• KOREAN JOURNAL OF CROP SCIENCE
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• v.67 no.4
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• pp.253-264
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• 2022

In this study, we investigated the occurrence of viral diseases in the early growth stage of soybean to establish management practices. We collected 83 soybean samples showing abnormal symptoms, approximately 3-4 weeks after seeding in the breeding field of the National Institute of Crop Science. Viruses were detected in the collected samples using reverse transcription polymerase chain reaction (RT-PCR) and metatranscriptome analysis of all those samples. The incidence of viral diseases in the field was less than 1% overall and up to 50% in certain cultivars and lines. RT-PCR and metatranscriptome analysis detected Soybean yellow mottle mosaic virus (SYMMV), Soybean mosaic virus (SMV), Soybean yellow common mosaic virus, Peanut stunt virus, and soybean geminivirus A (SGVA). Among these detected viruses, SYMMV and SMV were identified as major viruses causing infection in the early growth stage of soybean, with detection rates of 53.7% and 42.6%, respectively. Soybeans infected with SYMMV showed typical mosaic symptoms, whereas those infected with SMV showed a variety of symptoms such as mosaic, mottle, stunt, and chlorotic spots. Transmission characteristics of these viruses are variable, such that SMV is primarily transmitted by seeds, whereas SYMMV could be transmitted by insects, soil, and seeds. In this study, SGVA was detected in the early growth stage of soybean, and research on the current status and its effects on soybean after the early growth stage should be conducted.

• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.4
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• pp.243-248
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• 2022

This study was conducted to evaluate the effect of feeding the whole crop rice silage (WCRS) which partially replaces the imported grass hay crop on the milking performance of Holstein and profitability. Two experimental diets were used according to the traditional practice of dairy farms. The control diet (C) was composed of 13kg/day of mixed hay, 6.8kg/day concentrate, and orchardgrass/bermudagrass hay (1.8kg/day). The treatment diet (T) was composed of 9.6kg/day of mixed hay, 6.8kg/day of concentrate and 2.2kg/day of WCRS. The CP content of the WCRS (4.6%) was lower than orchardgrass (11.3%) and bermudagrass hay (8.4%) due to the harvest being 30days later than the optimum harvest date of rice. The lower intake was observed in T during the entire experiment period which seems to be related to the higher proportion of fiber in rice (p<0.05). No significant difference was found in milk production between C (26.9kg) and T (26.3kg) during the entire experiment period (p>0.05). Also, no difference in milk fat, milk protein, total solids, and milk composition was observed between the two diets. Higher income per head was resulted in T (21,141won) compared to C (21,915 won). These results indicate that the partial replacement of the grass hay by the WCRS can bring the profit to the dairy farm due to the no difference between the control diet and the treatment diet.

• Korean journal of applied entomology
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• v.61 no.4
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• pp.605-614
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• 2022

Two major problems currently threaten human survival on Earth: climate change and the rapid aging of the population in developed countries. Climate change is a result of the increase in greenhouse gas (GHG) concentrations in the atmosphere due to the increase in the use of fossil fuels owing to economic and transportation development. The rapid increase in the age of the population is a result of the rise in life expectancy due to the development of biomedical science and technology and the improvement of personal hygiene in developed countries. To avoid irreversible global climate change, it is necessary to quickly transition from the current fossil fuel-based economy to a zero-carbon renewable energy-based economy that does not emit GHGs. To achieve this goal, the dairy and livestock industry, which generates the most GHGs in the agricultural sector, must transition to using low-carbon emission production methods while simultaneously increasing consumers' preference for low-carbon diets. Although 77% of currently available arable land globally is used to produce livestock feed, only 37% and 18% of the proteins and calories that humans consume come from dairy and livestock farming and industry. Therefore, using edible insects as a protein source represents a good alternative, as it generates less GHG and reduces water consumption and breeding space while ensuring a higher feed conversion rate than that of livestock. Additionally, utilizing the functionality of medicinal insects, such as silkworms, which have been proven to have certain health enhancement effects, it is possible to develop functional foods that can prevent or delay the onset of currently incurable degenerative diseases that occur more frequently in the elderly. Insects are among the first animals to have appeared on Earth, and regardless of whether humans survive, they will continue to adapt, evolve, and thrive. Therefore, the use of various edible and medicinal insects, including silkworms, in industry will provide an important foundation for human survival and prosperity on Earth in the near future by resolving the current two major problems.

