• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.3
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• pp.309-314
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• 1988

This study was carried out to get information for the breeding varieties and developing the cultural methods with representative 32 cultivars which were diffused from 1900 to 1982 and two cultural methods which were old one i.e., low dressing and late planting and modern one i.e., medium dressing and early planting. Duration of transplanting between cultural practices were 15 days but the duration of heading date were 5 days. Panicle projecting duration was 5-10 days in all cultivars, especially, it is 5 days in early maturing varieties, 6-7 days in medium maturing varieties and 7-10 days in late maturing varieties. Periods from transplanting date to effective ripening date were 99.8 days in low dressing and late planting method, 106.2 days in modern one but the periods from heading date to effective ripening date were 31.4 days in low dressing and late planting method, 30.2 days in modern one. Ripening speed was very active from 5 to 10 days after heading and the daily increase of 1000 grain weight was from 847.8mg to 1130mg in that time and it slightly increased from 5 to 35 days after heading in japonica varieties but increased after heading and suddenly decreased at 30 days after heading in Indica/Japonica varieties. Meteorological factors (temperature and amount of solar radiation) were positively correlated with the ripening speed but negatively correlated with the period of physiological and effective ripening.

• Korean Journal of Microbiology
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• v.50 no.1
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• pp.40-45
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• 2014

In order to increase the persistence of plant growth promoting rhizobacteria (PGPR) in rhizpsphere soil, the growth of tomato was examined after the application of Arthrobacter woluwensis ED immobilized in alginate bead, which was known as PGPR. When tomato seedlings were treated with A. woluwensis ED of $1{\times}10^6$ cells g $soil^{-1}$ and incubated for 30 days in a plant growth chamber, the shoot length, root length, fresh weight and dry weight of the grown tomato plants treated with the suspended inoculants significantly increased by 36.2, 59, 51.1, and 37.5%, respectively compared to those of the uninoculated control. The treatment of the immobilized bacteria increased those by 42, 67.4, 62.5, and 60.4%, respectively compared to those of the uninoculated control. Therefore, the enhancement of tomato growth by the treatment of the immobilized bacteria was higher than those by the suspended inoculants. The effects of the inoculation on indigenous bacterial community and the fate of the inoculated bacteria were monitored by denaturing gradient gel electrophoresis analysis. The DNA band intensity of A. woluwensis ED in the tomato rhizosphere treated with the suspended inoculants continuously decreased after the inoculation, but the band intensity in the tomato rhizosphere soils treated with the immobilized inoculants showed the maximum at 1 week after inoculation and the decreasing rate was less than that of the suspended inoculants, which indicated the longer maintenance of the immobilized bacteria at rhizosphere soils. Therefore, encapsulation of PGPR in alginate beads may be more effective than liquid inoculant for the plant growth promotion and survival of PGPR at plant rhizosphere.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.2
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• pp.162-168
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• 2007

Compatible and incompatible interactions of near-isogenic lines containing one of Xa1, Xa3, and Xa7 resistance genes with Japanese bacterial blight isolates (T7174, T7147, and T7133) were examined in order to determine the variation of bacterial blight resistance and the stability of resistance gene. IRBB 101 line having a Xal gene was compatible (host susceptible) with T7147 and T7133 isolates but incompatible (host resistant) with T7174 isolate at all the tested rice growth stages. IRBB 103 line having a Xa3 gene was susceptible or moderately resistant to the three isolates at seedling and maximum tillering stage but resistant at heading stage. IRBB 101 line having a Xa7 gene was semi-compatible with the three isolates at seedling stage but incompatible at the other growth stages. Overall there were clear differences between compatible and incompatible interactions of rice with Xanthomonas oryzae pv. oryzae races. In the mixed inoculations of compatible and incompatible isolates, the lesion length from near-isogenic lines decreased as the ratios of incompatible races increased. When the distinction between compatible and incompatible isolates was unclear, there was almost no variation of lesion length regardless of mixed ratios. The pathogenicity of the mixed races in the incompatible Interactions increased rather than the individual inoculation whereas the lesion length of compatible interactions was similar to that of the individual inoculation. These data indicate the incompatible races inhibit the virulence of a compatible race but compatible races increase the disease occurrence due to incompatible races. Furthermore, IRBB 107 line that showed resistance to all the isolates at all the tested growth stages was considered as a good parent f3r breeding of resistant variety.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.2
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• pp.190-198
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• 1996

