• Korean Journal of Breeding Science
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• v.41 no.2
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• pp.163-167
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• 2009

Jogwang is a new early maturing japonica rice developed in 2007 from a cross between Milyang187 and YR21113-B-B at the Department of Functional Crop Science, NICS, RDA. This cultivar is very suitable to the rice-cash crop double cropping system. Heading date of Jogwang is 2 days earlier than Keumobyeo under the late transplanting cultivation on July 10 at the Yeongnam plain. The tolerance level of this variety to leaf discoloration at seedling stage is very similar to Keumobyeo. It showed slightly lower viviparous germination and premature heading. This cultivar showed resistant reactions to leaf blast and rice stripe virus disease but susceptible to bacterial blight disease and major insect pests. The ratio of milling and head rice recovery of Jogwang is 76.5% and 64.5%, respectively. The milled kernels are translucent with non glutinous endosperm. This cultivar has 7.3% protein and 18.5% amylose content. In local adaptability test, showed that the milled rice yield of Jogwang is $4.90\;MT\;ha^{-1}$. This cultivar is suitable for planting in the plain paddy fields of Honam and Yeonnam regions in Korea.

• Korean journal of applied entomology
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• v.18 no.2 s.39
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• pp.101-106
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• 1979

Present studies were carried out to get a basic information for biological control of soybean rod borer, Grapholitha glycinivorella Matsumura, causing main injury in soybean cultivation in Korea. 1474 native strains were cultivated in field to evaluate the pod borer damage. Pubescence density and color, maturity group, seed coat color, aphid and general leaf damage and seed damage by pod borer were investigated, and determined among their relationships. As another basic study for ecological control of insect, 6 leading varieties were planted on different planting date with 3 levels of plant spacing, on which pod borer damage and some related agronomic characters were studied. The results obtained one summarized as follows: Average injury of soybean pod borer was $5.2\%$ ranging $0-38\%$ in 1474 strains planted on 20 May. Non-significant correlations were found between pod borer damage and pubescence density and color, while pod borer damage closely related with maturity groupand aphid damage at $5\%$ level ofttests. Most severe damage was found in green seed coast color and maturity group V. Late and sparse plantings tend to have more damages to the pod borer than those of early and dense plantings. Pod setting date and period of pod maturing seemed related with pod borer damage. Bongeui and Chungbuk-baik cultivars were resistance to soybean pod borer, while Clark and Kumkang-daerip were susceptible in field tests.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.4
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• pp.462-469
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• 1982

Since 1962, varietal development and dissemination for summer upland crops have been actively initiated by the Crop Experiment Station, Office of Rural Development, Suweon, Korea. The major breeding objectives of soybeans have been to develop varieties which are early maturing, disease resistant, and adaptable to late planting for after-barley cropping. Development of eleven new soybean varieties including Hwangkeumkong, Jangyeobkong, Danyeobkong, and Kwangkyo has greatly increased the soybean yield throughout country. For com, after development of Hwangok #2, a synthetic, in early 1960's, nine corn hybrids-single crosses, double-crosses, and three-way crosses-such as Jecheon-ok, Hoengseong-ok, Kwangok, Suweon #19, etc., have been disseminated mainly to Kangweon province, a major corn producing area in Korea, and drew up the yield over 4 tons per hectare. The major breeding objectives of sweet potato have been to develop varieties which have high starch content and root yield. Hwangmi, Hongmi, and Shinmi are three sweet potato varieties developed and disseminated by the Crop Experiment Station, Office of Rural Development and are grown most widely in Korea. Most of researches on cultural practices of upland crops have begun on a full scale from early 1960's. In soybeans, for example, no fertilizer but for barley was applied although the effects of phosphate and potassium fertilizers were great on soybeans in after-barley soybean croppings. The effects of heavy application of phosphate and calcium fertilizers on soybeans in newly reclaimed soils were recognized. Recently a mixed fertilizer for soybean (N; 40, P:70, K:60 kg/㏊) was developed and sold for soybean growers. The optimum planting densities of 220, 000 plants/ha in full-season cropping and 330, 000 pts/ha in after-barley cropping of soybeans were known from repeated experiments. For higher yield, a means of cultural practices such as transplanting-pinching, direct planting-pinching, and hilling-up, etc., were developed along with barley-stubble planting with no tillage and integrated herbicide application for labour savings. For sweet potato, cultural practices for planting date, harvesting date, fertilizer, and planting density were fully established. For early marketing, a technique of vinyl-mulching on sweet potato has also fully developed. For com, planting density of 37, 000 pts/ha in early 1960's has been changed to 55, 000 pts/ha for grain production and 67, 000 pts/ha for silage. The amounts of fertilizers have also been changed from 120-120-120kg/ha (N-P-K) in early 1960s to 180-150-150 kg/ha. These increases in number of plants per unit area and fertilizer levels have resulted in greater production for both grain and silage. At the same time, the production techniques of F1 seeds have also improved.

