玉米育种方法是随着玉米生产发展而不断前进与发展的。首先是应用不控制授粉的育种方法。这种方法是在不加控制的自由授粉条件下进行的。它对于改进生育期、株高和穗部性状等有一定效果,但对于提高产量作用并不明 Corn breeding method is with the development of corn production and continuous progress and development. The first is to apply breeding methods that do not control pollination. This method is carried out under uncontrolled free pollination conditions. It has some effect on improving the growth period, plant height and ear traits, but it is not clear to improve the yield