• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.3
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• pp.134-146
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• 2023

Phytophthora root rot (PRR) is a major soybean disease caused by an oomycete, Phytophthora sojae. PRR can be severe in poorly drained fields or wet soils. The disease management primarily relies on resistance genes called Rps (resistance to P. sojae). This study aimed to identify resistance loci associated with resistance to P. sojae isolate 40468 in Daepung × CheonAl recombinant inbred line (RIL) population. CheonAl is resistant to the isolate, while Daepung is generally susceptible. We genotyped the parents and RIL population via high-throughput single nucleotide polymorphism genotyping and constructed a set of genetic maps. The presence or absence of resistance to P. sojae was evaluated via hypocotyl inoculation technique, and phenotypic distribution fit to a ratio of 1:1 (R:S) (χ² = 0.57, p = 0.75), indicating single gene mediated inheritance. Single-marker association and the linkage analysis identified a highly significant genomic region of 55.9~56.4 megabase pairs on chromosome 18 that explained ~98% of phenotypic variance. Many previous studies have reported several Rps genes in this region, and also it contains nine genes that are annotated to code leucine-rich repeat or serine/threonine kinase within the approximate 500 kilobase pairs interval based on the reference genome database. CheonAl is the first domestic soybean genotype characterized for resistance against P. sojae isolate 40468. Therefore, CheonAl could be a valuable genetic source for breeding resistance to P. sojae.

• Korean Journal of Heritage: History & Science
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• v.57 no.3
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• pp.90-101
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• 2024

The test answer sheets submitted by examinees in the Joseon Dynasty were called Sigwon (test papers with answers, 試卷), and Siji (blank test papers, 試紙) were generally prepared by the examinees themselves. At that time, paper was not produced as a standard product, so there was no uniformity in size or manufacturing method. Mulberry paper in the Joseon Dynasty was basically transparent, so various paper processing methods were applied for examinees to write answers on both sides. In order for ink lines to be written smoothly, Dochim (hitting paper with a wooden bat on the stone, 搗砧) or surface processing was treated. We found a 19th-century Siji (試紙) that was processed in a unique way, which led to this study. An unusual Sigwon (試卷) is one by Lee Mangi (李晩耆) from 1848 owned by the National Folk Museum of Korea. We found that an opaque white substance was thickly applied between the papers of this Siji (試紙). Through component analysis using infrared spectrophotometry, fluorescence X-ray spectroscopy, optical and polarizing microscopy, and electron microscopy, this white substance was proved to be rice starch. From these analyses, it is presumed that this Siji (試紙) was made by soaking rice flour in water to remove a significant amount of protein, and then applying wet starch containing a small amount of protein between sheets of paper. In addition, with a Siji (試紙) reproduction experiment, we found that the paper reproduced by this processing method was thick and high in whiteness and opacity. This is believed to be a production method designed to produce double-sided paper without using multiple sheets of paper, which was difficult to obtain at that time. In this study, the material processed between the sheets of paper was disclosed only from < Lee Mangi (李晩耆)'s Sigwon (試卷)(Minsok 71745)>, but this appears to be one of several processing methods to treat the paper during the Joseon Dynasty. We hope that more similar Sigwons will be discovered in the future and that extensive research on processing methods will be conducted.

• Korean Journal of Agricultural and Forest Meteorology
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• v.26 no.3
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• pp.141-150
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• 2024

Garlic (Allium sativum L.) is considered as one of the most important vegetables with various uses throughout the many countries. Also, it is one of the most economically important Allium species, and has been widely cultivated for more than 5,000 years. In Korea, garlic is planted in late summer and is grown from autumn and spring of the next year. Bulb starts to form when temperature rises under longer photoperiods. Garlic growth is affected by various factors such as storage conditions, humidity, duration of minimum temperature, and photoperiod. Also, the storage conditions for propagation seed are known to potentially affect future vegetative stages. In this study, we evaluated to effect of the inter-bud growth and growth of the southern-type cultivar 'Namdo' according to storage temperatures. The inter-bud growth, emergence & sprouting rate, and initial growth of stored garlic at low temperatures (5~15℃) exhibited robust growth, while garlic stored at high temperatures (30℃) was investigated to be sluggish compared to another treatments. However, the bulb diameter of stored garlic at 10 ℃ and 15℃ increased to 148.7% and 154.0 % compared to untreated garlic, respectively. Also, the bulb weight of stored garlic increased to 285.7% and 294.4% compared to control, respectively. In contrast, garlic stored at 5℃ showed a decrease of 70 .5% in bulb dimeter and 70 .6% in bulb weight compared to the control. As a results, it was confirmed that the storage temperature of garlic affects the inter-bud growth, emergence & sprouting rate, growth, bulb diameter, and bulb weight. These results will be to the possibility that is possible to estimate the growth cycle of garlic using the growth index for the improvement of crop modeling.

