Genetic diversity and population structure of pencil yam (Vigna lanceolata) (Phaseoleae, Fabaceae), a wild herbaceous legume endemic to Australia, revealed by microsatellite markers

Pencil yam (Vigna lanceolata Benth.) (Phaseoleae, Fabaceae) is a herbaceous legume endemic to Australia. A previous morphological study suggested that pencil yam is a complex species of two or more related taxa with seven distinct morphological types (morphotypes) and, thus, taxonomic revision is necessary. In this study, we assessed genetic diversity and determined the genetic structure of a pencil yam collection of 62 accessions from seven morphotypes using 18 microsatellite (simple sequence repeat) markers with the aim to provide information for taxonomic study. In total, 138 alleles were detected with a mean of 7.67 alleles per locus. Polymorphism information content per marker varied between 0.06 and 0.90 with a mean of 0.61, while the overall gene diversity was 0.62. Bayesian clustering, principal coordinate, and neighbor-joining analyses consistently revealed that these accessions are grouped into two subpopulations with difference in number of alleles, allelic richness, and gene diversity. The pop...