Abstract
Two field experiments were carried out during the 2009-2010 growing season at the station of Directorate of Agricultural Researches/Erbil under dry farming conditions. The first experiment included 25 strains of durum wheat, and the second included 20 strains of bread wheat. Growth trait, yield and its components were studied, and then data are entered in the statistical genetic analysis, as well as the path coefficient analysis. The results showed high genetic variation, heritability and genetic advance for plant height, number of spikes, 1000 grain weight, biological yield and grain yield in durum wheat. While it was high in all traits in bread wheat. The grain yield was correlated genetically positive and significantly with 1000 grain weight, biological yield and harvest index in durum wheat, while showed genetically positive and significant correlation with all traits in bread wheat. The path coefficient analysis revealed that harvest index and biological yield had the maximum positive direct effects on grain yield in durum wheat reached 0.966 and 0.242, respectively. While the harvest index had the maximum positive direct effect (1.417) on grain yield in bread wheat, which was used as a criterion for the selection of superior genotypes in each group.
