• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.1
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• pp.101-108
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• 2014

This study was conducted to investigate the effect of nitrogen rates on the growth characteristics and yield of maize in agricultural fields with the stream. This indicates the necessity and optimal level of nitrous fertilization to examine the possibilities of quantity enhancement. Plant height and ear height of maize were not significantly different among the nitrogen rates. Stem diameter and leaf area index increased in the nitrogen treatment compared to untreated control. Changes of photosynthetic rate in maize leaves depending on nitrogen treatments increased as much as nitrogen rates were increased up to the highest level, 36 kg per 10a. NDF and ADF content levels of maize were investigated with different nitrogen rates regardless of treatments. In the case of NDF, it showed a tendency to decrease after 8 days of tasseling date. ADF had also decreased after 15 days of tasseling date. Nitrogen uptake of maize leaves with different nitrogen rates showed the highest level, $4.9g\;kg^{-1}$ with 36 kg per 10a on the tasseling date. Ear length and 100-kernel weight, there were no significant differences according to yield and the components with different nitrogen rates. Ear diameter and kernel number, nitrogen rates of 18 kg and 36 kg were increased compared to nitrogen rate of 9 kg per 10a and untreated control. The pericarps in 9 kg nitrogen rate and control were thicker than those of 18 kg and 36 kg treatment. The yield, 18 kg, 36 kg, and 9 kg treatments were increased by 10.96%, 9.27%, and 3.31%, compared to control. The component analysis on maize kernel with different nitrogen rates, starch showed no significant differences among treatments. Total sugar in 18 kg nitrogen treatment represented the highest content level, 6.37%. In addition, Amylopectin in 18 kg treatment showed the highest content level of 90.38%. However, amylose in 18 kg treatment showed the lowest level, 9.62% which drew a conclusion that waxy of 18 kg treatment is considered to be the strongest one. From the results described above, nitrous fertilization is essential to grow maize in agricultural fields with the stream. The optimum level of nitrous fertilization is considered 18 kg per 10a.

• Journal of The Korean Society of Grassland and Forage Science
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• v.36 no.4
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• pp.370-375
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• 2016

The purpose of development new variety 'Miho' (Hordeum vulgare L.) is a favorite with livestock feed and develop varieties resistant to disease and lodging. 'Miho' was carrying out the growth habit of group III with green and mid-wide leaf. Awn that is related to preference of livestock is a semi-smooth awn. This cultivar had 96 cm of culm length, 650 of spikes $per\;m^2$. Heading date of 'Miho' was April 27, and maturing date on May 30, which were later than cultivar 'Youngyang'. It also showed strong winter hardiness, and similar resistance to shattering and bariy yellow mosaic virus (BaYMV) compared with those of check one. The best thing among the traits of a good quality with the plant green at the latter growing period. The average forage dry matter yield in the regional yield trial was about 13.1, 12.1 MT per ha in upland and paddy field, respectively, which were 9%, 2% higher than that of the check cultivar. It's also showed 6.8% crude protein, 27.1% ADF (acid detergent fiber), and 67.5% TDN (total digestible nutrients), including higher silage quality for whole crop barley. This cultivar would be suitable for the area whose average minimum temperature was above $-8^{\circ}C$ January in Korean peninsula.

• Korean Journal of Environmental Agriculture
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• v.36 no.3
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• pp.169-174
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• 2017

