Theoretical and Applied Genetics 45, 47 -- 51 (1974) | by Springer-Verlag 1974

On the Evolution of Vicia faba L. J o s e I. CUBERO Instituto Nacional de Investigaciones Agrarias, Centro Regional de Andalueia, Cordoba (Spain) Summary. l)iallel crosses between seven inbred lines obtained from different botanical groups including the two known subspecies of V. faba permitted study of the genetics of seventeen quantitative characteristics; there were very few significant reciprocal differences, andin all cases but one they were only weakly dependent on genotype. These results accord very well with those obtained from a study on population distances among thirty unselected populations of V. faba; many of these lie very close, forming a strong nucleus, which carries the maximum of potentialities of the species and from which different populations branch. Nevertheless differentiation occurs: the genetic system which regulates seed length shows overdominance in the positive sense in some lines, but partial or complete dominance in the negative sense in the rest of the studied lines. Interpretations suggesting that V. faba has suffered very little intraspecific differentiation are substantiated by the studies showing the presence of a partial incompatibility system; this is stronger in the Central European populations studied, weak (to various degrees) in the Spanish ones and absent in at least one population of the paucijuga group.

Viola/aba is known to have been cultivated from the early Neolithic. It can be said that it has been known from the beginning of Agriculture. It is logical to suppose that the use of Vicia /aba as a cultivated species began in the Near East, following the Neolithic culture as it spread across the inhabited world (Cole, t97(/). This does not mean that the plant was unknown in other regions, particularly in the Mediterranean countries. Philological studies (Hanelt 1972a) show that its names in the Indoeuropean languages have the same root (ba), except in the Greek (leyamos) ; this is an interesting exception because of the proximity of Greece to the Near East. Possibly the primitive (/reeks found a people who knew the bean and named it because it would be useful (Acheens were present at Micenes towards 1800 BC ; at this time, the culture of beans must have been known in Greece because of its proximity to the Near East) ; the Hebrew root is fia, very close to the Indoeuropean one and, perhaps, to the original and unknown word used by an unknown people to name the beans. The Arabic word (/~tl) is a similar case to the Greek one : it could have come from a people who knew the plant before the culture. Three different roots (Greek, Hebrew, Arabic) in a relatively small region: is it possible to deduce that the plant was known by different peoples even if only one of them began to cultivate it ? We can suppose that there were different routes radiating from the Near East (Fig. t). The first could be the European one: across Anatolia and perhaps included in the Troyan interchange with Europe (particularly with the Vinca culture), the culture of beans had to pass to Greece, the Illyric coast (perhaps also to the Danubian regions) and to Italv. Front the mediterranean regions it could pass to tl~e rest of Europe.

Fig. 1. Expansion of the culture A second route could also begin at tile Delta, go towards the West, along the Mediterranean coast, to the 5Iogreb and the Iberic Peninsula (Cole, 1970). The third way could begin at the Nile Delta (Low E g y p t and Mesopotamy was the same thing from the point of view of culture; see, for example, Pirenne 1963), following the Great River and finishing at Abisinia. Tile fourth and last route could begin in Mesopot a m y again, but this time would go toward the East carried by the Indoeuropeans of the Indoiranian group. This culture raised India. Tile existence of a fifth way from 3Iesopotamy across the Caucaso to the Pontic peoples is doubtful. I think that this dispersion must have been more indirect than direct, that is, that primitive peoples transmitted knowledge about the culture and not the seeds directly, even allowing for some transmission of grains from hand to hand. In the first place, the basic vegetable material originally cultivated had to be the wild plants of the considered species. This

48

Josd [. Cubero: On the Evolution of l~iciafaba L.

