Abstract

A phenomic approach was undertaken to characterize seventy one accessions of sesame (Sesamum indicum L.) procured from India, Venezuela and USDA following the descriptor of NBPGR and IPGRI. The phenotypic traits varied extensively and the degree of polymorphism was highest in case of seed coat colour while few traits exhibited only binary type character state. Morphological observation revealedVenezuelan genotypes as the most derived ones while the Indian accessions, be it under NBPGR or USDA repository possess some of the wild character state of the traits. The hierarchical axial representation of phenogram indicated that one Indian accession under USDA repository (USIN06) was unique while the Venezuelan genotypes fell in a common cluster in neighbour-joining WPGMA tree. Principal coordinate analysis further resolved the relative distances between genotypes within each cluster/sub cluster. The traits related to trichomes of different plant parts showed highest correlation coefficients. A simple homology based algorithm; considering the character states as different colour codes and comparison of the codes of each genotype with that of a postulated ‘target sesame’ resulted in few Indian and exotic accessions of sesame on the basis of high ‘scores’, which will probably lead to a more precise means of selection of genotypes for future marker assisted breeding program.

Key words: Phenotypic traits, sesame accessions, phenogram, principal component analysis (PCA).