Early Generation Selection Parameters for Genetic Improvement using Morpho-physiological and Seed Yield Components in Brassica species

Aims: To determine the best selection indices for seed yield improvement in Brassica crops Place of Study: Experimental Farm of Department of Genetics & Plant Breeding, CSK HPKV, Palampur, during rabi 2018-19. Methodology: The experimental material for the investigation comprised of twenty five advanced breeding lines including released varieties of four different Brassica species laid out in randomized complete block design with three replications which were evaluated for correlation (genotypic and phenotypic) studies, direct and indirect effects using various growth parameters and yield contributing traits. Results: Analysis of variance revealed significant genotypic variances for all the growth parameters and seed yield components under study except for Leaf Area Index (LAI), number of primary branches per plant, number of secondary branches per plant, siliquae per plant and harvest index. Correlation coefficients at phenotypic level indicated that seed yield per plant had significant positive correlations with relative growth rate (RGR), leaf area ratio (LAR), number of secondary branches per plant, siliquae per plant, seeds per siliqua, 1000-seed weight, biological yield per plant and harvest index while it had significant negative association with specific leaf weight (SLW), days to 50% flowering, days to 75% maturity and number of primary branches per plant. Path coefficient analysis revealed that biological yield per plant followed by harvest index had high positive direct as well as indirect effects on seed yield. Conclusion: Biological yield per plant and harvest index could be considered most important characters for improvement of seed yield both directly and indirectly in different Brassica species. Therefore, these traits could be preferred as the best selection indices in future for genetic improvement of rapeseed-mustard.