the combining ability and inheritance type of some morphological traits in bread wheat under drought stress using diallel analysis

breeding for drought stress is one the important purposes in wheat cultivars breeding programs. grain yield under drought stress is depended on phonological, morphological and physiological features. in order to investigate the general and specific combining ability and genes function under drought stress in three and two bread wheat lines and cultivars respectively, diallel one way cross was performed in agricultural and natural resource research station, tehran. parents and hybrids (f1) seeds in the fall 2013, were planted in a randomized completely block design with three replicates. number of grain in spike, number of infertile florets in spike, days to flowering, kernel weight and grain yield traits were evaluated. results from analysis of variance showed that there are significant differences between genotypes. results from diallel analysis based on griffing’s experimental method ii, model b showed that general combining ability (gca) effect in all traits and specific combining ability (sca) effect in all traits except number of infertile florets in spike were significant (p≤0.01). in addition, the ratio of gca to sca mean of squares was significant in all traits except days to flowering. higher portion of additive genetic variance in mentioned traits indicate the higher heritability of these traits and this prepares the selection possibility in early generation for these traits.