A diallel crass among seven bread wheat genotypes (parents) namely; Shakha 8, Sakha 69, Sids 1, Attila, Opata, Line 88 and Giza 168 were evaluated for yield and its components as well as some other agronomic characters in the Fl and F2 generations. Genotypes mean squares were significant for ail studied characters. Mean squares for parents vs crosses as an indication for heteroasis were significant for all studied characters in the F_l and F2 except for number of spikelets/spike in the F₁ and F3 and for maturiety date in the F2 only. Both general and specific combining ability (GCA and SCA, respectively), were significant for all studied characters in the F₁ and F₂, except for number of spikelets/spike, number of kemels/spike in the F1 and for maturity date in the F2. These results indicate the importance of both additive and dominance genetic variance in the inheritance of most characters. However, the additive gene action (GCA) was of great importance in the performance of most studied characters. Moreover, the parents P6 (Line 88) and P3 (sids 1) were the best combiners for grain yield. Meanwhile, significant SCA effects for grain yield were found in the crosses between P_i x P3, P2 XP5 and P4 x P5 in the F_l and P₁ x P3, P_i x1³₄ and P₄ x P₆ in the F2. The additive variance effects were significant for all studied characters except for 100 kernel weight in the F₁ and was significant for most characters in the F2. Over dominance effects of heterozygous loci were significant for most studied characters in the F, and F2 Values of H₂/41^-1₁ analysis being less than 0.25 indicated asymmetric distribution of positive and negative alleles among parents for all characters in the F₁ and F3 ; except for maturity date in the F2. On the other hand, narrow sense heritability was low for some characters , indicating the importance non-additive genetic effects.