The Neomycin resistant gene in transposon 5 (Tn5) was introduced into a mutant of Bradyrhizobium japonicum RJB 6 $str^rnal^r$ by conjugation. This marked strain was used in coinoculation of soybean with Pseudomonas fluorescens(Ps-3) and Bacillus subtilis(BCAC-4) and in antibiotic treatment of soybean for studying rate of nodule formation and growth promoting effect on soybean plant. When the marked strain RJB 6 $str^rnal^rneo^r$ with Ps-3, BCAC-4, and Ps-3 plus BCAC-4 was coinoculated into two soils, the recovery rate of the marked strain was 8.5, 4.3 and 2.9 percent in soybean cultivated soil, and 10.3. 6.0 and 5.0 percent in soybean uncultivated soil. The best growth promoting effect of coinoculation on soybean plant was found with the marked strain plus Ps-3. When the marked strain was inoculated into soybean with antibiotic treatment, the rate of nodule formation in soybean cultivated soil was between 12.5 and 25.4 percent, while that in soybean uncultivated soil was between 23.7 and 43.2 percent. The highest rate of nodule formation with the marked strain was found in streptomycin 1000 ppm treatment plot.

• Korean Journal of Soil Science and Fertilizer
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• v.26 no.4
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• pp.265-270
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• 1993

The symbiotic dynamics of Bradyrhiwbium japonicum YCK strains indigenous to Korean soils were investigated accordingly to their competitive conditions for nodulation. For this experiment the single strain inoculants of YCK strains and the mixed inoculants of one YCK strain and one USDA strain were applied to Korean Jangbaekkong and American Clark soybeans at mollisol soils(Torroxic Haplustoll, pH 6.8). The results were summarized as follows : 1. The symbiotic effectiveness of B. japonicum YCK strains was increased on the average of nitrogen accumulation by mixing with USDA strains, especially with strain USDA 110. 2. The effectiveness of each mixed inoculant was affected by soybean cultivar. 3. YCK strains occupied on the average of 83 and 86 % of the nodules against strain USDA 110 on Jangbaekkong and Clark soybeans, respectitvely. 4. The most effective strain among three YCK strains was strain YCK 213 as a single inoculant and was strain YCK 141 as a mixed inoculant with USDA strains. 5. The mixed inoculants of YCK strains and strain USDA 123 showed antagonism for nodulation.

• Korean Journal of Soil Science and Fertilizer
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• v.26 no.4
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• pp.271-277
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• 1993

An antagonistic bacteria was isolated from rhiaosphere of pepper and corn and identified as Bacillus (B.) subtilis. These B. subtilis B-5 was transformed and marked with the plasmid pCPP4 which possess neomycine resistan. gene. The marked stranins showed growth inhibition to Rhizoctonia (R.) solani, Fusarium (F.) solani, and F. oxysporum in vitro, and were used in studying growth promoting effects on sesame and cabbage. All the identified strains utilize glucose, sucrose, fructose, lactose, mannitol and sorbitol as carbon source, but not rhamnose, and the marked strains also showed characteristics similar to wild-type strains. Germination rate of chinese cabbage and sesame seeds was increased by about 10% or more in the plot to which these strains were inoculated and the effect was higher in soil than in petri dish. The early growth promoting effects of these strains appeared higher, as compared with control plot, in the plots to which B. subtilis B-5 and pathogenic fungi was inoculated together. When the marked strains, B. subtilis B-5NEOr, were inoculated in the rhizosphere of chinese cabbage and sesame with $1.1{\times}10^8CFU/g$ dry soil, the number of inoculated strain was decreased slowly to the level of $10^5{\sim}10^6CFU/g$ dry soil after 4 weeks and the number of Pseudomonas spp. maintanied the level of $10^5CFU/g$ dry soil throught total period, but the number of fungi was decreased rapidly from the early level of $10^8CFU/g$ dry soil to $10^3CFU/g$ dry soil after 4 weeks.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.2
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• pp.192-197
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• 1981

