Genetic analysis of diallel crosses in wheat under drought and normal irrigation treatments

Abstract EN

Seven bread wheat genotypes were crossed in a7x7half diallel scheme in 2017/2018.

Parents and their 21 F1 crosses were evaluated under normal and stress conditions during 2018/2019 in two field experiments.

The results of analysis of variance were significant for all studied traits.

The highest mean values were detected by parents P1, P1, P2, P3, P2 and p2 for plant height, spike length, No of spikes/ plant, 1000-kernel weight, biological yield/ plant and grain yield/ plant, respectively.

While, the highest mean values were recorded with crosses P3xP5 for biological yield/ plant and grain yield / plant.

Mean squares for both general (GCA) and specific (SCA) combining ability estimates were highly significant for most studied traits.

The ratios between GCA and SCA exceeded the unity for all studied traits, except biological yield/ plant under drought, revealing that additive and additive x additive types of gene action are more important than non-additive gene action in controlling these traits.

P6 exhibited positive and significant ĝi effects for biological yield/ plant.

P7 gave positive and significant combiner for spike length, No of spikes/ plant and grain yield/ plant.

The highest desirable SCA effects were obtained with P₁ x P₆, P₁ x P₇, P₂ x P_7, P₃ x P₅ and P₄ x P₇for grain yield/ plant which exhibited significant and positive ŝij effects