l a and H e r m s e n . U n i l a t e r a l i n c o m p a t i b i l i t y in Y. faba is t h e f i r s t
It i s p o s s i b l e that s o m e V. faba p o p u l a t i ons a r e
The h y p o t h e s i z e d s t e p s e x p r e s s the p o s s i b i l i t y of the e v o l u t i o n of a c r o s s - f e r t i l i z e d s y s t e m f r o m a s e l f - f e r t i l i z e d one ( s e e a l s o A b d al l a and H e r m s e n
r e p o r t e d o c c u r r e n c e of this p h e n o m e n o n a m o n g d i f f e r -
1972). It is a l s o p o s s i b l e that s e l f - i n c o m p a t i b l e s p e -
ent s e l f - c o m p a t i b l e p o p u l a t io n s of the s a m e s p e c i e s
cies have evolved from s e l f - c o m p a t i b l e ones follow-
l a c k i n g SI r e l a t i v e s . It can be e x p l a i n e d on the s i m i -
ing s o m e o r all of the following s t e p s l e a d i n g to the
l a r b a s i s of the e v o l u t i o n of u n i l a t e r a l i n c o m p a t i b i l i t y ,
different changes :
a s o u t l i n e d in the t w o - p o w e r c o m p e t i t i o n h y p o t h e s i s . The U__~Ig e n e s p r e s e n t on the s i d e of low s e l f - f e r t i l e p o p u l a t i o n s will p r o t e c t t h e m f r o m the d r a w b a c k s of
S H F -* SF -* SLF -* SC -* Sl (Scl SCl --UI I --UI 1 or
t h e " s e l f - f e r t i l i t y d i s e a s e " . The " s e l f - f e r t i l i t y d i s si
e a s e " e x p e c t e d to o c c u r in p r o g e n i e s of l o w e r s e l f -
si).
f e r t i l e when c r o s s e d with h i g h e r s e l f - f e r t i l e p o p u l a t i o n s is c o m p a r a b l e to the " s e l f - c o m p a t i b i l i t y d i s e a s e " that o c c u r s a f t e r c r o s s i n g s e l f - i n c o m p a t i b l e with s e l f - c o m p a t i b l e s p e c i e s .
The UI in V. faba o r any o t h e r s p e c i e s will d e v e l op on the s i d e of p o p u l at i o n s that a r e t h r e a t e n e d and e n d a n g e r e d in t h e i r e v o l u t i o n a r y pathways o r in t h e i r p e r s i s t e n c e . In V. ]'aba the U._~I-genes will d e v e l o p f a v o u r i n g low f e r t i l i t y p o p u l a t i o n s a g a i n s t highly f e r -
E v o l u t i o n of s e l f - i n c o m p a t i b i l i t y f r o m s e l f - c o m p a t i -
t i l e o n e s . In SI s p e c i e s , U_~Ig e n e s will d e v e l o p
bility
favouring s e l f - i n c o m p a t i b l e populations against s e l f compatible relatives.
It m a y be a r g u e d that V. f a b a e v o l v e d f r o m an a u t o -
The s c h e m e ab o v e r u l e s out t h e p o s s i b i l i t y of the
g a m o u s a n c e s t o r , o r f r o m an a l l o g a m o u s o n e - n e v e r
dual function of s e l f - i n c o m p a t i b i l i t y a l l e l e s (Lewis
found - that was f o r c e d to i n b r e e d and has u n d e r g o n e
and C r o w e 1958 and o t h e r s ) . It a l s o i m p l i e s that SI
a c h a n g e l e a d i n g to a t u o g a m i c n a t u r e . W h a t e v e r the
s p e c i e s should p o s s e s s U._~tg e n e s a g a i n s t SC r e l a -
a n c e s t o r w a s , the c u l t i v a t e d V. faba i s a s s u m e d to
t i v e s , e s p e c i a l l y ' o l d ' o n e s ; and that UI g e n e s ma y
h a v e d e v e l o p e d f r o m highly s e l f - f e r t i l e p o p u l a t i o n s
be p r e s e n t f a v o u r i n g d i f f e r e n t SC p o p u l a t i o n s a g a i n s t
that p o s s e s s g e n e s s p e c i f i c f o r high f e r t i l i t y ( S H F ) .
o t h e r SC o n e s , in p a r t i c u l a r on the s i d e of low s e l f -
A c h a n g e co u ld h a v e happend l e a d i n g to s e l f - f e r t i l e
f e r t i l i t y a g a i n s t high s e l f - f e r t i l i t y and c r o s s - f e r t i -
p o p u l a t i o n s ( S F ) , s i m i l a r to s o m e s m a l l - s e e d e d and
lized against self-fertilized.
