Effects of daylength and temperature on the spike differentiation of winter wheat

The spike differentiation processes of 3 winter wheat varieties under different sowing dates were studied.The results show that the excessive sensitive stages to daylength and temperature are single and double ridge stages of winter wheat，however the sensitivity of other stages to those is related to the ecological type of winter wheat.The major factor which affects the spike differentiation is the mean daily temperature in the experiment，therefore，the progress of spike differentiation of winter wheat could be regulated by controlling sowing date as climate becoming warm.