Eight bread wheat cultivars were used to study some earliness and yield and its component traits. The parental cultivars were employed to produce 28 F₁ hybrids following 8 x 8 half Diallel crossing without reciprocals. The seeds of 28 F₁ hybrids and their parents were planted to estimate mean squares due to parents and their crosses which were significant for all studied traits. The parental variety P₃ was the best parent for earliness. However, P₈ was the best for remained traits. The crosses (P₁ x P₄) and (P₂ x P₄) were the best combinations for earliness traits, while the six crosses were the best for remained traits. Highly significant negative desirable heterotic effects were detected for earliness, on the contrary for remained traits relative to mid and better parent. The mean squares associated with general and specific combining abilities detected significant and highly significant estimates for all studied traits. Results indicated that P₄ (Sids12) was good combiner for earliness traits and most of yield and its component traits. The best cross combinations displayed fair amount of SCA effect were obtained from (P₂ x P₄) and (P₄ x P₅) for earliness traits, the six crosses for remained traits. The graphical analysis Wr/Vr indicated the importance of over dominance gene effects in controlling all traits. The results indicated the importance of additive and dominance genetic variances in controlling these traits. The "a" item was significant for most studied traits and more than "b" item. Narrow sense heritability was less than (0.50) for all traits except plant height trait (0.80). Positive alleles were not equally distributed among parents (H₂/4H₁ ≠ 0.25) for all studied traits. The magnitude of dominance (H₁/H₂) was significant or highly significant higher than additive components (D) for all traits, expect plant height trait. All estimates of environmental variance (E) were positive significant and highly significant for all studied traits indicating that all studied traits have greatly affected by environmental factors.