• Korean Journal of Organic Agriculture
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• v.27 no.2
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• pp.205-224
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• 2019

This study was carried out in order to evaluate the growth promotion effects on tomato crops and to assess the mineral nutrient concentrations of farm-made liquid fertilizers used in organic cultivation in South Korea. We hope that this study will help to develop of a standardized manufacturing technique for these organic liquid fertilizers. We collected 62 farm-made liquid fertilizers made from various raw materials including fish, seaweed, food scraps, plant and crop by-products, and other materials. Two groups of tomato seedlings were treated at different times, one at 20 days and the other at 40 days after sowing. We used both foliar and soil applications. These seedlings were treated using liquid fertilizers at various dilution rates (x1000, x500 and x100). When foliar application was used, seedlings after 20 days had a 20-30% increase in shoot fresh weight with 47-48 fertilizers and seedlings after 40 days had a 20-30% increase in shoot fresh weight with 17-32 fertilizers. When soil application was used, seedlings after 20 days had the same increase in shoot fresh weight with 30-31 fertilizers and seedlings after 40 days also saw the same increase with 6-7 fertilizers. Therefore, our studies showed that application of liquid fertilizers to seedlings 20 days after sowing was most effective and that foliar treatment was more effective than soil treatments. We also observed that the higher the concentrations of fertilizer, particularly when applied twice rather than just once, the higher the rates of growth, which promoted shoot fresh weight more than plant height. Our results imply that mineral nutrients in liquid fertilizers seem to be the probable cause for the growth promotion observed in this study. However, more study is required to determine exactly which mineral nutrients are most effective.

• Korean Journal of Agricultural and Forest Meteorology
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• v.22 no.3
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• pp.176-182
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• 2020

National Institute of crop Science of the Rural Development Administration (RDA) has conducted long-term monitoring studies to find out the relationship between crop yield and climatic factors for major food crops including rice. Rice growth and y ield have been monitored in 17 regions where the branches of the National Institute of Crop science and the Provincial Agricultural Research and Extension Service locate. The data obtained from monitoring studies for rice growth and yield include the observation of vegetative growth status and yield components, which include leaf number, biomass and the weight of 1000 grains. These data have been collected from rice fields where standard management procedures have been applied. The observation data for crop growth and yield monitoring studies from 1999 to 2019 are open to public through agricultural science library operated by RDA.

• Korean Journal of Environmental Biology
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• v.37 no.4
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• pp.493-502
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• 2019

Maize (Zea mays L.) is a C4-plant and one of the three major crops grown worldwide. Because of its high productivity, maize is considered as one of the most important food and feed stocks in the world. Recently, bioethanol from maize was predominantly generated in the USA and Brazil. Infection of maize by several diseases resulted in a huge disaster and prevented maize production. Downy mildew, caused by Peronosclerospora sorghi, is one of the most serious diseases of maize. Despite efforts to develop downy mildew-resistant cultivars or seed treatment with metalaxyl, downy mildew persists as a serious pathogen and is still prevalent in specific geographical locations. Analysis of soils infected with downy mildew and investigation of candidates associated with downy mildew resistance is an attractive method to overcome downy mildew damage in maize. In a previous study, we reported that maize chromosome 6 carries a possible candidate gene for downy mildew resistance. Using bioinformatics tools and RT-PCR analysis, five novel genes including bZIP, OFP transcription factor, and Ppr were identified as candidate genes associated with downy mildew resistance.

• Journal of The Korean Society of Grassland and Forage Science
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• v.27 no.2
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• pp.109-116
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• 2007

Environmental stress is the major limiting factor in plant productivity. As an effort to solve the global food and environmental problems using the plant biotechnology, we have developed transgenic tall fescue (Festuca arundinacea Schreb.) plants via Agrobacterium-mediated gene transfer method. To develop transgenic tall fescue plants with enhanced tolerance to the environmental stresses, both CuZn superoxide dismutase (CuZnSOD) and ascorbate peroxidase (APX) genes were incorporated in a pIG121 binary vector and the both of the genes were controlled separately by an oxidative stress-inducible sweet potato peroxidase 2 (SWPA2) premoter expressed in chloroplasts. Leaf discs of transgenic plants showed 10-30% less damage compared to the wild-type when they exposed to a wide range of environmental stresses including methyl viologen (MV), $H_2O_2$ and heavy metals. In addition, when $200{\mu}M$ MV was sprayed onto the whole plants, transgenic plants showed a significant reduction of visible damage compared to wild-type plants that were almost damaged. These results suggest that over expression of CuZnSOD and APX genes in transgenic plants might be a useful strategy to protect the crops against a wide range of environmental stresses.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.1
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• pp.60-65
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• 1982

In order to observe the degree and response of drought-resistance and its physiological mechanism in barley and wheat seedling stage, 5 species (16 cultivars) were tested for the changes of nitrate reductase and protease activity and the accumulation of free proline, by being subjected to water stress by withholding watering for 8 days at 10 days (at the 3rd leaf stage) after emergence and by imposing water stress to the excised first leaf by polyethyleneglycol solution (osmotic potential, -20 bars) for 48 hours. The average rate of decrease of all cultivars was 42% in nitrate reductase activity and 73% in protease activity. But proline content in water stress was increased 10 folds more than that of control. The decrease4 rate of nitrate reductase activity in 5 species was in the order of wheat < rye < covered barley < naked barley < two-row barley: wheat being the lowest. The decreased rate of protease activity in 5 species was in the order of wheat > rye > two-row barley > covered barley > naked barley: wheat being the" heighest. The accumulated amount of free proline in 5 species by water stress was in the order of wheat > covered barley > rye > naked barley > two-row barley. And the increased ratio (folds) of free proline of water stress to control was in the order of rye(13) > wheat. covered barley(11) > naked barley(99) > two-row barley(7): rye being the highest. In terms of the enzymatic activity and the physiotically adaptive metabolism during the processing leading to drought-resistance, the degree of drought-resistance of 5 species to water stress at seedling stage was shown to be in the order of wheat > rye > covered barley > naked barley > two-row barley.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.5
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• pp.545-553
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• 2017

