Response of three wheat cultivars to different moisture regimes during vegetative and reproductive stages under field conditions

Under condition of limited water supply, determination of minimum water requisite to keep potential yield should be considered as an important target. With this respect, a field experiment was conducted at research farm of university college of agriculture and natural resources, university of Tehran, in 2012-2013, Karaj, Iran. The experiment was conducted in a split plot, based on randomized complete design with three replications. Three wheat cultivars, recommended for conditions similar to the experimental site, (Parsi, Sivand and Pishtaz) and nine moisture regimes (a combination of 3 at vegetative an 3 at reproductive stages) were arranged in main and sub plots, respectively. Increase in irrigation intervals from 70 to 90 mm, based on class A evaporation pot, during vegetative stage did not affect grain yield. Irrigation after 110 mm pot evaporation at this growth stage, however, reduced yield by 14%. At any moisture regimes during vegetative stage, increase in irrigation intervals from 90 to even 110 mm pot evaporation during reproductive stage, did not affect grain yield. The highest WUE were obtained in T79 and T711 treatments. Decrease in moisture regimes, in a range applied in this experiment, increased harvest index. Reduced grain yield was accompanied with decrease in biomass and leaf area under low moisture regimes. Among the cultivars, Parsi showed the highest value of stem reserve accumulation, but lowest value of remobilization. Highest stem reserve remobilization was found in Pishtaz which showed highest grain yield under reduced moisture regimes. Decrease in moisture regimes was accompanied with decline in stem reserves but increase in reserve remobilization.