• Microbiology and Biotechnology Letters
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• v.10 no.1
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• pp.33-37
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• 1982

The work has been carried out for the development of antifungal antibiotics possessing curative effect in the control of sheath blight disease of rice plant. Soil samples were collected from over 1600 spots throughout the country. More than 1300 specimens which seem to be the genus Streptomyces were isolated from the soil samples. Screening procedures consist of respective processes by four steps. Those are growth inhibition test in liquid culture, paper disk method, dendroid test and green house test. 102 isolates appeared to be active against Pellicularia sasakii when all specimens isolated were examined by the first growth inhibition test. Finally a strain of Streptomyces forming strong antifungal substances against P. sasakii was selected from a soil sample of Mt. Soyo, Kyeongi Province. Antifungal substances formed by the strain were isolated and purified from the culture broth and examined for antimicrobial activities as to be specific against fungi but not active on bacterial growth.

• Korean journal of applied entomology
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• v.20 no.2 s.47
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• pp.71-75
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• 1981

The percentage of lesion height vs. plant height was higher in Yushin than Jinheung within the same nitrogen level. The infection occurred at the same level of waterline and the symptoms developed with the same speed for two varieties, but the damage was greater in Yushin as the symptoms reached faster to the top due to the short length of the 1st and 2nd internodes from the top.

• Journal of Practical Agriculture & Fisheries Research
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• v.20 no.1
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• pp.5-18
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• 2018

The field trial was performed to evaluate the rice growth and yield in direct seeding cultivation with iron-coated rice seeds. The required time for seed emergence was for 9~11days in the tested direct seeding methods. That was 1~2days earlier in direct seeding with pregerminated seeds than that of direct seeding with iron-coated seeds. The seedling establishment was highest in water seeding with iron-coated seeds but there was not significant difference in terms of statistical analysis. The rice plant height was taller in water seeding with broadcasting method than that of wet hill-seeding methods and in direct seeding with iron-coated seeds than that of direct seeding with pregerminated seeds. The tiller number in the rice plant was the highest in machine transplanting at 30days after direct seeding(June 17) and in water seeding with iron-coated seeds at 45days after seeding(DAS) and 60DAS. The tiller number of 75 and 90DAS in the tested rice cultivation methods being with 352~405/m² was not significantly different in terms of statistical analysis. The heading time was not different in rice direct seeding methods but 2 day earlier in direct seeding with iron-coated seeds than that of direct seeding with pregerminated seeds. The culm length was the highest in water seeding with iron-coated seeds and the panicle length was the longest in wet hill-seeding with pregerminated seeds. The panicle number per m² was highest in water seeding with iron-coated seeds but not significant difference among the tested rice cultivation methods. The water seeding with iron-coated seeds resulted in the highest spikelet number per m² and the heaviest grain weight of brown rice. Percentage of ripened kernel was the highest in wet hill-seeding with iron-coated seeds. But there were not significant among the tested rice cultivation methods. The milled rice yield in direct seeding methods was 3~21% higher than that in machine transplanting. Water seeding with iron-coated seeds recorded the highest milled rice yield being with 6.86t/ha.The occurrence of sheath blight was high according to machine transplanting>wet hill-seeding>water seeding. Weed occurrence was the highest in water seeding with pregerminated seeds. Weedy rice occurred not in machine transplanting but occured 0.6~0.7% in direct seeding methods with pregerminated seeds and 0.1% in direct seeding with iron-coated seeds.

