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A Complete diallel cross, including reciprocals, was made between five bread wheat varieties. The cultivars were crossed in all possible combinations The characters studied were :plant height(cm) spike length (mm),kernel width(mm), kernel length (mm), grian yield per plant (gr),day to heading harvest index (%), 1000 kernel weight (gr), grain protein content (%) and grain ashes content(%)
Variance components attributed to both general combining ability (UCA) and specific combining ability (SCA) br plant height and grain yield per plant were highly significant , but GCA mean squares were larger than SCA for plant height. The GCA mean squares were siginificant for harvest index ,days to heading ,1000 kernel weight and grain protein content.
Additive genetic variance was found as the main source of variation for days to heading
harvest index, 1000-kernel weight and grain protein content. For plant height and grain yield per plant, additive and non-additive genetic variation were pronounced , while non-additive gene
effects appeared to he equal to additive gene effects in expression of grain yield per plant.
The parent No:2 is good general combiner for plant height and 1000-kernel weight ,as is parent No: 1 for grain yeild per plant . day to heading and , harvest index and parent No: 5 for grain protetn content.
In this study heterosis and cytoplamic effects were not bound for any traits.