Investigation of the genetic diversity of common bean (Phaseolus vulgaris.) cultivars using molecular markers
The common bean (Phaseolus vulgaris) is a widespread crop in Brazil of dietary and economic importance, and it is cultivated primarily through family farming. Knowledge of genetic variability in landraces and improved bean cultivars is essential to explore the existing diversity, identify superior genotypes adapted to the climatic conditions of specific regions, and support genetic improvement strategies. Estimates of genetic diversity can be obtained using DNA molecular markers, and ISSR markers are widely used. We evaluated the genetic diversity of 57 common bean genotypes, including accessions provided by the Brazilian Agricultural Research Corporation (EMBRAPA - Wheat), local genotypes of the Fortaleza community (Muqui-Espírito Santo) and commercial cultivars, using ISSR markers. A total of 11 primers were used, generating 51 fragments, of which 76%were polymorphic. The polymorphic information content ranged from 0.19 to 0.48, with a mean of 0.36. There was an unequal distribution between genetic distances, ranging from 0.00 to 1.0, and a mean of 0.44, evidencing wide genetic variability. The Pérola cultivar stood out as it showed the highest mean dissimilarity (0.76). Cluster analysis revealed the formation of 11 groups, with a tendency to cluster genotypes by the region of origin and growth habit. There was wide genetic diversity among the genotypes of the Fortaleza community and a narrower diversity for the EMBRAPA and commercial cultivars. ISSR markers were efficient in quantifying the genetic diversity of the genotypes; the most divergent markers will help select candidates for conservation in germplasm banks.