• Korean Journal of Agricultural and Forest Meteorology
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• v.15 no.1
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• pp.26-39
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• 2013

Yield reduction in major cereal grains seems unavoidable with the existing cropping systems under the projected climate change in Korea. Crop models were used to predict the effects of planting date shift on grain yields of rice, winter barley and soybeans at 64 agroclimatic zones in Korea. The shift of planting date by 7, 14, and 21 days before and after the recommended planting dates were incorporated in DSSAT experiment files to simulate growth, development and grain yields of major cereal crops. These included 3 rice cultivars representing early-, medium- and late-maturity groups, 1 winter barley and 1 soybean cultivars. Partial mitigation in yield reduction was found with earlier planting in the early maturing rice cultivar and with delayed planting in the late maturing rice cultivar under the RCP8.5 projected climate change in Korea. Additional yield increase in winter barley was expected by earlier planting treatments. Soybean showed a positive effect on grain yield with earlier planting. However, the rate was much lower than the case with winter barley and delayed planting caused yield reduction.

• Horticultural Science & Technology
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• v.19 no.3
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• pp.329-333
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• 2001

The study was performed to investigate the effect of a plug culture method in the early stage of a potato breeding program. The 105, 200 and 288-cell plug trays were used for raising potato seedlings. The % germination in plug trays ranged between 94 and 96%. Percent tuberization measured at 50 and 60, and 70 days after sowing was the greatest in 105-cell and 200-cell trays, respectively. However, tuberization was most delayed in 288-cell trays. Thus, it is considered that 105-cell tray is the most effective for the selection of early maturing plants. Plant maturity was determined by the morphological characteristics at the seedling stage of stolons cultured in plug trays. Most of seedlings with shorter stolons at seedling stage (1st generation) were the early-maturing, while most of seedlings with longer stolons were the late-maturing at the clonal stage (2nd generation). These results mean that the plant maturity in the early potato breeding program can be effectively grouped by observing the morphological characteristics of stolons after plug culture.

• Korean Journal of Agricultural Science
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• v.25 no.1
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• pp.6-11
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• 1998

Bean sprout is one of the traditional vegetable in Korea and produced by sprouting soybean (Glycine max L.) cultivars. This experiments was conducted to investigate the ecological characteristics in collected small grain soybean lines from Chungnam province region. Thirty varieties were used in this study. Seed coat color of collected small soybean lines showed eight different types. Major seed coat color type was yellow as 8 lines of total 35 lines. The stem height, number of nodes and number of branches averaged 58.5 cm, 16.5 nodes and 11.8 branches, respectively. The average number of main stem pods and number of branching pod were appeared 43.1 and 62.7 respectively. One hundred seed weight averaged 9.9g which was lower than 10~12g of sprouting soybean cultivars as breeding goal of Korea. The average of node width showed 13.2cm and long stem open types and short stem close types were classified 1 line and 14 lines. The flower dates of collecting small soybean lines were between 8 Aug. and 13 Aug. and flowering duration was 74~85 days. The date of maturity were between 12 Sep. and 12 Oct., and maturity duration showed great variation among cultivated soybean lines.

• Korean journal of applied entomology
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• v.47 no.1
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• pp.9-15
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• 2008

This study was conducted to investigate the seasonal occurrence of chestnut weevil, Curculio sikkimensis. The chestnuts infected by the weevils were collected from Gongju, Buyeo, and Cheongyang in Chungnam Province, Republic of Korea. Investigation was focus on the escape period of chestnut weevil larvae from the fruits, invading time and vertical distribution in soil, survival rates of larvae during overwintering, emergence period, emergence rate, and sex ratio and longevity of adults. For precocious species, larvae escaped the chestnut from the mid-September to the early-October, middle species and slow species, were escaped from the late-September to the mid-October and from the early-October to the mid-November. After escaping from the chestnut fruits all of the larvae burrowed into the soil within 35 minutes. Overwintering larvae inhabited in the range of $0{\sim}48cm$ from the soil surface and highly distributed in the range of $18{\sim}36cm$. The 74.1 % of wintering chamber were distributed within $18{\sim}36cm$ from the surface. Survival rates observed were 38.0% in 1st year, 16.0% in 2nd years, and 2% in 3rd years, respectively. Seasonal occurrence period of C. sikkimensis was from the early-Aug. to early-Oct. and the optimal occurrence period was the early and mid-Sept. Emergence rate decreased to 8.4% in 1st year, 3.6% in 2nd years, and 0.8% in 3rd years, respectively. Sex ratio was showed in the range of 0.51-0.55. It is female biased ratio. Longevity of adults was 9.9 days for female and 8.9 days for male.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.spc1
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• pp.41-45
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• 2005

This experiment was carried out to identify the proper transplanting time at reclaimed saline land in the southwestern area of Korea from 2002 to 2004. The rice cultivars tested were Samcheonbyeo(Early maturing one), Nampyeongbyeo (Medium maturing one) and Hwaseongbyeo(Mid-late maturing one). The results are summarized as follows: No. of spikelet per the unit area was higher at transplanting on May 20 than those of the other transplanting time. when Samcheonbyeo was transplanted early, the ripened grain rate was high. But, Hwaseongbyeo and Nampyeongbyeo wasn't differ among transplanting time. The yield of milled and head rice(YMHR) was high transplanted May 20 in Samcheonbyeo, May 30 in Hwaseongbyeo, from May 20 to June 9 in Nampyeongbyeo. Among the varieties YMHR was higher in the order of Hwaseongbyeo, Samcheonbyeo and Nampyeongbyeo. There wasn't different of amylose and protein content among the transplanting time and varieties. But, palatability value was low transplanted early(May 20). Considering the rice growth, the rice good quality, the yield of milled and head rice, the proper transplanting time was May 20 to May 30 in Samcheonbyeo and Hwaseongbyeo, whereas Nampyeongbyeo was from May 20 to-June 9.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.spc1
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• pp.62-68
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• 2005