• Journal of Bio-Environment Control
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• v.32 no.4
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• pp.278-284
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• 2023

Recently, a closed-type plant factory has been receiving attention as a advanced agricultural method. It has diverse advantages such as climate-independence, high productivity and stable year-round production. However, high energy cost caused by environmental control system is considered as a challenges of a closed-type plant factory. In order to reduce the energy cost, investigation about energy load which is directly connected to energy consumption needs to be conducted. In this study, energy load changes of a plant factory have been analytically analyzed according to the environmental changes. The target plant factory was a lettuce growing container farm. Firstly, the impact of photoperiod, set temperature and relative humidity change were examined. Under the climate condition of Daejeon in South Korea, increase of photoperiod and set temperature rose a yearly energy demand of a container farm. However, increase of set relative humidity decreased a yearly energy demand. Secondly, the climate environment effect was compared by investigating the energy demand under 9 different climate conditions. As a result, the difference between maximum and minimum value of the yearly energy demand showed 21.7%. Lastly, sensitivity analysis of each parameter (photoperiod, set temperature and relative humidity) has been suggested under 3 different climate conditions. The ratio of heating and cooling demand was varied depending on the climate, so the effect of each parameter became different.

• Journal of Bio-Environment Control
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• v.32 no.4
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• pp.342-352
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• 2023

Ultra-violet (UV) light is one of abiotic stress factors and causes oxidative stress in plants, but a suitable level of UV radiation can be used to enhance the phytochemical content of plants. The accumulation of antioxidant phenolic compounds in UV-exposed plants may vary depending on the conditions of plant (species, cultivar, age, etc.) and UV (wavelength, energy, irradiation period, etc.). To date, however, little research has been conducted on how leaf thickness affects the pattern of phytochemical accumulation. In this study, we conducted an experiment to find out how the antioxidant phenolic content of kale (Brassica oleracea var. acephala) leaves with different thicknesses react to UV-A light. Kale seedlings were grown in a controlled growth chamber for four weeks under the following conditions: 20℃ temperature, 60% relative humidity, 12-hour photoperiod, light source (fluorescent lamp), and photosynthetic photon flux density of 121±10 µmol m^-2 s^-1. The kale plants were then transferred to two chambers with different CO₂ concentrations (382±3.2 and 1,027±11.7 µmol mol^-1), and grown for 10 days. After then, each group of kale plants were subjected to UV-A LED (275+285 nm at peak wavelength) light of 25.4 W m^-2 for 5 days. As a result, when kale plants with thickened leaves from treatment with high CO₂ were exposed to UV-A, they had lower UV sensitivity than thinner leaves. The Fv/Fm (maximum quantum yield on photosystem II) in the leaves of kale exposed to UV-A in a low-concentration CO₂ environment decreased abruptly and significantly immediately after UV treatment, but not in kale leaves exposed to UV-A in a high-concentration CO₂ environment. The accumulation pattern of total phenolic content, antioxidant capacity and individual phenolic compounds varied according to leaf thickness. In conclusion, this experiment suggests that the UV intensity should vary based on the leaf thickness (age etc.) during UV treatment for phytochemical enhancement.

• Journal of Bio-Environment Control
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• v.32 no.4
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• pp.267-277
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• 2023

