• Korean Journal Plant Pathology
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• v.11 no.1
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• pp.94-97
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• 1995

In 1994, an abnormal rice growth was observed in a 0.5-ha scale farmer's field located at Chogye-Myeon, Hapcheon-Gun, Gyeongnam Province where rice cv. Hwayeongbyeo was seeded directly in dry paddy field conditions. The major symptoms were less stands per acreage, short leaf length, and hypertrophy of root tip portion. The disorder was identified as rice seeding bight caused by Rhizopus sp. The average plant stand per m2 in the infested field was 108, while it was 375 in the normal field, and leaf growth was retarded to less than one-third of healthy plant. The average leaf lengths of infected and healthy seedlings were 12.8cm and 38.9cm, respectively. When the infected seedlings were transplanted to pots, flooded-soil conditions developed no new root growth but upland conditions allowed 11.2 new roots emerging. The length of newly emerged root in infested soil was 5.3cm in upland and 7.1cm in intermediate flooding conditions. However, it was 10.9cm in non-infested soil with intermediate flooding conditions. When the plants were matured, the stem length of infected plants was reduced slightly as compared to normal plants, whereas the length of panicle was not significantly different between infected and healthy plants. The number of panicle per plant, however, greatly different with variation of infection degree. Grain quality such as the number of complete and incomplete grains per panicle, the complete grain weight per panicle, and the weight of 1000 grains was not significantly different.

• Korean Journal of Veterinary Research
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• v.54 no.3
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• pp.131-137
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• 2014

The purpose of present study was to investigate the antimicrobial resistance in Escherichia coli isolated from healthy animals in all provinces of the Republic of Korea. A total of 2,085 E. coli strains isolated from 11,336 fecal samples of healthy animals during 2010-2012 were examined for antimicrobial resistance. Comparison of average resistance rate through the years revealed that tetracycline (47.0% and 76.1%) and streptomycin resistance (42.6% and 64.6%) was most frequently observed in cattle and pigs, respectively. Whereas, in chicken isolates, resistance against nalidixic acid (90.9%) was highest among the antimicrobials tested. Percentage of E. coli that showed multidrug resistance (resistance against ${\geq}$ three subclasses of antimicrobial agents) was 17.6% (151/860) in cattle, 69.4% (506/729) in pigs, and 86.1% (427/496) in chickens. Overall, the rates of resistance are apparently different between animal species and, in particular, resistance was less prevalent in cattle than in pigs and chickens. In conclusion, this study showed higher prevalence of resistance in commensal E. coli strains to antimicrobial agents in Korean livestock and highlighted the urgent need for measures to regulate the abuse of antimicrobial agents.

• The Plant Pathology Journal
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• v.21 no.2
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• pp.87-92
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• 2005

The structural differences between healthy and diseasedpanicle necks caused by Pyricularia oryzae were observed using electron-microscope. In the diseased panicle neck, the infection hyphae of the rice blast pathogen grew through the sclerenchymatous fiber tissue and reached to the central internal lacuna. Since the pathogen grew through the sclerenchymatous fiber tissues, the vascular bundle composed with xylem and phloem had been destroyed and finally the nutrients from the leaf and stem were not able to be transported into the grains. Infection of panicle base by the blast pathogen until 20 days after heading caused more than 50% of yield loss in both Jinmibyeo and Chucheongbyeo. There was a positive correlation between incidence of the panicle blast and rice yield losses. The regression equations between incidence of the panicle blast and yield losses were y= -3.61+496.7 ($R^2$=0.70) in Jinmibyeoand y=-3.93+520.2 ($R^2$=0.82) in Juanbyeo. The panicleblast caused deterioration of grain quality. Healthy grain rate was reduced by increase of panicle blast infection.

