The study investigates the genetic basis of key traits in Indian mustard (Brassica juncea) using
the additive-dominance model, with a focus on genotype × environment interactions. Conducted
over two Rabi seasons (2021-22 and 2022-23) at Sri Karan Narendra College of Agriculture,
Rajasthan, the research involved ten genetically diverse mustard genotypes crossed in a 10 × 10
half-diallel mating design. The parents and F 1 hybrids were evaluated under three sowing
conditions to simulate different environmental scenarios. Significant genotypic, environmental,
and genotype × environment interactions were observed for various traits, including days to
flowering, plant height, siliquae per plant, and seed yield per plant. Diallel analysis revealed the
suitability of the additive-dominance model for several traits, with both additive and dominant
genetic effects playing substantial roles. Dominance gene action predominated for most traits,
with overdominance observed for plant height, seed yield, and siliqua length. Genetic diversity
among parents was evident, with specific genotypes showing dominance for traits like early
flowering, plant height, and seed yield. These findings provide valuable insights into the genetic
architecture of mustard traits and offer strategies for improving yield, stress tolerance, and
adaptability in mustard breeding programs, ensuring better productivity in varying
environmental conditions.