• Korean Journal of Breeding Science
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• v.40 no.2
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• pp.188-191
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• 2008

'Hwangkeumnuri' is a japonica rice variety developed and registered by the rice breeding team of Honam Agricultural Research Institute, NICS, RDA in 2006. This variety was derived from a cross between 'Milyang 165' (Junambyeo) with good quality and high yield and HR14732-B-67-2-3 with multi-disease resistance. This variety has about 125 days growth duration from transplanting to harvesting in west-southern coast, Honam and Youngnam plain of Korea. It is about 76 cm in culm length and tolerance to lodging. In reaction to biotic and abiotic stresses, it shows resistance to blast, bacterial blight pathogen from $K_1$ to $K_3$ and stripe virus, but susceptible to other major diseases and insect pests. The milled rice of 'Hwangkeumnuri' exhibits translucent, relatively clear non-glutinous endosperm and midium short grain. It has similar amylose content of 18.9% and lower protein content of 6.2%, and good palatability of cooked rice compared with 'Nampyeongbyeo'. The milled rice yield performance of this variety is about 5.74 MT/ha in local adaptability test for three years. 'Hwangkeumnuri' would be adaptable to west-southern coast, Honam and Yeongnam plain of Korea.

• Korean Journal of Environment and Ecology
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• v.25 no.6
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• pp.893-902
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• 2011

The purpose of this study was to survey structures and growth conditions of Pinus densiflora village groves, and to establish management strategies for their desirable growth and conservation. Twelve village groves were selected in western Gangwon province for the study. The age of the study groves ranged from 50 to 200 years. Average dbh (diameter at breast height) and density of trees for each study grove were 27~52cm and 0.5~9.3 trees/$100m^2$, respectively. Soil environments were favorable to Pinus densiflora growth in the majority of the study groves, but 2 study groves with sandy soils showed considerably poor nutrient contents. Low tree vitality was found in some of the study groves due to poor conditions of root growth from soil fill and trampling. There were detachment of cambial tissue and damage of stem cavity at 6 study groves, which were caused by artificial injury, careless pruning, and frost damage. Light disease damage by Rhizosphaera kalkhoffii and phomopsis blight were found at 6 study groves. Light pest damage by Thecodiplosis japonensis was also found at 6 study groves, but the pest damage at 2 study groves was relatively considerable. Thus, major factors limiting normal growth of Pinus densiflora village groves were infertility, soil fill and trampling, stem damage, and disease and pest. Desirable management strategies were explored to solve growth-related problems and to conserve the study groves. The management strategies included fertilization of organic matter and lime, removal of soil fill, soil plowing and graveling, wood-trail installation or woodchip mulching, supply of wood fences and protective frames, surgical operation for damaged stems, vitality enhancement, and trunk injection to improve growth environments or control stem damage and disease/pest.

• Korean Journal of Weed Science
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• v.32 no.2
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• pp.98-106
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• 2012

This research has been carried out to find out the highest effect on insecticidal, fungicidal and herbicidal activities in leaves, stem and tuber extracts of yacon (Smallanthus sonchifolius) and extraction methods such as water, boiling water and methanol. Characteristics of potential herbicidal components among extraction methods were investigated by solvent fractions such as hexane, chloroform, ethyl acetate, butanol, and water. Generally, methanol extract was the best on inhibition of germination rate, plant height, and root length in cucumber and barley. On the other hand, the inhibition effect on growth in cucumber and barley was the best in tuber among plant parts of yacon. Inhibition of germination rate, plant height, and root length in cucumber and barley in solvent fractions was the best in water fraction, but there were no differences in other fractions. Digitaria sanguinalis L. and Solanum nigrum L. by 5 and 10% extractions of yacon tuber were controlled by more than 70~80% and 95~100%, respectively. However, there was no inhibition effect on foliar treatment in cucumber and barley as affected by 5 and 10% extractions of yacon tuber. Mortality of green peach aphid (Myzus persicae Sulzer) was 50% at 3 days after treatment of 5% extracts of yacon leaves. Mortality of brown plant hopper (Nilaparvata lugens Stal) was only 24% in 5% extracts of stems and leaves with midrib, but was 57% in 5% extracts of leaves without midrib. There was no fungicidal effect on anthracnose (Colletotrichum truncatum), wilt disease (Fusarium oxysporum), verticillium wilt (Verticillium dahliae), bacterial blight (Xanthomonus oryzae) in 5% extracts of yacon leaves.

