• Korean Journal of Environmental Agriculture
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• v.31 no.1
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• pp.30-36
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• 2012

BACKGROUND: The resistance of rice bakanae disease pathogens against the fungicide prochloraz has been reported. Understanding the resistance mechanisms is an important for better control of the pathogens. In the present study, we investigated the resistance mechanisms of Fusarium fujikuroi CF337 (CF337) against prochloraz. METHODS AND RESULTS: Morphological changes in the cell wall of CF337 grown in potato dextrose broth (PDB) with or without prochloraz was investigated by transmission electron microscopy. Growth inhibition of CF337 was examined in PDB containing prochloraz or an ABC transporter inhibitor or both of them. Cell wall thickness of CF337 grown in PDB with prochloraz was significantly increased from $80.73{\pm}1.99nm$ to $193.11{\pm}7.07nm$. Significant inhibition in the growth of CF337 was observed in the presence of both prochloraz and the inhibitor, but no growth inhibition was observed in the presence of the inhibitor or prochloraz. Sequence analysis of ATP-binding cassette transporter (ABC) gene of CF337 showed 70 to 80% similarities to the genes of the pathogens resistant to other fungicides. CONCLUSION: Efflux transporter system and changes in cell wall thickness were suggested as resistance mechanisms of CF337 against prochloraz.

• Korean Journal of Agricultural Science
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• v.35 no.1
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• pp.69-83
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• 2008

The self-supply rate of Korea in 2006 was approximately 27.3 % by importing 13.99Mt for 19.79Mt of demanded amount. Among the imported crops, wheat, corn, and soybean consumed 95 % for the total imported amount, and wheat, corn, and soybean were 3.5Mt(Table use : 0.22Mt; Feed stuff : 0.13Mt), 8.7Mt(Table use : 0.19Mt; Feed stuff : 0.68Mt), and 1.2Mt (Table use : 0.03Mt; Feed stuff : 0.09Mt), respectively. On the other hand, our government has prepared the strategies for a great fear of food according to sharp price rise of the international crops by maintaining the self-supply rate of 5 % excluding 5.23Mt of rice in Korea. Also concern for recycled energy known as future energy for era of high oil price and global warming due to green house gas is rapidly growing. Therefore, our country which has relied on import of the whole oil needed in Korea and has to keep Kyoto Agent to request reduction of green house gas fully support research and practical use for agricultural products as resource of alternate energy. At first, we have to develop the mass production technology in order to secure a program of self-supply of food for bioenergy production utilizing agricultural product in Korea. But we assume that this matter is difficult to achieve under the current agriculture system that more emphasizes the environment conservation such as environmentally-friendly agriculture than production of food.

• The Plant Pathology Journal
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• v.34 no.1
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• pp.35-43
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• 2018

Root-knot nematodes (Meloidogyne spp.) are parasites that attack many field crops and orchard trees, and affect both the quantity and quality of the products. A root-colonizing bacterium, Pseudomonas chlororaphis O6, possesses beneficial traits including strong nematicidal activity. To determine the molecular mechanisms involved in the nematicidal activity of P. chlororaphis O6, we constructed two mutants; one lacking hydrogen cyanide production, and a second lacking an insecticidal toxin, FitD. Root drenching with wild-type P. chlororaphis O6 cells caused juvenile mortality in vitro and in planta. Efficacy was not altered in the fitD mutant compared to the wild-type but was reduced in both bioassays for the mutant lacking hydrogen cyanide production. The reduced number of galls on tomato plants caused by the wild-type strain was comparable to that of a standard chemical nematicide. These findings suggest that hydrogen cyanide-producing root colonizers, such as P. chlororaphis O6, could be formulated as "green" nematicides that are compatible with many crops and offer agricultural sustainability.

• The Plant Pathology Journal
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• v.36 no.5
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• pp.497-502
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• 2020

Barley yellow dwarf virus (BYDV) is an economically important plant pathogen that causes stunted growth, delayed heading, leaf yellowing, and purple leaf tip, thereby reducing the yields of cereal crops worldwide. In the present study, a reverse transcription recombinase polymerase amplification (RT-RPA) assay was developed for the detection of BYDV in oat leaf samples. The RT-RPA assay involved incubation at an isothermal temperature (42℃) and could be performed rapidly in 5 min. In addition, no cross-reactivity was observed to occur with other cereal-infecting viruses, and the method was 100 times more sensitive than conventional reverse transcription polymerase chain reaction. Furthermore, the assay was validated for the detection of BYDV in both field-collected oat leaves and viruliferous aphids. Thus, the RT-RPA assay developed in the present study represents a simple, rapid, sensitive, and reliable method for detecting BYDV in oats.

• Korean Journal of Organic Agriculture
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• v.26 no.1
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• pp.1-17
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• 2018

This study analyzes the management performance of environmentally-friendly rice farms using GCM method based on the multifaceted approach. This approach compares the management performance of GCM farms before and after the introduction of GCM, as well as the performance of GCM farms with the performance of conventional farms. It also compares the technical and managerial competence level of surveyed GCM farms with that of conventional farms based on the standard diagnosis table developed by Rural Development Adminstration. Results showed that average income has increased after the introduction of the GCM method and the average income of GCM farms was higher than that of conventional farms, while the level of rice production in farms using GCM method was lower than that of conventional farms. In addition, the technical and managerial competence score of surveyed farms using GCM method was higher than that of conventional farms. These results implies that the higher management performance of GCM farms compared to the conventional farms is attributed to not only the GCM method but also the competence level of farms using GCM method.