BACKGROUND:Kiwifruit growers build their vineyards using many windbreaks to protect their kiwifruit vines from defoliation injury by strong winds such as typhoon. In this study, we have compared fruit quality, budbreak rate and floral bud as affected by windbreaks. And also we surveyed several microclimate indices of kiwifruit orchard depending on the covering materials of arch-type windbreaks. METHODS AND RESULTS: Five different windbreak materials including polyethylene film (PE), blue- and white-colored nets were tested in pipe-framed archtype kiwifruit vineyards as the covering materials. Photosynthetically active radiation (PAR), annual mean temperature (AMT) and chill unit (CU) as well as fruit quality were compared among the covering materials. In all treatments, annual PAR was more than $400{\mu}mol\;m^{-2}s^{-1}$, in which kiwifruit leaf could reach its maximum photosynthesis, since the leaves were emerged. Annual mean temperature was greater in 0.1 mm-PE covering as much as $1-2^{\circ}C$ than other windbreaks. In CU calculated by three different models, all windbreaks showed more than 1400 CU that is fully fulfilled CU for kiwifruit rest completion. There were no difference in budbreak rate among the covering materials. Fruit weight was heavier in 0.1 mm-PE and white-net (4 mm) than other windbreaks. CONCLUSION: Regardless of the windbreak materials, the PAR quantity was enough for kiwifruit photosynthesis. And CU for kiwifruit rest completion was fully achieved in all treatments. However, with respect to fruit weight, quantity of PAR, and AMT, etc., It is highly recommended for kiwifruit growers to choose 0.1 mm-PE and white-net (4 mm) as for their windbreaks materials.

• Korean Journal of Plant Resources
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• v.10 no.1
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• pp.100-104
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• 1997

A new baekji(Angelica dahurica Bentham et Hooker) variety, Baekji l, was developed through a pure line selection at the Gyeongbug Provincial RDA during the period of 1990 to 1995. The variety was characterized to have high plant height. Long root length and large root diameter as compared with a check varicty of Bonghwa baekji but emergence date, flowering date and leaf number of Baekji l was similar to that of the check variety, and it was also more tolerant to nematode and heat stress. Peeled root color of Backji l was yellowbrown but number of the lateral root of the variety was greater. The dried-root yield of Baekji l in yield trial, regional adaptation trial and farmer's field trial was always $21\sim31%$ higher than that of the check variety.

• The Korean Journal of Ecology
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• v.13 no.3
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• pp.225-236
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• 1990

We studied that seeds of wild radish with different size of weight can be obtained for the purpose of differentiation and growth of these seeds by total growth periods. This study is practised a view of plant eco-physiological side and dry-matter production. Through whole growth periods, we knowthat seed weight of L plots was higher than that of M and S plots. In the 33th day after day after germination, growth values of L, M and S plots were 13.93, 7.77, and 4.61 g/plant, respectively. Growth of shoot (cotyledon and leaf) area and shoot weight were shown the similar trends with individual plant dry-amtter weight. In the 33th day after germination, shoot area of L, M and S plots were 21.55, 11.81 and 8.75 $cm^3$/plant and shoot dry weight of L, M and S plots were 10.83, 6.03, 3.50 g/plant, respectively. In the early stage of growth (the 10-14th day after germination), the values of RGR of seed weight of L, M, S plots were 0.2887, 0.2807 and 0.2365 g/g/day, in the late stage of growth, those values of RGR of L, M, S plote were 0.2721, 0.1716, 0.1727 g/g/day, respectively. In the early stage of growth (the 14th day after germination), the values of NAR or L, M and S plots were 0.1513, 0.1373, and 0.1094 g/$cm^2$/day, respectively. It is thought that seed weights were influenced seriously effect in the early stage of growth. The NAR value, in the late stage of growth (the-28-33th day after germination), of L, M and S plots were not large different as 0.1086, 0.1097 and 0.112 g/$cm^2$/day, respectively. The LAR values of M and S (2.0396, 2.1520 $m^2$/g) plots, in the early stage of growth, were higher than L (1.9037 $m^2$/g) plots. In the late stage of growth, the value of LAR of L plots were nearly same as M plots, but the value of S plots were higher than that of L and M plots (0.0458 $m^2$/g). And, in the early stage of growth, the values of SLA of L, M and S plots were 2.2123, 2.2107 and 2.8448 $m^2$/g, respectively. We measured the photosynthetic rates and the respiratory rates as the physiological characteristics of wild radish. In the early stage of growth, the photosynthetic rates of L, M and S plots were 12.4, 14.4, 9.8 $\mu$mol /$m^2$/sec and 9.4, 11.4, 9.8 $\mu$mol/$m^2$ /sec in the late stage of growth, respectively. In this result, it could be informed that photosynthetic rates in the late stage of growth were lower than the early stage. In the middle stage of growth, the respiratory rates were 0.793, $\mu$mol/$m^2$/min in shoot, and 3.28 $\mu$mol/$m^2$/min in root without relation to seed weight. The growth analysis of plants was used by Hunt & Parson s computer program (1974, 1981) and its results used this program were good. Therefore, in this sense, it could be expected that the computer program used and developed largely in researches of plant growth.

