Abstract: In order to provide basis for adjusting the sowing time and norm,the experiment with twelve sowing times spaned 67 days for winter wheat variety Jimai 20 was conducted to study the growth and required accumulated temperature.The results showed that the later the winter wheat was sowed,the more accumulated temperature(>0℃) was required from sowing stage to emergence of seedling stage.When winter wheat growed every leaf before over-wintering,the required accumulated temperature(>0℃) in the growing period after over-wintering and in the full growing period of winter wheat decreased significantly.The utilization rate of the accumulated temperature after seedling for the late sowing treatment increased significantly,which saved the solar energy and leave more accumulated temperature for previous crops to fill and ripe.

Key words: Winter wheat, Winter wheat, Jimai 20, Sowing time, Accumulated temperature