Combining ability and gene action study for grain yield and its attributing traits in bread wheat.

Combining ability and nature of gene interactions that contribute to grain yield and its attributing traits of wheat were investigated using 28 bread wheat hybrids developed by crossing 8 commercial varieties in a diallel mating design. The results revealed that mean squares due to GCA and SCA were highly significant for all the characters studied and indicatethe occurrence of both additive and non-additive type of gene interactions. The GCA and SCA ratio (2GCA/2SCA) was less than unity for all the traits except for days to 50 % flowering, number of spikelets per main spike, days to maturity and biological yield per plant. This indicated that non-additive components played relatively greater role in the inheritance of these traits. The estimate of GCA effects indicated that the parents GW-366, GW-411, K-583, KRL-213 and LOK-1, were identified as good general combiners revealing their ability in transmitting additive genes in the desirable direction to their progenies. The hybrids viz., GW-366 x HD-2687, GW-366 x LOK-1 and LOK-1 x KRL-213 were found to be the best specific crosses for grain yield per plant in which GW-366 x HD-2687 was found to be the best specific combiner for number of effective tillers per plant, length of main spike, number of spikelets per main spike, number of grains per main spike, 100 grain weight, biological yield per plant and harvest index (%), therefore, can be further exploited for selection of transgressive segregants.