• Journal of The Korean Society of Grassland and Forage Science
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• v.26 no.1
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• pp.9-14
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• 2006

This experiment was carried out to breed the cold-tolerant variety of Italian ryegrass (Lolium multiflorum Lam.) at the Grassland and Forage Crops Division, National Livestock Research Institute, RDA at Suwon, Korea, from 1999 to 2005. The new variety 'Kogreen' is a diploid variety with a green leaf color and had semi-erect habit in late autumn and erect growth habit in early spring. The heading date of 'Kogreen' was on May 4, and for 'Florida 80' was May 2, both are considered as early-heading variety. 'Kogreen' was wider by 0.7mm in flag leaf width, longer by 2 cm in flag leaf length and shorter by 1cm in plant length than the control variety, Florida 80. Stem width of 'Kogreen' was similar to that of 'Florida 80' and 'Hwasan 101'. cold tolerance of 'Kogreen' was better than that of 'Florida 80'. Dry matter(DM) yield (12,884kg/ha) of 'Kogreen' was 3% less than that of 'Florida 80'. in vitro dry matter digestibility was 74.7% and total digestible nutrient was 65.1%, which are 3.6% and 1.5% higher than those of 'Florida 80', respectively. Acid detergent fiber and neutral detergent fiber of 'Kogreen' were 30.1% and 54.1% which are 1.9% and 1.3% lower than those of 'Florida 80', respectively.

• Korean Journal of Agricultural and Forest Meteorology
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• v.8 no.4
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• pp.242-249
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• 2006

Potential impacts of the future climate change on crop production can be inferred by crop simulations at a landscape scale, if the climate data may be provided at appropriate spatial scales. Northern Gyunggi Province is one of the few prospective regions in South Korea for growing quality soybeans. Any geographical shift of production areas under the changing climate may influence the current land planning policy in this region. A soybean growth simulation was performed at 342 land units in northern Gyunggi province to test the potential geographical shift of the current production areas for quality soybeans in the near future (form 2011 to 2100). The land units for soybean cultivation were selected by the land use, the soil characteristics, and the minimum arable land area. Daily maximum and minimum temperature, precipitation, the number of rain days and solar radiation were extracted for each land unit from the future digital climate models (DCM, 2011-2040, 2041-2070, 2071-2100). Daily weather data for 30 years were randomly generated for each land unit for each normal year by using a well-known statistical method. They were used to run CROPGRO-Soybean model to simulate the growth, phonology, and yields of 3 cultivars representing different maturity groups grown at 342 land units. According to the model calculations, the warming trend in this region will accelerate the flowering and physiological maturity of all cultivars, resulting in a 7 to 9 days reduction in overall growing season and a 1 to 15% reduction in grain yield of early to medium maturity cultivars. There was a slight increase in grain yield of the late maturing cultivar under the projected climate by 2070, but a decreasing tend was dominant by the year 2100.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.7
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• pp.303-311
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• 2020

The acreage of tangerines in the U.S. sharply rose from 19,000 ha in 2009 to 27,000 ha in 2016, an increase of 42% in 7 years. Considering the recent surge in tangerine exports to Japan, the export volume of 6-7 thousand tons is highly likely to increase in the future. Therefore, the purpose of this study was to analyze the economic impact of U.S. tangerine imports on the Korean citrus industry under various scenarios. In order to examine the possibility of imports of U.S. tangerines, the unit price of U.S. exports to Japan was used since U.S. tangerines are not imported to South Korea. Citrus fruits are divided into field citrus, house citrus, and late-maturing citrus (including winter season citrus) based on the cultivation method and variety used to analyze. Considering both the field and house seasons, the import volume of U.S. tangerines can be expected to rise from roughly 4,700 tons in 2021 to 10,000 tons in 2027. Imports of U.S. tangerines may be pushed up or delayed depending not only on the harvest method and quality of domestic field and house citrus but also on the harvest of U.S. tangerines. However, it is necessary to note that tangerines could be imported after 2021, when the tariff rate on U.S. tangerines will fall below 50%.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.6
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• pp.697-704
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• 1995

This experiment was carried out to elucidate the effect of the midsummer drainage times and some growth regulators on lodging characters, lodging and yield in puddled-soil drill seeding in rice. Dongjinbyeo, the mid-late maturing rice variety was seeded at May 11 by seeding machine with 4cm of furrow depth. Experimental plots were divided two main treatment without midsummer drain and two time drains (30 and 50 days after seeding), Inabenfide(IBF) was applied 40days before heading(DBH) and IBP was applied at 30DBH, respectively. Culm length was shorten, the wall of N$_4$ was thicken, and the breaking weight was increased at two time drainage and growth regulators applied in order of Inabenfide, IBP, and Control. Lodging wasn't occurred at two time drainage but it was occurred at none drainage in the order of Control, IBP, and Inabenfide applied. Yield was higher at two time drainage compared with none drainage and higher in order of Inabenfide, IBP and Control in none drainage but wasn't significantly different among growth regulators applied in two time drainage. Therefore, two times midsummer soil drying is recommendable management method for puddled -soil drill seeding of rice. Rice, Direct seeding, Puddled-soil, Drill seeding, Midsummer drainage, Growth regulator, Lodging.

