Estimate of combining ability and correlation for yield and its components in bread wheat (Triticum aestivum L.)

The experiment was performed at the Experimental Farm of Agronomy Department, Faculty of Agricultural, Al-Azhar University (Assiut Branch), Assiut, Egypt during the three successive seasons of 2016/2017,2017/2018 and 2018/2019. Seven parents of bread wheat (Triticum aestivum, L.) of a wide diversity for some agronomic traits were selected for the study, namely Sids1 Sids12, Sids13, Shndaweel1, Giza 171, Gemmeiza 11 and Sakha 93. The parents were crossed in 2016/2017 and 2017/2018 growing seasons in a half diallel fashion. The parent and crosses were evaluated in 2018/2019. Results indicated that mean squares of genotypes, general and specific combining abilities were significant (p≤0.01) for all traits, except number of kernels /spike. The ratio of GCA/SCA genetic components were less than unity indicating the greater amount of non- additive gene action determining the performance of all traits. The crosses (Sids 12 × Sakha 93), (Giza 171 × Sakha 93), (Gemmeiza 11 × Sakha 93), (Shandaweel 1 × Sakha 93) and (Sids 12 × Giza 171) recorded greatest mean values for grain yield /plant. Sids1 and Giza171 were considered as the best general combiners for grain yield /plant. The best crosses showed significant (p≤0.01) SCA and heterotic effects for grain yield /plant were Sids 1 × Sids 13, Sids 12 × Shandaweel 1, Shandaweel 1 × Sakha 93, Giza 171 × Gemmeiza 11 and Giza 171 × Sakha 93 so, they could consider promising hybrids in breeding programs for crop improvement.