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 the genetics of seventeen quantitative characteristics; there were very few significant reciprocal differences, and in 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.