lqg. 2. I)istribution of V. ]abaL. (from Hanelt 1972, modified) can explain the actual absence of wild plants of V./aba: all these were immediately converted into cultivated ones (the problem is different when a cluster of species is considered, such as Triticum sp.). On the other hand, Fig. 2 shows t h a t minor populations a c c u m u l a t e d in I n d i a (with paucifitga also) and Abisinia, while at the same time major populations a c c u m u l a t e d more and more to the western limit of the species h a b i t a t , and so were on b o t h sides of the Mediterranean Sea. If we think t h a t tee archaeological r e m n a n t s (Hanelt, 1972) would actually be classified as belonging to the minor group, it is impossible t h a t primitive men t r a n s p o r t e d major or minor seeds, because t h e y did not exist as botanical entities. I shall t r y to prove in this work t h a t t h e y m u s t exist as genetical ones: I do not t h i n k t h a t in ancient times either major, equina or minor existed in t h a t actual form, b u t t h a t there m u s t have been populations with different e v o l u t i o n a r y potentialities. N a t u r a l migrations, previous to the cultural ones, m u s t be the main explanation of the actual geographical distribution. I m a i n t a i n t h a t it m u s t be more i m p o r t a n t t h a n the h u m a n (that is, cultural) transmission; if it was the opposite, the two Medit e r r a n e a n sides would present different spectra of botanical form~. I t can be argued against this idea t h a t equina and major were artificially o b t a i n e d (major appears in archaeological remains of the t 0 d c e n t u r y ; H a n e l t 1972) and then transmitted. First, Figure 2 shows a v e r y n a t u r a l separation of forms: evidently, m a n has played a role in the transmission; for example, in m o d e r n times some ma~or varieties have been introduced in E n g l a n d and France. B u t it is difficult to explain Fig. 2 this way. Secondly, if we a d m i t this a r g u m e n t (that is, the artificial transmission of some forms), it would be necessary to explain w h y in the western Mediterranean an a c c u m u l a t i o n of some forms (lentils, beans, chickpeas for example) with big seeds is registered in c o n t r a s t to the small-seeded forms of the same species on t e e other side of the old Thetis sea (western regions of India). I t seems that, at least for tile Vicieae genera, a "genetic n a t u r a l

m i g r a t i o n " happened. E n v i r o n m e n t a l conditions and independence of recessives h a d to play an imp o r t a n t role, even if archaeologically we can not distinguish between one population with the potential to become major or equ~na and a n o t h e r to stay as minor or to become pauci]uga. Man has acted to accelerate the morphological differentiation process. I have studied the problem from different points of view: distances hetween populations (Cubero, t973 a), studies on q u a n t i t a t i v e inheritance (Cubero t 9 7 0 a , t973b), relations between morphological characteristics and studies on the reproductive s y s t e m of this species (Cubero t970b). I think t h a t it is convenient to recapitulate before going on.

A Recapitulation of Methods and Materials I have used in the study sixty-seven populations: Thirt}~-eight m~/or, nine equina, eighteen minor and two paucuuga. Seven pure lines with at least five self-pollinations were used to study the inheritance of quantitative characteristics; Hayman's (t954) diallel analysis was followed. In principle it was intended to make the analysis using eight pure lines, but one of them was eliln~nated because of its lack of adaptability to Spanish conditions. Populations were classified according to the seed weight and number of leaflets per leaf. The first character is closely related to the main taxonomic characteristic of Muratova (1931), that is, the thickness/length ratio of the seed, whose suitability as a taxonomic index has been discussed (Cubero, 1973). Two formal classes were considered for paucijuga (P1 and P2) and three for major (M1, M2 and Ma). The weight intervals were: PI: less than 0,30 grams/seed; P2:0,31--0,40; minor: 0,41--0,60; equina: 0,61--1,10; M~: 1,11--1,40; M2:t,41 1,70 and Ma more than 1,71 grams/seed. From the total, thirty unselected populations (little unconscious selection has actually occurred over all ldnds of populations; our term "unselected" refers here to this circumstance), were taken out and the distances between them (in Mahalanobi's sense) were calculated (Rao t 952).

Results and D i s c u s s i o n Fig. 3 shows the between-groups graphic relations according to four characters previously studied (Cubero, 1970 a, b). I t can be seen t h a t the pa~.tcii'uga and minor are opposed groups in all cases b u t one. I n three grapes the straight line connecting the two representative points goes t h r o u g h tee major-equina conjoint. Equina shows a central position in all tee graphs, and the three major subgroups always lie together, and are closer to equina t h a n the other group. The two pauci]uga subpopulations are generally v e r y close to one another. I t is curious t h a t only one g r a p h (Fig. 3 f) seems to show a linear connection between our t a x o n o m i c character (seed weight) and the n u m b e r of ovules per o v a r y : a straight line joins pauci~uga, minor, equina and major, in t h a t order. TEe other figures show no connections of this kind at all. Tilree possibilities can be deduced fronl these figures: t) The primitive group is paucijuga, from which, b y two divergent routes, arise minor on one

