Combining Ability Over Environments in Durum Wheat

The comibing ability studies made over environments (sowing dates) for eight characters in durum wheat using 15 × 4 line-tester set revealed that both general combining ability (gca) and specific combining ability (sca) components of variance were significant for all the evaluated characters, viz., grain yield/plant, spikes/plant, spikelets/spike, grains/spike, 100-grain weight, plant height and days to flowering. Both gca and sca were influenced by environments. The parents JU 85, HDM 22550-3, Bansi, Jori C 69 and MACS 1269, having been observed as good combiners for grain yield and certain component traits also, offer the best possibilities of exploitation for the development of improved lines. The cross combinations A206 × Jori C 69, HDM 22550-3 × JU 12, and JU 85 × MACS 9 involving good × average general combiners and exhibiting significant positive specific effects for grain yield are expected to throw transgressive segregants and need exploitation in breeding programmes. As both additive and nonadditive gene effects played role in the inheritance of different attributes, their simultaneous exploitation through adoption of biparental approach in early generation mating Is advocated.