Genetic Diversity in Indian Mustard [Brassica juncea (L.) Czernj & Cosson] as Revealed by Agronomic Traits and RAPD Markers

Abstract

In present study, an attempt has been made to assess the genetic diversity among 50 genotypes of Indian mustard using agronomic traits and random amplified polymorphic DNA (RAPD) markers. Variability was observed for agronomic traits viz plant height (cm), main shoot length (cm), days to flower initiation, number of siliquae on main raceme, number of seeds per siliqua, seed yield per plot (g), biological yield per plot (g), harvest index (%), days to maturity and 1,000-seed weight (g). Cluster analysis based on agronomic traits revealed a high degree of diversity among the accessions. Maximum variability was recorded for biological yield followed by seed yield, while minimum variability was observed for days to maturity followed by days to flower initiation. RAPD marker OPB8 was found to be the most informative primer followed by OPB14, OPB11 and OPB2. Both agronomic traits and molecular markers were effective in discriminating genotypes into different clusters, however, clustering pattern varied for both agronomic traits and molecular markers. Different clustering pattern based on agronomic data and RAPD markers indicated lack of association between genetic and phenotypic diversity implying that polymorphism due to RAPD is not linked to phenotypic variation. There was no relationship between place of origin and clustering of genotypes, however, diverse genotypes could be identified on the basis of both and are likely to produce more variability in segregating generations as well as to serve as parents for high heterosis.