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Combining ability analysis was conducted in 9 × 9 parental diallel progenies for physiological traits (peduncle length, flag leaf area and grain filling period) in spring wheat. Peduncle length was observed to be controlled by mainly GGA variance (additive genetic variance) while, both GCA and SCA (non-additive component) variances were important for flag leaf area and grain filling period. However, flag leaf area had higher influence of additive gene effect as compared to the non-additive one, whereas for grain filling period both additive and non-additive genetic components of variation were equally important. The parents HUW 81 and K 68 were good general combiners for peduncle length and HUW 12, HUW 117 and HD 2160 for flag leaf area. HUW 37, WG 377, HD 2204 and HUW 117 were good general combiners for prolonged grain,filling period. Mean performance of the lines was, observed to be related with their GCA effects in most of the cases. The cross combinations which showed high SCA effects were involved in majority of the cases, both poor combiners and in some cases, one being good and the other being poor combiner.
