答:玉米秃尖的原因有三,一是遗传性秃尖。果穗苞叶短小的玉米品种,由于轴顶端外露,顶部籽粒易受雨淋、虫咬、鸟啄,造成穗尖霉烂、无粒;二是由于肥水不足,后期脱肥,或因密度过大,群体发育受阻,穗尖籽粒不实;三是雄穗开花散粉、雌穗吐丝受精期,遇高温(32％以上) A: There are three reasons for bald tip of corn, one is hereditary bald tip. Ears bract short corn varieties, due to the top of the shaft exposed, the top of the grain susceptible to rain, insect bites, birds pecking, resulting in spike rotten, no grain; second is due to inadequate water, late fat, or due to excessive density, Population development blocked, spikelets false; Third, tassel flowering powder, spike silkworm fertilization period, in case of high temperature (32% or more)