• Journal of Practical Agriculture & Fisheries Research
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• v.16 no.1
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• pp.37-53
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• 2014

The purpose of this research is to find what difficulties the agricultural successors, the Korea National College of Agriculture and Fisheries (KNCAF) graduates, face with in implementing eco-friendly agriculture in Jeju, and what solutions they can be provided with. This research, a case study on the basis of open-ended survey questions, has 6 cases out of 8 graduates who have or had implemented eco-friendly citrus farming. In Jeju, 24 graduates have involved in citrus farming. According to the case study, only one case was environment-friendly farming method at the pesticide-free level, and the others at organic farming level. All the cases have tried to alter main crops or to diversify management for coping with global climate change and market-opening. On analyzing operating cost to gain product of merchantable quality, it revealed that the environment-friendly farming method needs much more managing efforts than the conventional farming does. But to the contrary, the materials cost in the environment-friendly farming method was lower than in the conventional farming method. In the total production and the price, the environment-friendly farming was 20~50% lower and 10~50% higher than the conventional farming, respectively. Difficulties which the graduates confronted with in implementing the environment-friendly agriculture are as below. Firstly, many of the difficulties have resulted from lack of the environment-friendly farming techniques, and the high cost of farm scale improvement due to high price of land and topographical features of Jeju. Secondly, the agricultural successors, the KNCAF graduates, have trouble in obtaining approval of their parents to changeover from the conventional farming to the environment-friendly farming. Lastly, there is no advisory organizations and experts for environment-friendly farming in the given area. For shift to the environment-friendly farming, followings are needed. Agricultural Technology & Extension center, with cooperation of leading farms in environment-friendly farming, should have a key role in offering education and consults on the environment-friendly farming techniques. Also, this organization should inform rapidly the research results to the farmers, and their feed-back should be involved in the next research. Therefore, it is suggested that the forum called 'Environment-friendly Organic Farming Forum in Jeju' tentatively is organized.

• Journal of Practical Agriculture & Fisheries Research
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• v.10 no.1
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• pp.43-58
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• 2008

This research was conducted to determine the alternative tool of chemical spray for rice cultivation using the unmanned helicopter(Yamaha, R-Max Type 2G-remote controlled system) at farmer's field in Korea. The unmanned helicopter tested was introduced form Japan. In Korea the application of chemicals by machine sprayer for pest management in rice cultivation has been ordinarily used at the farmer's level. However, it involved a relatively high cost and laborious for the small scale of cultivation per farm household. Farm population has been highly decreased to 7.5% in 2002 and the population is expected to rapidly reduce by 3.5% in 2012. In Japan, pest control depending on unmanned helicopter has been increased by leaps and bounds. This was due in part to the materialization of the low-cost production technology under agricultural policy and demand environmentally friendly farm products. The practicability of the unmanned helicopter in terms of super efficiency and effectiveness has been proven, and the farmers have understood that the unmanned helicopter is indispensable in the future farming system that they visualized. Also, the unmanned helicopter has been applied to rice, wheat, soybean, vegetables, fruit trees, pine trees for spraying chemicals and/or fertilizers in Japan Effect of disease control by unmanned helicopter was partially approved against rice blast and sheath blight. However, the result was not satisfactory due to the weather conditions and cultural practices. The spray density was also determined in this experiment at 0, 15, 30, and 60cm height from the paddy soil surface and there was 968 spots at 0cm, 1,560 spots at 15cm, 1,923 spots at 30cm, and 2,999 spots at 60cm height. However, no significant difference was found among the treatments. At the same time, there was no phytotoxicity observed under the chemical stray using this unmanned helicopter, nor the rice plant itself was damaged by the wind during the operation.

