Effect of Drought Stress and Planting Date on Grain Yield and Water Use Efficiency of Autumn Wheat in Kashmar Region

Presently, the main challenge of agricultural sector is improvement of crop water productivity (CWP). To evaluate the effect of water stress and planting date on grain yield, water productivity and yield components of wheat (Pishgam var.), an experiment was conducted as split plot based on complete randomized design with three replications, at Kashmar Agricultural Research Station, in 2018-2019. Irrigation treatments included 100% of irrigation water requirement (IWR), 80% IWR, 60% IWR, and 40% IWR as the main treatments, and three planting dates including 23rd September, 23rd October and 23rd November as sub treatments. The results showed that water stress had significant effect on grain yield, water use efficiency (WUE), and harvest index (HI) at 1% probability level, such that with increasing water stress, the grain yield, HI and WUE was decreased. Also, the results showed that the effect of sowing date on grain yield, thousand kernel weight, and number of kernels per panicle, HI, and WUE was significant. The highest values of grain yield, HI, and WUE were 7227.33 kg/ha, 32.77 %, and 2.51 kg/m3, respectively, and belonged to 23rd October and 100% IWR treatment. The lowest of these values were 2000 kg/ha, 15.3%, and 1.14 kg/m3, respectively, related to 23rd November and 40% IWR treatment. The interaction between water stress and planting date had significant effect on all agronomic traits, except the number of kernels per panicle and WUE. According to the results of this study, irrigation treatment of 100% IWR and planting date of 23rd October can be considered for autumn wheat cultivar (Pishgam var.) in arid and semi-arid region of Kashmar.