• Horticultural Science & Technology
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• v.29 no.6
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• pp.539-548
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• 2011

This study was conducted to control unseasonable flowering in a standard chrysanthemum 'Baekma' bred in Korea by 2-chloroethylphosphonic acid (ethephon) and night temperature (NT) through suppression of the transition from a vegetative to a reproductive stage under long day length caused by high NT in summer season. Ethephon was applied either once or twice at a concentration of 0, 200, 400, or $800mg{\cdot}L^{-1}$. The NT within controlled mini-plastic houses was maintained at 13, 17, or $21^{\circ}C$. The NT at $13^{\circ}C$ showed the greatest inhibiting effect of unseasonable flowering among all NTs regardless of various combinations of ethephon concentration and frequency. Moreover, the inhibition tendency of unseasonable flowering was distinctly decreased in a NT-dependant manner. Higher NTs reduced cut flower length and number of leaves, but increased the number of young leaves attached to top part of the flower. Higher ethephon concentrations and lower NTs increased cut flower length and the fresh weight of total, stem, and leaves due to the extension of vegetative growth period. Thus, if it is difficult to control the NT below $21^{\circ}C$ in greenhouses in the summer season, we recommended to spray more than $200mg{\cdot}L^{-1}$ ethephon once after planting to suppress unseasonable flowering and to ensure sufficient length of cut flowers.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.6
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• pp.483-488
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• 1993

This study was conducted to obtain the basic information for easily judgement to level of salinity stress of the reclaimed land. Rice varieties used were Nakdongbyeo and Chilsungbyeo. In seedling stage, 13 day-old seedlings were subjected to salt solution (0, 30, 60, 90mM) for 8 days. In reproductive stage, 30 day-old seedlings were transplanted 3 hills(3 seedlings /hill) per plastic pot (diameter 28${\times}$depth 30cm). Salinity stress was given by immersing pot in the salt solution(sea water) with 4 concentrations(0, 30, 60, 90mM)for 8 days at booting stage. The stomatal resistance was increased with salinity concentrations. Salinity stress appeared to be more sensitive in seedling stage than in reproductive stage in each concentrations. The photosynthesis was decreased in salinity treatment. Salt-treated periods influenced unfavorably stomatal resistance in each stages. The leaf chlorophyll content was remarkably decreased by increasing salt concentrations. The absorption of Na+ and Cl￣ were increased as salt concentration in the culturing medium became higher, but there was no appearent difference in the absorption of K+, Mg++, and Ca++. The plant height and root length were decreased in salinity treatment. The inhibitory effect of salinity stress on root growth was more severe than in shoot growth. The stomatal resistance could have been used as bio-information.

• The Korean Journal of Pesticide Science
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• v.18 no.3
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• pp.191-195
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• 2014

Occurrence of soybean pod gall midge (SPGM), Asphondylia yushimai, and soybean pod damage caused by SPGM, and its control efficacy treated with ethofenprox 20EC were first observed at Miryang from 2006 to 2008 in Korea. The typical damage symptoms in soybean pod caused by SPGM were brownish coloration and malformation. By beating method occurrence of SPGM was observed from beginning bloom of soybean and its collected population increased with season until middle September. Soybean pod damage caused by SPGM was heaviest at seeding date of 10th May, followed by 11th June and 26th May. Control efficacy against SPGM sprayed with one time application of ethofenprox 20EC at different spray time in soybean reproductive stage was highest with 92.9% at R2.5, followed by 87.9% at R2 and 83.6% at R3, and was low from about 19 to 66% at other spray time. Accordingly, the most effective spray time of insecticide for control of SPGM in soybean field was found to be R2.5 which is between R2 and R3.

• Horticultural Science & Technology
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• v.16 no.1
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• pp.33-36
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• 1998

This study was carried out to examine the effects of cutting dates and rooting promoters on rooting of the Rhododendron mucronulatum Turcz. The rooting percentage in greenwood cutting was high in June and decreased after July 3, when reproductive growth began. The best rooting percentage(92.5%) occurred when cutting was completed on June 12. There was no difference in rooting potentials between the greenwood straight cutting and the greenwood heel cutting. Cuttings of R. mucronulatum for. albiflora showed high rooting percentage(85%) similar to the cuttings of R. mucronulatum. Dipping cuttings in NAA $2,000mg{\cdot}L^{-1}$ solution for 15 sec increased the rooting percentage up to 97.5%, and also promoted root growth.

• Journal of radiological science and technology
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• v.39 no.3
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• pp.323-328
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• 2016

The spatial dose distribution was measured with ionization chamber as preliminary study to evaluate operator dose and to study dose reduction during neuro-interventional procedures. The zone of operators was divided into four area (45, 135, 225, and 315 degree).We supposed that operator exist on the four area and indicated location of critical organs(eyes, breast, gonad). The spatial doses were measured depending on distance( 80, 100, 120, and 140 cm) and location of critical organs. The spatial doses of area of 225 degree were 114.5 mR/h (eyes location), 143.1 mR/h (breast location) and 147 mR/h (gonad location) in 80 cm. When changed location of x-ray generator, spatial dose increased in $18.1{\pm}10.5%$, averagely. We certified spatial dose in the operator locations, Using the results of this study, It is feasible to protect operator from radiation in neuro-interventional procedures.