• Analytical Science and Technology
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• v.19 no.3
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• pp.263-271
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• 2006

The levels of total PCBs, Co-PCBs and PCDD/Fs in the transformer insulation oil samples obtained using GC/ECD and HRGC/HRMS were ranged from N.D. to 77.3 ppm, from 0.0863 to 2.49 ppm and from N.D. to 0.00241 ppm, respectively. In terms of WHO-TEQ values, Co-PCBs and PCDD/Fs were ranged from 23.3 to 600 pgTEQ/g and from N.D. to 128 pgTEQ/g, respectively (${\Sigma}Co$-PCBs+PCDD/Fs concentration was calculated 24.4~728 pgTEQ/g). Although, the contribution of PCDD/Fs was below 12% in total TEQ concentration, it is suggested contamination of PCDD/Fs in transformer insulation oils. Among 10 samples, 4 samples showed higher concentration than 2 ppm (specific waste criterion of Korea) and Aroclor 1242, 1248, 1254 and 1260 was detected in samples as a single or mixture of Aroclor. It was shown reliable relationship between concentration of Co-PCBs and those of PCDD/Fs (p<0.003), however, was not shown between production year of transformer and concentration of PCBs. The distribution pattern of Co-PCB congeners showed that the ratios of mono-ortho substituted congeners were higher than non-ortho substituted congeners. Among that, PCB-118 congener was predominant. In addition, the OCDD congener was predominated in PCDD/Fs congeners as above 53%. Moreover, the congener pattern of Co-PCBs was similar to that of Aroclor as well as ambient air, which suggested that PCBs volatilization from transformer insulation oil affected the pattern of Co-PCBs in ambient air.

• Journal of Practical Agriculture & Fisheries Research
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• v.20 no.1
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• pp.163-174
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• 2018

Rice cultivation is immensely affected by many climatic factors including temperature, precipitation, etc, and imbalanced climatic conditions negatively affect the growth of rice. In this study, we investigated the effects of different agroclimatic zones of Chungnam Province on rice quality and examined the correlations between climatic characteristics and rice yield components. Average temperatures and rainfall were higher in 'Western Sobaek Inland' than those in the 'South Western coastal zone, and precipitation records showed a wide variation among counties due to typhoons during the examined periods. The average accumulative temperature affecting the magnitude of production during reproductive growth periods was higher in "Cheon-An", "Gong-Ju", "Yeon-Gi (Se-Jong)", "Bo-Ryeong", and "Dang-Jin" counties than those in other counties. The plant height was higher in 'Western Sobaek Inland' counties such as "Yeon-Gi(Se-Jong)" and "Cheon-An", and 'Southern Charyeong Plain' counties such as "Cheong-Yang", "Dang-Jin", and "A-San", than those in other counties. The number of tillers during the 40 days after rice transplantation in "Seo-Cheon" and "Bo-Ryeong" counties increased compared to other counties. This result was relevant to the fact that the date of rice transplantation in those counties was 3 to 4 days later than those in other counties of Chung-Nam Province. The average yield (milled rice basis) was the highest in 'Western Sobaek Inland' zone, showing 3,756 kg ha^-1, followed by 'Southern Charyeong Plain' zone showing 3,621kg ha^-1, and was the lowest in 'South Western coastal zone by 3,315kg ha^-1. "Yeon-Gi(Se-Jong)" and "Dang-Jin" counties showed the highest yields of 4,100kg ha^-1. "Seo-San", "Seo-Cheon", and "Tae-An" counties were relatively lower yields of 3,240~3,280kg ha^-1 in comparison of other counties.

• Korean Journal of Environment and Ecology
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• v.38 no.1
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• pp.90-107
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• 2024

