• 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.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.3
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• pp.291-297
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• 1984

The peanut, unlike other plants, has three distinct steps in the reproductive process. These are the flowers, the peg and the fruit. This research was designed in the field to determine the difference of fruiting habit for each of plant types of peanut (Arachis hypogaea L.) in peanut culture limiting region. Eight cultivars representing four plant types, i.e., Virginia, Spanish, Valencia and Shinpung types. Number of pegs per plant produced in order of Spanish, Valencia, Virginia, Shinpung, Virginia type. The Virginia small seed type produced the most pods per plant. The shinpung type showed more percentage of matured pod than other types and early pot-set habit. Distribution of mature pods for each of branch positions to total mature pods occupied 63% on two cotyledonary branchs, 34% on 3rd to 5th branchs, 3% on over 6th branchs. Shinpung type was considered more favorable plant type than other types for breeding of early maturing high yielding variety because of early pot-set and high percentage of mature pod.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.3
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• pp.303-309
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• 1989

Present study was conducted to reveal the effects of the herbicides, Lasso and Devrinol, on the soybean growth and the nodulation in field condition. Emergence rate was reduced positively in proportion to increase in the concentration of herbicides regardless of the herbicidal difference and it was significantly reduced even in the recommended concentration as compared to untreated plot, showing marked abnormal symptom on seedlings. Plant height, fresh weight of the plant, number of internodes, branches, pods, seeds per plant and 100-seed weight were reduced with increase in the concentration of herbicides and were highly significant in difference between the untreated plot and double concentration plot, eventhough most were nonsignificant in difference from the recommended concentration. Nodulation was significantly decreased with increase in the concentration of herbicides. The reduction was remarkably different with soybean varieties and consistently appeared from three weeks to six weeks after sawing. Significant correlation was realized between the reduction of nodulation and the agronomic characters of soybean and it was considered that the reduction of nodulation by misapplication of the herbicides might be a causal factor for decrease in soybean yield.

• Korean Journal of Environmental Agriculture
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• v.17 no.1
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• pp.76-83
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• 1998

The most remarkable aspect in the hormesis law is that dose of harmful agents can produce effect that are diametrically opposite to the effect found with high doses of the same agent. Minute quantities of a harmful agent bring about very small change in the organism and control mechanisms appear to subjugate normal processes to place the organism in a state of albert and repair. The stimulated organism in more responsive to changes in environmental factors than it did before being alerted. Routine functions, including repair and defense, have priority for available energy and matetial. The alerted organism utilizes nutrients more efficiently, grows faster, shows improved defense, and lives longer. Accelerated germination, sprouting, growth, development, blooming and ripening, and increased crop yield and resistance to disease are found in plants. Another concept supported by the data in that low doses of ionizing radiation provide increased resistance to subsequent high doses of radiation. The hormesis varies with subject plant, variety, state of seed, environmental and cultural conditions, physiologic function measured, dose rate and total exposure. The results of hormesis are less consistently found, probably due to the great number of uncontrolled variables in the experiments. The general dosage for radiation homlesis in about 100 (10 to 1,000) times ambient or 100 (10 to 1,000) times less than a definitely harmful dose, but these must be modified to the occasion. Although little is known about most mechanisms of homzesis reaction, overcompensation of repair mechanism is offered as one mechanism.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.5
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• pp.608-618
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• 1995

This study was conducted to determine physiobiochemical basis of heterosis using rice hybrids such as Shanyou 63 (Zhenshan 97As Minhui 63) and Teyou 63 (Longtepu A Minhui 63) as compared with inbred rice like Milyang 23. Seed protein patterns of rice hybrid showed complementary genetic characteristics inherited from their parents. Hybrid rice had larger embryo and higher $\alpha$-amylase activity than those of inbred rice. The larger embryo of hybrid was significantly correlated with tillering ability and high number of low node tillers jplant increased by 60~70% in Shanyou 63, leading to higher productive tillers/plant which directly influenced on grain yield of hybrid rice. These characters were further supported by high chlorophyll content in hybrids. Exogenous application of GA$_3$ (0.02 ppm) on inbred rice like Milyang 23, increased significantly $\alpha$-amylase activity, but no effect of GA$_3$ on hybrid rice was observed, indicating that sufficient amount of GA$_3$ is endogenously present in hybrid rice, showing 1 to 3.5 fold higher activity of $\alpha$-amylase in hybrid rice, which trigger heterosis from the germinating stage. Further, activity of cytochrome c oxidase was 2.66 to 5.52 fold higher in hybrid rice than that of inbred rice, indicating that rice hybrids have very active metabolism reflecting vigorous growth starting from the germinating stage, in turn leading to higher tillering ability.