M . M . F . A b d a l l a : I n t r a s p e c i f i c U n i l a t e r a l I n c o m p a t i b i l i t y in Vicia faba L. U n i l a t e r a l i n t r a s p e c i f i c i n c o m p a t i b i l i t y in
d e p r e s s i o n was c l e a r l y d e m o n s t r a t e d also in
Lycopersicon
persicon
231
Lyco-
i n b r e d s (Hogenboom 1972a) ; (3) r e j e c t e d
the r o l e of evolution and n a t u r a l s e l e c t i o n in b u i l d i n g C a s e s of u n i l a t e r a l i n t r a s p e c i f i c i n c o m p a t i b i l i t y w e r e
up a U._~.I-gene-S-gene s y s t e m ( A b d a l l a and H e r m s e n
reported in Lycopersicon by M a r t i n (1961, 1963,
1972).
1964). These i n v o l v e d SI and SC p o p u l a t i o n s . The
C o m p a r e d with the t w o - p o w e r c o m p e t i t i o n hypo-
r e s u l t s r e p o r t e d by M a r t i n (1964) on the l i n e s Banjos
t h e s i s , the i n c o n g r u i t y model cannot f u r n i s h an a c -
and S u r c o of the b o t a n i c a l t y p e s ' g l a b r a t u m ' and
c e p t a b l e e x p l a n a t i o n for the d i f f e r i n g r e s u l t s r e p o r t e d
'hirsutum'
of L. hirsutum a r e i n t e r e s t i n g . The two
i n the l i t e r a t u r e , such a s : b e h a v i o u r of h y b r i d s b e -
l i n e s a r e SC but d i f f e r e d in t h e i r f e r t i l i t y . B a n o s
tween SC and SI p a r e n t s and t h e i r s e g r e g a t i n g p r o -
b e i n g m o r e f e r t i l e (40 9 3 s e e d s p e r f r u i t ) , a n d Surco
g e n i e s in c o n n e c t i o n with s e l f - c o m p a t i b i l i t y and s e l f -
l e s s f e r t i l e (18 9 9 s e e d s p e r f r u i t ) . Surco r e j e c t e d
i n c o m p a t i b i l i t y ; the a s s o c i a t i o n of s e l f - i n c o m p a t i b i l i -
f e r t i l i z a t i o n by p o l l e n f r o m B a n o s ; the r e c i p r o c a l -
ty and u n i l a t e r a l i n c o m p a t i b i l i t y in h y b r i d s b e t w e e n
c r o s s s u c c e e d e d . The f a i l u r e of the c r o s s was in the
SC and SI p a r e n t s ; the o c c u r r e n c e of SC p r o g e n i e s
d i r e c t i o n of f e m a l e l e s s f e r t i l e • m a l e m o r e f e r t i l e ,
a m o n g S I x SI h y b r i d s and SI p r o g e n i e s in SC • SC
a g r e e i n g with the p r e s e n t m o d e l . The SI l i n e ( C a j a -
h y b r i d s . Also the r e s u l t s of G r u n and A u b e r t i n
m a r c a ) r e j e c t e d f e r t i l i z a t i o n f r o m both SC l i n e s
( 1 9 6 6 ) , Hogenboom (1972d), H e r m s e n et a l . (1974)
which also a g r e e s with the model p r e s e n t e d a b o v e .
and Spoor ( 1 9 7 6 ) , and the b e h a v i o u r of ' m a j o r ' C 2
The fact that UI o c c u r s b e t w e e n p l a n t s of the s a m e s p e c i e s ( V i c i a and
Lycopersicon)
is i n t e r e s t -
in o u r r e s u l t s , a r e a n t a g o n i s t i c to the i n c o n g r u i t y m o d e l . These r e s u l t s dealt with the s u c c e s s f u l r e -
i n g . This j u s t i f i e s the a r g u m e n t that this p h e n o m e -
c i p r o c a l c r o s s i n g b e t w e e n p l a n t s that accept and those
non evolved due to the c h a l l e n g e of h y b r i d i z a t i o n b e tween d i f f e r e n t p l a n t s , and c o n t r o l l e d by s p e c i f i c U._~I
that r e j e c t S - c a r r y i n g p o l l e n . All the r e s u l t s r e p o r t c ed c a n be s{-mply explained on the b a s i s of the two-
g e n e s . It a l s o shows that UI o c c u r s b e f o r e s p e c i a -
power competition hypothesis.
