Abstract
Frozen damage of young wheat spikes and its influence upon the growth have been studied. The results are briefly summarized as follows. Both the Spring Wheats and Winter Wheats were equally suffered frozen damage by cold temperature (below zero) when the young spikes reached the stage of differentiation of the parts in the flower, that is to say the initials of stamens can be seen as round papillae in the most advanced flower, or the differentiation more advanced. But the spikes that were not reached the differentiation as described above, were relieved of the damage. The damage was larger in Spring Wheats and early sown wheats because the differentiation was more quicker. By these damage, when it was early and great, the growth of the plants was stopped for a time, the large number of small and weak stems were appeared, the escape of ear became remarkably irregular, and the yields were greatly diminished. But when the damage was slight (in lately sown Spring Wheats and early sown Winter Wheats the damage was slight) the influences were not so remarkable. From these results it may be said in our district that in Spring Wheats late sowing is safety, and in Winter Wheats early sowing is profitable but there is a certain limit by the frozen damage.