• Journal of Bio-Environment Control
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• v.10 no.3
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• pp.187-196
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• 2001

Asparagus varieties popular in the foreign countries were collected and tested on their productivities and qualities for five years under rain shelter and open field conditions. Among the tested varieties, cultivars of UC309 and Excel showed superior productivity to the others in spear weight but the initial growth was not different among the tested varieties. However, the growth index was higher than the other varieties. According to the result from eight-year experiment, the best variety in productivity and quality were UC309 and Excel both for rain shelter and open field cultivations. To avoid the damage caused by stem blight, rain shelter and soil surface mulching treatments were tested with var. Excel. The spear sprouting and first harvesting date were a few days earlier in rain shelter cultivation than in open field, but there were no differences among the mulching materials. The number of spears and the spear weight per plant were increased in rain shelter cultivation, especially with rice straw and black P.E. mulching treatments. Marketable yield also increased by 253% in black P.E film mulching in rain shelter cultivation compared to non-mulching in open field. The stem blight examined in the autumn, 1997 was not observed under rain shelter treatment, but severe damage was observed in the open field regardless of the mulching materials. In the experiments, high asparagus yield could be achieved by black P.E. film mulching in rain shelter cultivation without the occurrence of stem blight.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.5
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• pp.476-479
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• 2002

We observed the succession and appearence species of the marine benthic diatoms for the effective seed production of shellfish culture on wave plates in indoor mass culture tanks. Every five days, the existence species and densitiy of diatoms were counted during the 20 culture days. Experimental conditions were 8.5 $\pm$ 0.3$^{\circ}C$ of water temperature, 1.0250$\~$1.0260 of specific gravity, 2,200$\~$13,000 lux of light intensity. The total density of appearence species was rapidly increased with the lapse of time. However, the number of appearence species decreased on the 20th day. The diatoms observed were 10 species; Navicula sp. of, viridula, Cylindrotheca closterium, Licmophora sp., Pleurosisma normnii, Bacillaria Paradoxa Asterionella glacialis, Stephanopuis sp. cf, turris, Entomoneis sp., Odontella aurita and Cocconeis sp, cf, scutellum. Of them, Navicula sp, of, viridula was most dominant throughout the experiment.

• Journal of Aquaculture
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• v.20 no.1
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• pp.26-30
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• 2007

Resources of the sea cucumber, Stichopus japonicus in the west coast of Korea are decreasing sharply due to overfishing and severe marine pollutions. Artificial seed production and release of this species need to be conducted to maintain sea cucumber stock in the region. In this study, to provide basic information for such works, reproductive cycle of sea cucumber collected from Anmyondo in the region was histologically studied for a year from October 2004 to September 2005. This species was dioecious, and its gonads was composed of a number of gametogenic follicles. The gonadosomatic index (GSI) was reached the maximum in June (7.91), and the minimum in October (0.42). The main spawning occurs between June and August. The reproductive cycle of the sea cucumber could be divided into five stages: multiplicative stage (January to March), growing stage (March to April), mature stage (April to July), spawning.

• Korean Journal of Plant Resources
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• v.25 no.2
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• pp.293-297
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• 2012

A new asiatic lily cultivar 'Point' was derived from a cross between $Lilium$ $concolor$ var. $partheneion$ and 97-5 with orange colored petals made in 2000. The selection and the survey for the flower characteristics were conducted from 2005 to 2008 by using vinyl tunnels and greenhouse at Highland Agriculture Research Center, NICS, RDA. Based on flower color, 'Point' cultivar belongs to orange red group (O-R N30C). There was lots of spots in petal. The flowers had brown stigma and dark brown pollen. The stem color was dark purple. The flowering date was July 8. The plant height was 88.2 cm and flower numbers were 5.4 ea. The length and width of petal were 6.3 cm and 3.2 cm, respectively. The flower size was smaller than that of 'Prato' cultivar. The number of leaves was 12.2 ea. The length and width of leaves were 9.2 cm and 1.1 cm, respectively. The weight and circumference of bulb were about 24.6 g and 11.6 cm, respectively. 'Point' cultivar had resistance to bulb rot disease. The flowering duration was 16.1 days. The preference was good to 4.1 on 5 grades. 'Point' cultivar was registered as a new variety with No. 3446 in Korea Seed and Variety Service on April 2011.

• Korean Journal of Plant Resources
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• v.29 no.1
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• pp.128-135
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• 2016

This study examined radiation damage and the optimal gamma-ray dose for mutation breeding in oat (Avena sativa L. cv. Samhan). The seed germination rate decreased as the dose increased over 500 Gy. The median lethal dose (LD₅₀) was approximately 392 Gy. The median reduction dose (RD₅₀) for plant height, tiller number, root length, and flash weight was 411, 403, 394, and 411 Gy, respectively. The optimal dose of gamma irradiation for inducing oat mutation appears to be in the range 300-400 Gy. We performed the comet assay to observe nuclear DNA damage induced by gamma-ray irradiation. This assay showed a clear difference with gamma-ray treatments. DNA damage increased temporarily 7 days after treatment depending on the dose, while no significant difference was identified in response to 300 Gy 30 days after the gamma-ray treatments. The growth characteristics of the M₂ generation decreased as the dose increased over 400 Gy.