Theoret. dppl. Genetics, Vol. 45, No. 2

Jos6 [. Cubero: On the Evolution of Vicia fi, ba L. side a n d equina a n d major on t h e other. 2) The prim i t i v e g r o u p is minor, w i t h pauc@tga o r i g i n a t i n g on one side a n d equina a n d ma~or on t h e other. 3) A prim i t i v e group, p o s s i b l y classified a r c h a e o l o g i c a l l y as minor b u t g e n e t i c a l l y richer (at l e a s t t h a n t h e a c t u a l minor), ew)lves g i v i n g a s t r o n g nucleus f o r m e d by' equina 'and ma~or; minor, a n d p e r h a p s paucijuga, w o u l d be relicts, or the e n d of t h e series. I suggest this t h i r d e x p l a n a t i o n . i t is n e c e s s a r y to a s s e r t t h a t i do n o t m a i n t a i n t h a t equina a n d major are t h e m o s t p r i m i t i v e as bot a n i c a l t y p e s b u t t h a t t h e i r g e n e t i c a l s y s t e m s are t h o s e w i t h t h e m a x i m u m possibilities, g i v i n g t h e n e c e s s a r y v a r i a b i l i t y to e v o l v e a n d f o r m new m o r pllological forms. I n p r e v i o u s w o r k (Cubero, 1973a), [ h a v e shown t h a t this is p o s s i b l y so. Using the p o p u l a t i o n d i s t a n ces b e t w e e n t h i r t y p o p u l a t i o n s t a k e n from t h e t o t a l (see M e t h o d s a n d Materials), I h a v e d e f i n e d a C e n t r a l N u c l e u s of E v o l u t i o n which includes m o s t equina a n d some major p o p u l a t i o n s . I t is possible t h a t some major p o p u l a t i o n s of the N u c l e u s b e c o m e m o r e differe n t i a t e d , arising from an u n d i f f e r e n t i a t e d g r o u p f o r m e d b y t h e equina a n d t h e lesser major, b u t it is n o t possible to decide this at the naoment.

9 Paucijuga

Theoret. ,4ppl. Genetics, Vol. 45, No. 2

oMinor

9 Equina

a

,2

.2

1A

1,0~

x- M a j o r

b

4

uJ ~b

3~

o

X 3 o

0,50

A1

_a o 2

3

0

FLOWE RS/RACEME

FLOWERS/RACEME

C

>- 4,0.

X.2

9

,3

>

[]

w

d o

O.4

0

1,2

0,8 PODS/NODE

2,01

A n i n t e r e s t i n g consequence is t h a t , even if t h e e x i s t e n c e of such a C e n t r a l N u c l e u s is t a k e n as subj e c t i v e , t h a t is, as a f u n c t i o n of t h e n u m b e r of v a r i a t e s a n d of t h e p o p u l a t i o n s considered, t h e r e l a t i v e distances between extreme populations showed that some major were f a r t h e r front one a n o t h e r t h a n each was f r o m paucijuga, w h i c h h a s t h e categ o r y of subspecies in M u r a t o v a ' s t a x o n o m y . This gives rise to s t r o n g d o u b t s a b o u t t h e classic T a x o n o m y ; it is possible t h a t , at least in this species, a s t e m - l i k e s t r u c t u r e exists, w h i c h grows a n d o r i g i n a tes s p e c i a l i z e d b r a n c h e s . This s t e m seems n o t to be g e o g r a p h y - d e p e n d e n t : d i s t a n c e s to t h e C e n t r a l N u c l e u s were, in general, i n d e p e n d e n t of g e o g r a p h i c a l s i t u a t i o n ; major p o p u l a t i o n s f r o m close s i t u a t i o n s can be v e r y far a p a r t t a x o n o m i c a l l y a n d vice v e r s a (Cubero t973 a). B u t tl~e C e n t r a l N u c l e u s can n o t be a calculus artifice. W e h a v e m a d e a s i m i l a r s t u d y on Cicer arietinum (not p u b l i s h e d d a t a ) a n d t h e g r a p h i c p i c t u r e does n o t suggest a g r o w i n g stem, b u t a r u g b y ball. T h e s a m e t e c h n i q u e t h a t d e t e c t s a N u c l e u s in the first case fails in the second. Such a N u c l e u s suggests a h i g h degree of undiffer e n t i a t i o n in Vicia /aba. If we a p p l y i n v e r s e l y t h e argument that the greater the differentiation the g r e a t e r t h e differences b e t w e e n r e c i p r o c a l s , we h a v e t h a t t h e less the d i f f e r e n t i a t i o n the less t h e r e c i p r o c a l differences. Using this idea, I h a v e a n a l y z e d a 7 • 7 d i a l l e l cross (Cubero, 1973b), which was v e r y h e t e r o geneous f r o m t h e p o i n t of view of t h e origin of p a r e n t a l lines: two S p a n i s h ~ajor, two minor a n d one equina of C e n t r a l - E u r o p e a n origin a n d two I n d i a n

