Molecular characterization of common bean accessions using microsatellite markers

ABSTRACT The common bean, a legume of significant economic importance, is renowned for its extensive genetic variability. It is crucial to comprehend genetic diversity, analyze population structure, and understand relationships among commercial classes of accessions to facilitate genetic improvement. This study aimed to molecularly characterize 143 common bean accessions by employing 25 SSR molecular markers. The objectives were to estimate genetic diversity, analyze genetic structure, and cluster populations using the UPGMA and PCoA methods. A total of 105 alleles were amplified using microsatellite loci, and the observed heterozygosity was lower than expected across all loci, indicating inbreeding within the populations. Among the loci, 22 were highly informative, demonstrating their effectiveness and polymorphism in detecting genetic diversity. The genetic variability within the population was found to be the highest, while variation between populations was the lowest. The analysis of population structure revealed the presence of three populations with a notable rate of gene introgression. The UPGMA analysis categorized the accessions into 15 groups, but they did not form distinct clusters based on their geographic regions or gene pool. The first two principal coordinates accounted for 13.95% of the total variation among the accessions. The SSR markers employed effectively detected genetic variability among the common bean accessions, revealing that their genetic diversity was not correlated with their geographic distribution in this study.