Studies on Genetic Variability and Divergence in Relation to Heterosis for Some Metric Traits in Indian Mustard

Genetic variability and divergence were studied for some metric traits in 23 Indian mustard genotypes under timely and late sown conditions to assess the impact of environments. The results revealed presence of wide exploitable variability in the material. The high values of phenotypic coefficient of variation closely followed by genotypic coefficient of variation for seed yield per plant in both the conditions while, all the characters except oil content, days to flowering and days to maturity showed moderate to high estimates of genetic advance in (%) of mean coupled with high heritability. The genotypes were grouped into 9 clusters under timely sown (E₁) and 6 clusters under late sown conditions (E₂), where cluster I was the largest and contained 5 genotypes in E₁, 13 genotypes in E₂. Maximum inter cluster distance was noticed between the clusters IV and IX in E₁ and cluster II and VI in E₂, which could be made use of in heterosis and recombination breeding. Plant height and days to maturity contributed maximum to genetic diversity in both the conditions. The genotypes NDYR-32 and NDRE-4 genotypes do not cluster in a single cluster in both the environments, therefore could be used in breeding programme for obtaining the desirable recombinants.