The results showed that the grain number per ear was a more changeable factor than 1000-grain weight. In comparison with 1000-grain weight,the grain number per ear made a greater contribution to yield. The key stage for grain number was from silking to 14 days after silking. Improve nutrition during a period from silking to 24 days after silking had greater importance to increase 1000-grain weight. Therefore,it would increase yield to enhance management in this period. Steady grain number and higher grain w...