• Korean Journal of Soil Science and Fertilizer
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• v.35 no.5
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• pp.290-295
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• 2002

Fertilizer granulation test was carried out by a small pan granulator. A premixture composed of SOP 60%, urea 22% and RP powder 18% was rolled in the pan granulator while 10% phosphoric acid solution(binder) was sprayed on the rolling powder bed. Granules were developed very fast along with a little amount of binder. Hardness, brittle ratio in water and hygroscopicity of granules were improved enough to evaluate physical properties of the fertilizer. Growth responses of tobacco plant to the fertilizer were investigated at seedling and flowering stage by pot experiment under plastic film roof. Seedlings showed poor growth at nursery pot cell. In virgin soil with deficient available phosphate tobacco plant showed poor growth until budding and flowering stage but good growth in tillage soil with high cumulative phosphate.

• Korean Journal of Microbiology
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• v.43 no.4
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• pp.279-284
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• 2007

Two bacterial strains isolated from soil (Bacillus subtilis strains: PS2 and RFO41) were evaluated to determine their promoting effect on the growth of tomato seedling under axonic and pot conditions. The production of phytohormone, such as indole-3-acetic acid, indole-3-butyric acid, gibberellin and zeatin by these two strains was investigated as possible mechanisms for plant growth stimulation. Both PS2 and RFO41 were shown to produce various phytohormones, and. the production of phytohormones was stimulated by the addition of peptone-rich brain heart broth medium. In addition, these bacteria exhibited high levels of phosphatase activity, which ranged from 2.18 to $2.7\;{\mu}\;{\rho}-nitrophenol/ml/hr$. PS2 and RFO41 were applied to the pot test for growth of tomato seed with phosphate. Root and shoot lengths of germinated tomato after 15 days were 45.5% and 36.5% longer than that of control in RFO41 treated samples, respectively. Baciller sp. PS2 and RFO41 may have a potential for biofertilizer in the agriculture.

• Research in Plant Disease
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• v.20 no.2
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• pp.126-128
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• 2014

This study was carried out to assay the disease incidence degree of Sclerotium rot caused by Sclerotium rolfsii in sixteen most popular commercial cultivars of sweet potato (Ipomoea batatas) in Republic of Korea. The degree of disease incidence was evaluated on pot experiments. In pot experiments using artificial inoculation, the Sclerotium rolfsii caused a stem rot on seedling of sweet potato plants and causes a crown rot on lower stems near or at the soil line at favorable environmental conditions. White mycelial mats and sclerotia were formed at the infection sites. Plants severely infected were fell over or died because lower stems near soil surface were rotten. The degree of disease incidence was varied according to cultivars. Two cultivars, Bio-mi and Deayumi, were very resistant, while five cultivars, Shinjami, Shingeonmi, Hongmi, Yeonjami, and Shinhung-3 were highly susceptible.

• Korean Journal Plant Pathology
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• v.10 no.2
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• pp.112-118
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• 1994

Forth microbial isolates out of 167 isolates from the soil of controlled cultivation areas inhibited mycelial growth of Rhizoctonia solani AG2-1 causing the strawberry bud rot in vitro. Among the isolates, Kr013 and Kr020 showed suppressive effect to R. solani AG2-1 on seedlings of chinese cabbage treated by root immersion, charcoal carrier granule and drenching on 1.0% infested soil in pot. Furthemore, the corresponding effect was also revealed when the charcoal carrier granule of the isolates were treated on the seedling of strawberry that were planted on the planting hole in pot. To examine the effects of biological control in green house, it had been tested the infection rates by using two different treatments. First, the strawberry runner were planted on the nursery soil mixed with 20% charcoal carrier granule of Kr013 and Kr020 isolate respectively, and grown for 20 days before transplanting. Then the young plants form the mother plant were separated and transplanted on the 1.0% infested soil. Another method was that the charcoal carrier of Kr013 and Kr020 isolates applied to planting hole of 1.0% infested soil just before transplanting. Then the young plants were grown for 20 days on the sterilized nursery soil before transplanting. From the results, the effects of biological control was significantly higher on former treatment (e.g. the infection rates were 7.3 and 5.7%, respectively) than on the latter treatment (e.g. the corresponding value were 16.7 and 15.7%, respectively). The antagonistic isolates of Kr013 and Kr020 were respectively identified as Pseudomonas cepacia with the similarity of 55.0% and 60.0% by using the Biolog GN Microplate system.