Alfalfa (Medicago sativa L. cv. Luna) seeded in agar was inoculated with two strains of Rhizobium meliloti isolated from root nodules of alfalfa for assessment of nodulation. The seedling growth after six weeks was remarkably increased by adding each rhizobia strains into agar media and also by nitrate application (70ug N/ml), but there was no significant difference among them. Nodulations started one week after inoculation and increased its numbers and sizes as seedling grew. Therefore, the two strains isolated from alfalfa root were concluded to be effective strains. For determining seed inoculation method the same cultivar was inoculated with both rhizobia strains using different inoculation methods such as broth-vacuum, peat-adhesive, peat & lime pelleting. They were seeded in pots of river sand and supplied with culture solution excluded nitrogen. The peat & lime pelleting was recognized the best method in both of nodulation and seedling growth after eight weeks growth. There were significant correlations between the weight of nodules and the shoot or root dry weight of alfalfa in both rhizobia strains.

• Korean Journal of Microbiology
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• v.46 no.1
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• pp.33-37
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• 2010

Rhizobacterial strain isolated from barren soil, Bacillus subtilis RFO41 exhibits a high level of phosphate solubilizing activity and produces some phytohormones. Its promoting effect on the growth of Xanthium italicum Moore, a wild plant growing at lakeside barren land and thus a good candidate plant for revegetation of barren lakeside was evaluated in the in situ test for 19 weeks at Lake Paro, Kangwon-do. Strain RFO41 could enhance the dry weight of X. italicum by 67.7%. It also increased the shoot length of X. italicum plant by 21.1% compared to that of uninoculated control. Both growth enhancements had statistical significance. However, the inoculation did not show any effect on the root growth, which might be due to the breakage of tiny root. Denaturing gradient gel electrophoresis analysis showed that the inoculated bacteria were maintained in the soils, and the indigenous bacterial community did not exhibit any significant change. This plant growth promoting capability may be utilized as an environment-friendly and low cost revegetation method, especially for the sensitive areas such as barren lakeside lands.

• Korean journal of applied entomology
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• v.19 no.1 s.42
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• pp.11-20
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• 1980

Percent penetration on a specific rice variety was more affected by blast fungus isolate or predisposition temperature than by temperature and isolate combinations. A susceptible variety tested remained continuously susceptible regardless of whether the variety was grown at different temperature regimes and exposed to isolates/races with differences in pathogenicity and virulence. The expression of virulence by a particular blast fungus isolate race was observed to be changed by subjecting rice host plants to different predisposing temperature conditions prior to inoculation.

• Korean Journal Plant Pathology
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• v.3 no.3
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• pp.203-209
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• 1987

The substances obtained from the leaf, stem and root of tobacco plants inoculated with avirulent and virulent isolates of Pseudomonas solanacearum were at R_f\;0.6$ and R_f\;0.9$ on TLC plate, respectively. Both substances showed antibacterial activities not only on P. solanacearum but also on Erwinia carotovora subsp. carotovora and Escherichia coli in vitro. However, the antibacterial substances were not detectable from the filtrate of the autoclaves tobacco sap medium, in which the avirulent or virulent bacterium was cultured for 3 days. Peroxidase and poly phenoloxidase activities and their isozyme patterns did not differ significantly between plants treated with the virulent and avirulent isolates, or between the susceptible cultivar BY 4 and the resistant cultivar NC 82. However, activities of the two enzymes were increased in leaves of the susceptible cultivar BY 4 treated with either the virulent or the avirulent isolate.