Genetic Analysis for Yield Improvement in Brassica Species: Insights from Variability and Trait Relationships

Brassica spp. is a major oilseed group in India, valued for its adaptability to semi-arid environments and high economic returns. The present investigation was conducted during the Rabi, 2024-25 at ZARS, Morena, RVSKVV, Gwalior to assess the extent of genetic variability, heritability, genetic advance and the interrelationship among different agronomical traits among seventy-three Brassica genotypes. The experiment was conducted using a Randomized Block Design with two replications to evaluate 16 quantitative traits. The ANOVA revealed highly significant differences among genotypes for all traits, reflecting the existence of considerable genetic variability. High genotypic (GCV) and phenotypic (PCV) coefficients of variation were observed for seed yield per plant (GCV = 44.90%, PCV = 45.17%), biological yield per plant (GCV = 36.94%, PCV = 37.26%), and number of secondary branches per plant (GCV = 33.42%, PCV = 34.10%), indicating considerable scope for selection. Broad-sense heritability estimates ranged from 92.60% (number of primary branches) to 99.95% (number of siliquae per plant), with high genetic advance as a percentage of the mean recorded for seed yield per plant (79.94%) and biological yield per plant (63.44%), suggesting predominance of additive gene action. Seed yield per plant exhibited strong positive correlations with biological yield per plant (r = 0.7107), number of seeds per plant (r = 0.7775) and number of siliquae per plant (r = 0.7504), highlighting these as key selection indices. Path coefficient analysis further confirmed the direct and positive contributions of these traits toward seed yield at both genotypic and phenotypic levels, whereas traits like days to flowering initiation, days to 50% flowering and maturity exhibited strong negative direct effects. The results provide a valuable genetic framework for developing high-yielding, climate-resilient Brassica cultivars adapted to semi-arid ecologies. These findings highlight the potential of early-flowering, high biomass, and high seed-bearing genotype (s) as promising candidates for yield improvement in Brassica breeding programmes.