玉米是辽宁省播种面积最大的粮食和饲料作物,也是重要工业原料。近年来,玉米单产出现了较长时期缓慢上升阶段。玉米单产出现徘徊原因主要是由于第一,玉米杂交种亲本自交系遗传基础狭窄,育成的高配合力自交系少,组配出突破性的强优组合难。第二,以前组配的杂交种及选育的自交系 Corn is the largest sown area of ​​food and feed crops in Liaoning Province, is also an important industrial raw materials. In recent years, the yield of corn has risen slowly for a longer period of time. The reason for the wandering of corn yield is mainly due to the fact that the first is that the genetic basis of the parent inbred lines of maize hybrids is narrow and there are few inbred lines with high combined inbreds. Second, the previous combination of hybrids and breeding inbred lines