• Korean journal of applied entomology
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• v.26 no.2 s.71
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• pp.99-106
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• 1987

Three post-harvest fields each in four rice growing areas, Iri, Naju, Jinju and Taegu were randomly selected and surveyed during December 1986 to examine sclerotial density of Rhizoctonia solani overwintering in the field. Surface soil of $0.09m^2$ area was sampled in each field with three replications and sieved to collect sclerotia. Germiability and pathogenicity of collected sclerotia were examined in the laboratory. Number of sclerotia $({\times}10^6)/ha$ in Iri, Naju, Jinju, and Taegu was estimated from the sample as 2.7, 1.2, 0.7 and 0.6, respectively. Based on sample variance with simple random sampling in each area, number of sampling required for estimating average sclerotial density with the precision of 10% apart from a chance of 1 in 20 was calculated to 41, 132, 232, and 395 for Iri, Naju, Jinju and Taegu, respectively. Percentage of germination of sampled sclerotia on potato sucrose agar (PSA) ranged from 42 to 78% depending on the area, and averaged 60%. About 49% of the germinated sclerotia were pathogenic to a rice cultivar Jinheung that was used to test pathogenicity of the sclerotia. Proportion of viable sclerotia that have both germiability and pathogenicity was thus estimated to 0.29 of total sclerotia collected. R. solani cultures obtained from the sclerotia could be distinguished into three groups based on colony morphology on PSA. Size and number of sclerotia formed on PSA differed between group but were not associated with pathogenicity to Jinheung.

• The Korean Journal of Pesticide Science
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• v.10 no.4
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• pp.249-261
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• 2006

Fifty compounds such as ester, sulfonyl ester, carbamate, ether and phosphoyl ester derivatives of 4-isopropyl-3-methylphenol(I) and 5-isopropyl-3-methylphenol(II) were synthesized. These derivatives were identified by IR, GC/MS and $^1H$-NMR spectra. Their in vitro antifungal activities were tested against 10 plant pathogenic fungi. Among them, several compounds showed potent in vitro antifungal activity. The selected compounds showing potent in vitro antifungal activity were tested for their in vivo antifungal activities against 5 plant diseases such as rice blast, rice sheath blast, cucumber anthracnose, cucumber gray mold and tomato late blight. As a result, 4-isopropyl-3-methylphenyl(2-amino-thiazole-4-yl)methoxyiminoacetate(I-7a) showed a potent in vivo antifungal activity against rice blast. Both methyl (4-isopropyl-3-methylphenoxy)acetate(I-4d) and methyl (5-isopropyl-3-methylphenoxy)acetate(II-4d) effectively inhibited the development of cucumber gray mold.

• Korean Journal of Organic Agriculture
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• v.19 no.1
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• pp.55-64
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• 2011

To investigate a comparison of rice yield and quality by a utilization of green crops using barley and hairyvetch, this study was carried out in rice (Oryza sativa L.) organic cultivation field. Convention barley harvest (CBH), Green barley crop (GBC), Green barley+Green Hairyvetch crop (GB+HVC), and Non-Green crop (NGC) were treated in rice cultivation field. The results obtained as following: 1) Culm length and pancile length in Convention barley harvest (CBH) cultivation were longer than organic cultivation but were not significant difference in all treatments. Yields of milled rice in Green barley crop (GBC) and Green barley+Green Hairyvetch crop (GB+HVC) were by 90.3% and 95.9%, respectively. 2) Protein contents in Green barley crop (GBC) and Green barley+Green Hairyvetch crop (GB+HVC) were by 5.7% lower than 6.6% in Convention barley harvest (CBH) cultivation. Amylose contents in all treatment were similar as range 18.8% to 19.1%. Whiteness contents in Green barley crop (GBC) and Green barley+Green Hairyvetch crop (GB+HVC) were slightly higher by 38.9% and 39.1%, respectively, than 37.7% in Convention barley harvest (CBH) cultivation. 3) Palatability values in Barley harvest (BH) and Non-Green crop (NGC) were slightly higher by 82.0 and 83.8, respectively, than 77.6 in Convention barley harvest (CBH) cultivation. 4) Head rice in Non-Green crop (NGC) was 95.5%, while that of Convention barley harvest (CBH), Green barley crop (GBC), and Green barley+Green Hairy-vetch crop (GB+HVC) were slightly low as range 93.8% to 94.2%. White core and belly rice in Convention barley harvest (CBH) cultivation was the highest level by 1.7%. 5) Leaf blast, neck blast, sheath blight, rice stem maggot, rice leaf roller, rice leaf-tier, and green rice leafhopper were occurred lightly in rice field.

