This experiment was carried out to clear optimum planting time for yield enlargement by comparing yield with dry matter at Miryang from 2005 to 2006. Variety used were Daewon, Daepung, Daol and Cheongja 3. Seeding was performed on April 30 to June 30 with 20day intervals and planting density was 142,857 palnts/ha (70×20㎝, 2plants per hill) with black vinyl mulching. In R2～R4 stages, crop growth rate(CGR) was largest on June 10 seeding. Although net assimilation rate(NAR) increased as seeding date was delayed, NAR on June 10 seeding was the highest throughout the growth period. Positive relationships were observed between NAR from R2 to R4 the ratio of pod to total dry matter weight. The LAI and total dry matter weight at the R4 stage was higher at earlier seeding date. In the case when seeding date was delayed, the ratio of leaf(source) and pod(sink) increased. From the comparison of all factors such as dry weight, optimum LAI, and of source to sink, the optimum planting date for high seed production was June 10. The highest yield was recorded with on June 10 seeding. Also, this seeding date showed high ratio of seed yield to dry matter in R2 stage. Difference between surveyed pod no. and theological pod no. which was calculated by dry matter ratio compared with standard seeding date(June 10) at R2 stage was the smallest in June 10 seeding.

This study was carried out to obtain general agronomic characteristics and identify its relationship with seeding date for high quality soybean seed production. One hundred(100) domestic soybean varieties were used and seeding date were scheduled at April 30 and May 30. This experiment was carried out at YARI, NICE situated at Miryang from 2005 to 2006. Maturity Group(MG) was classified by Kweon et al's method (1974). Correlation analysis of major agronomic characters showed positive relationship between days to flowering and growth days, seed weight and lodging in MG ,seed crack and growth days in Ⅳ～Ⅴ MG0～Ⅲ,seed crack and days to flowering in MGⅣ～Ⅴ and MGⅥ～Ⅶ, seed crack and lodging in MGⅣ～Ⅴ and MGⅥ～Ⅶ, seed crack and seed weight in MGⅣ～Ⅴ and MGⅥ～Ⅶ, purple seed and growth days in MGⅣ～Ⅴ , purple seed and seed weight in MGⅥ～Ⅶ, phomopsis and growth days in MGⅣ～Ⅴ and MGⅥ～Ⅶ, and phomopsis and purple seed in MGⅣ～Ⅴ and MGⅥ～Ⅶ. In contrast, a negative relationship was observed between seed weight and lodging in MG0～Ⅲ. Correlating yield and major characters revealed negative relationship between days to flowering and growth days in MG0～Ⅲ and MGⅣ～Ⅴ, whereas positive relationships were obtained on MGⅥ～Ⅶ seeded on April 30. Lodging, seed weight and seed crack were all negatively correlated with yield in MGⅣ～Ⅴ and MGⅥ～Ⅶ

This experiment was carried out to examine seed quality as affected by enviromental cutivation for the production of high quality domestic soybean variety at Miryang (altitude : 12m) and Muju(altitude : 600m). Variety used were Daewon, Daepung, Daol and Cheongja 3. Seeding was performed on April 30 to June 30 and planting density was 142,857 palnts/ha. Seed weight across regions was lighter as seeding date was delayed. Opposite trends between seed crack and seed weight was obtained. Seed crack decreased as seeding date was delayed and have higher occurrence in Miryang than in Muju. Perple seed and phomopsis decayed seed decreased as seeding date was delayed. There was a significant negative correlation between seed weight and mean temperature from R2 to R4 stages in all variety. Seed weight increased as mean temperature from R2 to R4 stage decreased to 22.0℃, which was greatly manifested on Daewon variety. At maturity time, Daewon variety had an average increase of 1.79g as mean temperature decreased by 1℃. Seed weight of Daewon obtained a significant negative correlation with mean temperature at R4～R6 stage and on rainfall at R4～R6 stage. Mean temperature and rainfall were able to estimate 100 seed weight of Daewon and Daepung variety with 98.1% and 96.6% probability, respectively. Phomopsis occurrence in late maturity type was closely related to rainfall during the R4～R6 stages.

This study was carried out to classify Korean soybean varieties based maturity group. One hundred (100) domestic soybean varieties ( 56 for fermentation, 26 for sprouting, 17 for mixed with rice) were used and seeding date was scheduled at April 30. This experiment carried out at Yeongnam Agricultural Research Institute, NICE situated at Miryang from 2005 to 2006. Classification of maturity group in 100 soybeans was followed by Kweon et al's method (1974) The main difference between this experiment and that of Kweon et al's method (1974) were the planting region and planting date. This experiment was conducted on April 30 at Miryang while Kweon et al. was conducted on May 23 in Seoul. Results of maturity grouping of Korean soybean varieties showed that Keunol, which was represented among 3 varieties, belonged to Group 0, Seonnok and Danmi in GroupⅡ, Shinrok in GroupⅢ, Seonyu, represented by 17 cultivars, in GroupⅣ, Taekwang, having 44 cultivars in GroupⅤ, Daewon, represented by 25 cultivars in GroupⅥ, and Kwangdu and Keumdu in GroupⅦ.