• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.3
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• pp.327-331
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• 2009

Korean government has promoted the policy of chemical fertilizer reduction by 40% reduction from 2003 to 2013. Hairy vetch (Vicia villosa Roth) fixes nitrogen from the atmosphere and rye (Secale cerale L.) accumulates soil nitrogen to reduce potential nitrogen loss. The objective of this research was to identify optimum seeding rates of hairy vetch-rye mixtures in the central regions of Korea. The experiment of mixture rate was carried out for maximum production in 2006 and 2007. The best seeding rate mixture for maximum biomass production was 6.75 kg hairy vetch and 5 kg rye per 10a. Pure hairy vetch and rye were used as control. The nitrogen production of mixture treatments were higher than pure rye. The hairy vetch and rye mixture can scavenge potentially leachable nitrogen, while maintaining soil fertility by adding fixed nitrogen to the cropping system.

• Korean Journal of Weed Science
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• v.15 no.3
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• pp.197-205
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• 1995

The objectives of the present study were to find out 1)the differences in growth of radish under foggy and non-foggy condition, 2)the weed competition between radish and major upland weeds including Echinochloa crus-galli, 3)difference in response of radish to herbicide and weed, and finally 4)the fundamental data for the establishment of radish weed control system under locational foggy regions. The research was carried out by tray in greenhouse equipped with Auto Foggy System(SAE KI RIN Co.) and results were summarized as follows. 1. Plant height and shoot fresh weight of radish cultivars(long skirt, delicious altari, green mascot) were not different at the early growth(8 to 38 days after seeding), but increased at 55 days after seeding under foggy condition. Root fresh weight increased only in green mascot cultivar tinder foggy condition. Chlorophyll contents were higher in all the cultivars of radish under foggy condition. 2. Plant height and shoot fresh weight increased at 0 and 20 days of weed competition under foggy condition. Root fresh weight increased at 0, 20 and 35 days of competition under foggy condition. Above 50 days-competition, there was no difference between foggy and non-foggy condition. 3. Napropamide, alachlor and linuron did not show any differences in plant height and shoot fresh weight between foggy and non-foggy condition. Molinate reduced the root fresh weight at 65 days after seeding tinder foggy condition. 4. No difference in weeding efficacy by any herbicides tested was found tinder foggy condition. Weeding efficacy of Aeschynomene indica was reduced under foggy condition.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.6
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• pp.666-672
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• 1997

Twenty years' daily mean air temperature data was used to calculate the critical early seeding date(CESD), the optimum heading date(OHD), the critical late heading date for stable ripening(CHDR) and the critical late ripening date(CLRD) for rice seeded on dry paddy in different agroclimatic zones in Korea. The CESD was defined as the first day with mean air temperature of 13$^{\circ}C$, and the OHD as the first day of the 40 consecutive days with mean air temperature of 22$^{\circ}C$ or above after heading. The CHDR was defined as the date after which the cumulative daily mean air temperature would be at least 76$0^{\circ}C$. Lastly, the CLRD was defined as the last day when daily mean air temperature remains above 15$^{\circ}C$. This information was used for the estimation of periods from the earliest date of seeding to optimum heading date, the latest possible date of heading and the latest possible date of ripening in respective regions. For instance, in Suwon, those respective periods mentioned were found to be 104days, 124days, and 165days.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.64 no.4
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• pp.336-343
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• 2019

Wet direct-seeding (WDS) is an important method for improving the competitiveness of rice production in South Korea. We analyzed the optimum direct-seeding date to establish the rice standing rate in each area and selected suitable areas for WHS by considering the heading stage limit date for improving cultivation safety. As a result, the rice direct-seeding date to control weedy rice was around 5.15, 5.17-5.19, and after 5.20 in southern Youngnam, southern Honam, and the Middle Coast areas, respectively. However, the optimum seeding date for good standing rice was in late March in most areas. Analyzing by area, most of the southern plains and parts of the central inland plain are suitable for WHS. However, most parts of Gwangwon-do, and the northern parts of Chungbuk, Gyeongbuk, and Yeonghonam areas are not suitable for WHS, and should therefore avoid WHS.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.2
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• pp.67-72
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• 2005

