Genetic variation in grain yield and its components in three bread wheat crosses [electronic resource].

Includes references.

Three experiments were carried out using the seven populations (P₁, P₂, F₁, BC₁, BC₁, F₂ and F₃) method to study the genetic make up of three crosess namely Gemmiza 9 x Dovin-2, Sids 1 x Sakha 93 and Sakha93 x Dovin-2. Results indicated significant positive heterosis effects for grain and biological yields/plant in all cross. Significant positive heterosis were also evident for plant height, no. of spikes/plant and kernel weight in the last two crosses. Heterosis was negative and insignificant for no. of spikes/plant, no. of kernels/spike and kernel weight. On the other hand, significant negative heterotic effect was found for plant height in the first cross. Heterotic increase were also evident for plant height, no. of spikes/plant and 100-kernels weight; no. of kernels/spikes and 100kernels weight seemed to account for the heterotic yield response observed in the second and third crosses, respectively. Inbreeding depression was significant for all studied characters except 100-kernels weight in the first cross; and for plant height and biological yield/plant in the second cross and 100-kernel weight In the third one. Over dominance towards the higher parent for grain and biological Yield/plant was observed in the first cross; for all characters except no. of kernels/spike in the second cross and for no. of spikes/plant in the third one. However, partial dominance towards the lower parent was estimated for plant height in the first cross, while, partial dominance was found for no. Of kernels/spike in the first and secand crosses; and no. of spikes/plant in the third one. Meanwhile, complete dominance was found for no. of spikes/plant and 100-kernel weight in the first cross. F₂ deviation (E₁) and backcross deviation (E2 were found to be significant for most of the characters under investigation. Moreover high to moderate values of heritability estimates were found to be associated with moderate and low genetic advance as percentage of F₂ and F₃ means in most characters.

Summary in Arabic.

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