Abstract: The effect of first irrigation delay in spring for winter wheat on yield and water use efficiency was analysed during 1991 - 1993.The rat fall in both years was less than normal during wheat growing season,in particular in winter and spring.The results showed that, when the first irrigation was delayed to stem elongation or about 10 days later, the high water use efficiency and high yield of wheat could be reached, if the same amount of water was given for the whole growing season.The water use efficiency could be improved further and high yield could be maintained, when water input reduced by about 75mm.In general, total water consumption reduced with the postponement of first irrigation; however, the response of different varieties differed.Varieties with high yield,early-middle maturity and adaptation to early water stress are more suitable for cultivation for high yield and water saving by delaying the first irrigation to the period of post-stem-elongation and pre-booting.In order to avoid yield reduction, varieties with late maturity,large spike,and large grain size are not suitable for delaying the first irrigation in spring.

Key words: Winter wheat, Irrigation timing, Variety, Yield, Water use efficiency

CLC Number: 

• S512.102