玉米自交系的选育方法很多，而从单交种中选育自交系即选育二环系是一项投资少、见效快的方法。在亲本选择上采用高起点的目标性状，重视国外种质的利用，同时对野生种质、整株持绿性等性状加强探索，是选育优良二环系不可忽视的几个环节。 Breeding methods of maize inbred lines are many, and breeding inbred lines from single crosses, that is, breeding of the second ring system is a less investment, quick method. In the choice of parents to use a high starting point of the trait, pay attention to the utilization of foreign germplasm, at the same time on the wild germplasm, green and other characteristics of the whole green to explore, is the selection of excellent two ring system can not be ignored several links.