tion t a k e s p l a c e . UI (and s e l f - and c r o s s - i n c o m p a t i b i l i t y ) f u n c t i o n s e q u a l l y well a m o n g p l a n t s of the s a m e s p e c i e s and b e t w e e n p l a n t s of d i f f e r e n t s p e c i e s . This c o n t r a d i c t s the r e p o r t s that UI f u n c t i o n s only b e t w e e n p o p u l a t i o n s (Hogenboom 1973 and o t h e r s ) .
D r . H o g e n b o o m ' s (1972b, c) r e s u l t s c a n be e x p l a i n e d on the b a s i s of the t w o - p o w e r c o m p e t i t i o n h y p o t h e s i s as follows: the SC i n b r e d s o b t a i n e d through m u t a t i o n , i n b r e e d i n g and s e l e c t i o n may p o s s e s s diff e r e n t S s t r u c t u r e s ; s o m e differ f r o m those u n a b l e to f e r t i i i z e U__~Igenotypes p r e s e n t in Lycopersicon
peruvianum, and will c r o s s r e c i p r o c a l l y with s i s t e r The i n c o n g r u i t y model
SI p l a n t s ; m u t a t i o n and i n b r e e d i n g may have r e s u l t e d
Hogenboom (1973) p r e s e n t e d what he c a l l e d the i n -
ones a g a i n s t L. esculentum p o l l e n ( m u t a t i o n of UI
in d i f f e r e n t U..~Ig e n o t y p e s , i n b r e e d i n g l e a d i n g to uiui c o n g r u i t y model to a c c o u n t for u n i l a t e r a l r e l a t i o n s .
g e n e s is not r u l e d o u t ) , and c o n s e q u e n t l y s o m e m a y
The model i s e s s e n t i a l l y M a r t i n ' s (1963) h y p o t h e s i s
also c r o s s r e c i p r o c a l l y with L. esculentum. The s e g -
of the p o l y g e n i c a l l y c o n t r o l l e d b a l a n c e of s u b s t a n c e s
r e g a t i o n of U__~I-genesin H o g e n b o o m ' s m a t e r i a l may
affecting p o l l e n tube growth and s t y l a r i n h i b i t i o n
e x p l a i n all his r e s u l t s . The e x p l a n a t i o n of Hogenboom
( s e e a l s o P a n d e y 1969). In addition to a r g u m e n t s
(1973) of the model of Lewis and C r o w e (1958) of the
p r e s e n t e d e a r l i e r a g a i n s t such i d e a s ( A b d a l l a 1970,
g r a d u a l m u t a t i o n f r o m SI s p e c i e s t h r o u g h Sc and S~
1974a; A b d a l l a and H e r m s e n 1972; de N e t t a n c o u r t
to SC o n e s is b a s e d on d i s p u t a b l e s u p p o s i t i o n s : "low-
et a l . 1974) it is o b s e r v e d that the i n c o n g r u i t y m o d e l :
e r i n g c a p a c i t i e s of m a n y b a r r i e r g e n e s " and " m a i n -
(1) failed to d i f f e r e n t i a t e b e t w e e n w i d e s p r e a d o c c u r -
r a i n i n g p e n e t r a t i o n c a p a c i t y " and " a d j u s t i n g p e n e t r a -
r e n c e of c e r t a i n b e h a v i o u r (SI • SC i n h i b i t i o n ) and
tion c a p a c i t y " a r e too m a n y a s s u m p t i o n s without
f i n d i n g s of r a r e e v e n t s ; (2) i g n o r e d the i m p o r t a n c e
p r o o f . The m u t a n t s a s s u m e d in the model of Lewis
of i n b r e e d i n g d e p r e s s i o n o c c u r r i n g i n SI p o p u l a t i o n s
and Crowe (1958) a r e e a s i l y e x p l a i n e d as a o n e - g e n e
following the i n t r o d u c t i o n of S a l l e l e s , although such
m u t a t i o n step in S o r U_.II-genes. On the b a s i s of the
232
Theor. Appl. G e n e t , 50 (1977)
t w o - p o w e r c o m p e t i t i o n h y p o t h e s i s the m u t a n t s m a y
the ' m a j o r ' c h a r a c t e r i s t i c . C 2 i s a ' m a j o r ' type
be given such genotypes as the following to a c c o u n t
with b e t t e r f e r t i l i t y c o m p a r e d with C 3.