This study is in order to the effect of 1-methlycyclopropene (1-MCP) treatment and film package as modified atmosphere packaging (MAP) on the changes in fruit quality factors of 'Daehong' peaches during cold storage. The concentrations of 1-MCP were treated at 1µL·L^-1 and 2µL·L^-1, and peaches in film package were stored for 28 days in cold storage at 5±1℃ and 85±5% RH. The fruits stored carton box were used as a control of MAP, and 1-MCP free fruits were used as the control of both packages. Rate of fresh weight loss during storage was not significantly different between groups with and without 1-MCP treatment, but was higher in the box package than in the MAP. The control group had a higher incidence of both gases with the 1-MCP treatment group showing statistically significantly low. Carbon dioxide in the package was lowered by about 12% compared to the non-treated group, and the ethylene concentration was maintained at 1µL·L^-1, showing a significance low compared to other treated groups. As the storage period elapsed, the firmness of 1-MCP and MAP treated fruits remained significant at 5-9% compared to the control group. Regardless of the packaging method Hunter a^* values of exocarp and mesocarp were significantly higher in fruit treated with 1-MCP 1µL·L^-1 treatment than in the control group, and anthocyanin was significantly higher in the fruit during the storage period, especially high in MAP. In summary, fruits of MAP group with 1-MCP 1µL·L^-1 had rate of lower respiration and ethylene production, and little changes in firmness, Hunter a^* values of exo-carp and meso-carp, and anthocyanin, which is considered the most suitable method for preserving postharvest quality of the peach cultivar during the storage.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.69 no.3
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• pp.170-180
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• 2024

This study aimed to evaluate the safety and efficacy of various biodegradable mulching films in maize cultivation by analyzing crop growth, yield, film degradation rate, as well as soil chemistry, temperature, and moisture. The results indicated that maize plant height, heading, and silking rates were lower in plots without mulching than in those with biodegradable mulching (F, H, and V) and polyethylene (PE) films. Plant height, heading, and silking rates were consistent throughout the study period between PE and biodegradable mulching films. At harvest, there were no significant differences in the number of leaves per plant, shoot fresh weight, stem length, ear length, ear width, maize count, and yield per 10a between the PE and biodegradable mulching films. However, the light transmittance was higher with biodegradable than with PE films during cultivation and post-harvest. At 63 days post-transplanting, the H film showed the highest transmittance of up to 45% compared to the F and V films. Additionally, the films were completely degraded by 14 days post-harvest. The deterioration level (0-5) of biodegradable mulching films increased over time after transplanting, while the deterioration of the PE film was minimal. At 70 days post-transplanting, the deterioration level of biodegradable films ranged from 2.7 to 4.3, and from 3 to 5 post-harvest, with the H film exhibiting the highest degradation. Up to 49 days post-transplanting, the degradation rate of the biodegradable mulching films was comparable to that of the PE film. However, at 63 days post-transplanting, the degradation rate of the biodegradable film was significantly higher than that of the PE film. The H film, with a degradation rate of 56%, showed the highest rate, followed by the V film at 11%, and the F film at 8%. Although soil pH, electrical conductivity (EC), and organic matter content fluctuated throughout the observation period, there were no significant differences between soils covered with biodegradable mulching films and those covered with PE film. The soil temperature and moisture levels were also similar between the two film types. However, the use of mulch films increased soil temperature by approximately 2 ℃ and soil moisture by 5-15% compared to non-mulched soil. Thus, the biodegradable mulch films used in this study can be safely used without adversely affecting maize growth, yield, or the soil environment.

• Korean Journal of Soil Science and Fertilizer
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• v.10 no.3
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• pp.171-188
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• 1977

