成单九号是四川省农科院作物所用玉米自交系黄早四作母本,自选自交系成一7(33—757)为父本杂交选配而成的中早熟玉米杂交种。1984—1985年参加省玉米杂交种区域试验(中早熟组),两年产量均名列第一,平均亩产431.4公斤和416.5公斤,比对照种成单四号分别增产6.9％和14.7％。两年平均亩产423.95公斤,比对照种成单四号增产10.6％,顺利通过区试,进入生产示范。 Cheng Dan 9 is a maize inbred line used in the crop of Sichuan Academy of Agricultural Sciences Huangzao four as female parent, optional inbred lines into a 7 (33-757) for the male parent hybrid selected from the early maturing corn hybrids. From 1984 to 1985, he took part in the provincial maize hybrids regional test (middle-early-maturing group) with the highest output in two years, with an average yield of 431.4 kilograms and 416.5 kilograms, respectively, up 6.9% and 14.7% respectively over that of the control. The average annual output of 423.95 kilos in two years was 10.6% higher than that of the single control on the fourth. It successfully passed the regional test and entered the production demonstration.