玉米起源于热带,在系统发育上要求较高的温度、短日照及较好的水肥条件。玉米属光饱和点高、补偿点低、非光呼吸的 C_4植物,适应性强,在温带最热月平均气温高于20℃,中低纬度海拔在2,600—2,800米地区都可广泛种植。我省东起太行山,西至黄河沿岸,北至长城,南到中条山,各地均有玉米种植。1979年全省玉米播种面积达1,100万亩左右,占粮食作物面积的21.2%,以晋东南、晋 Corn originated in the tropics, the system development requires higher temperatures, short sunshine and better water and fertilizer conditions. Corn is rich in light saturation point, low compensation point, non-photorespiratory C_4 plants, strong adaptability, the hottest month in the temperate zone average temperature above 20 ℃, low altitude latitude 2,600-2,800 meters above sea level can be widely planted. From the Taihang Mountains to the east, to the Yellow River to the west, to the Great Wall to the north, and Zhongtiaoshan to the south, corn cultivation is all over the province. In 1979, the sown area of ​​maize in the whole province reached about 11 million mu, accounting for 21.2% of the total area of ​​grain crops. In southeastern Jin and Jin