49

FLOWE R S / R A C E M E

,3

e

f

,3

~2

1,0

2

2

0

1,2

0,8

0,4

PODS/NODE

a ua

w

1,, 0

2~

2

4 OVULES/OVARY

l.'ig. 3. [~clationships between botanical groups Table 1. Sig,,ificance of reciprocal differences

(from Cubero, 1973b)

Characteristic

Level of Characteristic Sig. (1)

Level of Sig. (I)

Plant height Rachis length Leaflets/leaf Leaflet width width l ,eaflet length Totalweight/plant Seeds/plant

*** (g) Pods/node ns Ovules/ovary ns Seeds/pod ns Pod width Seed length ns thickness ** (g) Seed length (*) (g) Seed weight Days to blossonl *** (g) l)ays to m a t u r i t y

11s * (g) ns ns ** (a) ,, (a) ns ns ns

Flowers/raceme

(t) * * * < 1% 0; ** < 1"'-o, * < 5%; ( * ) < m " ; ; ns: not significant g: genotype dependent; a: genotype independent

paucijuga. T a b l e t c o n t a i n s t h e r e s u l t s of the seventeen s t u d i e d c h a r a c t e r i s t i c s , o n l y in c o n n e c t i o n w i t h our p r o b l e m . O n l y five c h a r a c t e r i s t i c s s h o w e d recip r o c a l differences: two at the t~ level, two at t h e

jos6 I. Cubero: On the Evolution of Vicia faba 1..

~0

1% a n d one at t h e 5% level. E v e n if we a d d a n o t h e r c h a r a c t e r i s t i c , n u m b e r of seeds per p l a n t , b o t h because of its s t r o n g c o r r e l a t i o n w i t h t h e t o t a l w e i g h t p e r p l a n t a n d its n e a r significance at t h e 5% level, we h a v e o n l y six c h a r a c t e r i s t i c s , one t h i r d of w h i c h p r e s e n t a low level of significance. If we consider t h a t t h e a n a l y s e s were c a r r i e d o u t w i t h p a r e n t a l lines t h a t i n c l u d e t h e whole v a r i a t i o n range of t h e species, it m u s t be c o n c l u d e d t h a t t h e d i f f e r e n t i a t i o n is n o t g r e a t b u t v e r y small. B u t it e x i s t s a n d it can be d e n l o n s t r a t e d b y m e a n s of t h r e e d i f f e r e n t k i n d s of result. Table 2. Reciprocal differences: parental efJects ( t)

(from Cubero, 1973b) Parental line (considered as female) Characteristic

164

t65

166

168 169 t71 t72

Plant height \Veight/plant Seeds/plant Flowers/raceme Ovules/ovary thickness Seed length

A A A A A

A A A A A

1) 1) 1) ]) l)

1) 1) l) D 1)

A A

l) -

1)

-A

l) --

1) D D

1)

A

--

A

--

I)

D

1)

