作物育种的基础材料选择,因为在基础群体中的有利基因频率很低,并有基因连锁,所以受到很大限制。又加上新品种、新杂交种本身亲缘越来越狭窄以及一些遗传资源的损失,使育种材料的遗传基础日趋贫乏,影响育种效果。因此,采用轮回选择积累和选择有利基因,丰富遗传基础,达到改良亲本材料和群体的目的。国外已十分重视这方面的 The choice of basic material for crop breeding is limited because of the low frequency of favorable genes in the base population and the genetic linkage. Coupled with new varieties, the new hybrids are becoming more and more closely related to each other and the losses of some genetic resources make the genetic basis of breeding materials increasingly poor and affect the breeding effect. Therefore, the use of cycle selection and accumulation of favorable genes, rich genetic basis to achieve the purpose of improving parental materials and groups. Foreign countries attach great importance to this aspect