Genetic Diversity Assessment and Phylogenetic Analysis of Peanut (Arachis hypogaea L.) in RDA Genebank Collection using SSRs

It is very crucial to evaluate the genetic diversity of peanut genetic resources for identification of peanut germplasm accessions and variety improvement. Cultivated peanut generally has two subspecies, hypogaea and fastigiata. In this study, we identified peanut into three plant types, virginia (var. hypogaea), spanish (var. vulgaris), and valencia (var. fastigiata). Former one belongs to ssp. hypogaea and latter two are involved in ssp. fastigiata. Twenty SSR markers were used to assess the genetic variation of three sets, hypogaea, vulgaris, and fastigiata, respectively. Out of variety-specific SSR primers tried in this study, ten pairs of SSR primers showed polymorphisms. Each accession could be identified by a specific set of polymorphic SSR primers, and allele number was evaluated among accessions, with an average of 6.7 in var. hypogaea and 5.4 in var. vulgaris and fastigiata. For evaluation of genetic diversity, gene diversity ranged from 0.336 to 0.844 and PIC (polymorphism information contents) ranged from 0.324 to 0.827 were investigated. Dendrograms based on genetic distances were constructed, which showed the existence of three different clusters. And these three different clusters might be associated with the genes involved in three plant types. The results also suggested that there were plentiful SSR polymorphisms among peanut germplasm accessions in RDA (Rural Development Administration, Korea) Genebank and SSRs might play an important role in evaluating peanut accessions and cultivar improvement.