Assessment of genetic diversity of sesame (Sesamum indicum L.) genotypes using morphological and RAPD markers

Abstract

A comparison was made between phenotypic and molecular markers (RAPD) to assess the genetic diversity of twenty sesame genotypes representing, different agroecological zones of India. A higher range of genetic similarity (0.88-0.99) was observed on the basis of 20 phenotypic markers whereas, it was less (0.78-0.95) on the basis of RAPD markers, indicating better distinction between and within population of sesame when RAPD markers were used. Genotypes in RAPD based dendrogram were clustered into their respective geographical group while, a random grouping was observed in dendrogram based on the morphological markers. The genotypic classification agreed closely with the grouping observed in RAPD based principal coordinate analysis (PCA). The mean coefficient of genetic differentiation (Gst 0.619) indicated a high level of genetic diversity among population (Ht 0.169) and low level of genetic diversity within population (Hs 0.048). A negative correlation was found among discrimination power (Dj) and polymorphism information content (PIC) but the former was found effective in distinguishing all the populations as well as genotypes individually using specific band positions for them.