Abstract
Eight varieties of durum wheat were used in a complet diallel cross involving dialer cross involving, Leeds, Waha, Um-Rabie5, Azagar1, Um-Rabie 3,Brashua, Cyprus1 and Korfila to estimate the nature and magnitude of gene effect through variance components and graphical analysis for heading time, flag leaf area, maturity time, plant height, biological yield, number of tillers plant, number of spikes plant, grain yield, harvest index, 100 - grain weight, number of grains spike and grains protein contents. The additive variance was found to be significant for all characters, and dominance for the most characters, estimation of the additive variances were relatively higher than the additive one for heading time, flag leaf area, plant height and biological yield, while the reverse for others. Narrow sense heritability values ranged from 7.5% for harvest index to 86.2% for flag leaf area, and the ghraphic analysis revealed to the over dominance for plant height and biological yield whereas, partial dominance for the remnant. The genetic variability among varaieties for the most characters suggesting the recurrent selection for exploiting prevalent types of gene action in order to evolve a superior varieties of durum wheat
