大豆의 世代短縮에 關한 硏究 Ⅱ. 日長處理가 開花 및 成熟에 미치는 影響

Studies on rapid generation advancement of soybean Ⅱ. Effect of day length on flowering and maturing

For the four times of rapid generation advancement(RGA) of soybean in a year including two times of RGA in the greenhouse during winter, this experiment was conducted to investigate the method of two times of RGA for six months from May to October under different day lengths with natural temperature condition. For this experiment four soybean cultivars, H-25(maturity group, Ⅱ), Ishiharadaizu(Ⅱ), Milyangkong(Ⅲ-Ⅳ), Essex(Ⅴ) were planted on May 1 and August 1 in 1987 in 1/2,000a pots at the Yeongnam Crop Experiment Station(35° 29’ N, 128° 45’ E). And four different day lengths(natural, 12 hour, 10 hour and 8 hour photoperiods) were applied from unifoliate stage to flowering of soybean. The days from planting to flowering(DPF), flowering to maturity(DFM) and planting to maturity(DPM) were shortened effectively at the 10 hours day length at planting on May 1. DFM of Ishiharadaizu was the shortest by 84 days, and it of Essex was the longest by 97 days under 10 hours photoperiod among four cultivars planted on May 1. Also at planting on August 1, DFM of Ishiharadaizu was the shortest by 79 days and it of Milyangkong was the longest by 90 days under 10 hours photoperiod. Under 10 hours day length, the number of grains per plant of four cultivars were ranged from 33 to 59 at planting on May 1, and from 20 to 30 at planting on August 1. These results suggested that two times of generation could be advanced for six months from May 1 to October 31 by applying 10 hours day length from unifoliate to flowering, by harvesting immature soybean seeds before 15 to 20 days of maturity which have germinability over 80 percent.