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西南玉米协作区于1974年开始进行工作,历时十个春秋,共进行了五个周期的试验,鉴定了本协作区选育的一批玉米良种35个,其中双交种4个,顶交种1个,单交种30个,和外区单交种3个。本区玉米面积约6200～6500万亩。试验前的1973年杂交种面积约为798万亩,占12.8％;1981年杂交玉米面积达2712万亩,占39.2％;为1973年的3.4倍。单产由200斤提高到1980年的400～450斤。据不完全统计,前四周期评选出的
The Southwest Corn Cooperation Area started its work in 1974 and lasted for ten years. A total of 35 maize varieties bred in this zone were identified. Among them, 4 were double cross and 4 were top cross 1, 30 single cross, and 3 single cross-border species. The area of corn area of about 6200 ~ 6500 mu. Before the test, the hybrid area in 1973 was about 798 mu, accounting for 12.8%. In 1981, the area of hybrid maize reached 27.12 million mu, accounting for 39.2% of the total; in 1973, it was 3.4 times that of 1973. The yield increased from 200 to 400 kg in 1980. According to incomplete statistics, the first four cycles were selected