仅次于水稻、小麦的杂交玉米产量,始终左右着全国粮食总产。近年来,若干骨干品种亲本自交系,随着使用年限的延长和生产、科研单位间的不断交换,以及繁种水平的差异等,出现了一些异源同名系和异质同名系。自交系失去了原有的典型性状,配合力下降,影响了杂交种的高产、稳产性能。对此,通常采用“提纯复壮”等方式进行选择。由于长期套袋自交,繁殖世代较长,必然引起性状分离和纯合,自交系遗传组成失去平衡。同时,操作过程不可能完全避免外 The output of hybrid corn, second only to rice and wheat, has always dominated the national grain output. In recent years, some of the key varieties inbred lines of parents, with the extension of the useful life and production, continuous exchange of scientific research units, as well as the level of variety differences, there have been some of the same name with the same name and the same name system. Inbred lines lost the original typical traits, with decreased ability to affect the high yield of hybrids, stable performance. In this regard, usually using “purification and rejuvenation” and other ways to choose. Because of long-term bagging selfing, longer propagation age, it is bound to cause trait separation and homozygosity, and the genetic composition of inbred lines is out of balance. At the same time, the operation can not be completely avoided