What is the cause of Tillering death in Rice and Wheat

Q: I am from Sihong County. Here, many of the tillers of wheat do not grow and eventually shrink and die, and so does rice. In addition, there are several grains missing at the base of the wheat ear, or the branchlets at the base of the rice ear do not bear particles as if they had been rolled. What is the reason for this? Answer: a large number of tillers died in the middle and later stages of wheat and rice growth, which is usually a normal phenomenon. Generally speaking, the small tillers of wheat and rice with less than 3 leaves at the beginning of jointing can not form spikes and will die quickly after jointing. These tillers are invalid tillers. When the number of peak seedlings is too large, when the field population is too large, many large tillers with more than 3 leaves at jointing can not form spikes, and eventually die, which is also an ineffective tiller. In the process of cultivation, the population of wheat and rice should be controlled at an appropriate level according to local conditions, and the population in the middle and later stage should not be too large, otherwise too many ineffective tillers will not be conducive to large spike and high yield, and it is easy to cause lodging in the later stage. In general, the number of peak seedlings of wheat should not exceed 500000 per mu, and the number of spikes per mu should be about 350000; the number of peak seedlings of medium japonica rice should not exceed 300000 and 220000 ~ 240000 per mu. The spikelets in the lower part of the rachis of wheat and rice ears differentiate and develop late and are at a nutritional disadvantage in light, density and fertilizer. When temperature and other conditions are not suitable for the growth and spike differentiation and development of rice and wheat, these spikelets are often underdeveloped.