Response of Different Growth Stages of Wheat to Moisture Tension in a Semiarid Land

This investigation was done in order to study the response of grain yield and yield components of bread wheat cultivars to drought stress in western Iran in 2008-2009. The main plots were levels of drought stress (full irrigation, stress at early stem elongation, flowering and grain filling stages) and subplots were five cultivars (Chamran, Dez and Verinak). The results indicated that the effect of drought on grain yield and yield components was significant. Drought stress at all growth stages induced reducing grain yield and yield components. Drought stress at stages of stem elongation, flowering and grain filling stages induced 32%, 32% and 35% reduce in grain yield, respectively. Stress at stem elongation stage had the highest sensitivity than other growth stages. Also, The most and least number of spikes/m were observed in full irrigation and Chamran 2 cultivar and in stress at stem elongation stage and Dez cultivar, respectively. As a result, we can use Verinak cultivar for conditions which irrigation is not possible or water deficit occurs in same regions of western iran.