• Korean Journal of Soil Science and Fertilizer
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• v.30 no.4
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• pp.377-383
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• 1997

Studies were conducted on the nature of allelopathic effect of the substances in the waste of ginkgo leaves from pharmaceutic factory. In the first step, to find out whether there was any allelophatic effect, young seedlings of radish and rice were grown in the water (crude) extract of ginkgo leaf waste and in different liquid/lquid partitioned fractions of EtOAc at pH 9, EtOAc at pH 3, and BuOH. As second step, attempts were made to isolate and identify the allelophatic substance in different liquid/liquid partitioned fractions using GC/MS and NMR techniques. The water (crude) extract of ginkgo leaf waste retarded the growth of radish seedlings under 10% concentration. In case of rice seedlings, the water extract of ginkgo leaf extract showed adverse effect on the growth when combined with $3.3{\times}10^{-6}M$ gibberellin A3. All of the liquid/liquid fractions of crude extract showed strong retardation of seedling growth of radish and rice at the concentration of 1%. Allelophatic substance was isolated from the crude extract using liquid/liquid partition, column chromatography and HPLC techniques. The analytical results of isolated componet using GC/MS and NMR proved that the allelophatic substance in the ginkgo leaf wastes is catechol; one of phenol compounds. Based on the experiences current study, a practical method for the testing of allelophatic effect of crude extract of some materials was proposed. In this method, rice seeds were allowed to sprout until the length of coleoptile to reach 0.5 mm. Such seedlings were submerged in the solution containing supposedly allelophatic substance and the length of shoot and root was measured 3 days after treatment.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.2
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• pp.157-167
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• 1996

The method of direct seeding on flooded paddy surface in rice is known to be the most labor saving cultural practice in rice. However, this method has a problem in practical use such as severe lodging occurring at the reproductive growth stage. The objectives of this study were observated degree of field lodging and variation of lodging-related characteristics with different seeding dates. The number of seedlings per m$^2$ were from 91 to 144 plants, and seedling ratios were from ranged from 61.7% to 91.8%. Days from seeding to flowering were shortened from 5 to 15 days by the later seeding dates. Heading dates of Ilpumbyeo, Seoanbyeo, Daecheongbyeo and Donjinbyeo on June 9 showed slightly elapsed on the critical stable heading time from, August 28 to 29. The culm length was effective in longer clum varieties than semidwarf varieties. The degree field lodging (degree of lodging: 0~9< 9 : complete lodging) in Obongbyeo and S101 with semidwarf varieties were 0.17, whereas 1.25 in Dongjinbyeo with long culm. The lodging resistant varieties and later seeding dates shortened the length of fibrous in the clum, and thickened fibrous in the clum, respectively. Obongbyeo and Sl0l showed stronger resistance to field lodging. The lodging resistant varieties, Obongbyeo and Sl0l, showed lower values of lodging index from 1.03 to 1.15 than those of lodging susceptible varieties, Daecheongbyeo and Palgongbyeo ranged from 1.42 to 1.70. Bending moment with leaf sheath were greater in lodging resistant varieties (Obongbyeo and Sl0l),1510.0~1930.4g.cm, than those in the lodging susceptible varieties (Daecheongbyeo and Palgongbyeo), 1127.2~1287.6g.cm.

• Applied Biological Chemistry
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• v.45 no.4
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• pp.185-189
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• 2002

Along with the worldwide rapid increase of the cultivation area and commercial production of genetically modified (GM) crops, the amount of GM grains imported to Korea has also been increasing. Roundup-Ready soybean (RRS) was introduced with 5-enolpyruvyl shikimate-3-photphate synthase (EPSPS) gene derived from Agrobacterium CP4 to confer the resistance to herbicide, glyphosate. In this study, we tried to develop PCR-based analytical method to detection the presence of RRS among non-GM soybeans. In order to detect RRS specifically, oligonucleotide primers were specifically designed based on the nucleotide sequence of EPSPS transgene. Qualitative PCR method was established and its specificity and accuracy were confirmed by analysing the nucleotide sequence of PCR DNA fragments. Bioassay was also conducted by spraying glyphosate at seedling stage. Survived individuals showed obvious resistance to Roundup Ready, however all of non-GM seedlings died in two weeks after spray. Conclusively, the highly selective detection systems for RRS were successfully established by both PCR using specific primers to EPSPS transgene and bioassay using the herbicide resistance of RRS. In addition to, the imported soybean showed to be mixed to several varieties regarding to 100-seed weight and hilum color.

