Gene Effects for Seed Yield, its Related Characters and Oil Content in Indian Mustard [Brassica Juncea (L.) Czern & Coss]

The three varietal crosses, viz. T-59 x RH-30, T-59 x Pusa Bold and T-59 x RL-1359 were chosen to find out the relative importance and contribution of the components of genetic variance, additive (d), dominance (h) and epistatic (i, j and I) towards the mean for yield and yield contributing traits through generation mean analysis on six generations (P₁, P₂, F₁, F₂, BC₁ and BC₂). The scaling test showed that all the crosses had significant epistatic gene effects for all the characters except one cross, T-59 x Pusa Bold for days to flower. Six parameter model revealed that among the main effects, dominant gene effect (h) were more important than the additive (d) effect due to higher magnitude for all the ten characters studied except for plant height in one cross. Among the epistatic effects, dominant x dominant (I) and additive x additive (I) components were more important as compared to additive x dominant (j) for most of the traits. Complementary epistasis was observed for main raceme length, number of primary branches, number of secondary branches and seed yield/plant and oil content/plant which appeared desirable in two crosses out of three and would be helpful in further improvement of these traits. Duplicate gene action was recorded for plant height, siliquae number on main raceme, siliquae length and 1000- seed weight characters as h and l estimates were found with opposite signs.