The response and effect on main upland crops to potassium were discussed and summarized as follows. 1. Adequate average amounts of potash per 10a were 32kg for forage crop; 22.5kg for vegetable crops; 17.3kg for fruit trees; 13.3kg for potatoes; and 6.5kg for cereal crops. Demand of potassium fertilizer in the future will be increased by expanding the acreage of forage crops, vegetable crops and fruit trees. 2. On the average, optimum potash rates on barley, wheat, soybean, corn, white potato and sweet potato were 6.5, 6.9, 4.5, 8.1, 8.9, and 17.7kg per 10a respectively. Yield increaments per 1kg of potash per 10a were 4-5kgs on the average for cereal crops, 68kg for white potato, and 24kg for sweet potato. 3. According to the soil testing data, the exchangeable potassium in the coastal area was higher than that in the inland area and medium in the mountainous area. The exchangeable potassium per province in decreasing order is Jeju>Jeonnam>Kangweon>Kyongnam. Barley : 4. The response of barley to an adequate rate of potassium seemed to be affected more by differences in climatic conditions than to the nature of the soil. 5. The response and the adequate rate of potassium in the southern area, where the temperature is higher, were low because of more release of potassium from the soil. However, the adequate rate of phosphorus was increased due to the fixation of applied phosphorus into the soil in high temperature regions. The more nitrogen application would be required in the southern area due to its high precipitation. 6. The average response of barley to potassium was lower in the southern provinces than northern provinces. Kyongsangpukdo, a southern province, showed a relatively higher response because of the low exchangeable potassium content in the soil and the low-temperature environment in most of cultivation area. 7. Large annual variations in the response to and adequate rates of potassium on barley were noticed. In a cold year, the response of barley to potassium was 2 to 3 times higher than in a normal year. And in the year affected by moisture and drought damage, the responses to potassium was low but adequate rates was higher than cold year. 8. The content of exchangeable potassium in the soil parent materials, in increasing order was Crystalline Schist, Granite, Sedimentary and Basalt. The response of barley to potash occurred in the opposite order with the smallest response being in Crystalline Schist soil. There was a negative correlation between the response and exchangeable potassium contents but there was nearly no difference in the adequate rates of potassium. 9. Exchangeable potassium according to the mode of soil deposition was Alluvium>Residium>Old alluvium>Valley alluvium. The highest response to potash was obtained in Valley alluvium while the other s showed only small differences in responses. 10. Response and adequate rates of potassium seemed to be affected greatly by differences in soil texture. The response to potassium was higher in Sandy loam and Loam soils but the optimum rate of potassium was higher in Clay and Clay loam. Especially when excess amount of potassium was applied in Sandy loam and Loam soils the yield was decreased. 11. The application of potassium retarded the heading date by 1.7 days and increased the length of culm. the number of spikelet per plant, the 1,000 grain weight and the ratio of grain weight to straw. Soybean : 12. Average response of soybean to potassium was the lowest among other cereal crops but 28kg of grain yield was incrased by applying potash at 8kg/10a in newly reclaimed soils. 13. The response in the parent materials soil was in the order of Basalt (Jeju)>Sedimentay>Granite>Lime stone but this response has very wide variations year to year. Corn : 14. The response of corn to potassium decreased in soils where the exchangeable potassium content was high. However, the optimum rate of applied potassium was increased as the soil potassium content was increased because corn production is proportional to the content of soil potassium. 15. An interaction between the response to potassium and the level of phosphorus was noted. A higher response to potassium and higher rates of applied potassium was observed in soils contained optimum level of phosphorus. Potatoes : 16. White potato had a higher requirement for nitrogen than for potassium, which may imply that potato seems to have a higher capability of soil potassium uptake. 17. The yield of white potato was higher in Sandy loam than in Clay loam soil. Potato yields were also higher in soils where the exchangeable potassium content was high even in the same soil texture. However, the response to applied potassium was higher in Clay loam soils than in Sandy loam soils and in paddy soil than in upland soil. 18. The requirement for nitrogen and phosphorus by sweet potato was relatively low. The sweet potato yield is relatively high even under unfavorable soil conditions. A characteristics of sweet potatoes is to require higher level of potassium and to show significant responses to potassium. 19. The response of sweet potato to potassium varied according to soil texture. Higher yields were obtained in Sandy soil, which has a low exchangeable potassium content, by applying sufficient potassium. 20. When the optimum rate of potassium was applied, the yields of sweet potato in newly reclaimed soil were comparable to that in older upland soils.

• Journal of Aquaculture
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• v.21 no.4
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• pp.203-212
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• 2008

