Analysis of Difference in Water Use Efficiency of Winter Wheat Cultivars Released in Different Eras

To understand the dynamic changes of water use efficiency(WUE) of winter wheat during the course of the varietal improvement,field experiments were carried out to investigate the characteristics of crop water requirement,grain yield and WUE of winter wheat cultivars released in different eras.Results shown that crop water consumption of winter wheat cultivars released in different eras was basically similar regardless of the differences in crop water consumption of winter wheat cultivars.The average water consumption of the low-water,mediate-water and high-water treatment was 289.40 mm,357.64 mm and 402.70 mm,respectively.Compared to the cultivars released in fifties-sixties of the last century,the grain yield and WUE of the modern winter wheat cultivars increased by 53%(low-water treatment),78%(mediate-water treatment),46.6%(high-water treatment) and 45.6%(low-water treatment),63.4%(mediate-water treatment),57.8%(high-water treatment),respectively.Under the condition of crop water consumption keep stable,the increase of grain yield of winter wheat is the dominant factor of WUE improvement.