• Korean Journal of Medicinal Crop Science
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• v.9 no.4
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• pp.301-309
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• 2001

This study was conducted to provide the basic information on safflower collections and to identify the variations which could be utilized in safflower breeding programs. The agronomic characteristics was used to clarify the genetic relationships among safflower collections and to classify them into distint genetic groups. There were 21 early maturing collections with less than 80 days in number of days from planting to flowering. The number of primary and secondary branches ranged ${3.8{\sim}14.8\;and\;0{\sim}26.9}$, respectively, and two collections, IT201434 and IT202723, were found to be high branch types. The 101 safflower collections were classified into 11 groups based on the complete linkage cluster analysis using agronomic characteristics. The I, II, III, IV, IX, X and ? groups included the 25%, 33%, 14%, 8%, 2%, 1% and 1% of the collections, respectively. All the collections in the group III were Korean landraces. The collections in group X could be characterized as early emergence, late flowering and high yield components such as the number of capitula per plant, number of seeds per capitula and seed weight per plant. The number of capitula per plant and seed weight per plant, i.e., the two main yield components, had the highly significant positive correlations with stem diameter, number of the primary branches, number of the secondary branches, number of leaves and leaf length.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.5
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• pp.632-639
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• 1997

The experiment which imposed the water stress to tobacco(Nicotiana tabacum L.) plant was carried at the late of maximum growth period. In order to know the influence of drought stress on the growth and developmemt of tobacco leaves of different position and to elucidate the physiological response of plant to various soil water content, stomatal conductance, and leaf water potential were measured. The drought stress at the maximum growth period negatively affected to the overall growth characteristics of shoot. The response of the growth was small at the middle and the lower leaves, and great at the upper leaves. The relative water content of upper, middle, and lower leaves at the fifth day after treatment were 74, 64, and 59%, respectively, as soil water content was reduced by 4.3%. This suggested that the wilting point of tobacco leaf was about 75%. The leaf water potential was -0.58 MPa in control and dropped to -1.20 MPa at the fifth day after treatment. This indicated that wilting of leaf may occur at the condition in which the difference of water potential between treatment and control, well watered, was greater than about 20%. Stomatal conductance at the fifth day after treatment dropped from 12 mol /$\textrm{m}^2 sec^{-1}$ to 0.8 mol /$\textrm{m}^2 sec^{-1}$ in the middle and the upper leaves. Stomatal conductance of lower leaves already matured were not affected highly by drought stress at the maximum growth period, but maturing leaves, middle and upper leaves, were highly affected by limitation of soil water.

• Journal of The Korean Society of Grassland and Forage Science
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• v.17 no.4
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• pp.315-322
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• 1997

Sixteen cultivars of corn(Zea mays L.) hybrids have been recommended as the government recommended corn hybrids since 1984, however, their forage performances have been mostly tested at two locations, such as Suweon and Sunghwan in the Middle parts of Korea. Therefore, the objective of this experiment was to retest the agronomic characteristics and yield of eleven of sixteen government recommended corn hybrids at five scattered locations, such as Icheon, Suweon, Sunghwan, Keonpan and Kwangju in 1993 and 1995 with the intention of improving recommendations to dairy farmers. Among the corn hybrids tested, 'Suweon 19' was susceptible to foliar diseases and poor stay green at all locations in 1993 and 1995. Generally, all hybrids have less lodging and infection rate of rice black streaked dwarf virus(RBSDV) varied by location but mostly not exceed 10%. Infection rate at Sunghwan and Kwangju among locations was the highest as 13.5 and 15.3% respectively. Among the corn hybrids tested, 'Suweon 19' was the highest RBSDV infection rate, but that of 'Kwanganok' and '3282' was lower than other hybrids. At all locations, '3352' and '3394' were the earliest in growth stage, but 'Kwanganok', '3282', 'DK729', 'G4624' and 'DK713' were the latest among the corn hybrids. Ear percentage in total DM of '3352', '3394' and 'G4624' was higher than other hybrids, but that of 'DK713' was the lowest among the corn hybrids. '3352' and '3394' showed the most suitable DM content for silage production at harvest. Among the corn hybrids tested, 'Suweon 19' and '3282' were the lowest DM yield at all locations in 1993 and 1995, but the highest DM yield varied by location. At Icheon, '3144W' and 'G4743', at Suweon, '3352' and '3144W, at Sunghwan, 'DK729' and '3144W', at Keongsan, '3352' and 'DK729', and at Kwangju, '3352' and 'DK689' were the highest DM yield in 1993 and 1995, respectively. Then, '3394' was higher than other hybrids at all locations in 1995. The government recommended corn hybrids tested were generally adapted across the country. However, in forage production situations where wrn should be harvested before the rainy season in late summer, earlymedium maturing corn hybrids, '3352' and '3394' might be preferred.