玉米果穗是由茎秆中上部叶腋的腋芽分化而成。植株最上部4－6个的腋芽一般不发育，以下各节的腋芽虽有形成果穗的可能性，但在果穗分化过程中下部腋芽由于不能优先得到充足养分，往往不能形成雌穗或有雌穗而不结实。空秆的发生与品种的遗传特性，栽培管理过程中水肥不足；弱晚 Corn ear stems from the upper axillary axils bud differentiation. The axillary buds of 4-6 uppermost plants are generally undeveloped. The axillary buds in the following sections have the possibility of forming ears, however, the lower axillary buds may not be able to give priority to sufficient nutrition during the process of ear differentiation. Not strong. Occurrence of empty stalks and varieties of genetic characteristics, lack of water and fertilizer in the cultivation and management process; Weak late