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.3
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• pp.200-205
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• 1991

To evaluate cold tolerance of rice cultivars on the basis of a relationship between cold tolerance in the field test and a biochemical character, transition-temperature of respiratory activity of mitochondria(TRM) which were isolated from different parts and at different growth stages and from etiolated rice seedling was investigated, and its relationship with degree of cold tolerance(DCT) in the field experiment was studied. The results obtained were summarized as follows. 1. The transition-temperature of respiratory activity of mitochodria (TRM) isolated from etiolated seedling ($25^{\circ}C$, two week-grown in the dark) of cold tolerant cultivars tended to be low, while that of cold susceptible cultivars to be high. 2. The correlation between TRM of etiolated seedling and the degree of cold tolerance(DCT) was $r=0.8935^{**}$ in 1988 and $r=0.8236^{**}$ in 1989. The correlation coefficient between TRM of 4-leaf seedling and DCT was $0.6239^{**}$ 3. TRM of young panicle was correlated with DCT except a few varieties. 4. TRM of seedling increased with growth as $12.5^{\circ}C$, $14.5^{\circ}C$, $15.5^{\circ}C$ and $16.5^{\circ}C$ at 1, 2, 3~4 and 5weeks respectively. 5. The transition temperature of mitochondrial respiratory activity was not significantly influenced by growth stages as $15.0{\sim}16.0^{\circ}C$ in Pungsanbyeo and $17.0{\sim}18.0^{\circ}C$ in Satbyelbyeo, while it was significantly different depending upon the degree of cold tolerance(tolerant, medium, susceptible).

• Korean Journal of Weed Science
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• v.8 no.2
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• pp.187-198
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• 1988

The second leaves from 30 days old seedlings of two rice cultivars which were selected as tolerant (cv. Chokoto) and susceptible (cv. Weld pally) cultivar were soaked in the concentration of $10^{-6}$, $10^{-5}$, $10^{-4}$ and $10^{-3}M$ of oxyfluorfen for 10, 15 and 22hrs and anatomical characteristics were abserved. Dipping to the solutions were carried out either directly to the attached leaves or to the seperated leaves. Development of any symptoms in epidermis, bundle sheath, mesophyll cells and bulliform cells were microscopically inspected. Both cultivars showed reductionin leaf thickness, but the susceptible ones was more sensitive than the tolerant. The degradation and disappearance of epidermal cell layer, breakage of bundle sheath cells, shrinkage of mesophyll cells and disappearance of bulliform cells were general response as affected by oxyfluorfen treatment. The susceptible cultivars showed such responses at the concentration of $10^{-5}M$ for 10 hrs while tolerant ones $10^{-3}M$, for 10 hrs. Those treatments were more effective in seperated leaves than in attached ones. The epicuticular wax layer of leaves treated as above for 20 hrs was inspected by SEM. Weld pally, the susceptible cultivar (Weld pally) showed rapid cleavage of wax layer under $10^{-5}M$ concentration while the tolerant (Chokoto) showed only minor damage on wax layer at the concentration of $10^{-3}M$.

• The Korean Journal of Mycology
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• v.32 no.1
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• pp.31-38
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• 2004