• Plant Disease and Agriculture
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• v.5 no.2
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• pp.90-94
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• 1999

Effect of inoculum concentration inoculation method and plant age on development of clubroot disease of Chinese cabbage seedling were examined in growth chambers. Root galls were developed at the concentration of 105 resting spore or above per ml of incoulum and as the inoculum concentration became higher rate of development of root galls was faster. In the plants with root gall development fresh weight of above ground parts was reduced to 30-44% of that of healthy plants but root weight increased by 4-10 times. Growth of diseased plants was greatly reduced as compared to healthy plants. Planting in the diseased soil as a inoculation method was most effective for disease development showing uniform infections but time of initial root gall development was delayed by root soaking inoculation. Some plants inoculated by soil drenching method did not develop root galls. However root gall enlargement after its initial formation did not differ greatly among inoculation methods. Nine-day-old seedlings showed poor development of root gall but 16-days-old seedlings was found to be most adequate for inoculation for gall development.

• Journal of Plant Biotechnology
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• v.7 no.4
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• pp.247-257
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• 2005

An efficient, rapid and large-scale in vitro clonal propagation of agronomically important Indian cereal crop genotypes (NSH27 & K5) of Sorghum bicolor (L.) Moench. by enhanced shoot proliferation in shoot tip segments was designed. MS medium fortified with plant growth regulators and coconut water markedly influenced in vitro propagation of Sorghum bicolor. In vitro plantlet production system has been investigated on Murashige and Skoog (MS) medium with the synergistic combination of 6-benzyladenine ($22.2\;{\mu}M$), kinetin ($4.6\;{\mu}M$), adenine sulphate ($2.8\;{\mu}M$), 5% coconut water and 3% sucrose which promoted the maximum number of shoots as well as beneficial shoot length. Subculturing of shoot tip segments on a similar medium enabled continuous production of more than 100 healthy shoots with similar frequency. When the healthy shoot clumps were cultured on MS medium fortified with 6-benzyladenine ($22.2\;{\mu}M$), kinetin ($4.6\;{\mu}M$), adenine sulphate ($2.8\;{\mu}M$), ${\alpha}$-naphthaleneacetic acid ($2.7\;{\mu}M$), ascorbic acid ($30.0\;{\mu}M$) and 5% coconut water, a rapid production of axillary and adventitious buds was developed after 8 wk culture. More than 300 shoots were produced 10 wk after culture. Rooting was highest (100%) on half strength MS medium containing 22.8 mM IAA. Micropropagated plants established in garden soil, farmyard soil and sand (2:1:1) were uniform and identical to the donor plant with respect to growth characteristics. These plants grew normally without showing any traits.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1996.05a
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• pp.41-62
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• 1996

Since 1966 tissue culture has been used as a tool for the production of disease indexed stocks from selected plants and their rapid (clonal) mass propagation through the procedure now referred to as micropropagation. The major advantages have been the rapid introduction of new plant cultivars, created within conventional and mutation breeding programmes, as healthy stock for beneficial distribution and the expansion of the world wide horticultural industry. (omitted)

• Journal of Forest and Environmental Science
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• v.25 no.2
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• pp.111-118
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• 2009

Multiple shoot induction and plant regeneration using apical bud and nodal explants of 100 year old tree of Anthocephalus cadamba, an important sacred and medicinal tree in India was achieved for the first time. Aseptic explants cultured in Murashige and Skoog (MS) medium augmented with different concentrations of BAP (0.1, 0.5, 1.0, 2.5, 5.0 and 10 mg/l), when maintained for 60 days, healthy shoots were induced in presence of BAP (1 mg/l). Lower concentrations of BAP (0.1 - 0.5 mg/l) induced only one shoot per explant. Increase in number of shoots per explant was observed in presence of higher concentrations of BAP (2.5, 5.0 and 10 mg/l). However, elongation of shoots was completely inhibited. Bud break and shoot regeneration was largely associated with seasonal factors. Apical buds cultured during June to August exhibited early bud break within two weeks of initial culture. In rest of the months, bud break and shoot regeneration was very slow irrespective of the various concentrations of BAP used in the medium. Explants sourced from three different maturity levels of shoots indicated that actively growing shoots from the mother plant with 1 - 2 nodal segments was more suitable for culture initiation than the explants collected from mature shoots at dormant stage. Regenerated shoots with 2 - 3 pairs of leaves when transferred to half strength MS medium fortified with IBA (1 mg/l), 60% of the shoots induced healthy roots, indicating the possibility of large scale micropropagation.