Overwintering capacity, closely related to winter hardiness, of Chinese milk vetch planted with different sowing times and sowing practices was investigated to improve the incorporation into cropping system in Korea. The tolerance to low temperature was evaluated with $LT_50$ using leaf disc leaching method. Dry weight of CMV was reduced remarkably with delayed planting from Sep. 5 to Oct. 20. The differences in tolerance to freezing temperature were not conspicuous among CMV genotypes, however, the differences between genotype (collections at different regions) were due to the plant architecture, mainly to the leaf angle. The crouching genotype collected at central region of Korean peninsula, which showed excellent freezing tolerant, has planophile leaves. The feature of internal constituents of CMV genotypes did not show any noticeable differences with respect to the freezing tolerance which evaluated by leaf disc leaching experiment. To overcome the poor overwintering capacity, tolerant genotype should be developed by selection with considering the plant architecture. The reduction of CMV growth during overwintering period was ameliorated with furrow-sowing under late-sown condition, therefore, when the CMV is inevitably sown late after recommended time, the seeds should be sown on furrow to overcome the cold stress.

• Journal of The Korean Society of Grassland and Forage Science
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• v.38 no.4
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• pp.231-242
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• 2018

This experiment was carried out to study the effects of different environmental conditions and production techniques on forage productivity of Italian ryegrass (IRG) in central and southern regions of Korea from 2016 to 2017. Average dry matter yield of 27 IRG cultivation regions was 6,940kg/ha. Forage productivity of IRG have positive correlation with cultivation techniques(p<0.01) but not correlated with cultivation environments. Forage productivity of IRG have positive correlation with seeding and field management techniques(p<0.01) but not correlated with fertilization techniques. This results suggests that practices of cultivation techniques are more important than cultivation environments for increasing the forage productivity of IRG. Therefore, yield prediction techniques of IRG in Korea have to be considered the practices of cultivation techniques along with soil and climate conditions.

• Journal of Korean Neurosurgical Society
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• v.30 no.12
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• pp.1381-1387
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• 2001

Objective : Endodermal sinus tumor or yolk sac tumor is an uncommon malignant germ-cell neoplasm. This tumor was originally described as a germ cell tumor of the ovary or the testis. Intracranial endodermal sinus tumor is extremely rare and usually develop in the pineal or suprasellar regions. The authors evaluated the effect of adjuvant therapy(chemotherapy combined with radiotherapy) and radical removal of intracranial endodermal sinus tumors. Material and Methods : Between 1996 and 2001, four patients of intracranial endodermal sinus tumor were diagnosed with tumor marker(AFP) and biopsy. Three patients were treated with surgical removal and chemotherapy with cisplatin($20mg/m^2$), etoposide($100mg/m^2$) and bleomycin($15mg/m^2$) as well as external beam radiation therapy. We compared the management problems for these tumors. Result : In all three patients the tumor size and the level of tumor marker decresed during initial adjuvant therapy. However, Tumors showed regrowth with elevated AFP of serum and CSF possibly related to delayed chemotherapeutic treatment or inadequate administration of chemotherapeutic drugs due to severe bone marrow suppression. An additional chemotherapy and external radiation therapy were given, but tumors could not be controlled with leptomeningeal seeding. Conclusion : Radiotherapy is considered to be less effective. The combination chemotherapy with PVB(cisplatin, vinblastine, bleomycine) or PE(cisplatin, etoposide) is considered to be value in prolongation of the survival rate. But the role of chemotherapy in this tumor has not yet been clarified due to bone marrow suppression and drug resistance. Further study with large series of this tumor is necessary to establish the optimal management.