(1) A: to augment the F 1 value: D: to diminish it; --: no effect, Accession number t64 and t65: major; t66 and 168: minor; t69 equina; 171 and 172: paucifuga F i r s t , a m o r e d e t a i l e d a n a l y s i s of t h e r e c i p r o c a l differences (Table 2) s h o w e d t h a t t h e equina a n d major c y t o p l a s m s u n i f o r m l y increase t h e F 1 v a l u e of t h e s t u d i e d c h a r a c t e r i s t i c s ; t h e o p p o s i t e effect is pres e n t e d b y minor a n d paucijuga. T h e r e are two exceptions to this rule, b o t h p r e s e n t e d b y seed t h i c k n e s s / l e n g t h ; this was t h e o n l y c h a r a c t e r s h o w i n g a v e r y s t r o n g e n v i r o n m e n t a l influence in t h e r e c i p r o c a l differences. Second, t h e equina andminor lines used show differe n t b e h a v i o u r f r o m t h e o t h e r p a r e n t a l lines in conn e c t i o n w i t h t h e q u a n t i t a t i v e i n h e r i t a n c e of four c h a r a c t e r i s t i c s . W e can a n a l y z e t h e four s m a l l 3 • 3 s u b d i a l l e l t a b l e s a n d c o m p a r e t h e results w i t h those of one 4 • 4 d i a l l e l cross p r e v i o u s l y a n a l y z e d (this one was o n l y p e r f o r m e d w i t h C e n t r a l - E u r o p e a n lines ; Cubero 1970a). The r e s u l t s can be seen in T a b l e 3, a n d it is e v i d e n t t h a t t h e C e n t r a l - E u r o p e a n lines

differ from t h e rest of the p a r e n t a l lines in the genet i c a l s y s t e m s c o n t r o l l i n g p l a n t h e i g h t , t h e n u m b e r of flowers p e r raceme, seed l e n g t h a n d seed w e i g h t ; in these two l a s t cases, even t h e d o m i n a n c e sense changes. I t is clear t h a t t h e C e n t r a l - E u r o p e a n lines are specialized in some senses. I t is logical to s u p p o s e t h a t in n o t v e r y s u n n y c o u n t r i e s ( c o m p a r e d to the M e d i t e r r a n e a n ones) h e i g h t m u s t be an i m p o r t a n t a d a p t i v e c h a r a c t e r i s t i c , a n d f r o m here, the overd o m i n a n c e is d e t e c t e d ; it is also logical t h a t in p l a n t s which are n o t s t r o n g l y b r a n c h e d (the C e n t r a l - E u r o p e a n used in this work), to h a v e a g r e a t n u m b e r of flowers m u s t i m p r o v e fitness. I t is m o r e difficult to discuss t h e o v e r d o m i n a n c e in t h e p o s i t i v e sense pres e n t e d b y seed l e n g t h a n d w e i g h t ; if we c o m p a r e these results w i t h t h e n e g a t i v e d o m i n a n c e of these c h a r a c t e r i s t i c s in t h e major s t u d i e d (Cubero, 197~b), p e r h a p s t h e m o s t p r o b a b l e m e a n is t h a t an o p t i m u m seed size m u s t exist, in such a w a y t h a t the a m o u n t of reserve s u b s t a n c e s in each seed a n d t h e n e c e s s i t y of p r o d u c i n g a g r e a t n u m b e r of seeds m u s t be in equilibrium. T h i r d l y , the i n c o m p a t i b i l i t y . T h e species has a p a r t i a l i n c o m p a t i b i l i t y s y s t e m (Cubero 1970b), v e r y s t r o n g in some p o p u l a t i o n s b u t v e r y w e a k in others. I t does n o t e x i s t in one line of paucijuga at least, which is f u n c t i o n a l l y a u t o g a m o u s . I n some S p a n i s h p o p u l a t i o n s it is n o t difficult to b r e e d to obtain cultivars with a very weak incompatibility s y s t e m , g e t t i n g a high degree of self c o m p a t i b i l i t y . This is n o t e a s y to do. in C e n t r a l - E u r o p e a n p o p u l a tions, a t least u n d e r our conditions. T a b l e 4 shows these r e s u l t s : t h e two pa.ucijuga lines (171 a n d t 72) c o n s i d e r e d as female p a r e n t s show a v e r y h i g h degree of i n t e r c o m p a t i b i l i t y , while t h e 168 a n d 169 lines show a v e r y low degree. As male p a r e n t s , all lines show s i m i l a r p e r c e n t a g e s . I t is curious to notice the different b e h a v i o u r of t h e paucijuga lines c o n s i d e r e d e i t h e r as female or as m a l e p a r e n t s . I t m i g h t be supposed that the generally weak incompatibility s y s t e m (strong in t h e C e n t r a l - E u r o p e a n lines) is v e r y r e d u c e d , even nil, in paucijuga, p e r h a p s b e c a u s e of t h e p a r t i a l lack of f u n c t i o n of t h e i n c o m p a t i b i l i t y genes of t h e style. Briefly, i n t r a s p e c i f i c d i f f e r e n t i a t i o n exists, b u t it is n o t s t r o n g e n o u g h to h a v e c u t t h e genetic flux