• Journal of Life Science
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• v.25 no.10
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• pp.1091-1097
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• 2015

We have isolated and characterized an ascorbate peroxidase (APx) gene, OsAPx1 from rice. Northern and Western blot analyses indicated that at young seedling stage, OsAPx1 mRNA was expressed highly in root, shoot apical meristem (SAM) and leaf sheath than leaf. In mature plant, OsAPx1 gene expressed highly in root, stem and flower but weakly in leaf. OsAPx1 gene and protein expression level was induced in leaves inoculated with Magnaporthe oryzae (M. oryzae) and Xanthomonas oryzae pv. oryzae (Xoo). Phytohormones treatment showed that OsAPx1 was up-regulated by jasmonic acid (JA), but was down regulated by ABA and SA co-treatments with JA, resulting that they have antagonistic effect on pathogen responsive OsAPx1 expression. Phylogenetic analysis illustrated that Arabidopsis AtAPx1 has a close relationship with OsAPx1. In AtAPx1 knock out lines, the accumulation of O₂^- and H₂O₂ are all highly detected than wild type, revealing that the high concentration of exogenous H₂O₂ cause the intercellular superoxide anion and hydrogen peroxide accumulation in AtAPx1 knockout plant. These results suggested that OsAPx1 gene may be associated with the pathogen defense cascades as the mediator for balancing redox state by acting ROS scavenger and is associated with response to the pathogen defense via Jasmonic acid signaling pathway.

• Research in Plant Disease
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• v.10 no.2
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• pp.100-104
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• 2004

Two species of Phytophthora were isolated from a leaf blight disease found on castor bean plants growing at a residential area of Hwanggeum-dong in Daegu city. One species was producing conspicuously papillate, noncaducous, ovoid to obpyriform sporangia, 31.2-58.5 ${\times}$ 25.4-44.1 ${\mu}{\textrm}{m}$ in range with an average of 46.4 $\pm$ 6.5 ${\times}$ 35.9 $\pm$ 4.7 ${\mu}{\textrm}{m}$ on simple sympodial sporangiophores, was heterothallic with oogonia globose, 22.5-35.0 ${\mu}{\textrm}{m}$ with an average of 30 $\pm$ 3.3 ${\mu}{\textrm}{m}$ in diameter, oospores plerotic, 18.8-30.0 ${\mu}{\textrm}{m}$ in range averaging 25.4 $\pm$ 2.8 ${\mu}{\textrm}{m}$, and with antheridia amphigynous. This species was identified as P. nicotianae Breda de Haan. The other species produced papillate, caducous, ovoid to ellipsoid sporangia with pedicel, 21.5-54.6 ${\times}$ 17.6-34.3 ${\mu}{\textrm}{m}$ in range with an average of 41.7 $\pm$ 7.1 ${\times}$ 28.4 $\pm$ 4.0 ${\mu}{\textrm}{m}$, and was heterothallic with oogonia globose, 21.3-26.8 ${\mu}{\textrm}{m}$ with an average of 23.0 $\pm$ 1.6 ${\mu}{\textrm}{m}$ in diameter, oospores plerotic, 17.5-23.8 ${\mu}{\textrm}{m}$ in range averaging 20.2 $\pm$ 1.8 ${\mu}{\textrm}{m}$, and with antheridia amphigynous. This species was identified as P. palmivora (Butler) Butler. Both species produced chlamydospores. Pathogenicity of the 2 speices was confirmed by foliar inoculation of castor bean seedlings. Both species have been reported to infect castor bean plants in a few foreign countries but it is the first that a disease of castor bean plants caused by either or both of the species was found in Korea.

