• Journal of Microbiology and Biotechnology
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• v.21 no.4
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• pp.333-340
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• 2011

Herbicide-tolerant Zoysia grass has been previously developed through Agrobacterium-mediated transformation. We investigated the effects of genetically modified (GM) Zoysia grass and the associated herbicide application on bacterial community structure by using culture-independent approaches. To assess the possible horizontal gene transfer (HGT) of transgenic DNA to soil microorganisms, total soil DNAs were amplified by PCR with two primer sets for the bar and hpt genes, which were introduced into the GM Zoysia grass by a callus-type transformation. The transgenic genes were not detected from the total genomic DNAs extracted from 1.5 g of each rhizosphere soils of GM and non-GM Zoysia grasses. The structures and diversities of the bacterial communities in rhizosphere soils of GM and non-GM Zoysia grasses were investigated by constructing 16S rDNA clone libraries. Classifier, provided in the RDP II, assigned 100 clones in the 16S rRNA gene sequences library into 11 bacterial phyla. The most abundant phyla in both clone libraries were Acidobacteria and Proteobacteria. The bacterial diversity of the GM clone library was lower than that of the non- GM library. The former contained four phyla, whereas the latter had seven phyla. Phylogenetic trees were constructed to confirm these results. Phylogenetic analyses of the two clone libraries revealed considerable difference from each other. The significance of difference between clone libraries was examined with LIBSHUFF statistics. LIBSHUFF analysis revealed that the two clone libraries differed significantly (P<0.025), suggesting alterations in the composition of the microbial community associated with GM Zoysia grass.

• Journal of The Korean Society of Grassland and Forage Science
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• v.35 no.4
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• pp.303-308
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• 2015

Cultivating genetically modified (GM) crops is believed to be a practical solution to meet the increasing food demand, but GM crops are not legal in Korea mainly due to food safety issues. Even though the general public might not be ready to consume GM food, GM crops are imported and consumed as food and feed. To analyze farmers's willingness to grow GM crops for feed, a survey was conducted among crop farmers and 640 valid responses were collected by mail. In the questionnaire, the farmers were asked to select either 'yes' or 'no' if they were willing or not willing to cultivate GM rice and GM grass, respectively, under the given hypothetical income increase rate (i.e., 10%, 20%, 30%, 40%, 50%, 60%, or 70%). Logit regression was used to estimate the two dichotomous choices by explanatory variables including hypothetical income increase rate. The results show that farmers are willing to cultivate GM rice and grass when their income is expected to increase by 47% and 43%, respectively.

• Proceedings of the Korean Society of Crop Science Conference
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• 2020.11a
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• pp.148-148
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• 2020

• Carbon letters
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• v.15 no.2
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• pp.105-112
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• 2014

Wastewater from textile industries is a major cause of water pollution in most developing countries. In order to address the issues of water pollution and high cost for treatment processes, the use of an inexpensive and environmentally benign adsorbents has been studied. The objective was to find a better alternative to the conventional methods. Lemon grass waste (ash) collected from a lemon grass stream distillation subunit in Bhutan was tested for dye removal from aqueous solutions. The study investigated the removal of methylene blue using the following operational parameters: initial concentration (100-600 mg/L), contact time, adsorbent dose (0.1-0.55 gm/100 mL), and pH (3-10). It was found that the percentage removal of dye increased with a decrease of the initial concentration and increased contact time and dose of adsorbent. The basic pH solution of dye showed better adsorption capacity as compared to the acidic dye solution. Langmuir and Freundlich adsorption isotherms were fitted to the data well. Data fitted better to Lagergren pseudo 2nd order kinetics than a 1st order kinetic model. Surface morphology was also examined via scanning electron microscopy. An elemental analysis was also carried out and the chemical composition and functional groups were analyzed using energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy techniques, respectively. The obtained results indicate that lemon grass ash could be employed as a low cost alternative to commercial activated carbon in wastewater treatment for the removal of dyes.

• Korean Journal of Environmental Agriculture
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• v.27 no.4
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• pp.343-348
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• 2008

To investigate the effects of incorporation of green manures (GM) into a sandy loam soil on growth, yield, and nutrient uptake of tomato (Lycoperiscon esculentum Mill.) and nutrient balances (input minus offtake of nutrients), five tomato production systems were compared under the condition of plastic film house: 1) a no input system (no additional amendment or inputs, 0-To-0-To); 2) a conventional system (application of N-P-K chemical fertilizers, Cf-To-Cf-To); 3) a leguminous GM-containing system (hairy vetch-tomato-soybean-tomato, Hv-To-Sb-To); 4) a graminaceous GM-containing system (rye-tomato-sudan grass-tomato, Ry-To-Sd-To); and 5) system mixed with leguminous and graminaceous GMs (rye-tomatosoybean- tomato, Ry-To-Sb-To). Here, hairy vetch and rye were cultivated as winter cover crops during late $Dec{\sim}late$ Feb and soybean and sudan grass were cultivated as summer cover crops during late $Jun{\sim}mid$ Aug. All of them cut before tomato planting and then incorporated into soil. Biomass of GMs was greater in summer season than that of winter season. Nitrogen amount fixed by a leguminous plants was about $126\;kg\;ha^{-1}$ per a cropping season, corresponding to 60% N level needed for tomato production, which was comparable to 50 and $96\;kg\;ha^{-1}$ fixed by rye and sudan grass. As a result, tomato yield of Hv-To-Sb-To system (legume GM treatment) was similar to Cf-To-Cf-To (conventional), but that in Ry-To-Sd-To system (graminaceous GM treatment) was not attained to a half level of conventional treatment. Nutrient budgets for N, P and K on the conventional farm were balanced or somewhat positive exception for minus-balanced K. Ry-To-Sd-To system showed a positive N, P and K budgets due to the depressed growth of tomato which is caused by high C/N ratio and low N-fixing capacity of the GMs. Inversely, those of Hv-To-Sb-To system were negative in all of N, P and K budgets because of increased growth and yield of tomato with high nitrogen-supplying capacity as well as low C/N ratio of leguminous GM. In conclusion, although conventional cultivation has an advantage in relation to N, P and K nutrient budgets rather than GM-incorporated systems, a leguminous GMs could be recommended as nitrogen reservoir and soil amendment because the yield of tomato between use of leguminous GM and conventional cultivation was not only significantly difference, but also GMs commonly reduce nutrient loss and improve microbial communities.