for t h e i r a s s u m e d b e h a v i o u r [ s e e also A b d a l l a and
H y b r i d s a r e good y i e l d e r s and e x p r e s s high f e r t i l i -
H e r m s e n (1972) and A b d a l l a (1974a) for m o r e d e -
ty, but they s t i l l a r e difficult to p r o d u c e c o m m e r c i a l -
tails ] :
l y . Some i n b r e d s with high s e l f - f e r t i l i t y and which a r e l e a s t affected by e n v i r o n m e n t a l c o n d i t i o n s may be
Lewis and Crowe (1958) s p e c i e s
E x p e c t e d genotype a c c o r d i n g to the t w o - p o w e r c o m p e t i t i o n hypothesis
e q u a l l y good as h y b r i d s . H y b r i d i z a t i o n b e t w e e n ' m a j o r ' and o t h e r v a r i e t a l types is p o s s i b l e . R e c i p r o c a l c r o s s i n g and f a c i l i t a t -
SI
= SiS i U I l . . u i 2 u i 2 u i 3 u i 3
Sc
= Sc3Sc3UIiUIlUi2ui2ui3ui3
$6
= S c 2 S c 2 U i l u i l u i 2 u i 2 u i 3 u i3
ing the r e c o v e r y of useful s e g r e g a n t s n e c e s s i t a t e s u s i n g uiui gentoypes ( s e e A b d a l l a and H e r m s e n 1972). However, the p r a c t i c a b i l i t y of r e c o v e r i n g the o r i g i n a l typical ' m a j o r ' with f e r t i l i t y s i m i l a r to
SC
= S c l S c l U i l U i l u i 2 u i 2 u i 3 u i3
So f a r a s it has b e e n t e s t e d , the t w o - p o w e r c o m p e t i tion h y p o t h e s i s can s a t i s f a c t o r i l y and s i m p l y f u r n i s h a b a s i s to e x p l a i n the r e s u l t s of u n i l a t e r a l i n t e r s p e cific and i n t r a s p e c i f i c i n c o m p a t i b i l i t y p u b l i s h e d up to now. F r o m the p r a c t i c a l point of view uiui g e n o types a r e b e i n g used in r e s e a r c h in d i f f e r e n t plant s p e c ! e s . The s t u d i e s of m u t a t i o n , i n c o m p a t i b i l i t y and i n t r a - and i n t e r s p e c i f i c c r o s s i n g s a r e expected to r e v e a l i n t e r e s t i n g d i s c o v e r i e s in the p o t e n t i a l i t i e s of S Sc and UI genes and t h e i r i n t e r a c t i o n s . C o m p a r e d
q th
alleles, ~_ a l l e l e s have been given l e s s a t t e n -
tion.
paucijuga o r ' m i n o r ' types may be q u e s t i o n e d . It is being e x p e r i m e n t a l l y t e s t e d . Handling ' e q u i n a ' p o p u l a t i o n s may be p r o m i s i n g in different a s p e c t s . It would be i n t e r e s t i n g to t h r o w m o r e light on the r e l a t i o n s h i p and the p r o d u c t s of r e c o m b i n a t i o n of the d i f f e r e n t Sc a l l e l e s in V. faba ( s e e A b d a l l a 1977). The d i s c o v e r y of the p r e s e n c e of u n i l a t e r a l i n c o m p a t i b i l i t y in V. faba c a l l s for r e - a s s e s s m e n t of the d e g r e e of n a t u r a l c r o s s - f e r t i l i z a t i o n r e p o r t e d in this c r o p . If s o m e of the p l a n t s u s e d in the e a r l i e r s t u d i e s happened to be c a r r y i n g U I r e j e c t i n g g e n e s , such p l a n t s would fail to c r o s s as f e m a l e s l t h e r e f o r e , it is p o s s i b l e that e a r l i e r r e s u l t s may need to be r e checked.
