Migration of a Grain Legume, Phaseolus vulgaris, in Europe

Abstract

All common bean lines grown in Europe, as in other continents, are the result of a process of domestication and evolution (mutation, selection, migration and genetic drift), from wild forms (Phaseolus vulgaris var. aborigineus and Phaseolus vulgaris var. mexicanus) found exclusively in the Americas. Observations on morphological (e.g., bract shape), agronomic (e.g., seed size), biochemical (e.g., isozyme) and molecular variability for wild and cultivated lines, made it possible to distinguish at least two major centers of common bean domestication, namely Andean and Mesoamerican. Subsequently, new cultivars may have evolved within and between the two gene pools in Spain and Portugal, making southern Europe a secondary center of diversity for the common bean. Indeed, the first documented appearance of common bean in Europe, after the discovery of America, was in 1508 as an ornamental plant in France. This happened before it was possible to introduce common bean lines from the Andes, i.e., before Peru was explored by Pizarro in 1528. Both Andean and Mesoamerican germplasm differ by the diversity of phaseolin, a seed protein. Thus, most of the European germplasm is from Andean locations since the type T phaseolin is found in their seeds. It is thought that Mesoamerican lines were less popular because of their lower adaptability to winter cold and to short-duration summers. However, the type C phaseolin, is most frequently found in the Iberian Peninsula, although recent studies show that the populations found in northwestern Spain and Portugal are predominantly of the T-type phaseolin. Concerning their interaction with the root-symbiont rhizobia, genotypic variation has been recently found among various landraces from this region, including Great Northern, Caparr{ô}n, White Kidney and Canellini commercial types, for nodulation and the N2-dependent plant growth after inoculation with Rhizobium tropici CIAT 899. It is concluded that knowledge of the origin, evolution and dissemination of common bean in Europe may be valuable information for the improvement of this legume species.