• Korean journal of applied entomology
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• v.24 no.1 s.62
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• pp.25-28
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• 1985

Experiments were carried out to investigate the life cycle of the rice leaf beetle (RLB), (Oulema oryzae KUWAYAMA) ,yield losses by its damages, and control method in $1976{\sim}1983$ at the experimental field of Gangweon PORD. Peak occurrence of adult and larva rice beetle was late May and mid-June, respectively. Adult overwintered in the forest of mountain and move into the paddy field to lay eggs on the rice leaf from late seedling stage. A female adult laid eggs for 2 days, and egg, larval and pupal period was 9, 16, and 9 days, respectively. Leersia japonica MAKINO was damaged slightly by the beetle. The yield reduction by artifical defoliation ranged from 6 to 40% and yield reduction increased as leaf feeding delayed until mid-July. All insecicides show 100% of control value against RLB.

• Journal of Forest and Environmental Science
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• v.34 no.3
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• pp.224-234
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• 2018

An efficient method to select drought tolerant Korean native plants using in vitro culture system was established in this study. While the plant growths and root inductions of each plant were proportionately affected by concentrations of mannitol on in vitro culturing seven plant species to test tolerance to osmotic stress, growth index (GI) and number of root induction of Chrysanthemi zawadskii var. latilobum and Dianthus chinensis var. semperflorens plantlets were higher than the others in 125mM mannitol. In test with polyethylene glycol (PEG), plantlets of C. zawadskii var. latilobum and D. chinensis var. semperflorens showed higher GI and number of root induction than the others in 33.3mM. On testing whether the well grown plants under osmotic stress are tolerant to virtual drought stress, there were significant differences in the withering rates of C. zawadskii var. latilobum and D. chinensis and those of were Aster yomena and Centaurea cyanus after 12 days without watering. It was found that significantly lower stomata numbers were shown in both drought tolerant plants than the sensitive plants. Averages of the stomata circumferences and the stomata area in the plantlets of the tolerant species were larger than those of the sensitive plants D. chinensis var. semperflorens showed the lowest transpiration level per unit area. The highest stomatal area per unit area was found in C. zawadskii, followed by D. chinensis var. semperflorens, Aster yomena and C. cyanus. In conclusion, C. zawadskii var. latilobum and D. chinensis var. semperflorens were more tolerant to drought than other two species. Furthermore in vitro selection was successfully used to screen drought tolerance species of native plant species.

• Korean Journal of Plant Resources
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• v.29 no.5
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• pp.564-573
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• 2016

This research was performed to develop mass propagation method of round-leaved sundew (Drosera rotundifolia L.) for improving horticultural usefulness. Seeds were collected around Hwaseong-si, Gyeonggi-do in October of 2011 and experimented upon while being dry-stored at 4 ± 1.0℃ (darkness). Seed length of a major and minor axis were 1.58 ± 0.060 and 0.21 ± 0.016 ㎜, respecrively, and weight of 1,000 seeds was 6.24 ± 0.172 ㎎. Seeds were thus classified as ‘dwarf seeds’. Regarding the dormancy type, since round-leaved sundew seeds were dormancy broken and germinated at 20~30℃ under the light condition after wet-chilling treatment for 12 weeks, seeds were estimated to have physiological dormancy. Germination conditions of dormancy broken seeds were found to be 20℃ and light condition (54.7%), but germination decreased at higher temperature. Percent germination (PG), germination energy (GE), mean germination time (MGT) and T₅₀ were effectively improved by chemical treatment such as GA₃ 200 ㎎/L + kinetin 20 ㎎/L and wet-chilling treatment for 14 weeks. In conclusion these optimal conditions were thought to be a useful method for raising seedling uniformly.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.225-225
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• 2017

This study is to investigate the effect of split application and adapted fertilization application cultivation in stable medicinal herbs production of Acorus graminens S. And it accomplished one's purpose to GAP guide manual established standard method of cultivation technology, contribute to the enlargement of farm's income. Method of fertilization application were conducted under five condition compose to standard application(N-P-K-Compost: fermented mixed oil cake fertilizer applied at $4-2-6-300kg.10a^{-1}$, twofold application(N-P-K-Compost applied at $8-4-12-600kg.10a^{-1}$) cultivation. Compost (fermented mixed oil cake fertilizer) and fused phosphate applied at 100% of basal fertilizer in April 14. The split application level of standard application and twofold application(N-K) applied at 100%, 50%, 40% of basal fertilizer in April 14, 50% and 40% of top dressing were three times application (N-K) in June 1, July 15, August 15, 25% and 20% respectively. Transplanting with Naju varieties in May 12 by growing pot seedling for 40 days in 2015. Planting density were spaced 30 cm apart in rows 30 cm apart with black vinyl mulching on open cultivation. Plot design randomized block 3 repetition. Therefore, growth characteristics by 50% and 40% of top dressing were three times application (N-K) compared to standard application and twofold application (N-K) applied at 100% basal fertilizer, aerial part as a result were so many such amount of growth as number of leaf per plant, etc., Length of diameter and main root of subterranean part growth increment rising highest. Dried roots yields treated standard fertilizer 100% application($250kg.10a^{-1}$) compared to 100% from twofold application (N-K) applied at 50% basal fertilizer, 50% and 40% of top dressing were three times application increased by 16%, 20%. respectively.

