• Korean Journal of Plant Resources
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• v.26 no.6
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• pp.695-700
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• 2013

Flax (Linum usitatissimum L.) has been used for the only edible oil in Korea. We carried out the field experiment in order to investigate the possibly combined effects of mepiquat chloride (MC) and trinexapac-ethyl (TE) on oil composition, lignan content, seed yield and endogenous gibberellins content of flax cultivar. Plant growth retardants mepiquat chloride (300 and 600 ppm) and trinexapac-ethyl (100, 200 and 300 ppm) were foliar-sprayed to flax plant at 50days after seeding. The plant height was decreased in the combination of mepiquat chloride 600 ppm with trinexapac-ethyl 100, 200 and 300 ppm. Mepiquat chloride treatment combined with trinexapac-ethyl observed the highest response on seed yield, followed by mepiquat chloride 300 ppm with trinexapac-ethyl 100 ppm, mepiquat chloride 300 ppm with trinexapac-ethyl 200 ppm and mepiquat chloride 300 ppm with trinexapac-ethyl 300 ppm. Lignan content was increased in all of the combination treatments. It concludes that the combination of mepiquat chloride 300 ppm with trinexapac-ethyl 300 ppm will be useful to increasing oil and lignan content in flax plants.

• The Plant Pathology Journal
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• v.29 no.4
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• pp.418-426
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• 2013

Pseudomonas isolates from different crop plants were screened for in vitro growth inhibition of Phytophthora capsici and production of biosurfactant. Two in vivo experiments were performed to determine the efficacy of selected Pseudomonas strains against Phytophthora blight of pepper by comparing two fungicide treatments [acibenzolar-S-methyl (ASM) and ASM + mefenoxam]. Bacterial isolates were applied by soil drenching ($1{\times}10^9$ cells/ml), ASM ($0.1{\mu}g$ a.i./ml) and ASM + mefenoxam (0.2 mg product/ml) were applied by foliar spraying, and P. capsici inoculum was incorporated into the pot soil three days after treatments. In the first experiment, four Pseudomonas strains resulted in significant reduction from 48.4 to 61.3% in Phytophthora blight severity. In the second experiment, bacterial treatments combining with olive oil (5 mL per plant) significantly enhanced biological control activity, resulting in a reduction of disease level ranging from 56.8 to 81.1%. ASM + mefenoxam was the most effective treatment while ASM alone was less effective in both bioassays. These results indicate that our Pseudomonas fluorescens strains (6L10, 6ba6 and 3ss9) that have biosurfactant-producing abilities are effective against P. capsici on pepper, and enhanced disease suppression could be achieved when they were used in combination with olive oil.

• The Korean Journal of Mycology
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• v.40 no.4
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• pp.299-302
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• 2012

Yeast cell wall extract (YCWE) was treated on leaves and roots of pepper seedlings at the dosage of 4 mg/mL and salicylic acid (SA) production in pepper was detected by ultra high performance liquid chromatography (UHPLC). The SA production in pepper stem was induced by YCWE. SA was produced at the highest level of 20.29 ${\mu}g/g$ after 48 hrs of foliar spray with YCWE, which is 3.7 times higher than that of root perfusion with YCWM. SA production was gradually reduced after 72 hrs of YCWE treatment.

• The Plant Pathology Journal
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• v.32 no.6
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• pp.508-518
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• 2016

