| This paper deals with the relation between young spike differentiation of ecotypes of wheat at different sowing date in spring and temperature and leaf emergence. The result show that the later the sowing date of wheat is, the shorter the young spike differentiation of ecotypes of wheat lasts, the longer the process of the winter wheat lasts, the higher the accumulated temperatures are for the winter wheat, the accumulated temperatures are relatively stable for the spring wheat. The days and accumulated temperatures are higher for winter wheat than spring wheat; the leaf emergence on main stem at all spike differentiation stages vary with ecotype, the leaf numbers are more for winter wheat than those of spring wheat. |