• Korean Journal of Weed Science
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• v.15 no.1
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• pp.39-45
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• 1995

This experiment was carried out at Yeongnam Crop Experiment Station since 1992 to obtain basic information on ecology of weeds and weedy rice in direct-seeded rice fields. Annual grass weeds of Echinochloa sp., Leptochloa sp., Digitaria sp. and Setaria sp.(C4 plant) and weedy rice(C3 plant) were important species in direct seeded rice compared to transplanted rice field. Period of seedling emergence of barnyard grass was varied from 8 days to 20 days depending on seeding date while it was shorter 4 to 6 days than rice. Weed occurrence and the degree of yield loss were varied by cultivation method. In direct seeding method weeds increased 2 to 3 times compared to manual transplanting. The greatest yield loss was recorded in direct seeding(40 to 100%) followed by mechanical transplanting(25 to 35%) and hand transplanting(10 to 20%), in order. Double cropping of rice-barley was reduced weeds about 30% than rice single crop due to alleopathic effect of barley residue or stubble. Weedy rice(red rice) occurrence was closely related with seeding date and tillage methods. Early seeding and reduced tillage enhanced the growth of weedy rice.

• Korean Journal of Medicinal Crop Science
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• v.20 no.2
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• pp.124-128
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• 2012

When ginseng seedlings are cultured in paddy fields, quality degradation and yield reduction are induced by severe plant loss with chlorosis on leaves occurred physiological disorder by excessive salt and poor drainage, rusty-root occurrence, and root rot etc. Accordingly, in order to solve these problems, this study was performed to investigate the treatment method, concentrations and time of activated ion calcium as environment-friendly agricultural materials. Activated ion calcium is an enriched and purified water-soluble mineral calcium component for absorbing quickly into plant as a highly functional calcium and it is an alkaline calcium of 37% (370 $m{\ell}$/1 ${\ell}$) concentration with pH 13. Treatment method was that ginseng seeds were sown after removing water in the shade after seed immersion for 1 minute with active ion calcium of 20-fold diluted solution, and then irrigated $4{\ell}$ per 3.3 $m^2$ with 200-fold, 400-fold, and 600-fold diluted solution before emergence on late March, and supplied 1 time on leaves with 500-fold diluted solution in June and July respectively. The disease rate by treatment of activated ion calcium was that on the treatment of soil irrigated with 200-fold diluted solution compared to non-treated soil, damping-off was 33%, anthracnose was 100% reduced and the occurrence rate of rusty-root was 30% reduced. In addition, when active ion calcium of 200-fold diluted solution were soil irrigated, first and second grade ginseng were respectively 26% and 22% produced more, compared with control.

• Journal of Korean Society of Forest Science
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• v.95 no.6
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• pp.636-642
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• 2006

To make a new fairy ring of Tricholoma matsutake in situ, the way of production and transplanting of ectomycorrhizal seedlings of T. matsutake using Pinus densiflora was investigated after transplanting from 2000 to 2005 as well as the method to improve their survival rate for the fungus. For the production of ectomycorrhizal pine seedlings, the seedlings planted at the edge of fairy ring of T. matsutake in November showed 97% of the survival rate, while those planted in April showed 80% of the rate. For the complete infection of the T. matsutake, it required more than two years after planting. The infection rate of mycelia for the ectomycorrhizal seedlings was 17.6% when the natural seedlings were used, whereas it was relatively low when the seedlings prepared from the nursery were used. The survival of T. matsutake mycelium reached up to 22% by the transplanting in April, while the mycelium transplanted in October and November showed less than 5% of the survival. The survival of T. matsutake on the transplanted seedlings was the highest in the seedlings having 50% of infection rate before transplanting. Excavation of the ectomycorrhizal seedling to examine the vitality of ectomycorrhizal roots of T. matsutake resulted in the perishing of them. Therefore, the method using a 'rice bag triers' to check living mycelium of T. matsutake without digging of transplanted seedlings was introduced in this study. In addition, it is recommended that the examination has to be conducted at least two years after transplanting.