• Korean Journal of Plant Resources
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• v.10 no.4
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• pp.351-359
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• 1997

Antifungal activities of the crude extracts of Anemarrhena asphodeloides. Coptis japonica and Phellodendron amurense were tested against Phvtophthora capsici. and the control effect on red-pepper phytophthora hlight and phytotoxicities of red-pepper were investigated. The results were summarized as follows; Mycelial growth and zoosporangial germination of the red-peppcr phytophthora hlight organism P. capsici were inhihited hy thc crude extracts of plant materials. Methanol extracts or plant materials had hctter antifungal activity than water extracts at hoth a room temperature and a hoiling condition. Antifungal activities of three crude extracts were gradually decreased with prolonged storage period. Red-pepper phytophthora hlight was effectively controlled hy the crude extracts of three plant materials. Of these. the crude extract of C. japonica was marvelously effective. Phytotoxic symptom to red-pepper seedling showed hy water cultural method hut not by pot test. Seed germination and radicle growth of red-pepper were inhihited hy the crude extracts of three plant materials. Phytotoxic symptoms in the leaves and fruits of red-pepper were not ohserved with exogenous foliage application of the three crude extracts.

• Korean journal of applied entomology
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• v.16 no.1 s.30
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• pp.13-19
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• 1977

The smaller brown planthopper overwinters mostly as the fourth instar nymph. The emerged adult disperses to winter barley or wheat plants. The adult of the first generation disperses into the rice field, and spends three generations in the rice field. The population densities of the adults of the first generation and the overall density of the second generations are the most important in relation to the incidents of the rice stripe disease which is transmitted by this insects. This study was intended to analyse the population increases in these important generations in relation to the kind and the different growing stage of the host plants. The insects were reared on potted host plants of different growing stage in the insect cages. The population increases of the insects in the cages were compared with those on the rice seedlings in the laboratory. The results are as follows: 1. The average longevities of the adults of the generations were 13.4 days for the overwintered, 12.9 days for the first, and 10.2 days for the second generation, and showed no significant differences between the generations even they seemed to be shorter than normal condition probably caused by the frequent disturbance at the time of food renewal in 2 or 3 days. 2. When they were reared on the rice seedling, the average numbers of the eggs per female were 131.2 for the overwintered generation, 124.9 for the first generation grown on the barley, and 142.3 for the second generation grown on rice, and shelved no significant differences between the generations. More than $90\%$ of the eggs were laid within 3 weeks. 3. The hatchabilities of the eggs laid on the rice seedling in laboratory were $77.4\%$ for the first generation, $93.1\%$ for the second generation and $62.1\%$ for the third generation. The estimated hatchabilities of the eggs were $67.5\%$ for the first generation, $84.1\%$for the second generation, and $21.9\%$ for the third generation with the growing plants on the plots. The hatchability on the eggs laid by the adults infested on the barley on May 17 was $13.5\%$ compared with $67.5\%$ for the eggs laid by those infested on barley in late April. 4. The average total nymphal periods were 19.4 days for the first generation, and 13.3 days for the second generation in the laboratory and the mortalities of the nymphs seemed to related with the growing stages of the host plants. 5. With the pot experiments, the average per cents of the emerged adults were $37.2\%$ for the first generation, $55.3\%$ for the second generation, and $11.6\%$, for the third generation. The average numbers of the emerged adults were $7.4\%$ for the pots infested on the barley on May 17, instead of $37.2\%$ adults for those infested in late April. 6. From above results, it may suggest that the innate qualities of the insect are not significantly different between generations, and the differences in the increase of the population for the generations might effected considerably by the differences in the physiological conditions of tile host plant, besides the differences in physical and other biological factors.

• Journal of Applied Biological Chemistry
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• v.43 no.2
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• pp.104-108
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• 2000

The plant growth-promoting activity of Acremonium strictum MJN1 isolated from roots of Panox ginseng was explored. The myceliaI extract of A. strictum MJN1 enhanced the rice seedling growth by 14.5 and 9.0% in the dried weight of shoots and roots, and the growth of red pepper by 54 and 85% in the top length and the dried weight in pot experiments, respectively. The plant growth-promoting substances in the myceliaI extract of Acremonium strictum MJN1 were identified as D-adenosine and glycerol. Both commercial D-adenosine and glycerol also promoted significantly the rice seedling growth but, unlike the mycelial extract of A. strictum MJN1, hardly affected the yields of plants grown in pots or field. Therefore, it is possible that other plant growth-promoting substances are produced by A. strictum MJN1. However, this study shows that A. strictum MJN1 has a great potential as a biofertilizer.

