• Korean journal of applied entomology
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• v.44 no.3 s.140
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• pp.177-187
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• 2005

For the comparison of feeding behavior of Nilaparvata lugens among different rice varieties, electrical penetration graph (EPG) technique was used. Ten rice varieties were selected from national-widely recommended rice varieties cultivating in Chungnam province. The correlation between feeding duration and honeydew amount excreted was investigated, and the types of EPG pattern were analyzed among rice varieties. The EPG patterns divided into 6 types according to electrical specific feature, respectively. Type 1 pattern was a searching feeding sites, resting or wandering on a rice plant. Type 2 pattern was appeared when the insect untaken from phloem sieve element. Type 3 pattern was observed when the insect piercing into the rice plant. Type 4 pattern was observed when the insect salivating in rice plant. Type 5 pattern was observed when the insect ingesting from the xylem. Type 6 pattern was observed when the stylet moving in cell. Feeding duration time on Gum-nam was significantly shorter than Dong-jin, Dae-ahn, Dong-ahn, Dae-san. Also, on Gun-nam, it was shown that the brown planthopper did not penetrate the cuticle for a long time. The total number of excreted honeydew droplets by the brown planthopper was the greatest in Dong-jin variety and the least in Gum-nam variety. In proportion to phloem feeding time, the number of honeydew droplets had been increased. According to the results of EPG patterns and honeydew droplets analysis, N. lugens seems to prefer Dong-jin, Dong-ahn, Dae-san, and Dae-ahn to Gum-nam, Da-san, and Nam-chun rice plant variety.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.6
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• pp.473-477
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• 2001

Chinese milkvetch (Astragalus sinicus L.) has been traditionally used as a green manure supplying mineral N and organic matters to soil. In rice-Chinese milkvetch interrelay cropping system, three rice cultivating methods (no-till direct seeding, no-till transplanting, and tillage transplanting) were evaluated for stand reestablishment without reseeding Chinese milkvetch with two cropping times (May 25 and June 4) for two years. Chinese milkvetch incorporated was decomposed rapidly in the first week. Decomposition was fast in topsoil than in subsoil. Natural milkvetch reestablishment (NMR), following harvest of no-till-direct-sown rice was good enough to cover the paddy field in both cropping times, but rice yield of this method was lower than that of transplanted rice on paddy field without milkvetch cultivation. Even though good NMR was secured in no-till rice transplanting, the shoot of milkvetch should be removed before machine-transplanting of rice seedlings. NMR was better in rice cropping at the mid-ripening stage of milkvetch (June 4) than at the late-bloom stage (May 25). Rice yield was higher in tillage transplanting at the mid-ripening stage of milkvetch (June 4) than in the other rice cropping method.

• Korean Journal of Breeding Science
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• v.43 no.1
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• pp.81-91
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• 2011

Rice wild relatives have been recognized as reservoirs of genetic reinforcements to improve cultivating rice against biotic and abiotic stresses. A wild relative, Oryza. minuta(BBCC; Acc. 101141), was hybridized with a Korean Japonica cultivar, 'Hwaseong'(AA), followed by ovule culture and several times of back crossings to overcome high level of sterility. During evaluation of the introgression lines, breeding line exhibited resistance to bacterial blight with reasonable agronomic performances, and nominated as an elite breeding line, the 'Suweon497'. A mapping population, to dissect genetic basis of the resistance, was constructed by using $F_2$ progenies of the 'Suweon497' ${\times}$ 'Milyang23'. Association analysis between SSR marker genotypes and pathogenisity levels of each $F_2$ progeny revealed the end terminal region of rice chromosome 11 as the nesting place for the wild rice derived bacterial blight resistance gene, where at least four other genes, Xa3, Xa4, Xa26 and Xa31, have been reported.

• Korean Journal of Environmental Agriculture
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• v.32 no.2
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• pp.95-101
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• 2013

BACKGROUND: Rice (Oryza sativa) is the most important staple food of over half the world's population. This study was conducted to evaluate the possible impact of transgenic rice cultivation on the soil microbial community. METHODS AND RESULTS: Microorganisms were isolated from the rhizosphere of GM and non-GM rice cultivation soils. Microbial community was identified based on the culture-dependent and molecular biology methods. The total numbers of bacteria, fungi, and actinomycete in the rhizosphere soils cultivated with GM and non-GM rice were similar to each other, and there was no significant difference between GM and non-GM rice. Dominant bacterial phyla in the rhizosphere soils cultivated with GM and non-GM rice were Actinobacteria, Firmicutes, and Proteobacteria. The microbial communities in GM and non-GM rice cultivated soils were characterized using the denaturing gradient gel electrophoresis (DGGE). The DGGE profiles showed similar patterns, but didn't show significant difference to each other. DNAs were isolated from soils cultivating GM and non-GM rice and analyzed for persistence of inserted gene in the soil by using PCR. The PCR analysis revealed that there were no amplified protox gene in soil DNA. CONCLUSION(S): These data suggest that transgenic rice does not have a significant impact on soil microbial communities, although continued research may be necessary.