F e r t i l i t y and field b e a n b r e e d i n g
Literature With r e s p e c t to the f e r t i l i t y c h a r a c t e r i s t i c , differing s p e c i f i c i t i e s a r e known i n V. faba, d i f f e r e n t ones of which m a y be p r e s e n t in s i m i l a r o r d i f f e r e n t b o t a n i cal t y p e s . The n a t u r e of the Sc a l l e l e s r e m a i n s to be thoroughly i n v e s t i g a t e d . An i n t e r e s t i n g d i s c o v e r y by A b d a l l a and H u s s e i n (1977) is the m u t a t i o n of an ' e q u i n a ' to a ' m a j o r ' type. 'Major',
' e q u i n a ' and ' m i n o r ' t y p e s p o s s e s s
s t o c k s with different f e r t i l i t i e s , paucijuga is highly ' a u t o f e r t i l e ' but a v e r y low y i e l d e r . I m p r o v i n g f e r t i l ity t h r o u g h i n d i v i d u a l - p l a n t s e l e c t i o n may be a c h i e v e d in c e r t a i n s t o c k s but not in o t h e r s ( A b d a l l a 1976). S m a l l - s e e d e d populations a r e g e n e r a l l y m o r e s e l f f e r t i l e . ' M a j o r ' stocks a r e m o s t l y low in f e r t i l i t y . In o r d e r to i m p r o v e the f e r t i l i t y of such p o p u l a t i o n s , one may t r y to change the
_S-specificity
towards bet-
t e r f e r t i l i t y but at the s a m e t i m e g r e a t l y i n a f f e c t i n g
Abdalla, M . M . F . : Inbreeding, heterosis, fertility, p l a s m o n d i f f e r e n t i a t i o n and PhF~ophthoz~ r e s i s t a n c e in Solarium ver~cosum Schlechtd., and s o m e interspecific crosses in Solarium.Agric. ires. Rep. Wageningen (the Netherlands) 748, 1-213 (1970) Abdalla, M . M . F. : Unilateral incompatibility in plant species: analysis and implications. Egypt. J. G e n e t . Cytol. 3, 133-154 (1974a) A b d a l l a , M . M . F . : U n i l a t e r a l i n c o m p a t i b i l i t y in field b e a n s , Vicia faba L. I n c o m p a t i b i l i t y N e w s l e t t e r 4, 16 (1974b) Abdalla, M.M.F. : Inbreeding, selection and hybridization in field beans, Vicia faba L. Egypt. J. Genet. tyrol. 4_, 473 (Abst.) (1975) Abdalla, M . M . F. : Natural variability and selection in s o m e local and exotic populations of field beans, Vicia faba L. Z. Pflanzenz(ichtg. 76, 332341 (1976) A b d a l l a , M . M . F . : P e r f o r m a n c e of Fr and F2 h y b r i d s of Vicia faba L. Egypt. J. Genet. Cytol. 6_, 108-121 (1977) Abdalla, M . M . F . ; Hermsen, J.G.Th. : Unilateral incompatibility: hypotheses, debate and its implications for plant breeding. Euphyfica 21, 32-47 (1972)
M.M.F.
A b d a l l a : I n t r a s p e c i f i c U n i l a t e r a l I n c o m p a t i b i l i t y in Vicia faba L.
233
A b d a l l a , M . M . F . ; H u s s e i n , H . A . S . : E f f e c t s of s i n g l e and c o m b i n e d t r e a t m e n t s of g a m m a - r a y s and EMS on M ~ - q u a n t i t a t i v e v a r i a t i o n in Vicia faba L. Z . P f l a n z e n z f i c h t g . 78, 57-64 (1977) G r u n , P . ; A u b e r t i n , M. : The i n h e r i t a n c e and e x p r e s s i o n of u n i l a t e r a l i n c o m p a t i b i l i t y in Solarium. H e r e d i t y 21, 131-138 (1966) H e r m s e n , J . G . T h . ; O l d s d e r , J . ; J a n s e n , P . ; Hov i n g , E . : A c c e p t a n c e of s e l f - c o m p a t i b l e p o l l e n f r o m So~num verrucosum in d i h a p l o i d s f r o m S. tuberosum. In: Fertilization in higher plants (ed. Linskens, H.F. ) 37-40. A m s t e r d a m : NorthHolland Publ. Co. 1974 Hermsen, J.G.Th. ; Ramanna, M.S. : Barriers to hybridization of Solanum bulbocastanum Dun. and S. verrucosum Schlechtd. and structural hybridity in their F~ plants. Euphytica 25, I-I0 (1976) Hogenboom, N.G. : Breaking breeding barriers in Lycopersicon. 