The characters associated with the rice quality and the factors as the proper harvesting time of rice were examined from 2002 to 2004 at Iksan in Honam plaine area. The rice cultivars tested were Samcheonbyeo (Early maturing one). Hwaseongbyeo(Medium maturing one) and Nampyeongbyeo(Mid-late maturing one). The ripened grain rates were high when the harvesting dates after heading were between 50 to 55 days,55 to 60 days, and 60 days for Samcheonbyeo, Hwaseongbyeo and Nampyeongbyeo, respectively. The yield of rice were higher when harvested 45 to 50 days, 50 to 55 days, and 55 to 60 days after heading for Samcheonbyeo, Hwaseongbyeo and Nampyeongbyeo. The highest yields of head rice were obtained when harvested 45 days after heading, 50 days and 55 to 60 days for Samcheonbyeo, Hwaseongbyeo and Nampyeongbyeo. In conclusion, in Honam plain, taking the head rice production, rice quality level, protein content and palatability of rice into account, the best harvest times were found to be 52 days(accumulated temp. : $1,213^{\circ}C$) after heading, 56 days$(1,221^{\circ}C)$, and 60 days $(1,207^{\circ}C)$, for Samcheonbyeo, Hwaseongbyeo and Nampyeongbyeo, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.spc1
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• pp.94-98
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• 2005

This study was carried out to provide the geographic information based on the distribution of rice qualities and palatability in Gyeoungbuk province of Korea. The rice grain quality and environmental factors were analyzed using 513 sampling sites based on different five-agroclimtic regions of Gyeoungbuk province during three years from 2002 to 2004. In rice grain quality characteristics, the average palatability was low in South eastern coastal and Tabaek semi alpine regions as $67.6\~68.3$ and the coefficient of variation (CV) was relatively high as $6.2\~7.4\%$. The average head rice rates were low in South and Central eastern coastal regions as $87.3\~88.2\%$ and CV was high as $8.2\~8.3\%$. The average protein content was high in Central eastern coastal regions as $8.0\%$ and CV was high as $8.2\~8.3\%$. In case of palatability, the variation was differed clearly between high and low agroclimatic regions; it means that it is possible to divide the same agroclimatic region of high CV into two or three areas by CV of palatability. As the results of subdividing each existing agroclimatic regions based on the palatability, the variation of grain quality characteristics was become lower than that of existing five-agroclimatic regions. Therefore, the re-establishing of agroclimatic region based on rice grain quality was very important for precise cultivation for rice.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.3
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• pp.277-285
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• 1986

A total of 16 varieties from Korea and Indonesia were tested at Suwon, Korea (126$^{\circ}$19'E, 37$^{\circ}$16'N and 37m above sea level) and Bali, Indonesia (115$^{\circ}$ 14'E, 8$^{\circ}$42'S and 10m above sea level). Japonica-type varieties showed pre-matured heading at Bali, tropical zone, while Bulu varieties showed no heading at Suwon, temperate zone. The varieties of Indica-type and Ind./Jap. showed faster heading in tropical zone than in temperate zone. Dry matter of the varieties weighed more difference among varietal groups in tropical than in temperate area, while plant height responsed differently depending on variety and test region.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.25 no.4
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• pp.59-65
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• 1980

An attempt was made to survey soybean cultivars that were nonsensitive to the photoperiod for selection as possible breeding materials for wide area adaptable varieties. Fifty-five cultivars were subjected to different day length conditions. The number of days from sowing until flowering was shortened under short day length conditions, and late varieties tended to be more sensitive to day length than early varieties. The response to day length of the tested cultivars might be divided into three groups; low, intermediate and high degree, by their accelerated rate of flowering. Especially four varieties in the low responding group, Gembokin, Wirth, Wayne and Pi.54613 were identified to be nonsensitive to day lengths, that is, neutral varieties. They also showed little variation in morphological characteristics under different day length conditions.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.2
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• pp.184-188
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• 1997

To investigate the absorption and transfer factor(TF) of Sr-85 by rice(Oryza sativa L.), experiments were carried out through pot cultivations on a sandy-loam soil treated 74 and 222Bq per gram of soil in a plastic film house. Sr-85 absorption rates of Ilpoombyeo, late maturing variety and Odaebyeo, early maturing variety, at harvesting stage, were 0.39-0.43% and 0.66-0.73%, respectively. Sr-85 absorption rates of Odaebyeo were about 1.5 times higher than those of Ilpoombyeo. Ratios of Sr-85 radiation and Sr-85 concentration in brown rice were much lower compared with those in straw and husk. Sr-85 concentrations in each part of Odaebyeo were remarkably higher than those of Ilpoombyeo. Transfer factor of Sr-85 from soil to plant ranged from 0.037 of brown rice to 4.13 of rice straw at harvesting stage. The order of the Sr-85 transfer factor in plant parts was straw>husk>brown rice. Sr-85 concentrations treated in soil had no effect on the growth and yield of rice.