• Journal of Plant Biotechnology
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• v.35 no.4
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• pp.245-256
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• 2008

The current legislation in South Korea clearly states that the tolerance threshold on the adventitious presence of GMO in environment-friendly agricultural products is 3.0% and no GM seed should be detected in their planting seed batches. To date, in Korea, there is no approved GM crop for commercial cultivation in field. However, several GM crops including rice, Chinese cabbage, potato and wild turf grass are currently under risk assessment for their environmental release. Also Korean government (Rural Development Administration, RDA) announced that 11 institutes including universities have been currently certified to carry out a risk assessment of GM crops. Meanwhile, the cultivated area and certified quantities of environment-friendly crops (organic, pesticide-free and low-pesticide) are sharply increasing every year according to the report of National Agricultural Products Quality Management Service (NAQS). In detail, in 2007, the certified quantities of environment-friendly agricultural products were elevated up to 100-fold for organic, 171-fold for pesticide-free and 2,324-fold for low-pesticide crops when compared with those in 1999. The total certified quantity of environment-friendly cereal crops in 2007 was equivalent to 6.4% of total production of cereal crops. Moreover, 24% of total production of root and tuber crops such as potato and sweet potato were certified for environment-friendly agricultural products. In these circumstances, I strongly suggest that current legislations on GM crop's safety management should be revised to include strategies for the coexistence of GM with non-GM crops, especially environment-friendly crops before GM crop is approved to be cultivated for commercialization. Since all types of crops are grown in an open environment, the adventitious presence of GM crops among non-GM crops is inevitable if appropriate measures for coexistence are not established for species by species such as isolation distance, workable management measures to minimize admixture.

• Weed & Turfgrass Science
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• v.3 no.4
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• pp.370-377
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• 2014

Research was initiated to evaluate cool-season grass (CSG) overseeding effects on coverage and species transition in Korean lawngrass (Zoysia japonica Steud.) and to determine CSGs and their seeding rate for a practical overseeding. Treatments were comprised of Kentucky bluegrass (KB, Poa pratensis L.), perennial ryegrass (PR, Lolium perenne L.), tall fescue (TF, Festuca arundinacea Schreb.) and their mixtures. Significant differences were observed in turfgrass coverage and species transition. Since overseeding, the coverage was highest in PR, followed by TF and lowest in KB. The highest coverage in polystand was associated with Mixture IV (TF 50 + PR 50) at a seeding rate of $150gm^{-2}$ which had highest PR and TF, but without KB. Regarding turfgrass transition, zoysiagrass recovery continued to come back up to 80% from late March. But it reduced after early October. Zoysiagrass in monostand was greatest in KB and lowest in TF, but variable in polystand. For the fast and great coverage in winter, it would be the best to apply with PR at $100gm^{-2}$ and equal combination of PR and TF by 1/2 in the mixture at $150gm^{-2}$. For the smooth spring transition to zoysiagrass, however, KB application at $50gm^{-2}$ is recommended.

• Journal of Plant Biotechnology
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• v.38 no.2
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• pp.105-116
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• 2011

Transgenic zoysiagrass (Zoysia japonica Steud.) expressing the bar gene inserted in the plant genome has been generated previously through Agrobacterium tumefaciens-mediated transformation. The GM zoysiagrass (event: JG21) permits efficient management of weed control of widely cultivated zoysiagrass fields, reducing the frequency and cost of using various herbicides for weed control. Now we have carried out the environmental risk assessment of JG21 prior to applying to the governmental regulatory agency for the commercial release of the GM turf grass outside of test plots. The morphological phenotypes, molecular analysis, weediness and gene flow from each test plot of JG21 and wild-type zoysiagrasses have been evaluated by selectively analyzing environmental effects. There were no marked differences in morphological phenotypes between JG21 and wild-type grasses. The JG21 retained its stable integration in the host plant in T1 generation, exhibiting a 3:1 segregation ratio according to the Mendelian genetics. We confirmed the copy number (1) of JG21 by using Southern blot analysis, as the transgenic plants were tolerant to ammonium glufosinate throughout the culture period. From cross-fertilization and gene flow studies, we found a 9% cross-pollination rate at the center of JG21 field and 0% at distances over 3 m from the field. The JG21 and wild-type zoysiagrass plants are not considered "weed" because zoysiagrasses generally are not dominant and do not spread into weedy areas easily. We assessed the horizontal gene transfer (HGT) of the transgene DNA to soil microorganisms from JG21 and wild-type plants. The bar gene was not detected from the total genomic DNA extracted from each rhizosphere soil of GM and non-GM Zoysia grass fields. Through the monitoring of JG21 transgene's unintentional release into the environment, we found no evidence for either pollen mediated gene flow of zoysiagrass or seed dispersal from the test field within a 3 km radius of the natural habitat.