Generation mean analysis was used for study the natural of gene action for yield and its attributes in three hybrids of bread wheat. Six parameters model was used in three wheat hybrids under optimum sown (25^th Nov.) and late sown (25^th Des.). The results cleared that the (P₁, P₂, F₁, F₂, Bc₁ and Bc₂) mean values in late sown were less than the optimum sown for all the studied characters in all hybrids. Heterosis relative to mid-parent and better parent was found to be positive significant for most characters under optimum and late sowing dates. The relative consequence of additive and dominance effects differed for characters in all hybrids under two different sowing dates. Dominance effects were generally more important than additive for most the characters in all the studied hybrids under two different sowing dates. Indicating, dominant genes played a part in the inheritance of these characters. Dominance × dominance gene interaction was higher in extent than additive × additive and additive × dominance in most the studied traits under two different sowing dates. Indicating, these traits are greatly influenced by dominance and dominance x dominance interactions. Therefore, it is approved to lateness selection to late segregating generations to raise homozygosity. Heritability values in narrow sense were moderate to high for all the studied characters in all hybrids under two different sowing dates. Genetic advance was ranged from low to high for all characters in all hybrids under two different sowing dates.