• Korean Journal of Breeding Science
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• v.51 no.4
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• pp.395-403
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• 2019

Rice blast caused by the fungus Magnaporthe grisea (anamorphic: Pyricularia oryzae) is an important disease in rice and development of resistant varieties to blast is one of the most important goals in rice breeding programs. A japonica rice variety, Palgong, has shown resistance to the Korean blast pathogen since it was developed in 1996. Nine blast resistance quantitative trait loci (QTLs) in Palgong alleles were identified on chromosomes 2, 4, 7, and 11. Four QTLs of qBn2.3, qBn4.2, qBn11.1, and qBn11.2 explained 28-56.7% of total phenotypic variation, while five QTLs of qBn2.2, qBn2.4, qBn4.1, qBn7.1, and qBn7.2 explained 9.7-18.8%. In a previous study, one to four resistance genes were located on the loci qBn2.2, qBn2.3, qBn4.2, qBn11.1, and qBn11.2, however, resistance genes were not located on the loci qBn2.4, qBn4.1, and qBn7.1. A major QTL, qBn11.2, explaining 56.7% of total phenotypic variation was related to the durable resistance of Palgong. Additionally, rice stripe virus resistance of Palgong was assumed to be based on the Stvb-i gene, which is located on a major QTL qBn11.2.

• Korean Journal of Breeding Science
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• v.42 no.6
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• pp.638-644
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• 2010

A new rice variety 'Haeoreumi' is a japonica rice (Oryza sativa L.) with lodging tolerance, resistance to rice stripe virus (RSV) and bacterial leaf blight (BLB), and high grain quality. It was developed by the rice breeding team of Yeongdeog Substation, National Institute of Crop Science (NICS), RDA in 2008. This variety was derived from a cross between 'Milyang165' with good grain quality and lodging resistance, and 'Haepyeongbyeo' with wind tolerance in winter season of 2000/2001. A promising line, YR22375-B-B-1, selected by pedigree breeding method, was designated as the name of 'Yeongdeog46' in 2005. 'Yeongdeog46' was released as the name of 'Haeoreumi' in 2008 after the local adaptability test that was carried out at nine locations from 2006 to 2008. 'Haeoreumi' has 74 cm short culm length as and medium maturating growth duration. This variety showed resistance to $K_1,\;K_2$, and $K_3$ races of bacterial blight, and stripe virus and moderate resistant to leaf blast disease with durable resistance, and also has tolerance to unfavorable environment such as cold, dry and cold salty wind. 'Haeoreumi' has translucent and clear milled rice kernel without white core and white belly rice, and good eating quality as a result of panel test. The yield potential of 'Haeoreumi' in milled rice is about 5.58MT/ha at ordinary fertilizer level of local adaptability test. This cultivar would be adaptable to Middle plain, mid-west costal area, and east-south coastal area.

• Korean journal of applied entomology
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• v.46 no.1 s.145
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• pp.63-69
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• 2007