2. Breakdown of self-incompatibility in n. peruvianum (L.) Mill. Euphytica 21, 228243 (1972a) Hogenboom, N.G. : Breaking breeding barriers in Lycopersicon. 3. Inheritance of self-compatibility in L. peruvianwn (L.) Mill. Euphytica 2_.!1 , 244256 (1972b) H o g e n b o o m , N . G . : B r e a k i n g b r e e d i n g b a r r i e r s in Lyeopersieon. 4. B r e a k d o w n of u n i l a t e r a l i n c o m p a t i b i l i t y b e t w e e n L. peruvianwn ( L . ) M i l l . and L. esculentwn M i l l . E u p h y t i c a 2_1, 397-404 (1972c) H o g e n b o o m , N . G . : B r e a k i n g b r e e d i n g b a r r i e r s in Lyeopersicon. 5. The i n h e r i t a n c e of the u n i l a t e r a l i n c o m p a t i b i l i t y b e t w e e n L. peruvianum ( L . ) M i l l . and L. eseulentum M i l l . and t h e g e n e t i c s of its b r e a k d o w n . E u p h y t i c a 2_!1, 405-414 (1972d)
H o g e n b o o m , N . G . : A m o d e l f o r i n c o n g r u i t y in i n t i m a t e p a r t n e r r e l a t i o n s h i p s . E u p h y t i c a 2_22, 219233 (1973) L e w i s , D. ; C r o w e , L . K . : U n i l a t e r a l i n t e r s p e c i f i c i n c o m p a t i b i l i t y in f l o w e r i n g p l a n t s . H e r e d i t y 12, 233-256 (1958) Martin, F . W . : Complex unilateral hybridization in Lycopersicon hirsutum. Proc. Nat. Acad. Sci. (USA) 47, 855-857 (1961) M a r t i n , F . W . : D i s t r i b u t i o n and i n t e r r e l a t i o n s h i p s of i n c o m p a t i b i l i t y b a r r i e r s in the Lycopersicon h i t suture Humb. and B o n p l . c o m p l e x . E v o l u t i o n 1._~7, 519-528 (1963) M a r t i n , F . W . : The i n h e r i t a n c e of u n i l a t e r a l i n c o m p a t i b i l i t y in Lycopersieon hirsutum. G e n e t i c s 50, 459-469 (1964) de Nettancourt, D. ~ Devreux, M. ~ Laneri, U. ; Pacin i , E . ; C r e s t i , M. ; S a r f a t t i , G. : U l t r a s t r u c t u r a l a s p e c t s of u n i l a t e r a l i n t e r s p e c i f i c i n c o m p a t i b i l i t y b e t w e e n Lycopersicon peruvianum and L. esculentum. C a r y o l o g i a 255, Suppl. 207-217 (1973) de N e t t a n c o u r t , D. ; D e v r e u x , M. ; L a n e r i , U. ; C r e s t i , M. ; P a c i n i , E . ; S a r f a t t i , G. : G e n e t i c a l and u l t r a s t r u c t u r a l a s p e c t s of s e l f and c r o s s i n c o m p a t i b i l i t y in i n t e r s p e c i f i c h y b r i d s b e t w e e n s e l f c o m p a t i b l e Lycopersicon esculentum and s e l f - i n c o m p a t i b l e L. peruvianwm T h e o r . A p p l . G e n e t . 4_.~4, 278-288 (1974) Pandey, K . K . : Elements of the S-gene complex V. Interspecific cross-compatibility relationships and t h e o r y of the e v o l u t i o n of the S - c o m p l e x . G e n e t i c a 40, 447-474 (1969) R a m a n n a , M . S . ~ M u t s a e r t s , M . C . A . : Unusual b e h a v i o u r of g r o w i n g p o l l e n t u b e s in the s t y l e s and o v u l e s of Spinacia oleracea L. E u p h y t i c a 20, 145-151 (1971) S p o o r , W. : I n t e r s p e c i f i c i n c o m p a t i b i l i t y in Lolium s s p . I n c o m p a t i b i l i t y N e w s l e t t e r 7--, 62-64 (1976)
A c c e p t e d D e c e m b e r 15, 1976/ M a r c h 15, 1977 C o m m u n i c a t e d by H . F . L i n s k e n s
Dr. M.M.F. Abdalla Associate Professor D e p a r t m e n t of A g r o n o m y F a c u l t y of A g r i c u l t u r e Cairo University Giza (Egypt)
Note Added in Proof The d i s c u s s i o n in t h i s and in p r e v i o u s p a p e r s a s s u m e d the r e j e c t i n g U_[I g e n e s to b e d o m i n a n t . P r e l i m i n a r y r e s u l t s in V. f a b a s h o w e d that t h i s m a y not b e a r u l e .
