Comparing genetic diversity and population structure of common beans grown in Kyrgyzstan using microsatellites

Common bean (Phaseolus vulgaris L.) is an important export crop in Kyrgyzstan. The aim of this study was to assess the extent of genetic diversity, determine the population structure, and relate to the main gene pools grown in Kyrgyzstan. Twenty-eight common bean accessions (including five Kyrgyz cultivars, and main references from the Mesoamerica and South America) were evaluated with microsatellites. Nine polymorphic microsatellites were used to estimate genetic diversity and heterozygosity. The number of alleles per microsatellite locus ranged from 2 to 4 and there were a total of 24 alleles. The observed heterozygosity of each accession over all loci ranged from 0 to 0.11 (with an average of 0.01), while the expected average heterozygosity was 0.05, which could reflect the self-pollinating breeding behavior of common beans. The analysis of molecular variance further revealed that 94.71% of the total variation was accounted by differences among accessions (Fst =0.947; p<0.001). Cluster analysis grouped accessions in two gene pools: 16 belong to the Andean and 12 to the Mesoamerican gene pool. The microsatellites separated accessions in Mesoamerican gene pool from Durango and Jalisco races, which were grouped together. We also observed that the most divergent accessions were the Kyrgyz cultivars, which may be related to the Mesoamerican races. Andean accessions were less diverse than Mesoamerican accessions in this study. This research confirms the ability of microsatellites to differentiate common bean accessions, even using a small sample size, and to be able to assign modern cultivars to their gene pools or races.