Hybridization between wild and domesticated types of Phaseolus vulgaris L. (Fabaceae) in Argentina

A polymorphic population of Phaseolus vulgaris L. var. aborigineus (Burkart) Baudet growing in north- western Argentina was studied. In order to know the origin of this polymorphism, plants belonging to the var. aborigineus, others showing floral dimorphism and individuals with weedy type characters were collected. Their seeds, obtained after fieldwork treatments of autogamy and free pollination in order to know their reproductive system, were sown in a greenhouse. Information of their growth was recorded and several numerical analyses were performed. With the results obtained, we concluded that those individuals that showed floral dimorphism are probably a result of hybridization and/or introgression between the var. aborigineus and cultivated forms that grow in the area. This hypothesis is supported by the presence of divergent segregation in the offspring. Also, the offspring of the F1 was followed and allowed us to conclude the possible existence of degeneration of the hybrid progeny. This degeneration indicates that an unwanted gene flow in the area could lead to a decline in the wild bean population. The vigour and high reproductive success of the offspring belonging to the individuals corresponding to the var. aborigineus, whose progenitor was treated for outcrossing, and the existence of plants with weedy type characteristics, are indicative of the necessity to preserve this germplasm in order to evaluate its agronomic potential as brief as possible. The population here studied constitutes a wild-weed–crop complex growing in Argentina.