0023-6152

AA00697606

4665

査読無

0023-6152

AA00697606

This study was carried out to investigate the agronomic characteristics of late-planted small seed soybean cultivars and to investigate the effect of number of pods and seeds on main stem and branch against seed yield in Korea. Seed were sown at 17 June 2003 and 16 June 2004 with on a 60cm row width and 10cm plant space. The flowering dates in small seed soybean cultivars were on July 26 to August 7 and the maturing dates were on September 23 to October 9. The days of from plantingto flowering date and to maturing date were ranged as 39~52 and 98~114, respectively. There was a highly significant difference (r=0.686, p<0.01) between total dry matter (TDM) and LAI at R5 stage. The number of pods on 2nd branch showed the highest velue by 7.6, and followed by that of 3rd, 1st and over 4th branch in this order. The seed yield varied from 168 to 289g m[-2] and the average of all soybean cultivars was 225g m[-2]. The relation between the seed yield and the days of flowering to maturing date was high significant difference (r=0.575, p<0.01) and there was a high significance difference (r=0.781, p<0.01) between the seed yield and the days of planting to flowering date. The level of singificant difference was higher in the period of vegetative stage than in the period of reproductive stage in small seed soybeans. There was high significance difference (r=0.556, p<0.01) between the seed yield and LAI in soybean cultivars. A range of LAI for optimal seed yield may be shown about 3.5~4.5 at R5 stage. Also, there was a relationship between the seed yield and the number of pods on 4th and above branch but was no significant relationship between the seed yield and number of pods on 1st branch. The correlation between the seed yield and the pods numbers showed the most vague by 0.460 (p<0.01) on 3rd branch, and followed 2nd branch, and 4th and above branch in this order. There was a high significant relationship (r=0.648, p<0.01) between the seed yield and the number of pods on total branch among 22 small seed soybean cultivars. However, the relationship between the seed yield and the number of pod on main stem showed no significant relationship (r=0.098, ns). These results indicated that in order to optimal seed yiedl of late planted (mid-June) small seed soybean, soybean cultivars forming more pods on the 2nd and 3rd branch should be bred.