Background and Aims:

In the climbing beans (Phaseolus vulgaris) three main forms are distinguished: cultivated, semi-wild and wild. The concept of form is used as a hierarchical category within a species according to morphological and genetic divergence, ecogeographic distribution, possibilities of hybridization and fertility of hybrids and derivatives. The objective was to investigate the genetic relationships between wild, semi-wild and cultivated bean populations from a region in western Mexico.

Methods:

An analysis of 30 common bean accessions with the molecular marker ISTR (Inverse Sequence Tagged Repeat) was realized, based on sequences of retrotransposons copia-like. The similarity among individual plants was calculated with Jaccard’s coefficient. Genetic structure was determined using a probabilistic Bayesian model.

Key results:

A high level of genetic differentiation (FST) was determined between cultivated and wild beans. The number of groups associated with hybridization was inferred, based on the similarity coefficient method. Analysis of genetic structure detected nine groups within the material studied. The ISTR marker is presented as an effective marker to distinguish between cultivated and wild material and establish the degree of similarity between accessions.

Conclusions:

Cultivated beans were associated with semi-wild accessions and clearly separated from wild ones. This information generates valuable data for the characterization of the genetic variability of this resource, as well as for assessing germplasm conditions for conservation and breeding programs.