• Korean Journal of Soil Science and Fertilizer
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• v.51 no.1
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• pp.50-60
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• 2018

This study was to evaluate the effect of organic amendments incorporation on soil properties and plant growth under two different soil salinity levels and various cultivated crops at Saemangeum reclaimed tidal land for three years from 2012 to 2014. The soil texture of the experimental site was sandy loam. Four different crops, sesbania (Sesbania grandiflora), sorghum-sudangrass hybrid (Sorghum bicolor-Sorghum sudanense), rice (Oryza sativa L.) and barley (Hordeum vulgare) were cultivated at low (< $1dS\;m^{-1}$) and high (> $4dS\;m^{-1}$) soil salinity levels. The soil salinity was significantly lowered at the rice cultivation site compared to continuous upland crops cultivation site in high soil salinity level. But the soil salinity was increased as cultivating sesbania coutinuously in low soil salinity level. The soil organic matter content was increased with the incorporation of straw at the continuous site of rice and barley, and the average of soil organic matter was increased by $0.9g\;kg^{-1}$ per year which was effective in soil aggregate formation. The highest biomass yield plot was found in barley (high salinity level) and sesbania (low salinity level) cultivation site, respectively. Our research indicates that rice cultivation in paddy field with high salinity level was effective in lowering soil salinity and sesbania cultivation was useful to biomass production at upland with low salinity. In conclusion, soil salinity and organic matter content should be considered for multiple land use in newly reclaimed tidal land.

• Mycobiology
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• v.35 no.4
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• pp.226-229
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• 2007

To produce fruiting bodies of Oudemansiella mucida, porcelain fungus, on the oak sawdust medium, additives suitable for the mycelial growth and fruiting body formation were screened. In general, the mycelial growth of the three strains of O. mucida used in this study have been good on oak sawdust mixed rice bran of $20{\sim}30%$. The mycelia incubated in potato dextrose broth for 7 days were inoculated on oak sawdust medium supplemented with various ratios of rice bran and incubated for 30 days at $25^{\circ}C$ in the dark condition until the mycelia of O. mucida fully colonized the media from top to bottom. Then, top surface of the media in the bottles were horizontally scratched with a spatula and filled with tap water for 3 hours. To induce the primordial formation of O. mucida, the bottles were transferred to the mushroom cultivating room under 12 hrs of light (350 lux) and dark condition with relative humidity of 95% at $17^{\circ}C$. The primordia of O. mucida were formed on the surface of oak sawdust media after 7 days of incubation. The mature fruiting bodies were observed 5 days after primordial formation. The fruiting bodies O. mucida were formed on oak sawdust medium mixed with 5 to 30% rice bran. However, abundant fruiting-bodies of O. mucida were produced in oak sawdust medium supplemented with 20% rice bran. This is the first report associated with an artificial fruiting body production of O. mucida in Korea.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.103-103
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• 2017

Vigorous root growth at the seedling stage in dry direct-seeded conditions is considered as a critical trait because it is involved in seedling emergence, early vegetative vigour, nutrient uptake as well as drought tolerance. In this study, we performed QTL mapping using the recombinant inbred lines obtained from the cross between Tongil-type Dasan and temperate japonica TR22183 (DT-RILs) to identify QTL underlying early root development. TR22183, which was previously reported to have high nitrogen utility and cold tolerance, showed vigorous root growth at the seedling stage in semi-drought conditions. Root length, fresh weight and dry weight of TR22183 were significantly higher than in Dasan. By QTL analysis with genotyping-by-sequencing method, we identified two QTLs for root fresh weight (RFW) in chromosome 7 and root dry weight (RDW) in chromosome 8, explaining phenotypic variances of 13.5% and 10.6%, respectively. These QTLs would be used to develop rice varieties adapted to direct-seeded cultivating system.

