Effect of cultural methods on seed production in summer type soybean.

Experiments were conducted to find out the possibilities of producing good quality seed of summer type soybean at Chuncheon, 74m above sea level and Jinboo, 600m above sea level in 1987. Local variety, Cheonan Jaelae was used. Seeds were sown June 25 harvested five times from 35 days after flowering with five days interval to 55 days. Vegetative period was longer in the early planting and high cool area, Jinboo, which resulted longer stem length than the late planting and in the plain area, Chuncheon. Pod number and 100 grain weight were shown more and heavier in Jinboo. Earlier planting and later harvesting resulted more pod number and heaveier 100grain weight. Grain yield was heigher in Jinboo, and earlier plainting shown more grain yield and its difference was greater in Jinboo. Long grain filling duration resulted more grain yield. Unripened seeds were produced more by earlier planting with earlier harvesting and earlier planting with late harvesting showed the high rates of pod and stem blight (Diaporthe Phaseolorum). Seed With high moisture content by early harvesting showed more rotten seeds in all planting dates production was more advantageous in the high cool area, Jinboo. Optimum planting date was between May 15 and June 5. Harvesting was desirable about 45-50 days after flowering with heigher germination rate seed yield.