Genetic variability and trait association studies in Indian mustard (Brassica juncea L. Czern & Coss)

Indian mustard (Brassica juncea L. Czern & Coss) is a crucial oilseed crop in India, contributing 13-15% of total edible oil production. Despite its importance, productivity remains below global averages, necessitating genetic improvement through breeding programs. To assess genetic variability, heritability, genetic advance, and trait associations among 24 Indian mustard genotypes to identify superior genotypes and key selection criteria for yield improvement. Twenty four mustard genotypes were evaluated in a Randomized Block Design with three replications during Rabi 2024-2025 at Sam Higginbottom University, Prayagraj. Eleven quantitative traits were recorded including days to 50% flowering, plant height, number of primary branches per plant, number of siliquae per plant, days to maturity, siliqua length, number of seeds per siliqua, seed index, biological yield per plant, harvest index, and seed yield per plant. Genetic parameters, correlation coefficients, and path analysis were computed. Analysis of variance revealed significant genotypic differences for most traits. High heritability was observed for number of siliquae per plant (80.01%), biological yield per plant (58.23%), and seed yield per plant (58.08%). Genetic advance as percentage of mean was highest for number of siliquae per plant (26.28%), followed by seed yield per plant (15.16%). Strong positive correlations were found between seed yield and biological yield (r = 0.94), and harvest index (r = 0.75). Path analysis identified biological yield per plant (0.745) and harvest index (0.371) as having the highest direct effects on seed yield. CS-60 recorded the highest seed yield (10.09 g) and biological yield (27.44 g), while Brijraj showed the highest harvest index (39.93%). Biological yield per plant and harvest index are the primary determinants of seed yield in mustard. Genotypes CS-60 and Brijraj are promising for breeding programs. High heritability estimates for key traits indicate good scope for genetic improvement through selection.