• Food Science and Preservation
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• v.8 no.1
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• pp.54-59
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• 2001

The three medicinal herbs, Astragali Radix, Glycyrrhizae Radix and Aurantii nobilis Pericarpium, irradiated with γ-rays have been tested for their possible genotoxicity. The hot water extracts of the 10 kGy γ-ray irradiated herbs were examined in the Salmonella mutagenicity test(histidine reversion assay; Ames test) using Salmonella. typhimurium TA98 and TA100 as tester strains. No mutagenicity was detected in this assay both with and without metabolic activation. The safety of the herbs irradiated with γ-rays at tactical doses needs to be evaluated in further tests of genotoxicity in vivo and chronic and reproductive toxicity.

• Korean Journal of Agricultural and Forest Meteorology
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• v.8 no.3
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• pp.125-131
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• 2006

This survey was carried out to investigate the characteristics of low temperature injury in rice plants at a southwestern alpine area of Korea in 2003. During vegetative, reproductive, and ripening stage in a southwestern alpine area, mean air temperature was lower by 0.4, 3.1 and $1.7^{\circ}C$, respectively, as compared to those of a normal year, Minimum air temperature during the reproductive and ripening stage was lower by 2.6 and $1.7^{\circ}C$, respectively, as compared to those of a normal year, Sunshine hours during vegetative, reproductive, and ripening stage were lower by 40.6, 81.3 and 8.4 hours, respectively, than those of a normal year. Spikelet-sterility type cold injury occurred from the latter part of June to the middle of July, which is from panicle formation stage to meiosis stage, at temperatures less than $17^{\circ}C$. Spikelet sterility under normal transplanting (May 20) ranged from 16 to 58%, which was lower than that under early transplanting in the latter part of April (29 to 83%). The total area impacted by cold damage was 2,723ha in Namwon, 510ha in Sunchang, 300ha in Jinan, 250ha in Muju, and 210ha in Jangsu. Average spiklet sterility in these regions was 44%. Rice cultivars Odaebyeo, Unbongbyeo, and Jinbubyeo showed greater tolerance to low temperature than CV, Chugwangbyeo.

• Korean journal of applied entomology
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• v.60 no.4
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• pp.431-448
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• 2021

We decided the efficient application timings of organo-synthetic insecticides for controlling the first generation larvae of O. furnacalis through investigations of insect stage-specific densities, damage aspects in maize, and effects of insecticides. A waxy maize cultivar, Ilmichal, was cultivated from April 20 (sowing) to July 26 (harvest, dough stage of maize) in Suwon, 2016. The maximum and 50% cumulative catch dates of the overwintering generation adults in the sex pheromone trapping were May 29 and May 31, respectively. Most of the first generation larvae finished their occurrence till the early reproductive stage of maize. The first generation larvae fed on leaves inside the whorl leaves before tassel and stem development of maize, sequentially moved to tassel and stem, and then moved finally to stem and ear parts. In the results of insecticide applications at different dates, the 9-11 leaf stage (June 10~17) and the 6-7 leaf stage (June 3) of maize were the most efficient application timings for direct spray of Etofenprox EC to maize, and for application of Carbofuran granules onto soil surface, respectively, which resulted in suppression of tunnelling damages. The timings for the two insecticides were 12-19 days and 5 days after the adult maximum catch date, respectively. Those timings after the 50% cumulative adult catch date were advanced 2 days.

• Journal of Korean Society of Forest Science
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• v.59 no.1
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• pp.31-36
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• 1983

Flowering time of Pinus rigida Mill and Pinus taeda L, in an $F_1$-hybrid seed orchard was investigated for five years from 1971 through 1975. The two tree species flowered during late April to early May at the observation site, Flowering patterns of the two species of different sex of the same species changed yearly during the five observation years. Floral development of the two species appeared to depend largely on temperature factor during the period of the initiation of floral organs up to flowering provided that other environmental factors are normal. Six-days difference in flowing time between female inflorescence of pitch (flower later) and male inflorescence of loblolly (flower earlier) pines effectively isolated the two species reproductively on population levels. Not all of selected trees of the two species for their synchronized flowering appeared to be useful as parental trees for the establishment of $F_1$-hybrid seed orchards. With the result from this investigation the author suggested to use a modified simple recurrent selection method for pitch-loblolly hybrid pine breeding.

• Korean Journal of Organic Agriculture
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• v.14 no.1
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• pp.55-67
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• 2006

A survey of 31 organic farmers were conducted to investigate the actual conditions of organic matter application. The amounts of organic matter application in the fields were higher in order of fruit, vegetable and rice farm. The average was 50 ton/ha in vegetable farms. In the green vegetable farms saw dust and animal manure were mainly utilized to make compost. Rice straw, wood chip, and forest bushes were also used for composting. In the fruit vegetable farms materials relatively lower in nitrogen content such as rice straw and cattle manure were used in vegetative period and materials higher in nitrogen content such as oil cake and wild grass were used in reproductive phase. Nutrient balance investigated in the farm in Icheon region who produce lettuce, angelica, and kale continuously in one cropping year indicated surplus in three major nutrients. Nitrogen and phosphorous were in excess by 29 and 10 kg respectively in the organic rice farm in yang-pyoung region. While soil chemical properties in the organic farms are within the adequate range in open field, it is much higher than the limits in the greenhouse soils. Overall application of organic matter is in an oversupply state. This results suggested that the organic matter management should be based on the soil conditions for sustainable cultivation. Chemical composition of organic matters and soil test reports should be considered prior to the application of organic matter.