我省地处祖国北部,纬度较高,气候寒冷,常因气温低,积温不足,使玉米在霜前不能正常成熟。这不但影响玉米产量的提高,也影响玉米种子的选留,熟期偏晚的杂交组合就更难选种。为了解决玉米的选留种子的问题,我们采取顶浆选留玉米种的方法,收到了良好的效果。所谓顶浆选留玉米种,就是在田间扒开玉米苞叶,看到籽粒已长到正常大小,种皮颜色开始变黄,用指甲划破种 The province is located in the northern part of the motherland, latitude higher, cold climate, often due to low temperature, lack of accumulated temperature, so that corn can not be mature before frost. This will not only affect the increase of corn yield, but also affect the selection of corn seeds. Hybrid combinations with late maturity will be more difficult to select. In order to solve the problem of selecting the seeds of corn, we adopted the method of selecting the corn seeds for the top-dressing and received the good results. The so-called top dressing selected corn species, that is, in the field opened the corn bract leaves, see the grain has grown to normal size, the color of the seed coat began to turn yellow,