This study was carried out to find a useful mushroom at Chungnam Agricultural Research And Extention Service. Twenty materials used were collected from domestic and exotic area. These races were compared bontanical characteristics to leading varieties by PCR-RAPD methods. Mycelial growth temperature of Chongpung and Myongwol were at 20 to 25 ℃ and 25 to 30 ℃ at PDA medium, respectively mycelial growth of these varieties were similiar at pH 6.5 to 7.5. In case of mushroom cultivation temperature ranges, Chongpung was at 5 to 26℃ and Myongwol was at 7 to 28℃, but the optimum temperature range of these were appeared at 15 to 19℃. Culture temperature of these was 23℃ and period of mycelial culture was needed 23 to 24 days under 850cc/pp, while was needed 11 to 12 days at waste cotton medium. Cap color of these at first inducing mushroom was all dark blue, but at late growing stages Chongpung was shown as grey, and Myongwol was shown as dark grey. Yield of Chongpung was appeared as 46kg/3.3m2 and that of Myongwol was 41kg /3.3m2, while Chunchu No2 as check was 40kg/3.3m2. Results from PDA medium and PCR-RAPD analysis two of these were different from others.

This experiment was conducted to investigate the changes of harvest index and the relationship between harvest index and yield determination factors by different planting times in the determinate soybean cultivars, Shinpaldal and Danbaeg. Optimum planting were 23 May in 1995 and 1996. Late planting were 13 June in 1995 and 6 June in 1996. Growth period from planting to physiological maturity (R7) was shortened as planting time was delayed in two cultivars due to shortening of reproductive growth period in Shinpaldal, and of vegetative growth period in Danbaeg. Stem weight was distinctly decreased in late planting compared to optimum planting, but seed weight of both cultivars was not different between planting times. Also, seed number per pod and harvest index were significantly increased in late planting and the high correlation was found between two factors. It was suggested that increase of harvest index in late planting would be related with high assimilate use efficiency due to increase of sink capacity. The results of correlation and principal component analysis for yield determination factors showed that main factor on yield determination was pod number per plant at R5 stage associated with dry matter accumulation during early reproductive growth period, seed number per pod and harvest index were the second factor, and one hundred seed weight was the third factor. The result of this experiment indicated that yield determination in soy-bean was dependent mainly on pod number per plant related to dry matter accumulation by early reproductive growth period, and the increase of seed number per pod and harvest index could compensate for yield decrease by shortening of vegetative growth period in late planting. Such result suggests that optimum planting date can be delayed from mid May to early June in improved soybean cultivars in Korea

Direct-seeding has major advantages such as labor and cost saving by eliminating preparation of seed bed and transplanting. But, it required increased input of fertilizers and pesticides because of the extended paddy period. Direct seeding in wet paddy (DSWP) gives faster growth and more uniform seedling emergence than direct-seeding in dry paddy. This research had an objective to develop an efficient N management practices for DSWP with split application of N fertilizer. A paddy field experiment was conducted to evaluate effects of starter N and N-topdressing which was delayed N application until 5-leaf stage, with comparison to transplanting (TP). Total amount of N application were two levels; 110kg and 77kg/ha. The N applications were split four times during rice growth stages; starter, topdressing at 5-leaf stage, top dressing at tillering stage, and topdressing at panicle initiation stage. DSWP had more tillers/m2 than TP, but with the delayed heading. The DSWP plots which received N-topdressing at 5-leaf stage without starter N had higher leaf area index (LAI) and leaf greenness than the TP plot. Also, these DSWP plots had high leaf-N concentration at the heading stage, as calculated from leaf chlorophyll meter readings. Rice yield in DSWP with N-topdressing at 5-leaf stage was significantly higher than that in TP and in DSWP with starter N. Energy and N use efficiency were improved in DSWP with N-topdressing at 5-leaf stage. But, there were no significant differences in grain yield between the two levels of total amounts of N applications, 77kg and 110kg/ha. We concluded that starter N could not be used effectively by rice seedlings, but topdressing N at 5-leaf stage was an efficient N management for rice growth and yield in DSWP system.

1. Polyacrylamide gel electrophoresis를 이용하여 국내외 재래종과 야생종 대두 계통들의 trypsin inhibitor의 변이를 규명하기 위하여 본 시험이 시도되었으며 1706계통의 한국산 재래종과 103계통의 한국 야생종콩, 그리고 167계통의 외래 재배종과 71계통의 외국 야생종 대두가 공시되었다. 2. Trypsin inhibitor를 함유하지 않은 ti/ti형과 Ti c/c형은 한국 재래종에서만 발견되었으며, Ti* c형을 Hymowitz도 일본 대두품종에서 보고한 바 있으나 그도 이 계통은 한국 도래종일 가능성이 크다고 보고 한 바 있다. 3. 한국기원의 콩에서 trypsin inhibitor에 관한 이형접합형의 출현빈도가 외국 기원 콩 계통에서 보다 비교적 높았으며, 재래종에서 3.6%(N=61)와 야생종에서 9.7%(N=10)이었으며 종합적으로 보아 중국, 일본 등의 대두에 비해 한국 기원의 콩이 가장 큰 변이를 나타내고 있음을 확인하였다.