AFLP analysis of gene pools of a wild bean core collection

Studies of diversity permit conclusions about the genetic structure of species. Systematically developed core collections are a particularly good tool for such purposes. The objective of this study was to evaluate the genetic structure between and within gene pools of a core collection of wild Phaseolus vulgaris L. using the technique of amplified restriction polymorphism (AFLP) analysis. DNA fingerprint patterns of 114 genotypes were analyzed by the NTSYS program. Major groups or gene pools were recognized in Mesoamerica, Colombia, the northern Andes of Ecuador and northern Peru, and the southern Andes, although the separation among gene pools was not wide. A unique segment of germplasm from northern Peru showed greater genetic distance than the other gene pools. Although most Mexican wild beans formed a rather homogenous group, a small number of accessions clustered with the Andean gene pool, and accessions from Guatemala tended to cluster apart from Mexican accessions. In the southern Andean gene pool, more discrete groups were formed which were associated with certain regions such as Argentina, possibly reflecting greater geographic and genetic isolation. Colombian accessions appeared to be highly introgressed with germplasm from other areas. AFLP analysis produced a large amount of data in a short period, thus permitting greater insights into the genetic structure of wild beans than had been possible with other methods of analysis.