• The Plant Pathology Journal
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• v.34 no.6
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• pp.575-579
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• 2018

Apple stem grooving virus (ASGV) is considered to cause the most economically important viral disease in pears in Korea. The current PCR-based methods used to diagnose ASGV are time-consuming in terms of target detection. In this study, a novel assay for specific ASGV detection that is based on reverse transcription-recombinase polymerase amplification is described. This assay has been shown to be reproducible and able to detect as little as $4.7ng/{\mu}l$ of purified RNA obtained from an ASGV-infected plant. The major advantage of this assay is that the reaction for the target virus is completed in 1 min, and amplification only requires an incubation temperature of $42^{\circ}C$. This assay is a promising alternative method for pear breeding programs or virus-free certification laboratories.

• Research in Plant Disease
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• v.28 no.2
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• pp.92-97
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• 2022

Apple stem grooving virus (ASGV) is a high-risk viral pathogen that infects many types of fruit trees, especially pear and apple, and causes serious economic losses across the globe. Thus, rapid and reliable detection assay is needed to identify ASGV infection and prevent its spread. A reliable reverse transcription loop-mediated isothermal amplification (RT-LAMP) was developed, optimize, and evaluated for the coding region of coat protein of ASGV in pear leaf. The developed RT-LAMP facilitated the simple screening of ASGV using visible fluorescence and electrophoresis. The optimized reaction conditions for the RT-LAMP were 63℃ for 50 min, and the results showed high specificity and 100-fold greater sensitivity than the reverse transcription polymerase chain reaction. In addition, the reliability of the RT-LAMP was validated using field-collected pear leaves. Furthermore, the potential application of paper-based RNA isolation, combined with RT-LAMP, was also evaluated for detecting ASGV from field-collected samples. These assays could be widely applied to ASGV detection in field conditions and to virus-free certification programs.

• Korean Journal of Organic Agriculture
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• v.16 no.4
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• pp.367-390
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• 2008

Consumer's concerns over beef safety are increasing according to resuming U.S. beef import. And a few beef producers have converted into organic beef recently. This organic beef must have taste, nutrition and safety that consumers demand for. Korean organic beef should be gone on sale at the shop under direct management of producer's organizations or the special shop for Environmentally friendly products. So they should win consumers' confidence for beef safety and transparency in producing and marketing process.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.4
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• pp.540-547
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• 2001

An experiment was conducted to investigate the effects of environmentally friendly agents (yucca extract, mineral feed additive, acidifier, nonspecific immunostimulating anionic alkali solution) on the growth performance, nutrient digestibility, nutrient excretion and carcass characteristics in growing-finishing pigs. A total of 125 pigs were allotted into 5 treatments with 5 replications, 5 pigs per pen in a completely randomized block design. Dietary treatments consisted of 1) control: basal diet, 2) YE: basal diet+120 mg/kg of yucca extract, 3) MFA: basal diet+50 mg/kg of mineral feed additive, 4) NIS: basal diet+3% of NIS (nonspecific immunostimulating anionic alkali solution), and 5) Acidifier: basal diet+0.5% of acidifier (organic acid complex). During the growing phase of the feeding trial, There were no significant differences in average daily feed intake (ADFI) and feed conversion ratio (F/G) among treatments, but the Acidifier group showed higher average daily gain (ADG) than the MFA group (p<0.05). During the finishing phase, there were no significant differences in growth performance among treatments, however YE supplementation increased ADG and F/G by 3.1 and 6.15%, respectively, when compared to control group. Proximate nutrients (dry matter, DM; crude protein, CP; crude ash, CA; crude fat, CF; gross energy, GE; calcium, Ca and phosphorus, P) digestibility did not show any significant differences among the treatments. And there were no significant differences in DM, N and P excretion as well. The supplementation of environmentally friendly agents tended to increase carcass weight compared to control group. Pigs fed MFA showed significantly heavier (p<0.05) carcass weight than those fed control or Acidifier diets. Addition of these agents except for NIS to diet for growing-finishing pigs caused a similar feed cost/kg weight gain than control group. Therefore, present study suggested that the optimum environmentally friendly agent would be yucca extracts, considering the effects on growth performance, nutrient digestibility, nutrient excretion, carcass characteristics and feed cost in growing-finishing pigs.

• Korean Journal of Organic Agriculture
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• v.21 no.2
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• pp.139-155
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• 2013

The purpose of this study is to analyze the effects of abolishing the low-pesticide agricultural product certification on environmentally friendly farming. A survey was conducted to quantitatively analyze farming practices and factors that change farming practice. It was found that only 17.0% of low-pesticide fruit farmers said that they will change their farming practice into organic or pesticide-free farming. With regard to the factors of farming practice change, binomial logistic regression model was applied for the analysis. In the analysis, it was found that farmers who grow the low-pesticide agricultural product are more likely to change their farming practice into organic or pesticide-free farming, as their expected price of organic or pesticide-free products is high, their area size is small, price premium of low-pesticide agricultural product is low, the frequency of their training is high. It is necessary to enhance the direct payment system to enlarge organic and nonpesticide acreage, and pest management techniques for fruits should be developed for low-pesticide fruit farmers to change their practice into organic and nonpesticide practice. Dissemination of cultivation manual, introduction of insurance to farmers, improvement of certificate system, and advertising and marketing of environment-friendly agricultural products are useful to develop environment-friendly agriculture.