This study was conducted to examine the problems that would arise in our cropping systems when introducing Gain Threshold (GT) which is an important element in determining Economic Injury Level (EIL). Cain Threshold (GT) can be defined as the amount of damage (=yield loss) to justify management, and calculated by dividing the management costs by the market crop price. GTs for some pests in rice, soybean, and greenhouse vegetable crops cultivation were estimated and also compared with those in foreign countries. GTs and percentage of yield loss equivalent to them were estimated to be 4.6-6.1kg/10a/season and 1.0-1.3% for brown planthopper, white-backed planthopper, rice water weevil, and sheath blight, whereas for rice blast in rice cultivation were 12.7kg/10a/season and 2.7%. In soybean cultivation, the values for bean bug were 6.2 kg/10a/season and 3.6%. GTs and percentage of yield loss estimated for melon thrips, whitefly, and downy mildew in cucumber cultivation were 10.0-12.6kg/10a/week, 1.4-1.7%, and the values for two spotted mite and gray mildew in strawberry cultivation were 3.1-3.5kg/10a/week, 1.3-1.5%, and the values for American leaf minor, whitefly, and gray mold in tomato were 8.4-9.7kg/10a/week, 1.7-1.9%. Overall GTs in our cropping systems were so low compared to those in foreign countries, which meant that the low GTs might yield the low EILs. Therefore, we could suggest that prior to direct introduction of GTs calculated from current cultivation systems in developing EILs it is necessary to seriously consider reasonable values of GTs or the yield loss equivalents to them.

• Microbiology and Biotechnology Letters
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• v.37 no.3
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• pp.280-286
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• 2009

To investigate anti-phytopathogenic fungal activity of Coptis chinensis, the methanol extract and its organic solvent fractions were prepared. Using the extract and the fractions, in-vitro spore-germination inhibition and mycelial-growth inhibition activities were evaluated against Colletotrichum gloeosporioides, Phytohpthora capsici, Pyricularia grisea, Rhizoctonia solani, Botryosphaeri dothidea, Glomerella cingulata, respectively. Treatment of the methanol extract (500 mg/mL) into the spore of phytopathogenic fungi completely inhibited germinations for 5 days, except B. dothidea, and showed strong antifungal activities against P. grisea and B. cinerea, and antioomycetes activity against P. capsici. The minimal growth inhibition concentrations of the methanol extract against P. grisea, B. cinerea and P. capsici were 300, 300, and 500 mg/mL, respectively. For practical application of C. chinensis in red-pepper field, the hot-water extract (1,000 mg/mL) was prepared in commercial facility, after evaluation of heat stability and solvent-extraction yields of antifungal substances. The 3-times leaf-spray of the extract from June to August, 2008 did not show any deleterious effect to red-pepper. In fact, the leaf-spray promoted plant growth including leaf, root and fruit. The average weight and rind of each fruit were increased to 119% and 117% comparison to those of without treatments. Our results suggest that C. chinensis is a useful source for control of red-pepper diseases and plant growth.

• The Korean Journal of Pesticide Science
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• v.8 no.4
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• pp.338-346
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• 2004

The methanol extract of Chloranthus japonicus roots effectively controlled the development of rice blast(Magnaporthe grisea), rice sheath blight(Corticium sasaki), tomato pay mold(Btrytis cinerea), tomato late blight(Phytophthora infestans), and wheat leaf rust(Puccinia recondita). From the methanol extract of C. japonicus roots, three antifungal substances were isolated. Their chemical structures were determined to be shizukanols B, C, and D mainly by mass and NMR spectral data. Among the three substances, shizukanol C showed the strongest inhibitory activity against mycelial growth of the plant pathogenic fungi tested; it completely inhibited mycelial growth of M. grisea. Colletotrichum gloeosporioides, and C. acutatum at concentrations of more than $12.5{\mu}g$/ and P. infestans at concentrations of more than $3.13{\mu}g/m\ell$. They also controlled effectively the development of rice blast and wheat leaf rust. On the other hand, they caused phytotoxic symptoms on barley leaves and inhibited the growth of duckweed (Lemna paucicostata) with $EC_{50}$ values of $30.0{\mu}g/m\ell$ for shizukanol B, $49.9{\mu}g/m\ell$ for shizukanol C, and $154{\mu}g/m\ell$ for shizukanol D. In addition, shizukanol C showed an insecticidal activity against brown planthopper (Nilaparavata lugens), peen peach aphid (Myzus persicae), diamond-back moth (Plutella xylostella), and tobacco cutworm (Spodoptera litura) of the 5 arthropod pests tested with mortality values of more than 60% at a concentration of $1,000{\mu}g/m\ell$.