• Research in Plant Disease
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• v.16 no.3
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• pp.224-231
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• 2010

Xanthomonas oryzae pv. oryzae, causal agent of bacterial leaf blight (BLB) of rice, had been collected and identified using Biolog and fatty acid analysis. Epidemics of BLB had been occurred all the times at several rice cultivating areas in Korea in 1999-2004. Most X. oryzae pv. oryzae isolated in 1999 and 2002 belonged to Korean race K1, but more than 50% of the pathogen isolated in 2003 belonged to Korean race K3. Especially, most pathogens isolated in Jeonnam and Joenbuk provinces belonged to Korean race K3. Inoculation test of near isogenic lines (NIL) of rice carrying single resistance genes against BLB showed that many isolates belonging to Korean race 1 reacted differently to diverse resistant monogenic lines of rice. Southern blot analysis also showed that the bacterial pathogens belonged to the same race had different numbers of avirulence genes. This results suggested that each Korean race type may respond to many resistance genes of rice. All the K3 races isolated in Jeonnam and Joenbuk provinces were able to cause disease on Xa3 monogenic lines of rice. Since most rice cultivars cultivated in Jeonnam and Jeonbuk were carrying Xa3 resistance genes, the bacterial pathogens isolated in Jeonnam and Jeonbuk were likely to develop to adapt to Xa3 resistance gene. Together with avirulence gene patterns of the bacterial isolates and the results of disease reaction of monogenic lines of rice to them, Korean X. oryzae pv. oryzae was classified into 19 pathotypes. This newly classified pathotypes should help the breeding of new resistance rice cultivars in Korea.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.58 no.3
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• pp.319-323
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• 2013

Red rice (Oryza sativa L.) is one of the most important weeds in most of rice cultivating area. Seed germination related experiments were done to evaluate germination percentage, emerging speed, and initial growth by seeding depth and soil moisture level. The four experiments, 1) temperature, 2) seeding depth, 3) soil moisture level, and 4) seeding position, were done with combination each other on phytotron for germination and seedling growth related experiments of redrice. The treatments levels were: 1) Temperatures were 20/15(Low), 25/20 (Mid.), $30/25{\circ}C$ (High), (day/night), 2) seeding depths were 0, 3, 6 cm, 3) soil moisture levels were 25, 35, 45, 55, 65% (VWC, %), and seeding position were furrow, ridge, ridge-top. The germination percentage and germination speed of red rice were higher and faster than Daeanbyeo in low temperature. Yoeongcheon redrice of seed germination percentage and seedling length was more vigor than Hapcheon red rice. Red rice was not germinated on 6 cm seeding depth until 11 days after seeding except high temperature treatment. Germination percentage increased with increasing soil water percentage in low temperature, however it was greatest in 45% in high soil moisture level between 25% to 65% in low temperature. Seed germination percentage and seedling length were not significantly different among the soil water level in mid- and high temperature levels. In conclusion, red rice could germinate in top soil (<6 cm) in mid- and high temperature range, so we might be control red rice by spraying herbicide after germination of red rice combined with delayed rotary cultivation.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.266-266
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• 2022

The outbreaks of blast, bacterial blight and viral diseases have been increasing in early maturing rice cultivating areas in the central northern regions, recently. As the occurrence of sudden insects pests and disasters increases due to global climate warming, it is urgent to develop a variety of disaster-tolerant, high-quality varieties in response. This study was carried out to elucidate the characteristics of early-maturing, high-quality and multiple disease resistant rice variety, Cheolweon109 that was adapted to cultivation in the mid-mountainous regions of the central northern regions. Cheolweon109 was derived from a cross between Suweon546, medium maturing variety, and Sangju44 which is early maturing and resistant to blast, bacterial blight and rice stripe virus. The heading date of Cheolweon109 was July 30, 3 days later than Odae. The culm length of Cheolweon109 was 79 cm, which was about 5 cm taller than Odae, and the ripening ratio was 85.1%, which was 10% higher than that of Odae. This variety had 5.54 MT/ha of milled rice productivity, which was 99% of the Odae. Although Cheolweon109 was tall, it was strong against lodging. It was strong against bacterial blight (K1, K2, K3 race), rice stripe virus, and the pre-harvest sprouting which rate was 2.4%. The appearance of the grains of rice was clean, the glossiness was 70.6, and the head rice ratio was 95.3% high. Because Cheolweon109 had superior disease resistance, disaster resistance, and high quality than Odae, it was expected that can be used to expand the diversity of early maturing and high-quality rice varieties in central northern regions.