This study analyzed the status of urban agricultural regulation of metropolitan governments on supporting multi-dimensional values to suggest a direction for improving urban agriculture regulations. Moreover, a Delphi survey was conducted to derive ways to identify improvement opportunities for functions that showed relatively insufficient support for urban agricultural regulations. As a result of the study, 12 out of 17 metropolitan governments and 116 of 226 municipalities have enacted urban agricultural regulations. However, the enactment of urban agricultural regulations has generally declined since 2011. Analysis of the contents of the urban agricultural regulations showed that they focused on matters relating to the creation and expansion of the foundation of urban agriculture. Among the multi-dimensional values of urban agricultural regulations, the foundation for supporting the securing of green spaces and utilizing food production functions was most widely available. On the other hand, the foundation for support of resource recycling, healing and health, social welfare, economic imbalance mitigation, and job creation functions has been shown to be relatively insufficient. A Delphi survey conducted to determine potential measures to improve urban agricultural regulations to support these functions found that 17 of the 18 ordinance improvement measures were valid. Therefore, to revitalize the multi-dimensional values of urban agriculture, it is first necessary to enact new ordinances. Also, to revitalize the multi-dimensional values of urban agriculture evenly, it is necessary to revise the ordinances to include resource recycling, healing and health, social welfare, mitigation of economic imbalances, and job creation functions. In this process, the development of urban agriculture technology, legal review of various urban farming spaces, and fostering of industries related to urban agriculture are necessary. Above all, steady interest in the multi-dimensional values of urban agriculture and the efforts of local governments to foster urban agriculture must be supported.

• Journal of Plant Biotechnology
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• v.50
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• pp.248-254
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• 2023

This study was conducted to establish an efficient plant regeneration system in 'Dayu', a Korean variety of Perilla frutescens developed for seed oil production, in conjunction with the previously studied variety 'Namcheon'. The healthiest callus was formed on the hypocotyl explants cultured on a medium containing 0.1 mg/L NAA and 0.5 mg/L BA, outperforming the leaf and cotyledon samples. In both dark and long-day conditions, Dayu consistently exhibited significantly higher shoot regeneration rates compared with Namcheon. The highest shoot regeneration rates in Dayu were observed from the hypocotyl explants cultured on 0.1 mg/L NAA and 0.5 mg/L BA media, with shoot regeneration rates of 84.4% and 86.7% under dark and long-day conditions, respectively. Various combinations of plant growth regulators were tested to establish the optimal shoot regeneration conditions for Dayu hypocotyl explants. The results demonstrated that the highest shoot regeneration rate (90%) was achieved when 0.5 mg/L of BA was added to the medium without NAA. Among the regenerated shoots, 70.5% were normal plants, while 19.3% were abnormal. The addition of NAA or an increase in its concentration led to a higher occurrence of abnormal plants. After the regenerated shoots were transferred to 1/2 MS medium, roots were observed within 10-15 days. By day 30, they had developed into complete plants. The results obtained from the regeneration experiments with the perilla variety Dayu can valuably inform molecular breeding reliant on transformation techniques such as genome-editing and genetic modification technology.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.2
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• pp.112-120
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• 2007

This paper reviews the use of parasites as 'biological tags' for studying stock analysis of salmonid fishes. Numerous definitions of stock concepts exist, but most of them essentially define a group of fish as having similar biological characteristics and being self-reproducing as stocks. It is important to manage fish stocks for human consumption and sustainable production and especially for salmonid fishes. Because these fry are considered as each country's property, it is necessary to identify and discriminate each fish stock in the open sea. Methods of separating fish stocks are very diverse. Artificial tags, parasites, otoliths scales and genetic characters have been used for stock analysis and each method has advantages and disadvantages. Of these parasites can be good biological tags because they are applied by nature at no cost. Parasites can be infected with susceptible host fishes when they enter into certain areas. Then if they move to the outside and are caught researchers can infer that the fish had been in the endemic area for a period of time during their life. Hence the host fish can be considered as naturally 'tagged' by parasites. However, if they do not pass the parasites-endemic. area, they will harbour no parasites. Therefore, researchers can discriminate each fish stocks and trace their migration routes with these biological tags. In this paper, several examples on the use of parasites as biological tags for studying salmonids, as well as other species, are listed. The advantages and limitations of parasites as biological tags are also discussed. Chum salmon (Oncorhynchus keta), the main salmonid species migrating to Korea, is distributed all around the North Pacific. Korean chum salmon are generally thought to move to the Sea of Okhotsk, the western North Pacific and the Bering Sea. However, there is no clear information on the distribution and migration pathways of Korean chum salmon, and no markers exist for separating them from others yet. Recent Korean chum salmon stock analysis including parasites information are mentioned.