利用优良玉米杂交种,是提高玉米产量的主要措施之一,单交种是当前生产上推广利用的主要杂交种,已为国内外生产实践所证明.但是,由于组成单交种的自交系遗传基础的单一,多年加代繁殖,易于引起生物学混杂,产生一种相似的“潜在杂株”,加上去雄不彻底、不及时,造成杂种一代群体中系内自交株等所占比例增大.种子质量不高,对粮食增产的影响是十分惊人的. The use of fine maize hybrids is one of the main measures to increase the yield of maize.It is one of the main hybrids currently being popularized and utilized in China.It has been proved by domestic and foreign practices.However, Genetic basis of a single, multi-generational multiplication, easy to cause biological hybrid, resulting in a similar “potential miscellaneous strains”, coupled with decontamination is not complete, not timely, resulting in hybrids inbred lines within the system increased by Large seed quality is not high, the impact on grain yield is very alarming.