Diallel Analysis of Grain Yield and its Components in Bread Wheat Genotypes under Drought Stress Conditions

In order to compare of inheritance, combining ability, heterosis and genes action in the genetic control of 1000-kernel weight, grain per spike, grain yield per spike and grain yield per plant in bread wheat genotypes under drought stress conditions, an experiment was conducted on eight genotypes using fixed method 2 of Griffing. Exception mean squares of grain per spike at specific combining ability (SCA), other traits were significant differences for general and specific combining abilities. It states important of inheritance additive and dominance gene effects under drought stress conditions. The GCA/SCA ratio was significant for grain per spike. For exception of grain per spike, non-additive gene effects were more important than additive. It is concluded that genetic improvement of grain per spike under drought stress conditions is possible at early generations by selecting from the best crosses, while selection for another traits is better that delayed until advanced generations and increase of its heritability.