Effects of Drought Stress on Water Use Efficiency of Different Winter Wheat Varieties at Grain Filling Stage

Taking Hengguan 35，Kaimai 21 and Zhengmai 366 as experimental materials，differences of water use efficiency of three different winter wheat varieties were studied through indoor incubator and field experiments.Results showed that drought resistance of Hengguan 35 and Kaimai 21 was higher than that of Zhengmai 366 under same drought stress at grain filling stage.Only under severe drought stress，yield decreased significantly.Water use efficiency of different winter wheat varieties increased under moderate drought stress and decreased under severe drought stress，while decrease range of water use efficiency of Hengguan 35 and Kaimai 21 under severe drought stress was smaller than that of Zhengmai 366.Effects of different water treatments on flag leaf water use efficiency of different wheat varieties were different，and influence time from long to short was Zhengmai 366，Hengguan 35 and Kaimai 21.On the whole，Hengguan 35 and Kaimai 21 belonged to wheat varieties with strong drought resistance，although Zhengmai 366 was a weak drought resistant variety，its yield was the highest under normal irrigation conditions.