• Journal of Environmental Science International
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• v.25 no.6
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• pp.889-895
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• 2016

In Danseong-myeon (myeon is a subdivision of), Sancheong-gun, and Sugok-myeon, Jinju City, pot seedling culture was used at the rates of 100% and 62%, respectively. Root restriction seedling culture was used relatively more frequently than pot seedling culture in Yangchon-myeon, Nonsan City, Guryong-myeon, Buyeo-gun, and Wolsan-myeon, Damyang-gun. Open-field seedling culture was used at the rates of 80% and 54% in Samnangjin-eup (eup is a subdivision of a gun), Miryang City and Ssangnim-myeon, Goryeong-gun, respectively. In Danseong, Sancheong, and Sugok, Jinju, granite soil was used as the medium for pot seedling culture at the rates of 90% and 80%, respectively. In Yangchon, Nonsan, Wolsan, Damyang, and Ssangnim, Goryeong, commercial bed soil and coir dust were used for seedling culture at the rates of 73%, 64%, and 60%, respectively. At the main production sites, the use of granite soil for seedling culture, highest rate in 2000-2005, continued to decrease; in 2011-2013, granite soil was used at the rate of 37%, while commercial bed soil and coir dust were used at the rates of 32% and 14%, respectively. The bulk density of commercial bed soil, expanded rice hulls, and coir dust was $0.11-0.16g/cm^{-3}$. Coir dust was the lightest material but had the highest and, 36.7% and 21.8%, respectively. In sandy loam soil and granite soil was low. The pH of all growth media was between 5.4 and 7.0, and the values were in the range of $0.15-0.66dS{\cdot}m^{-1}$. However it was necessary, to adjust the pH levels and enhance the of expanded rice hulls, sandy loam soil, and granite soil. Similarly, the fertilizer concentration and air permeability of coir dust need to be adjusted.

• Korean Journal of Agricultural Science
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• v.39 no.4
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• pp.477-482
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• 2012

Low-temperature germination is one of the major determinants for stable stand establishment in the rice direct seeding method in temperate regions and at high altitude areas. Quantitative trait loci (QTL) controlling low-temperature germinability in rice were identified using 96 introgression lines (ILs) derived from a cross between Oryza rufipogon and the Korean japonica cultivar, 'Hwaseongbyeo'. The germination rate at $15^{\circ}C$ was measured to represent low-temperature germination and used for QTL analysis. The germination rate at $15^{\circ}C$ for 7 days of Oryza rufipogon and Hwaseongbyeo was 93.3 and 28.7%, respectively, and that of progenies ranged from 0 to 48%. A linkage map was constructed using 135 simple sequence repeat (SSR) markers. Five putative QTLs associated with low-temperature germination were detected on chromosomes 1, 3, 4, 10 and 11. The QTL, qltg10 on chromosome 10 accounted for 19.2% of the total phenotypic variation for low-temperature germinability. Four additional QTL, accounted for 10.4 - 15.1% of the total phenotypic variation. The O. rufipogon alleles in all detected QTLs loci increased the low-temperature germination rate. No QTL associated with low temperature germinability has been detected near the qltg10 QTL in this study suggesting that qltg10 is a new QTL. The locus, qltg10 is of particular interest because of its independence from undesirable height and maturity effects. The DNA markers linked to the QTL for low temperature germinability would be useful in selecting lines with enhanced low temperature germinability in rice breeding program.

• Journal of Practical Agriculture & Fisheries Research
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• v.24 no.3
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• pp.25-31
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• 2022

Low-temperature germinability (LTG) is an important trait for the direct seeding of rice in temperate and high altitudes regions. Water temperature of rice fields at sowing season is frequently under 15℃ in Korea, resulting in poor seedlings establishment. The objective of this study was to phenotypically and genetically evaluate 600 rice germplasm composed of six rice subpopulations. In the phenotypic evaluation, aus (AUS) showed the highest visual rating (VR) and germination rate (GR) of 5 and 83.1%, respectively, than other subpopulations. The lowest value of VR (7.1) and GR (53.1%) was observed in aromatic (ARO) subpopulation. Association of the phenotype for LTG with the genotype for qLTG3-1, a major QTL for LTG, and other three SNP markers (LTG_8, qLTG4b-1, qLTG2-6) was conducted. The results suggested that the allele distribution of two markers, qLTG3-1 and qLTG2-6, affects the difference in VR and GR between subpopulations. qLTG4b-1 and LTG_8 were also highly significant with LTG in all subpopulations except that qLTG4b-1 did now show significance in AUS. Therefore, the combination use of these four markers might be effective for evaluation of LTG in rice germplasm.