A nutritional demand of oyster, Crassostrea gigas larva as part of research for improving of utilization of microalgae being used for the artificial oyster seed production. The change of body growth and biochemical compositions of larvae were investigated during larvae rearing in hatchery. The larvae were cultured in 60 M/T tank and fed mixture 6 different phytoplankton species, Isochrysis galbana (30%), Cheatoceros gracilis (20%), Pavlova lutheri (20%), Phaeodactylum triconutum (10%), Nannochryis oculata (10%) and Tetraselmis tetrathele (10%). The initial feeding amount was $0.3{\times}10^4cells/mL$ at three times a day to D-shaped larva and the feeding amount had been increased 30% gradually every two day since the larvae were raising. The larvae were developed from D shape to pediveliger stage for 12 days. The daily growth of shell length and hight were $5.8{\sim}30.8\;{\mu}m$ and $8.7{\sim}31.4\;{\mu}m$, respectively and weight gains were changed from D shape to pediveliger as follow: wet weight was $0.52{\sim}15.0\;{\mu}g/larva$, dry weight was $0.2{\sim}6.5\;{\mu}g/larva$, and ash free dry weight was $0.1{\sim}8.5\;{\mu}g/larva$. The larvae growth pattern shown a logarithmic phase from D shape to umbone stage but after that stage shown a exponential growth aspect. The crude protein, crude lipid and nitrogen free extract (NFE) of larvae during rearing periods were analyzed as $6.1{\sim}10.6%$, $0.6{\sim}1.1%$ and 1.0-2.7%, respectively. And the total amino acid contents of the larvae during rearing periods were in order as glutamic acid $1.26{\sim}2.24%$, aspartic acid $0.97{\sim}1.70%$, and methionine $0.12{\sim}0.33%$. Of the total fatty acid in the analyzed larvae, the saturated fatty acid (SSAFA) was decreased from 54.3% (D shaped larvae) to 17.1 % (pediveliger) as larvae development but the total mono-unsaturated fatty acid (${\Sigma}MOFA$) and Poly-unsaturated fatty acid (${\Sigma}PUFA$) were increased from 29.9% and 7.8% to 40.6% and 45.6%, respectively. By the way the each fatty acid of the larvae were composed of palmitic acid $9.89{\sim}36.95%$, oleic acid $12.17{\sim}32.29%$, linoleic acid $1.96{\sim}33.55%$, EPA $2.17{\sim}11.58%$ and DHA $1.95{\sim}4.51%$. As a result of this study, the larvae of oyster were demanded a various nutrients for healthy growth and the feeding control, expecially after umbone stage larvae are a rapidly growing time, is very important for success of artificial seed production.

• The Korean Journal of Quaternary Research
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• v.14 no.1
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• pp.7-31
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• 2000

Quaternary Geological and geophysical investigation was performed at the Eurimji reservoir of Jaechon City in order to interprete depositional environment and genesis of lake sediments. For this purpose, echo sounding, bottom sampling and columnar sampling by drilling on board and GPR survey were employed for a proper field investigation. Laboratory tests cover grain size population analysis, pollen analysis and $^{14}C$ datings for the lake sediments. The some parts of lake bottom sediments anthropogenically tubated and filled several times to date, indicating several mounds on the bottom surface which is difficult to explain by bottom current. Majority of natural sediments were accumulated both as rolling and suspended loads during seasonal flooding regime, when flash flow and current flow are relatively strong not only at bridge area of the western part of Eurimji, connected to stream valley, but at the several conduit or sewage system surrounding the lake. Most of uniform suspend sediments are accumulated at the lake center and lower bank area. Some parts of bottom sediments indicate the existence of turbid flow and mudflow probably due to piezometric overflowing from the lake bottom, the existence of which are proved by CM patterns of the lake bottom sediments. The columnar samples of the lake sediments in ER-1 and ER-3-1 boreholes indicate good condition without any human tubation. The grain size character of borehole samples shows poorly sorted population, predominantly composed of fine sand and muds, varying skewness and kurtosis, which indicate multi-processed lake deposits, very similar to lake bottom sediments. Borehole columnar section, echo sounding and GPR survey profilings, as well as processed data, indicate that organic mud layers of Eurimji lake deposits are deeper and thicker towards lower bank area, especially west of profile line-9. In addition the columnar sediments indicate plant coverage of the Eurimji area were divided into two pollen zones. Arboreal pollen ( AP) is predominant in the lower pollen zone, whreas non-aboreal pollen(NAP) is rich in the upper pollen zone. Both of the pollen zones are related to the vegetation coverage frequently found in coniferous and deciduous broad-leaved trees(mixed forest) surrounded by mountains and hilly areas and prevailing by aquatic or aquatic margin under the wet temperate climate. The $^{14}C$ age of the dark gray organic muds, ER1-12 sample, is 950$\pm$40 years B.P. As the sediments are anthropogenetically undisturbed, it is assumed that the reliability of age is high. Three $^{14}C$ ages of the dark gray organic muds, including ER3-1-8, ER3-1-10, ER3-1-11 samples, are 600$\pm$30 years B.P., 650$\pm$30 years B.P., 800$\pm$40 years B.P. in the descending order of stratigraphic columnar section. Based on the interpretation of depositional environments and formation ages, it is proved that Eurimji reservoir were constructed at least 950$\pm$40 years B.P., the calibrated ages of which ranges from 827 years, B.P. to 866 years B.P. Ancient people utilize the natural environment of the stream valley to meet the need of water irrigation for agriculture in the local valley center and old alluvium fan area.