玉米是我县的主要粮食作物,种植面积占到总耕地的50％以上,高寒山区更多,达到85.6％。高寒山区海拨一般在1300公尺左右,土浅、地薄、质硬。气温低(4—9月份日平均13.5℃),早春回升慢(4月日平均11.9℃),秋季降温快(9月日平均21.7℃),全生育期有效积温仅1843℃。雨量较多,年降雨750—1100毫米,集中于7—9月份,虽有利玉米生长,但湿度大,病害发生也较重,若雨季偏后年份则易秋封,籽粒成熟不好。当地种植的品种多为农家种,玉米产量较低,一般仅200斤左右。为了解决高寒山区的玉米品种问题,从外地引进过不少玉米杂交种进行试种,但大多因适应性差,产量不稳而告失败。分析原 Maize is the main grain crop in our county. The acreage accounts for more than 50% of the total cultivated land, more in the alpine mountainous area, reaching 85.6%. Alpine mountains generally about 1300 meters in altitude, shallow soil, thin, hard. Low temperature (average daily temperature in April-September was 13.5 ℃), slow recovery in early spring (daily average of 11.9 ℃ in April), rapid fall in autumn (average daily average of 21.7 ℃ in September) and effective accumulated temperature of only 1843 ℃ in the whole growth period. More rainfall, annual rainfall of 750-1100 mm, concentrated in July-September, although beneficial to the growth of corn, but the humidity, disease is also heavier, if the rainy season is easy autumn seal, poor grain ripening. Most of the cultivated varieties are farmer families, and the yield of maize is relatively low, generally only about 200 kg. In order to solve the problem of maize variety in the alpine region, many maize hybrids were introduced from the field for trial planting. However, most of them failed due to poor adaptability and unstable yield. Analysis of the original