A diailel cross among seven bread wheat (Triticum aestivum L) genotypes (parents) namely, Giza 164, Line 1, IRENA, Line 2, Sids 1, Sakha 8 and Gemmiza 7 were evaluated for yield and its components as well as some other agronomic characters in the F1 and F2 generations. Genotypes mean squares were significant for all studied characters. Mean squares for parents vs crosses as, an indication for heterosis, were significant for all characters in F2, and for heading date, number of kemels/spike, 100 kernel weight and grain yield/plant in F, Both general and specific combining ability (GCA and SCA, respectively), were significant for all studied , characters in the Fj and F2 except for grain yield/plant In the rz which was significant for SCA only. These results reflect the importance of both additive and dominance genetic variances in the inheritance of these characters. However, the additive gene action (GCA) was of great importance in the performance -for all studied characters except for number of kernels/spike in The F1 and gram yield/plant in the F2 were dominance was more pronounced. Moreover, the parents P2 (Line ¹), P3 (IRENA), P6 (Sakha 8) and P, (Gemmeiza 7) were the best combiners for grain yield/plant Meanwhile, significant SCA effects for grain yield were found in the crosses between P₁xP3, P2xP₅, P₂xP6, P₃xP₆, P₅xP_{6 and} P₅xP, in the Fl and P3xP₅ and RocP5 in the F2. The additive variance effects were significant for all characters except for number of kernels/spike in the F₁ and grain yield/plant in F, and F2. Over dominance effects of heterozygous loci (h2) were significant for number of kernels /spike, kernel weight and grain yield/plant in the F2 and heading date and number of spikes/plant, in the F2. Value of F12/4H₁ analysis being less 0.25 indicated asymmetric distribution of positive and negative allels among parents for 5 and 3 characters in the F, and F2, respectively. On the other hand, narrow sense hertiability was low for some characters, indicating the importance non-additive genetic effect.