Estimation of Heterosis and Combining Ability in Some Bread Wheat Crosses

This study was carried out within the cooperation between Faculty of Agricultural at Al Ba`ath University, the General Commission of Agricultural Scientific Research in Jossiet Al-kharab research center and Karahta station of field crops research during 2007-2008 and 2008-2009 seasons. Ten highly diverse bread wheat (Triticum aestivum L.) genotypes were used in the crossing block; Gairwel7, Azaz1, Florance- Auror, Sham4, Bouhoos8, Douma4, Sham8, Douma2, Zemamara1, and Soued, and crossed using half diallel cross mating method. The derived crosses along with their parents were grown in the second year, using a randomized complete block design with three replications to estimate general combining ability, specific combining ability, and both mid and better parent heterosis for traits, number of days to heading, plant height, grain yield per plant, number of spikes per plant, number of grains per spike, and thousand kernel weight. The results indicated non-additive type of gene action was predominant in some trait inheritance, including number of days to heading, grain yield per plant, number of spikes per plant, number of grains per spike. Also, It was found that additive and non-additive gene effects were equally included in the control of some trait including thousand kernel weight, but the preponderance of the additive gene action was noted plant height inheritance. Three parents had the high general combiners for grain yield, yield components. These were Douma4, Bouhoos8 and Sham4. Thus, progenies derived from these parents in a bread wheat program would have highly inherit their characters. Many positive specific combiners having both mid-and high-parent heterosis were derived from positive general combiners including (Gairwel7 x Bouhoos8), (Gairwel7 x Douma4), (Azaz1 x Bouhoos8), (Azaz1 x Douma4) and (Azaz1 x Sham8).