Box Plot Visualization and Genetic Analysis of Plant Height Traits in Brassica juncea: Differential Responses in Normal and Sodic Soils

This study investigates the genetic and environmental regulation of plant height traits in Brassica juncea under contrasting soil conditions, providing critical insights for breeding stress-resilient cultivars. Through ANOVA of multiple genotypes grown in normal (Kumarganj) and sodic (Masaudha) soil environments over two years (2023-24, 2024-25), we found highly significant (p < 0.01) location effects on all traits, with sodic soil conditions reducing plant height by 15-30% compared to normal soil. Genotype effects were significant for (Plant height at 1st primary branch) PHPB, (Plant height at flower initiation) PHFI, and (Main shoot length) MSL (F = 6.8-36.5), while notable genotype × location interactions revealed soil-specific adaptations. Boxplot analyses demonstrated Kumarganj’s superior phenotypic performance and stability (GCV d” 14%), while Masaudha showed constrained growth but identified stress-tolerant outliers. High heritability for PHPB (72.7%) and PHFI (87.3%) under normal soil conditions, coupled with strong genetic advance (up to 54.3%), highlights their breeding potential. In sodic soil, (Plant height at maturity) PHM showed low heritability (9.1%), indicating strong environmental suppression of genetic potential. Key findings include: (1) identification of genotypes with stable performance across soils, (2) quantification of sodic soil’s growth-limiting effects (25-40% reduction in trait means), and (3) demonstration of selectable genetic variation for sodic soil adaptation. These results provide a framework for developing Brassica juncea varieties tailored to specific soil conditions, with particular emphasis on exploiting high-heritability traits in normal soils and identifying stress-adapted genotypes for sodic environments. The 54.3% genetic advance for PHPB under normal soil conditions offers particularly valuable potential for rapid breeding progress.