Study on gene action, combining ability and heterosis for different traits in Indian mustard (Brassica juncea L. cxern & coss)

Combining ability and heterosis was investigated in mustard hybrids obtained from 7 × 7 half diallel cross. Twenty one F₁₈ along with seven parents were evaluated in Randomized Complete Block Design. The combined analysis of variance revealed very significant differences among the parents for all morphological variables with the exception of secondary branches and siliqua length, indicating wide diversity among the parental material used in the present study. Significant GCA and SCA variance indicated additive and non-additive gene action across all the characters. The SCA variance components were larger than the GCA variance components for most traits indicating the prevalence of non-additive gene effects. Jawahar mustard × PM-30, showed a significantly positive SCA and better parent heterosis for seed yield per plant whereas five hybrids (Kranti × PM-30, Gujarat Mustard-3 × Pusa Mahak, Jawahar Mustard × PM-30, Jawahar Mustard × Pusa Mahak and PM-30 × Pusa Mahak) exhibited significant positive SCA effect for number of siliqua/ plant. Jawahar Mustard × PM-30, Varuna×Jawahar Mustard, Gujarat Mustard-3 × PM-30, exhibited highly significant heterosis over the mid-parent.-