EFFECT OF DIFFERENT SOWING DATES ON GROWTH,DEVELOPMENT AND YIELD COMPONENTS IN CORN

An experiment was conducted with a corn hybrid, Guiding 1, using different sowing dates from Feb. to Sept. during the years of 1988 to 1989 in Guangzhou. The result showed that the effect of different sowing dates on total growth period, grain yield, plant height and the height from soil surface to the first ear were more significant than that on the number of leaves per plant and the ratio of the height from soil surface to the first ear to plant height. Compared with the corn sowing dates from April to August, the corn sowed in Feb. , March and Sept. had longer total growth period. The yields of different sowing dates from March to the first ten days of April and July to Sept. were higher than the yields of sowing dates in May and June. The total growth period of corn was affected mainly by temperature. The growth and development of corn was retarded at lower temperatures, and promoted at higher temperatures. The yield was affected by temperature. Among yield components, the grain weight and the number of grains on one row of an ear varied widely, and they correlated with the yield most closely.