Table 3. Characteristics that present discrepancy in the genetical systems 4 X 4 Diallel cross (2) (centroeuropean lines)

7 x 7 Diallel cross (t) Characteristics All

Plant height Flowers/raceme Seed length Seed weight

lines

partial partial partial partial

(I) FromCubero 1973b

dominance dominance dominance dominance

Dominance sense

Centroeuropean lines

Dominance sense

system

l)ominancc sense

positive positive negative negative

overdominance overdolninance overdominance doubtful

positive positive positive doubtful

overdominance overdominance overdominance overdominance

positive positive positive positive

(2) From Cubero 1970a

Theorel. Appl. Genetics, Vol. 4.5, No. 2

jos6 i. Cubero: On the F.volution of l'icia fttba L. Table 4. Percentage oj hybridization success (fifty flowers

by cross as minimum) (1) 9 ]Line 164 165 166 168 169 171 172

~ 164 -6,3 28,6 8,3

7,7 81,3 7S,6

165

166

168

1 69

38,5 --

25,O 4~,7

35,7 33,3 28,6

33,3 23,1 42,8

53,3 83,3

14,3 84,6 73,7

21,4 o,2 16,6 85,6 69,2

-7,7 7,1

--

171 .......

7,7 -85,6 71,5

35,7 f4,3 23,1 15,4

30,7 -84,6

172 16, 7 16,7 21,4 7,7 7,7 5o,o -

(1) Accession nunlber 164 and 165: mafor; i66 and 168: mimer; 169: equina; 17~ and 172: paucij~G'a b e t w e e n p o p u l a t i o n s , even b e t w e e n classic s u b s p e cies. Paucijuga seems to evolve t o w a r d s a u t o g a m y (at l e a s t t o w a r d s f u n c t i o n a l a u t o g a m y , b e c a u s e t h e y can be v i s i t e d b y p o l l i n a t o r insects), w i t h s t r o n g b r a n c h i n g , s m a l l h e i g h t , s m a l l n u m b e r of leaflets per leaf a n d v e r y s m a l l seed size. A n d t h e r e is a v e r y curious d e t a i l in t h e t h r e e paucijuga p o p u l a t i o n s k n o w n to us - - i n d e h i s c e n t pods. I t is curious because a t t h e o t h e r e x t r e m e of the h a b i t a t of Vicia/aba this c h a r a c t e r a p p e a r s in t h e m a j o r group, w h i c h is also at t h e o p p o s i t e e x t r e m e of t h e v a r i a b i l i t y r a n g e of tile species; it is e v i d e n t t h a t t h e " i n d e h i s c e n t " c h a r a c t e r was in t h e nucleus t h a t o r i g i n a t e d major a n d pauci~uga. I t is p r e s e n t in m y " C e n t r a l N u c l e u s " , which is c o m p o s e d of d e h i s c e n t a n d i n d e h i s c e n t forms, b e i n g an i n d i c a t i o n of its g e n e t i c richness a n d p o t e n t i a l i t y , b e c a u s e in t h e a c t u a l minor g r o u p i n d e h i s c e n c e n e v e r occurs. T h e minor g r o u p h a s f i x e d t o o m a n y c h a r a c t e r s a n d s u r e l y r e p r e s e n t s an e n d of series. T h i s is also the case for some major p o p u l a t i o n s w h i c h have detached from the nucleus at different moments a n d regions in such a w a y t h a t t h e r e can be m o r e differences b e t w e e n t h e m t h a n t h e r e are when t h e y are c o m p a r e d w i t h paucijuga. I n m a r g i n a l regions, a t the f r o n t i e r s of t h e species, some p a r t i c u l a r differentiations occur: strong selband inter-incompatibil i t y a n d d i f f e r e n t genetic s y s t e m s for some c h a r a c t e r i s t i c s in c o n n e c t i o n w i t h t h e rest of the species. I t will be i n t e r e s t i n g to see if these p a r t i c u l a r i t i e s are also p r e s e n t in o t h e r b o r d e r - f o r m s ; I h a v e b e g u n to s t u d y tEis m a t t e r . H a n e l t (~972b) h a s p r o p o s e d a new T a x o n o m y for Vicia /aba. H e recognizes two s u b s p e c i e s : minor (the oldest one) a n d / a b a , t h e l a t t e r h a v i n g two v a r i e ties, [aba a n d eq.uina. I t h i n k t h a t it is m o r e realistic