• The Plant Pathology Journal
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• v.33 no.5
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• pp.488-498
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• 2017

The aim of this study was to identify volatile and agardiffusible antifungal metabolites produced by Bacillus sp. G341 with strong antifungal activity against various phytopathogenic fungi. Strain G341 isolated from four-year-old roots of Korean ginseng with rot symptoms was identified as Bacillus velezensis based on 16S rDNA and gyrA sequences. Strain G341 inhibited mycelial growth of all phytopathogenic fungi tested. In vivo experiment results revealed that n-butanol extract of fermentation broth effectively controlled the development of rice sheath blight, tomato gray mold, tomato late blight, wheat leaf rust, barley powdery mildew, and red pepper anthracnose. Two antifungal compounds were isolated from strain G341 and identified as bacillomycin L and fengycin A by MS/MS analysis. Moreover, volatile compounds emitted from strain G341 were found to be able to inhibit mycelial growth of various phytopathogenic fungi. Based on volatile compound profiles of strain G341 obtained through headspace collection and analysis on GC-MS, dimethylsulfoxide, 1-butanol, and 3-hydroxy-2-butanone (acetoin) were identified. Taken together, these results suggest that B. valezensis G341 can be used as a biocontrol agent for various plant diseases caused by phytopathogenic fungi.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.4
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• pp.375-383
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• 2009

This study was carried out to develop transgenic rice cultivars with the CAX1 (accession no. U57411) gene. We successfully selected the transgenic rice plants over-expressing the Arabidopsis H+/$Ca^{2+}$ antiporter CAX1 (accession no. U57411) gene in T6 generation. The brown rice of the CAX1 expressing rice contained 13.4~68.0 % more calcium $(Ca^{2+})$ than that of the wild type and 5 lines were selected based on the phenotypes compared to the control cultivar at the GMO field. The CAX1 expressing transgenic rice plants were similar in phenotype to the wild type during the whole growth period. Also these selected 4 lines appeared to be resistant to blast, cold and water solution compared with the wild type. Difference in 1,000 grain weight of brown rice was observed among each line but grain shape did not show any morphological alternations. These results suggest the enhanced Ca-substrate specificity of CAX1 exchanger in donor plant. Therefore, intact CAX1 exchanger can be functionally useful for $Ca^{2+}$ nutrient enrichment of rice with reduced accumulation of undesirable cation.

• The Korean Journal of Pesticide Science
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• v.11 no.1
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• pp.32-37
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• 2007

The study was carried out to establish buffer zone for the protection of the non-target organisms by aerial pesticide application. The two pesticide combination of 3-way tank-mixing of three pesticides for aerial application, ferimzone tricyclazole SC + BPMC EC + validamycin-A SL and hexaconzole EC + isoprothiolane EC+phenthoate EC were selected for the simultaneous control of key pests on paddy rice as blast, sheath blight, brown planthopper and moth. Aquatic organisms including killifish and loach in the paddy field and nearby water reservoirs were not affected by aerial application of the pesticides. However, all the water flea were killed, when they were exposed 10 m from the aerially sprayed site, while the water flea exposed in 30 m away from the site were not affected. Honeybees within 50 m in the wind direction and 20 m in the opposite wind direction showed a mortality of $7{\sim}100%$. Residues concentration of the pesticides in paddy water were not detectable level after six days from aerial application. Drifting distance of aerially sprayed droplet from the target area was within 30 m in the wind direction and 20 m in the opposite direction. Consequently, it was the buffer zones in the aerial pesticides application for the protection of the non-target organisms should be at least 50 m for aquatic organisms and 100 m for honeybees.

• 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 $1,000{\mu}g/m\ell$.