Comparison of Population Genetic Structures between Asian and American Mungbean Accessions Using SSR Markers

The purpose of this study was to evaluate the genetic diversity and population structure of 65 mungbean accessions collected from East and Southeast Asia, the United States and Guatemala using 15 simple sequence repeat (SSR) markers. In total, 47 alleles were detected, the number of the alleles per locus range from two to six, with an average of 3.13. The mean major allele frequency (MAF), expected heterozygosity (HE), and polymorphic information content (PIC) of the 15 SSR loci were 0.76, 0.05, and 0.28, respectively. Of the 47 alleles, 17 (36.2%) were common, with a frequency of 0.05– 0.5; 16 (34.0%) were rare (frequency < 0.05) and 14 (29.8%) were abundant (frequency > 0.5). On the basis of the UPGMA dendrogram, most of the accessions were clustered into two main groups. The first group (Group I) included seven accessions and the second comprised 58 accessions, which were further divided into four subgroups. Four subpopulations were detected by model-based structure analysis. Fifty-five accessions (84.6%) showed a clear relation to each cluster based on their inferred ancestry value (>75%), while the remaining 10 accessions (15.4%) were categorized as admixtures. Mungbean accessions from US distributed to almost all clusters and 2 accessions shared genetic constituents showing it derived from mixed ancestry with Asean accessions. These results could be useful in identifying mungbean germplasms and facilitating their improvement programs.