Received October

1I,

1973

Communicated bv H. Stubbe

Theorel. Appl. Genetics, l'ol. 45, No. 2

51

t h a n M u r a t o v a ' s b u t in all cases I ant r e l u c t a n t to a d m i t two subspecies. I w o u l d p r e f e r to s p e a k o n l y of four g r o u p s or v a r i e t i e s (in the b o t a n i c a l c o n c e p t of this w o r d ) : paucijuga, minor, equina a n d ma~or. Most of t h e equina a n d some major p o p u l a t i o n s form t h e richest g r o u p s in g e n e t i c p o t e n t i a l i t y (the C e n t r a l Nucleus)" paucijuga a n d minor (this is t h e b o t a n i c a l p r i m i t i v e f o r m - - b o t a n i c a l , n o t genetical) are a c t u a l l y ends of series, relicts or b o r d e r - f o r m s . T h e major p o p u l a t i o n s n o t b e l o n g i n g to t h e N u c l e u s are d e r i v e d from this in a g e o g r a p h y i n d e p e n d e n t form. P r o b a b l y t h e e x t r e m e major (even t h e m e d i a n ones) m u s t be g r a t e f u l to Man for its existence. The p o s s i b i l i t y of i n t e r - a n d s e l f - f e r t i l i t y can e x p l a i n b o t h t h e d i f f e r e n t i a t i o n a n d c r e a t i o n of new forms a n d t h e u n i t y of t h e species f r o m t h e p o i n t of view of r e p r o d u c t i o n . I t seems t h a t t h e i n t r a s p e c i f i c d i f f e r e n t i a t i o n has been r e c e n t ; t h e f a c t t h a t wide crosses are easily o b t a i n e d w i t h m i n i m a l r e c i p r o c a l differences is a good i n d e x of t h e y o u t h of Vicia/aba. Literature

Cole, Sonia: The Neolithic Revolution, pg. 18. Trustees of the British Museum (Natural History), London (1970). Cubero, J. I. : Herencia de quince caracteres cuantitativos en Viciafaba. Anales I N I A 19 (1), 11--50 (1970a). Cubero, J. I.: Influencia de homocigosis y heterocigosis en la fertilidad de Vicia faba. Tesis Doctoral. Escuela T6cnica Superior de Ingenieros Agrdnomos, Madrid (1970b). Cubero, J. 1. : E v o l u t i o n a r y trends in Viciafaba L. Theor. Appl. Genetics 43 (2), 59--65 (1973a) Cubero, J . I . : Herencia de caracteres cuantitativos en Viciu .faba L. Tesis Doctoral. F a c u l t a d de Ciencias (Bioldgicas) Universidad Complutense de Madrid (1973b). Hanelt, P.: Zur Geschichte des Anbaues von Vicia faba und ihrer verschiedenen Formen. Die Kulturpflanze 20, 209--223 (i972a). Hanelt, P.: Die infraspezifische Variabilit~tt yon Vicia faba 1,. und ihrer Gliederung. Die Kulturpflanze 2o, 75--128 (1972b). Havman, B. i. : The theory and analysis of diallel crosses. (~enetics 39, 789--809 (1954). Muratova, V.: Common beans (Vicia faba L). Suppl. 50 Bull. Appl. Bot. Genet. Plant Breed. 285 pp. (t931). Pirenne, J.: Historia de la Civilizatidn del Antiguo Egipto. B a r c e l o n a : E d i t o r i a l Exito 1963. Rao, C. R.: Advanced statistical methods in biometric research. New York: John \Viley & Sons Inc. 1952.

l)r. J.-I. Cubero Instituto Nacional de Investigaciones Agrarias Centro Regional de Andahlcfa Apartado 240 COrdoba (Sp:tin)

On the evolution of Vicia faba L.

Diallel crosses between seven inbred lines obtained from different botanical groups including the two known subspecies of V. faba permitted study of t...
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