• Journal of Bio-Environment Control
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• v.29 no.4
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• pp.354-364
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• 2020

This study was conducted to examine the potential of inducing salinity stress on cylindrical paper pot tomato seedlings to inhibit overgrowth. Potassium fertilizers, sulfate of potash (K₂SO₄), muriate of potash (KCl), and monopotassium phosphate (KH₂PO₄), were prepared as two solutions of (5 and 10) dS·m^-1 salinity level, respectively, to investigate the influence on tomato (Lycopersicon esculentum Mill.) seedling growth. We also investigated the adaptability and survivability of treated tomato seedlings with high-salinity potassium (10 dS·m^-1 KCl) to harsh environmental conditions (water deficit, low temperature, and storage conditions). Repeated addition of high-salinity level KCl, K₂SO₄, or KH₂PO₄ markedly decreased the dry matter of shoot and root, leaf area, and net assimilate rates (NAR) but increased the stem diameter of seedlings. Among the three sources, the relative growth rate of plant height (RGR_H) was most sensitive to KCl addition; increasing salinity levels of KCl solution decreased the RGR_H of seedlings. The compactness, which directly reflects the stocky growth index, increased in KCl or KH₂PO₄ treatments. After a week's water deficit, severely wilted seedlings were observed in control seedlings (untreated with KCl), but no wilted seedlings were observed in the KCl treated seedlings, and the relative water content (RWC) of the untreated seedlings significantly decreased by 23 %, while that of the pretreated seedlings only decreased by 8 %. The increase in ion leakage of KCl treated seedlings at low temperatures was less than that of untreated seedlings. Furthermore, there was far lower damage proportion on pretreated seedlings at (9, 12, and 15)℃ storage temperatures after 20 days, compared with on unpretreated seedlings. Our results suggest that high-salinity potassium fertilizer, especially KCl, is effective in preventing tomato seedling overgrowth, while it also improves tolerance.

• Research in Plant Disease
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• v.16 no.1
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• pp.41-47
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• 2010

A total of 10,753 oligotrophic bacteria were isolated from the cultivated soils of red-pepper infected by Phytophthora blight disease in various regions of Korea (Chungju, Anmyon, Taean, Andong, Eumsung and Goesan). Seven bacteria isolates among these collected resources were selected by the first screening of in vitro antagonistic assay against major several plant pathogenic fungi including Phytophthora capsici. Finally, strain 7F was selected by pot assay for a possible biological control agent against Phytophthora blight disease of pepper seedling in the greenhouse. Strain 7F was identified as Bacillus subtilis on the basis of its 16S rDNA sequence analysis and as standardized biochemical characteristics assay kits such as API20 NE. In the experiment of P. capsici zoospore infected red-pepper on the pot test, infection rate of red-pepper with nonetreatment to Phytophthora blight disease was 87%, while the rate was only 6% in the pot treated with strain 7F. This result indicated that the Bacillus subtilis strain 7F will be useful as a potential biocontrol agent for Phytophthora blight disease of red-pepper.

• Korean Journal of Soil Science and Fertilizer
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• v.23 no.1
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• pp.34-39
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• 1990

The experiment was conducted in the pots of flooded saline paddy soil to evaluate influence of rice straw and gypsum application on germination and early growth status of directly sowed rice seedlings. 1. Germination percentage of rice seedlings were higher in treatment sowing at 1 day after submergence than that of treatment sowing at 21 days after submergence, and was severely interrupted by rice straw application. 2. Application of rice straw promoted the release of bicarbonate and volatile fatty acid of submerged water, while the amount of sulfate and soluble cations were decreased as compared to control. 3. Germination percentage of rice seedling had significant negative correlations with chemical characters of submerged water, and was highly affected by submerged water at 7 days after sowing. 4. Rice straw application interrupted germination of rice seedling by increasing pH of submerged water over critical level, and gypsum application depressed the early growth of young seedling dues to high salt concentration. 5. The relaease of bicarbonate was remarkedly increased with increasing pH over 7.5 of submerged water.