The present study was conducted to evaluate genetic and epistatic effects governing the inheritance of seed cotton yield and yield components using the four crosses viz., CPD 420 x LK 861, CPD 420 x 4084, NA 1325 x LK 861 and NA 1325 x 4084 and their F2, parents and back cross generations for seven characters. Estimates of gene effects through joint scaling test of three, six parameter and sequential fit model revealed that simple additive dominance model exhibited lack of good fit for all the traits indicating the role of non-allelic interactions. Differential model schemes for same trait in different crosses were noticed in the present investigation which was due to different parents involved with variable gene frequency with opposing and reinforcing gene effects. The magnitude of [d] was relatively small to that of other gene effects indicating its minor role in the inheritance of these traits. All the traits exhibited the three types of epistatic interactions viz., add x add (i), add x dom (j) and dom x dom and duplicate type of interaction in one or other cross and none of the traits showed complementary type of interaction. Linkage or higher order interactions were also observed in all the crosses which were evidenced by the significance of all the tested parameters and χ2 value.
Cotton, Gene action, Additive, Dominance, Epistasis, Generation mean