Microalgae can offer an attractive way of generating renewable and sustainable biodiesel. Biodiesel derived from microagae can have lower impact on the environment and food supply than biodiesel produced from crops. But biodiesel derived from microagae have poor fuel properties at low temperature depending on their species. In this study, it was investigated that fuel characteristics of biodiesel derived from Tetraselmis sp. and cold weather performance of biodiesel blend (BD3, 3 vol.% biodiesel - 97 vol.% diesel). The startability and operability of the passenger car in BD3 was good at $-20^{\circ}C$.

• Korean Journal of Plant Resources
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• v.26 no.5
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• pp.548-556
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• 2013

The objective of this study was to determine the effect of antioxidant enzyme activity and radical scavenging activities of cucumber grown greenhouse. The analytic method of antioxidant activities were measured by estimating DPPH free radical scavenging, nitrite scavenging ability activity and ABTS radical scavenging ability. The DPPH free radical scavenging activity of Jangjukcheongjang was the highest in most of the growth stage. The Nitrite scavenging ability at pH 1.2 was more than 40% in all cultivars and growth stages. The ABTS radical scavenging ability of Jangjukcheongjang and Nulpureuncheongjang showed relatively little higher than Janghyeongnakhap and Sinjoeunbaekdadagi. The SOD activity showed higher activity than 95% in all cultivars and growth stages. The activity of CAT was highest in the Nulpureuncheongjang of 2 (12~16cm) growth stage, and the APX activity of Nulpureuncheongjang and Janghyeongnakhap showed a relatively high activity. The POX activity showed distinctly different trends depending on the growth stage, and that is, the activity at harvest stage was significantly reduced. These results suggest that the cucumber had the potent biological activities, and that in the future, the availability of cucumber will be increase in the field of high-value cosmetic and food products.

• Korean Journal of Plant Resources
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• v.24 no.2
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• pp.195-199
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• 2011

Tomato (Lycopersicon esculentum M.) is one of the most important crops to the fresh vegetable market and the food processing industry. To evaluate genetic variation in tomato fruits, major characteristics such as soluble solids, acidity and carotenoid contents were analyzed for 771 genetic resource lines. Lines in red color was about 85% which is the largest one followed by peach color, yellow, green, orange, and black. The sweetness of juice ranged from 2.2 to 11.5% (in brix), the average being 5.6%. The acidity ranged from 0.124% to 1.665%, and the average was 0.881%. The lycopine contents was up to 80.4 ${\mu}g/g$, and 43.4 ${\mu}g/g$ in average. ${\beta}$-carotine ranged 1.8 to 48.8 ${\mu}g/g$ and it average was 10.8 ${\mu}g/g$. Statistical analysis indicates that there is coefficient of correlation between acidity and sweetness, acidity and pH, pH and lycopine, lycopine and ${\beta}$-carotine. It is expected that the result of this study can be used for breeding more competitive species with respect to contents in sugar or functional chemicals from the selected characteristic species.

• Microbiology and Biotechnology Letters
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• v.39 no.3
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• pp.308-312
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• 2011

Plant lactic acid bacteria were isolated from plant-associated fermentative foods and crops, and their probiotic properties were investigated. Isolates K27 and O2 were isolated from Kimchi and onion, and identified as Lactobacillus plantarum on the basis of 16S rRNA gene analysis. The two strains were highly resistant to acid (an MRS broth at pH 2.5), where the survival rates of L. plantarum K27 and L. plantarum O2 were 90.2% and 97.3%, respectively. L. plantarum K27 and L. plantarum O2 also showed high bile resistance to 0.5% oxgall, with a more than 70% survival rate. They showed an inhibitory effect against pathogenic strains of Escherichia coli KCCM 40880 and Pseudomonas aeruginosa ATCC 10145. The antibacterial effect of the two strains was probably due to the presence of lactic acid. ACE inhibitory activities of the two strains ranged from 72.8% to 80.6% in MRS broth. Notably, the two strains showed high ACE inhibitory activity (89.2~98.2%) in MRS broth containing 10% skim milk. Antioxidant activity was tested by DPPH radical scavenging activity, with antioxidant activities of the strains being in the range of 56.8~61.5%. The results obtained in this study suggest that L. plantarum K27 and L. plantarum O2 may be potential probiotic starter cultures with applications with fermentative products.

• Korean Journal of Agricultural Science
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• v.2 no.1
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• pp.151-177
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• 1975

To obtain the informations on the checking factors of the effecient utilization of paddies in chungnam province and study on the effecient working system and high productive cropping system in paddies, the utilization state of paddies including environmental conditions were investigated at sample 1,500 farms. The results obtained are summarized as follows; 1. The difficulty of drainage in paddies was the most important factor checking the utility of paddies. Delayed transplanting of rice and lack of labour were also important checking factors on the efficient utilization of paddies. 2. The utilization of paddies was rather effecient at small size farms of which farmers were almost poor, and most of them cultivated barley for their own food. 3. Considering climatic conditions, pre-crops of rice must be harvested before June 10 tho and the marginal transplanting date of rice plant is June 25 th. 4. In case of planting barley as a post-crop after rice, the spread seeding by rotary before plowing was most efficient with lowest cost. 5. Considering rice cultivation, yield of barley and net income, the most efficient cropping system was "Josaengtongil + Olbori".