Evaluation of genetic diversity of the USDA<i>Lablab purpureus</i>germplasm collection using simple sequence repeat markers

Abstract

SummaryThe genetic diversity of the USDA Lablab purpureus germplasm collection was assessed with polymorphic simple sequence repeat (SSR) markers derived from Medicago, soybean and cowpea. This assessment indicated that the USDA cultivated L. purpureus (L.) spp. purpureus collection was genetically limited and should be expanded. Phylogenetic analysis partitioned 47 representative accessions into two main clades, which had clearly diverged: a wild clade producing small seeds, and a cultivated clade producing large seeds. Wild clade accessions were easily resolved, whereas it was more difficult to distinguish among accessions in the cultivated clade. The sequence similarity to M. truncatula was variable from amplicon to amplicon. Sequence analysis of Lablab amplicons with the same SSR marker showed that the sequence content of these amplicons was almost identical, except for some single nucleotide polymorphisms (SNPs). This indicates that amplicons generated with SSR primers derived from Medicago, soybean and cowpea can be used as DNA markers to distinguish L. purpureus germplasm accessions at the DNA fragment level. Sequence analysis, as well as morphological characterisation, confirmed the SSR taxonomic classification.