A study was conducted at Karaj Experiment Station, University of Tehran,to evaluate the effects of application of limited amounts of water at various growth stages on yield of winter wheat. The five irrigation treatments were: I1=preplant (pp), 12=PP+Jointing (JT), 13PP+JT+Flowering (FL), 14PP+JT+FL+Soft dough (SD) 15=PP+JT+FL+SD+Hard dough (HD). The Karaj-1 cultivar was planted at five seeding rates (dl=80,d2=110,d3=140,d4=170 and d5=200 Kg/ha ). The experimental design was asplit-plot with the main factor arranged in randomized-block. The analysis of variance for grain yield indicated highly significant differences among the five irrigation timing and seeding rates. The interaction between irrigation timing and seeding rates was also significant. the treatment 14 had the highest yield followed by 15, 13, 12, and Ii. The seeding rate treatment d3 had the highest yield followed by d5, d4, dl, and d2. The drought sensivity coefficients were estimated for the growth stages and the jointing stage had the greatest value.
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