昭通地区位于滇东北角,所属十县由北纬26°30′—28°43′,东经102°54′—105°21′,海拔350—3500公尺。高差大,跨幅广,南高北低,地形地势复杂,造成“隔里不同天”的农业区域。粮食作物以包谷、水稻、洋芋为主,其中包谷播种面积为280万亩左右,占总耕地面积60％以上,产量占粮食总产量的56％左右。但单产低,全区包谷平均单产仅200多斤。因此,提高包谷单位面积产量,为我区增产粮食的首要关键。国内外经验,选育杂交种是包谷坛产的主要措施,但是我区包谷杂交种选育的基础过去很差,并且多采取“想现成,走捷径靠外援”的办法,一九六二至一九六三年先后向全国各地引入双交种80多个。种植结果,大多数表现大斑病重,生育期长,需大水大肥,品质差,吃味淡,群 Zhaotong is located in the northeastern corner of Yunnan, belonging to ten counties from latitude 26 ° 30’-28 ° 43 ’, longitude 102 ° 54’-105 ° 21’, elevation 350-3500 meters. Large difference in height, wide span, high in the south and low in the north, topography is complicated, resulting in “different days in different areas” of the agricultural area. The grain crops are mainly composed of corn, rice and potato. Among them, the sown area of ​​paddy valley is about 2.8 million mu, accounting for more than 60% of the total cultivated land area, and the output accounts for about 56% of the total grain output. However, the yield is low, and the average yield of the whole valley is only 200 kilos. Therefore, it is the most important key to increase the output of grain per unit area of ​​paddy for our region. Domestic and foreign experience in selecting and breeding hybrid rice is the main measure for albuginea production. However, the basis for selection of hybrid rice in this area was poor in the past, and the method of “wanting to be available now and taking shortcuts by foreign aid” was adopted more frequently. In 1963, it successively introduced more than 80 double crosses to all parts of the country. Planting results, most of the performance of large spotted disease, long growth period, to be large water and fat, poor quality, eating light, group