• Research in Plant Disease
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• v.23 no.3
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• pp.278-282
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• 2017

Maize is one of the most cultivated cereals as a staple food in the world. The harvested maize is mainly stored after drying, but its quality and nutrition could be debased by fungal spoilage and mycotoxin contamination. In this study, we surveyed mycotoxin contamination fungal infection of maize kernels that were stored for almost one year after harvest in 2015. The amount of deoxynivalenol and zearalenone detected were higher than the other mycotoxin, such as aflatoxin, ochratoxin, fumonisin and T-2 toxin. In particular, level of deoxynivalenol was detected as $1200{\pm}610{\mu}g/kg$ in small size kernels, which was four to six times higher than the large and the medium size kernels. Moreover, the amount of deoxynivalenol, zearalenone, and fumonisin were increased with discolored kernels. 10 species including Fusarium spp., Aspergillus spp. and Penicillium spp. were isolated from the maize kernels. F. graminearum was predominant in the discolored kernels with detection rates of 60% (red) and 40% (brown). Our study shows that the mycotoxin contents of stored maize can be increased by discolored maize kernels mixed. Therefore elimination of the contaminated maize kernels will help prevent fungal infection and mycotoxin contamination in stored maize.

• Research in Plant Disease
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• v.22 no.1
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• pp.38-43
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• 2016

Wildfire caused by Pseudomonas amygdali pv. tabaci has been seen a steady increase in the incidence and prevalence on soybean in Korea. But up to know there is no official report on the prevalence of the disease in Korea. The nationwide survey of the occurrence of soybean wildfire showed that 19 out of 30 regions in 2014 and 9 out of 28 regions in 2015 had been infected with P. amygdali pv. tabaci. The severity of wildfire varied according to the cultivar, cultivation regions and climates. However, cultivar seoeitae was susceptible in both 2014 and 2015. The disease severity of 2014 was twice that of 2015. Since the temperature of 2014 and 2015 were very similar but the precipitation of 2014 was more than twice that of 2015, the precipitation of 2014 had a great impact on the wildfire disease severity.

• Research in Plant Disease
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• v.21 no.3
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• pp.243-249
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• 2015

Soybean frogeye leaf spot caused by the fungus Cercospora sojina Hara, has known to lead a severe reduction of crop yield. Since frogeye leaf spot on soybean has recently become a serious problem in Korea, the susceptibility of recent recommended cultivars against C. sojina had been tested. To standardize the disease severity of soybean, the optimum sporulation condition of C. sojina and the disease index were established in this study. Sporulation was maximized on the 10% V8 juice agar with 12 h light and 12 h dark at $25^{\circ}C$. Spore suspension ($10^5spores/ml$) was sprayed on the leaves of soybean (V6 stage), and the disease responses to each isolate were evaluated on 28 days after inoculation. As a result, Daepung, Shinpaldal2ho, Yeonpung and Cheonga showed the resistance reaction to 8, 7, 6, 6 isolates of C. sojina, respectively, whereas Cheongja, Hwangkeum, Taekwang, Daewon, Cheonsang and Sinhwa showed the susceptible reaction to 8 isolates of C. sojina. Breeding the resistant soybean cultivars against C. sojina requires a uniform resistance for screening technique. The disease index of frogeye leaf spot on soybean developed in this study can be effectively used for the accurate field assay to select the frogeye leaf spot resistant soybean.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.59-59
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• 2022

The transplanting date of rice affects grain yield and quality, and it is changed by the environment during cultivation. Thus, it is important to provide the optimal transplanting dates for rice growers under global warming environment. In this study, transplanting date experiments with thirty-day-old seedlings of three cultivars (early, mid, and mid-late maturity) were conducted at the National Institute of Crop Science in Suwon from 2018 to 2021 to determine the optimal transplanting dates for and quantify the effect of planting dates on yield and quality. Transplanting date was strongly associated with culitvar across every year. Clear relationships between transplanting date and head rice yield in early and mid-late maturing rice varieties were observed, and the highest head rice yields were observed during transplantings in mid and late June for early maturing cultivar and mid June for mid-late maturing cultivar. It is obvious that the optimal rice transplanting dates have been shifted and are better later than the optimal transplanting dates in 2002-2004. Days to heading was also strongly associated with the transplanting date and cultivar with 89% of the variation explained. Days to heading was reduced in the later transplanting dates. Grain yield was strongly associate with biomass production during ripening(R²=0.85), however translocated biomass from leaf and stem showed little association with grain yield. The results from this study reconfirmed the importance of shifting optimal transplanting dates to maximize head rice yield for the Mid-plain area in South Korea.

• Research in Plant Disease
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• v.25 no.4
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• pp.164-172
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• 2019

Rice blast disease caused by Magnaporthe oryzae is the most important disease of rice in both South and North Korea. Cultivation of disease-resistant cultivar is the best way to prevent this notorious disease, but M. oryzae races have been continuously changed to adapt a new cultivar. Therefore, it is important to get the information about the race and avirulence genes of the pathogen for developing blast-resistant rice cultivar. Since the entrance of North Korea was prohibited, the information about the races of M. oryzae in North Korea border areas and South Korea was collected to get the information about the diversity of rice blast pathogen in North Korea. The disease occurrence on monogenic lines carrying single resistant gene was investigated in Jeonju, Suwon, Cheorwon, Goseong, and Baengnyeongdo in Korea, and Dandong in China. The monogenic lines in Jeonju and Suwon showed diverse ranges of the response, while those in Baengnyeongdo and Dandong showed relatively high resistant responses to rice blast. All the field isolates of M. oryzae were characterized for rice blast races by the Korean differential varieties and screened for known avirulence genes to determine the spatial distribution of avirulence genes and the population of M. oryzae.