Early blight of tomato caused by Alternaria solani, is responsible for severe yield losses in tomato. The conidia survive on soil surface and old dry lower leaves of the plant and spread when suitable climatic conditions are available. Macroclimatic study reveals that highest inoculum concentration of Alternaria spores appeared in May 2012 to 2013 and lowest concentration during January 2012 to 2013. High night temperature positively correlated and significantly (P < 0.01) involved in conidial spore dispersal and low relative humidity (RH) displayed significant (P < 0.05) but negative correlation with conidial dispersal. The objective of the study was to modify microclimatic conditions of tomato crop canopy which may hamper conidial dispersal and reduce disease severity. We evaluated effect of marigold intercropping and plastic mulching singly and in consortia on A. solani conidial density, tomato leaf damage and microclimatic parameters as compar to tomato alone (T). Tomato-marigold intercropping-plastic mulching treatment (T + M + P) showed 35-39% reduction in disease intensity as compared to tomato alone. When intercropped with tomato, marigold served as barrier to conidial movement and plastic mulching prevented evapotranspiration and reduced the canopy RH that resulted in less germination of A. solani spores. Marigold intercropping and plastic mulching served successfully as physical barrier against conidial dissemination to diminish significantly the tomato foliar damage produced by A. solani.

• Journal of agriculture & life science
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• v.43 no.5
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• pp.43-46
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• 2009

The one of problems of plug seedlings production in winter season was a poor growth. This study was carried out to investigate the effects of treatments with yeast fertilizers on the growth of pepper seedlings in winter seasons. The plant height, internode length, and shoot and dry weight of pepper seedlings increased significantly by yeast fertilizers. The results showed that yeast fertilizer treatment could be more effective in soaking than foliar spray and that of dilution could be effective in $1,000{\times}$.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.63 no.2
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• pp.140-148
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• 2018

As the global warming causing desertification increase, there is growing concern about damage of crops. It was to investigate how the treatment with hydrogen peroxide before leaf development affects the growth and yield of sorghum for minimizing a damage of crops to drought. The germination experiment was conducted at alternating temperature of $25^{\circ}C/20^{\circ}C$(12 hr/12 hr) under water stress condition of 0 ~ -0.20 MPa adjusted with PEG solution containing 0 and 10 mM $H_2O_2$. In order to know the effect of foliar application of hydrogen peroxide on the growth of sorghum, 10 mM hydrogen peroxide was treated to leaves at 3-leaf stage of sorghum growing in greenhouse conditions. Seed germination rate was increased by 20% in hydrogen peroxide treatment as compared to the Control. under water stress conditions (-0.15 ~ -0.20 MPa). The length of seedlings was also on the rise by the hydrogen peroxide treatment. In the greenhouse pot experiment, the morphological characteristics (plant height, stem diameter, leaf length, and leaf number) and physiological characteristics (chlorophyll content, chlorophyll fluorescence (Fv/Fm), stomatal conductance) were higher in the plants treated with hydrogen peroxide under the drought stress condition than those of plants of $H_2O$ treatment. Experiment conducted with the soil moisture gradient system showed that the foliar application of hydrogen peroxide increased photosynthetic ability of sorghum plant with respect to SPAD value and stomatal conductance and rooting capacity (root weight and root length) under drought condition. Generally, hydrogen peroxide treatment in sorghum increased the tolerance to drought stress and maintained better growth due to ameliorating oxidative stress.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.4
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• pp.422-427
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• 1989

Weeds may compete detrimentally with the ginseng for moisture and nutrients but hand weeding is the only practical means of eliminating weeds after crop establishment. To define the effects of 2, 4-D herbicide application on the plant growth and root yield of Korean ginseng (Panax ginseng C. A. Meyer). the herbicide 2, 4-D was applied as a foliar spray with the rates of 0.5. 1.0. 1.5 and 2.0 times of the recommended herbicide dosage 70ml/l0a. The Korean ginseng treated with 2, 4-D in the rate of two times concentration was indistinguishable from nontreated plants in visual rating for foliar symptoms. There were no significant differences of the leaf length and width as well as the stem length and diameter in check plants and those recieving 2, 4-D treatments. The. berry maturing in 3 and 4-years old ginseng was not inhibited with 2, 4-D treatment. The root weight of the 4-years old ginseng plant was not reduced by 2, 4-D application of 2 times dosage. However. when the ginseng seedling was treated with 2, 4-D. detrimental phenomena as stem bending and dicoloration of marginal part of seedling leaf were occured but stem bending was recovered in a few days.

