Eight bread wheat genotypes were crossed in a8x8half diallelscheme in 2012/2013.Parents and their 28 F1 crosses were evaluated under normal and stress conditions during 2013/2014 in two field experiments. The results of analysis of variance were significant for all studied traits. The highest mean values were detected by parents P6, P5,P5,P3,P5 and p4 for plant height, spike length, no of spike/ plant, 1000-kernel weight, biological yield/ plant and grain yield/ plant in the combined analysis, respectively. While, the highest mean values were recorded under combined analysis with crosses P1×P4,P1×P3, P2×P6, P2×P3, P4×P5 and P2×P4grain yield/ plant. Mean squares for both general (GCA) and specific (SCA) combining ability estimates were highly significant for all studied traits. The ratios between GCA and SCA exceeded the unity for all studied traits except for plant height at normal irrigation and biological yield plant-1 in the combined analysis, revealing that additive and additive x additive types of gene action are more important than non-additive gene action in controlling these traits.The parental P2 exhibited significant and positive ĝi effects for plant height, no of spike/ plant, 1000-kernel weight, and grain yield.
The highest desirable SCA effects were obtained with P4 x P5 and P4xP6 for grain yield/ plant.P7 and the cross P2xP6exhibited the desirable susceptibility index (SI)for grain yield/ plant. |