• Journal of Convergence for Information Technology
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• v.7 no.1
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• pp.49-54
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• 2017

In this paper, we propose a system that can provide a environment for plant cultivation in connection with LED plant factories and enable users to participate in plant cultivation remotely to engage in personal hobbies. The proposed system can monitor the growth conditions of plants through various sensors and remotely adjust the cultivation environment required for plant growth through the Arduino system, so that users can feel the satisfaction of plant cultivation and harvesting as a hobby. On the other hand, we suggest a mutual benefit structure for plant factory and users by securing a certain amount of income source to factory, by paying the idle space to the individual online. This paper demonstrates the feasibility of the proposed system by making the prototype of the remote plant cultivation consignment system using the Arduino and Android application(App.), and contributes to popularize the LED plant factories and expand the business area in future.

• Korean Journal of Organic Agriculture
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• v.28 no.4
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• pp.579-589
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• 2020

This study was carried out to evaluate the effect of rye as green manure crop on the improvement of soil environment and reduction of Phytophthora blight in red pepper of open field where Phytophthora blight occurred frequently. Soil physical properties such as bulk density and porosity were increased in rye cultivation. In addition, gaseous was increased but liquid was decreased compared with conventional cultivation. The analysis of phospholipid fatty acids extracted from soil showed that rye cultivation significantly increased relative abundance of microbial community and ratio of aerobic to anaerobic bacteria. Furthermore, ratio of saturated to unsaturated fatty acids and cyclo-fatty acids to precursor. the indicators of increasing in environmental stresses, were reduced in rye cultivated field. Occurrence of Phytophthora blight in rye cultivation was reduced 30.7% compared with conventional cultivation. These results suggest that rye cultivation in red pepper of open field where Phytophthora blight occurred can improve soil environment and reduce damage of Phytophthora blight.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1997.11a
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• pp.36-43
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• 1997

국민소득 향상과 함께 식품소비구조도 변화되어 곡류의 소비량은 계속 감소하고 있는 반면, 신선채소, 화훼, 육류의 소비는 크게 늘어나는 추세에 있다. 소비형태도 계절소비에서 연중 소비로 변화됨에 따라 노지재배에서 시설재배로 전환되고 있으며, 작목별 10a당 노동투하시간도 1981년도에 벼농사는 92.8시간이 소요되던 것이'95년도에는 34.7시간으로 63%가 감소되어 그동안 기계화가 많이 이루어져 왔으나, 시설오이는 837시간에서 724시간으로 약 13%가 감소되었다. (중략)

• Mycobiology
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• v.36 no.3
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• pp.157-160
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• 2008

This study was carried out to determine the possibility of bottle cultivation utilizing recycled oyster mushroom culture waste as a cultivating substrate for P. ostreatus. Total nitrogen percentage was 0.76%, 1.13%, 1.16%, 1.36%, and 1.38% in the 1-, 2-, 3-, 4-, and 5-time mixed substrate, respectively; 0.95%, 1.04%, 1.34%, 1.36%, and 1.25% in the 1-, 2-, 3-, 4-, and 5-time postharvest substrate, respectively; and 0.72% and 0.68% in the 2- and 3-time nonadditive substrate, respectively. Weight of the fresh fruiting body harvest was 115 g, 120 g, 117 g, 118 g, and 114 g on 1-, 2-, 3-, 4-, and 5-time mixed substrate, respectively; and 105 g and 45 g on 2- and 3-time nonadditive substrate, respectively. The first mixed substrate (fresh) and recycled substrates generated no significant difference in the weight of fresh fruiting bodies harvested.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.172-172
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• 2022

The heading response of 40 genotypes, originated from South Korea, North Korea, and northern China, was tested under the temperature and day-length conditions of thirteen major rice production area in North Korea, with aims to select adaptable varieties to the given environment and crop period for each region. To simulate regional environment, seven-day mean temperature with 10℃ daily temperature range and day-length for each region were imposed at a weekly interval in the walk-in phytotrons. Olbyeo1, Olbyeo2 and Sonbong9 originated from North Korea, Kenjiandao3 and Nongdae3 from northern China, and Joun from South Korea demonstrated the earliest heading stage depending on the regional environment. Thirty-four varieties reached heading stage within the regional safe marginal heading date (SMHD) under Haeju and Sariwon conditions while 16-17 varieties reached the stage under Wonsan, Changjon, Supung, and Yongyon environment. Some of the middle and mid-late maturing varieties originated from South Korea could reach heading stage within SMHD under the temperature and day-length conditions of Kaesong, Haeju, Sariwon, Nampo, and Pyongyang located in west-southern plain. Majority of early maturing varieties, but not middle or mid-late ones, showed heading stage within SMHD under the conditions of Singye, Anju, Kusong and Sinuiju. Only some early maturing varieties demonstrated heading stage within SMHD under Yongyon, Changjon and Wonsan environment. These results provide basic information on the varieties able to complete their normal life cycle under the regional environment in North Korea. It it further suggested that yield performance of the selected varieties for each region in this study be tested to select high yielding rice varieties adaptable to North Korean environment.