• The Korean Journal of Pesticide Science
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• v.4 no.2
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• pp.37-43
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• 2000

Effects of silicon application on development of colonies of Sphaerotheca fuliginea were examined. Cucumber plants were applied with nutrient solutions amended with different concentrations of soluble silicon and selected leaves were inoculated with known concentrations of conidia of the pathogen. Colony number per leaf, colony area per leaf, and germination rate of conidia of S. fuliginea collected from the inoculated leaves were reduced as silicate concentrations in the nutrient solutions increased from 0.05 to 4.10 mM. The increase in resistance of plants to mildew infection was apparently due to silicate accumulation in leaves, and there was no correlation between cation or ionic strength effects and the silicate treatments. Silicate treatment in growth medium remarkably suppressed powdery mildew development on cucumber. Colonies of mildew fungus were visible with over approx. 38.3% of the mature leaf surface, while that of the leaves in high Si plants was 2.3% observed at 51 days after transplanting. No significant differences were observed between 1.7 mM and 3.4mM silicate treatments. Conidial germination rates were significantly reduced by increasing Si amendments. Conidial germination ranged from 14.7 to 20.3% for plants grown in low Si solution(<1.40 mM), and from 9.0 to 12.4% for plants grown in high Si solution(>1.8 mM). Foliar applications of Si with ${\geq}$ 17.0 mM decreased the number of powdery mildew colonies. Persistence of Si foliar sprays effects on cucumber demonstrated that the 17 mM Si spray applied 4 days before inoculation with S. fuliginea reduced mildew colony formation. The relationship was positive and linear.

• Korean Journal of Weed Science
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• v.6 no.1
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• pp.18-24
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• 1986

This study was conducted to determine the possible role of growth regulators and the effect of foliar part cutting on the tuber formation of C. serotinus. Foliar application of 6-benzylaminopurine (BA) increased tuber number and fresh weight of C. serotinus by an average of 24.7% and 32.4%, respectively, as compared with the untreated control. However, the tuberization of C. seratinus was inhibited by single treatment of abscisic acid (ABA) and gibberellic acid (GA) as the concentrations increased. As compared with the untreated control, BA at $10^{-4}$M and combination of BA $10^{-5}$ + GA $10^{-5}$M increased 31.8% and 53.7% of tuber number, respectively, but GA at $10^{-5}$M decreased tuber number by 21.9%. 15㎏/10a of nitrogen under three levels of BA resulted in the highest number of tuber formation of C. serotinus, an increase of 24.7% as compared with the untreated control. GA treated increased flowering of C. serotinus by an average of 4.8% based on the untreated control. Tuber number and fresh weight of C. serotinus was markedly inhibited as the number of cutting times increased. Three times cutting inhibited tuber number and fresh weight of C. serotinus by 76.1% and 96.6%, respectively, under nitrogen of 15kg per 10a as compared with the untreated control.

• Journal of Bio-Environment Control
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• v.16 no.4
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• pp.420-425
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• 2007

This study was conducted to find out the effect of vitamin C treatments on the storability of several baby vegetables; endive, green romaine lettuce, pak-choi, red romaine, lollo rosa, and ssamchoo. The vitamin C was treated by the foliar spray which was carried out 3 times before harvest or dipping in vitamin C solution for 5 minutes after harvest. The vitamin C contents of 6 different baby vegetables were higher in vitamin C treatments than control, whereas the difference of vitamin C content between treatments was disappeared after storage. The fresh weight of ssamchoo and lollo rosa lettuce treated by vitamin C was maintained higher than that of control. There was not significant difference in visual quality among treatments, though some of baby vegetables treated by washing with vitamin C showed better visual quality than the others. The contents of carbon dioxide, oxygen and ethylene in MAP with baby vegetables did not show any difference among treatments. As the result, high concentrated vitamin C treatment, such as the foliar spray and washing (dipping) had a role of increasing functionality, but the enhanced functionality, high vitamin C, did not affect storability in baby vegetables.