An endophytic bacterial strain EB215 that was isolated from cucumber (Cucumis sativus) roots displayed a potent in vivo antifungal activity against Colletotrichum species. The strain was identified as Burkholderia cepacia based on its physiological and biochemical characteristics, and 16S rDNA gene sequence. Optimal medium and incubation period for the production of antifungal substances by B. cepacia EB215 were nutrient broth (NB) and 3 days, respectively. An antifungal substance was isolated from the NB cultures of B. cepacia EB215 strain by centrifugation, n-hexane partitioning, silica gel column chromatography, preparative TLC, and in vitro bioassay. Its chemical structure was determined to be pyrrolnitrin by mass and NMR spectral analyses. Pyrrolnitrin showed potent disease control efficacy of more than 90% against pepper anthracnose (Colletotrichum coccodes), cucumber anthracnose (Colletotrichum orbiculare), rice blast (Magnaporthe grisea) and rice sheath blight (Corticium sasaki) even at a low concentration of $11.1\;{\mu}g/ml$. In addition, it effectively controlled the development of tomato gray mold (Botrytis cinerea) and wheat leaf rust (Puccinia recondita) at concentrations over $33.3\;{\mu}g/ml$. However, it had no antifungal activity against Phytophthora infestans on tomato plants. Further studies on the development of microbial fungicide using B. cepacia EB215 are in progress.

• Korean Journal of Medicinal Crop Science
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• v.15 no.3
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• pp.194-198
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• 2007

Yield and ginsenoside contents of ginseng (Panax ginseng C. A. Meyer) is affected by light intensity and quality, and the color and the thickness of PE shading net when PE net is utilized for shading material. This study was carried out to investigate the effect of light quality on root yield and ginsenoside contents off-year-old ginseng by using polyethylene shading net with each blue and yellow color, Spectral irradiance under blue and yellow shading net showed the peak at 498 nm and 606 nm, respectively, which made distinct difference in light quality. Heat injury ratio of blue shading net was increased distinctly more than that of yellow shading net in summer season because of higher transmitted quantum (23%)and air temperature (0.3 $^{\circ}$C) in blue shading net than those of yellow shading net. Chlorophyll content and leaf area under yellow shading net were higher than those of blue shading net, and its heat injury ratio was lower than those of blue. These effects may led to 48% higher increase of root yield under yellow shading net than that under blue shading net. The content of total ginsenoside in taproot was not significantly differed between blue and yellow shading net, while the content in lateral and fine root was significantly increased in blue shading net compared to yellow shading net. PDM ratio of blue shading net showed more significant increase in lateral root than that of yellow shading net. All of Rb$_1$/Rg$_1$ ratio in three parts of root under blue shading net was higher than that of yellow shading net, but there were no significant increase in the ratio of lateral root.

• Journal of Wetlands Research
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• v.11 no.3
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• pp.49-59
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• 2009

Seasonal changes of the growth characteristics and biomass of Scirpus fluviatilis, a aquatic emergent vascular plant, were investigated to reveal the phenology and the population dynamics and to provide the fundamental resources for the restoration counterplan of the wetland vegetation in the littoral zone of the Upo wetland, Changnyeong-gun, Gyeongsangnam-do, Korea from March 2006 to November 2006. Scirpus fluviatilis was distributed commonly in Upo, Mokpo, Sajipo, Jokjibyeol, and Topyeongcheon upstream and downstream of Upo wetland, and the density was highest in Mokpo. Distribution range for the water depth was 9~49cm, and the highest shoot density in 26~49cm, and the mean shoot density was $119/m^2$, and the mean shoot length was 122.3cm on May 28. The number of the tuber was $104.5/0.25m^2$, and the living tubers were 84.2%. The mean fresh biomass of the living tubers was 3.0g, and those of 1~4g was most as 57.9%. Germination rates of the living tubers was 43.8%, and the maximum rate was in 7~9g and more than 10g. In the pot cultivation, the shoot density of the germinated tubers and the dormant tubers were highest as 13.5 and 9.7, respectively in early August. In the field study, the shoot density had few change before typhoon damage, while the density increased abruptly in November after flooding accompanied with the typhoon 'Ewiniar'. The shoot length in the pot cultivation and in the field study were 100~116cm and 60~170cm, respectively in the growth-end. Biomass allocation rates into the stem, leaf, flower, and underground parts were 8.9%, 6.6%, 0%, and 84.5%, respectively in the pot cultivation of the germinated tubers, and those of the dormant tubers were 7.1%, 7.1%, 0%, and 85.8%, respectively. The tuber number increased to 1.4~4.1 times by the growth-end, so it is concluded that Scirpus fluviatilis is mostly propagated by the vegetative reproduction.