作物优良品种在栽培和繁育过程中,也会出现混杂和退化现象。混杂退化的种子纯度下降,性状变劣,品质变差,抗逆性减弱,产量降低。品种混杂退化的原因主要有: ①机械混杂。在作物的播种、收藏、脱粒、晒种、运输等过程中,种子发生人为的混杂现象,这是当前品种混杂的主要原因;②生 Good crop varieties in the cultivation and breeding process, there will be mixed and degenerate phenomenon. The purity of mixed degenerated seeds decreased, the characters became worse, the quality deteriorated, the resistance decreased and the yield decreased. The reasons for the variety of hybrid degradation are: ① mechanical hybrid. In crop sowing, collecting, threshing, drying, transportation and other processes, the phenomenon of man-made hybrid seeds, which is the main reason for the current varieties mixed;