Agronomical responses of wheat cultivars to deficient water stress

Two similar and concurrent experiments were carried out in the Agricultural Research Center of Islamic Azad University, Kermanshah Branch and Agricultural Research Center of Islamabad during 2016-2017. The experiments were performed in a split-plot format in a randomized complete-block design based on 3 replications. The main plots were assigned to 4 different regimes of irrigation: (11) full irrigation during the growth period followed by 50% of the soil moisture depletion; (12) water deficit stress from the start of the flowering stage (Z61) to the milking stage (Z77) associated with irrigation after 80% of the soil moisture depletion; (13) water deficit stress from the beginning of the flowering stage (Z61) to the ripening stage (Z93) followed by irrigation after 80% of the soil moisture depletion; and (14) water deficit stress from the start of the milking stage (Z77) to the ripening stage (Z93) followed by irrigation after 80% of the soil moisture depletion. The 3 cultivars of Cl (Sirvan), C2 (Pishtaz), and C3 (Marvdasht) were treated using the allocated sub-plots. The results revealed that by increasing the drought stress intensities on the wheat cultivars, the numbers of grains per spike and spikes per unit area, Thousand-Grain Weight (TGW), Grain Yield (GY), Biological Yield (BY), Harvest Index (HI) were decreased. The results of this study indicated that the wheat cultivars of Islamabad Agricultural Research Center had higher GY (5129 kg.h(-1)) and HI (42.05%), values than those of the Agricultural Research Center of Islamic Azad University, Kermanshah branch.