effective traits on grain yield of wheat genotypes under optimal irrigation and drought stress during reproductive phase

in order to determine traits which affected grain yield in optimal irrigation and terminal drought deficit conditions, a field experiments with 16 spring bread wheat genotypes as randomized complete block design with three replications conducted in neishabour during 2009-10 cropping seasons. results of combined analysis of variance showed, significant differences between many of traits vegetative stage included: specific weight and flag leaf area, rate and grain filling period and also yield components such, no. spike/m2, grain/spike and 1000 grain weight. grain yield in optimal and water stress were 7335 and 5493 kg/ha, respectively. mean of decreased grain yield of genotypes in water stress conditions was 25 percent, with range between 10-51 percent. hence some of genotypes have desirable and stable yield in two conditions. superior genotypes in drought condition have heavier grain and faster grain filling rate, and in optimal condition, they have more grain/spike, longer grain filling period, spike/m2 and larger flag leaf area. so traits that affected yield in two conditions were different. in general genotypes dn-11 and kauz/pastor in two conditions have acceptable grain yield.