Genetic diversity and population structure of lima bean (Phaseolus lunatus L.) based on cpSSR markers

Lima bean (Phaseolus lunatus L.) is a legume of high socioeconomic value with great potential to contribute to food security. However, it is increasingly affected by genetic erosion. In this study, 43 lima bean accessions from the germplasm collection of the Federal University of Piauí (PGB-UFPI, Brazil) were analyzed, comprising 27 domesticated and 16 wild accessions. Genetic characterization was performed using five chloroplast microsatellite markers (cpSSRs). All analyzed loci were polymorphic, each presenting two alleles per locus, resulting in the identification of eight distinct haplotypes. Analysis of molecular variance (AMOVA) revealed that 94% of genetic variation occurred between groups. Principal Coordinate Analysis (PCoA) indicated the formation of two distinct clusters, supporting the hypothesis of multiple domestication events and highlighting genetic differentiation between wild and domesticated accessions. Haplotype diversity was higher among wild accessions than among domesticated ones. The use of cpSSR markers was effectiveness for assessing the genetic diversity of lima beans, underscoring the need to conserve both wild and domesticated accessions. These findings provide essential insights for guiding genetic conservation strategies and strategic use of germplasm in breeding programs.