• Research in Plant Disease
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• v.10 no.1
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• pp.34-38
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• 2004

The damage of plant growth and alteration of cellular tissues of barley infected by Barley yellow mosaic virus (BaYMV) was explored. The infected plots significantly damaged in all of measured factors by the disease. In severely diseased plant, the viral infection affected on plant growth like as shorten culm length about 25cm, 36％ constrained ratio, comparing to healthy. The yield decreased over 70％ in diseased plots by fewer numbers of spike and kernel per square meter and spike, respectively. BaYMV constructed typical inclusion body like a pinwheel type inside barley leaves, and the infection affected on cellular elongation or growth not cell division in examined three parts as stem, neck of panicle and node, related to dwarfness of infected barley. The stem tissues were most severely affected on cell growth as restrained epidermis cell length in diameter and vascular bundle size. In neck of panicle tissues, distribution and size of tissues of fiber and cortex parts, respectively, showed differences between healthy and infected plants. In node part, healthy plant showed bigger tissue size as 1.5 times than infected plant. Theses results suggest that BaYMV infection could affect on the cell growth not cell division, and which resulted shorten culm length in plant growth and decreased yield, finally.

• Korean Journal of Plant Resources
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• v.31 no.6
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• pp.660-666
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• 2018

In order to understand the characteristics of soil according to the cultivation environment of Chinese bellflower (Platycodon grandiflorum A.), soil chemical properties of 12 collected soil samples from 6 cultivated fields in Okcheon, Chungbuk province in August. 2017 were analyzed. The soil pH was distributed within the range of 4.61 to 5.25 at all cultivation years and E.C (Electric Conductivity) and T-N (Total Nitrogen) of the cultivation year were not significant. Available $P_2O_5$ was higher than the average for medicinal crops and P. grandiflorum in Korea and C.E.C (Cation Exchange Capacity) was inconsistent for each cultivation year. In particularly, it was validated that the content of exchangeable cations K, Ca, Ma, and Na in this experiment was similar to that of C.E.C according to the cultivation years, because C.E.C had a high correlation with the exchangeable cations. For the available $P_2O_5$, as affected by trans-planting, 5Y-NT-H (cultivated 5 years and non-transplanted) had 58 mg/kg, while 5Y-T-H (cultivated 5 years and transplanted) had 246 mg/kg. The soil pH was found to be lower (acidic) in diseased soils than healthy soils. E.C was confirmed to be was higher in diseased soils than healthy soils except for the one cultivated for 2 years. The contents of T-N and available $P_2O_5$ were higher in diseased soil except for the one cultivated for 5 years and 11 years. The exchangeable cation K and Na tended to be higher in diseased soils rather than that in healthy soils, and the exchangeable cation Ca and Mg contents were higher in healthy soils than in diseased soils. The C.E.C of the soil was lower than that of healthy soils in all of the years except for the one which was cultivated for 5 years (transplanted).

• Journal of environmental and Sanitary engineering
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• v.13 no.3
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• pp.113-120
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• 1998

For a microbial control of a plant pathogenic Pseudomonas syringae, Bacillus sp. strain BT182-3 was isolated. The strain BT182-3 had a growth inhibition against P. syringae not only on agar plate but also on cultured broth. After heat treatment at $40^{\cird}C$ and $80^{\cird}C$ for 30min, the lytic substance from the strain BT182-3 had about 52% remaining activity and 17% remaining activity, respectively. The optimal pH and temperature of the lytic substance was 6.0 and $28^{\cird}C$, respectively. Germination ratio of healthy radish seeds was 87% at $25^{\cird}C$ for 5 days in 0.8% saline, and that of the radish seeds infected with P. syringae was 67%, while that of the radish seeds treated with cultured broth of the strain BT182-3 was 90%. The 5-days healthy radish seedlings were 3.90cm at high and the seedlings infected with P. syringae were 3.06cm at high, while the seedlings treated with cultured broth of the strain BT182-3 were 4.30cm at high. The growth of the radish seedlings infected with P. syringae was inhibited after cultivation for 40days on pots, while the growth of the infected radish seedlings with P. syringae was recovered at stem length, root length and total weight at the same as the healthy seedlings after treatment of a lytic substance from the strain BT182-3.