论文部分内容阅读
从60年代开始利用玉米杂交种至现在,吉林省玉米杂交种经历了三次更新:第一次,在1968年育成吉单101后,单交种种植面积逐年扩大。1976年推广面积达53万公顷,使玉米生产由双交种为主转向以单交种为主。全省玉米平均单产由每公顷1612.5公斤,提高到2850公斤。第二次,在1980年四单8审定推广后,单交种应用面积迅速增加。1985年全省单交种种植面积148.5万公顷,仅四单8推广面积就达89.8万公顷。使我省玉米平均单产由每公顷2850公斤提高到4725公斤。第三次,在1986年以后,开始引入推广丹玉13、中单2、铁单4(吉单131)等。1990年全省丹玉13种植面积30.6万公顷;中单2种植面积36万分顷;吉单131(铁单4)的种植面积62.8万公顷。使我省玉米单产水平由1985年每公顷4725公斤,提高到1990年的6892.5公斤(上述均包括栽培技术水平的提高和化肥施用量增加等因素)。1980年以
Since the 1960s, corn hybrids have been used up till now, and the maize hybrids in Jilin Province have undergone three updates: for the first time, the monoculture planting area expanded year by year after the Kyrgyzstan 101 was bred in 1968. In 1976, the promotion area reached 530,000 hectares, shifting the production of corn mainly from double crossbreed to monoculture. The average yield of corn in the province is 1612.5 kg per hectare, up to 2850 kg. The second time, in 1980, after the approval of the Ssangyong 8, the area of single cross-breeding species increased rapidly. In 1985, the province’s single cross-planting area of 1.485 million hectares, only four single 8 popularized area reached 898,000 hectares. So that the average yield of corn in our province increased from 2850 kilograms per hectare to 4725 kilograms. Third, after 1986, the introduction of promotion Dan Yu 13, Zhongdan 2, Tiedan 4 (Ji Dan 131) and so on. In 1990, the provincial Dan Yu 13 planting area of 306,000 hectares; medium single 2 planting area 360,000 hectares; Ji Dan 131 (Tie Dan 4) of the area of 628,000 hectares. So that the corn yield in our province increased from 4,725 kg per hectare in 1985 to 6,892.5 kg in 1990 (all of which include the improvement of cultivation techniques and the increase of chemical fertilizer application). 1980 years