Journal of Crop Breeding

In order to study the relationship between grain yield and some of agronomic traits under drought stress condition, an experiment with 305 bread wheat inbred lines derived from a cross between Roshan × Falat and 25 drought tolerant and susceptible varieties along with 4 check varieties (Roshan, Falat, Mahdavi and Shahpasand) was conducted in augmented complete block design, at Research Field of Shahid Bahonar university of Kerman during 2013-2014 growing season. Normal irrigation was applied until flowering stage. Irrigation-cut off was done at 50% of flowering stage. Different traits such as grain yield and some agronomic traits were measured. Grain yield showed significant correlation with all the yield components including number of spike per plant, number of grain per spike, number of grain per plant and 1000- seed weight. Based on stepwise multiple linear regression, four traits including number of grain per plant, plant weight, 1000- seed weight, and flag leaf pod length were entered to the model, and totally explained 80.52% of grain yield variation. Number of grain per plant was the first trait which entered to the model and explained 72% of grain yield variation. Based on path coefficient analysis number of grain per plant had the most direct effect on grain yield (0.75) while it showed the highest indirect effect through number of spike on grain yield (0.66). Based on the multiple linear regression and path analysis, it is concluded that number of grain per plant had the most important effect on grain yield variation. Therefore, it is effective trait for improving grain yield under drought stress conditions.