Determining the effective traits on bread wheat genotypes grain yield under drought stress and non-stress conditions

To determine effective factors on grain yield under drought stress and non stress conditions at the end of the season، 15 bread wheat genotypes were examined as two separated experiments in Research Center of Faculty of Agriculture in Islamic Azad University، Tabriz Branch during 2012-2013. The cultivars were compared based on completely random block design with three replications. All studied traits were significant and there was frequent diversity among studied genotypes in the studied traits in both experimental conditions. The grain yield under non stress and stress conditions were 2. 8 and 2. 23 ha، respectively and drought stress had the most effect. The correlation coefficients among grain yield، biologic yield and harvest index were positive and significant in both experimental conditions and also grain yield under without stress showed a positive and significant correlation with number of spikelets per spike under stress conditions with spike length. According to stepwise regression under without stress conditions، number of spikelets per spike determined 40% of the grain yield changes. Also، in non stress conditions number of spikelets per spike and in stress condition spike length، plant height and pollination were most effective on grain yield and justified variation in grain yield and also genotype 14 showed higher yield relative to other genotypes in both experimental conditions.