Analysis of genetic diversity among indigenous landraces from sesame (Sesamum indicum L.) core collection in China as revealed by SRAP and SSR markers

Abstract

The molecular genetic diversity of 404 indigenous landraces from sesame core collection in China were evaluated by 11 SRAP and 3 SSR markers, 175 fragments were generated, of which 126 were polymorphic with an average polymorphism rate of 72%. Jaccard’s genetic similarity coefficients (GS=0.7130), Nei’s gene diversity (h=0.2418) and Shannon’s Information index (I=0.3847) were calculated, a dendrogram of the 404 landraces was made, landraces from various zones were distributed throughout the dendrogram, accessions from different agro-ecological zones were indistinguishable by cluster analysis, geographical separation did not generally result in greater genetic distance, a similar pattern was obtained using principal coordinates (PCO) analysis. As to seven agro-ecological zones, the maximum Nei’s gene diversity (h = 0.2613) and Shannon index (I = 0.3980) values in zone VII indicated that they were genetically more diverse than those in other zones, while the least genetically diverse region was zone III (h = 0.1772, I = 0.2858). Nei’s genetic identity and genetic distance among landraces from seven agro-ecological zones were also analyzed, the genetic relationship of seven zones was inferred using the UPGMA method. This study demonstrated that SRAP and SSR markers were appropriate for evaluation of sesame genetic diversities. There existed extensive genetic diverse among indigenous landraces and the abundance of genetic diversity of landraces in different agro-ecological zones was various. Understanding of these characteristics of indigenous landraces in China can provide theoretical foundation for further collection, effective protection and reasonable utilization of these sesame landraces in breeding.