• Korean Journal of Plant Tissue Culture
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• v.28 no.6
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• pp.335-339
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• 2001

Grapevine leafroll-associated 3 closterovirus (GLRaV-3) is phloem limited virus, and one of the most severe viral diseases found in Korea. However, nonhomogenous distribution and low concentration and seasonal variations of GLRaV-3 in grapevines remain as main problems which prevent the introduction and molecular biology or serology experiments. Virus-infected plantlet in vitro was obtained from node tissue cuttings, which was GLRaV-3 infected 'kyoho' vines. The amount of purified virus was highest in vitro plantlet. Moreover, viruses seem to be relatively homogeneously distributed in all organs including leaf, stem and callus derived from in vitro plantlets. RT-PCR detection using in vitro plantlet tissue as template was most effective. When comparing ELISA to RT-PCR, RT-PCR detection was 1,000 times as effective as ELISA. These results can be explained by improved quality such as tenderness or less tannins in plantlet in vitro. In conclusion, until infected herbaceous host will be available, tissue culture can be usefully adopted as a technique for a good source of GLRaV-3 closterovirus for further studies.

• Journal of Bio-Environment Control
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• v.20 no.4
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• pp.283-289
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• 2011

This study was conducted to examine the effects of defoliation treatment on the growth and yield of strawberry ($Fragaria{\times}ananassa$ cv. Maehyang and Seolhyang) during nursery period. Leaves of strawberry plantlet had been removed except two, three and four fully expanded leaves until planting date. As the intensity of defoliation was strong, the petiole length was reduced and overgrowth of strawberry plantlet was suppressed. Outer diameter of crown in defoliation treatments significantly decreased but inner diameter of crown was not significant. Number of primary roots of the 3 leaves or 4 leaves defoliation treatment generally tended to increase, but there was not significantly different among treatments. Fresh weight and leaf area in the defoliation treatments significantly decreased and the root weight were higher in partial 3 leaves or 4 leaves defoliation treatment but was not significantly different among treatments. Because T/R ratio decreased significantly as growth inhibition of above-ground part compared to underground part, it is considered easy to take rooting after plantlet plating. As the intensity of defoliation was strong, chlorophyll contents tended to decrease significantly. Reduction of the endogenous nitrogen by defoliation effectively led to promote floral differentiation at low temperature and short day condition. This promoted timing of budding and flowering and also induced uniform flowering after plantlet planting. Marketable fruit yield of 3 leaves defoliation treatment tended to be higher than the control.

• Korean Journal of Environmental Agriculture
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• v.29 no.4
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• pp.374-380
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• 2010

This experiment was carried out to investigate the effect of light qualities and lighting types provided by LED Chamber System which designed by Rural Development Administration on growth and development of Chrysanthemum (Dendranthema grandiflorum L., cv. 'Cheonsu') plantlet cultured in vitro. The explants of single-node cuttings were exposed to monochromic or mixture radiation of blue, red, or green under continuous and intermittent lighting for 42 days. The intermittent lighting of 20 sec. on and off per minute significantly stimulated shoot elongation with lower number of internodes compared with continuous lighting treatments. However, continuous blue, red, or green light gave greater dry weight comparing the intermittent lighting, and the lowest weight was recorded at the continuous fluorescent lamp. Otherwise, the plantlet growth in dry weight or leaf area was inhibited by the green light controlled at 50 times intermittence but internode elongation was significantly increased. These results showed that the plantlets were successfully grown under the LED Chamber System controlled with different light qualities and lighting types. Quantitative growth of the plantlets was improved under the shorter photoperiod with a intermittent lighting cycle compared with continuous lighting using fluorescent lamps. It is concluded that the growth and development of in vitro plantlets such as single-node cuttings can be achieved by the controlling of light quality or lighting type during the photoperiod per day with a lower electric cost compared with conventional continuous lighting system.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11c
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• pp.764-769
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• 2000

A new transplant production system that produces high quality plug seedlings of specific crop has been studied. It is a plant factory designed to produce massive amount of virus free seedlings. The design concept for building this plant factory is to realize maximum energy efficiency and minimum initial investment and running cost. The basic production strategy is the sitespecific management. In this case, the management of the growth of individual plantlet is considered. This requires highly automated and information intensive production system in a closed aseptic environment the sterilized specific crops. One of the key components of this sophisticated system is the irrigation system. The conditions that this irrigation system has to satisfy are: 1. to perform the site specific crop management in irrigation and 2. to meet the no waste standard. The objective of this study is to develop an irrigation scheduling that can implement the no waste standard.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.1
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• pp.60-65
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• 2017

This study was conducted to dentify the optimum plantlet type of 'Solara' potatoes (Solanum tuberosum L.) for growth in an aeroponics system. Plantlets of 'Solara' were transplanted on March 16, 2015 in a greenhouse, and growth and yield characteristics were investigated at 70 and 78 days after transplanting, respectively. Stem length was shorter in plantlet of 15-day-old stem cuttings and acclimatization of culture, and the stem length of plantlets of stem cuttings tended to increase with increasing stem cutting age. The fresh weight of plants was the highest in the plantlets of 40-day-old stem cuttings and the lowest in non-rooted stem cuttings and acclimatization of culture. The highest number of first stolons was obtained in 35-day-old stem cuttings. The number of second stolons was the highest in plantlets of 35-day-old stem cuttings, acclimatization of culture, and 30- day-old stem cuttings. The total number of tubers was higher in plantlets of 35-day-old stem cuttings and acclimatization of culture, and the number of tubers above 3 g was the highest in plantlets of 35-day-old stem cuttings. The weight of tubers above 3 g was the heaviest in plantlets of 35-day-old stem cuttings(1,947 g per 10 plants), followed by plantlets of 30-day-old stem cuttings. These results indicate that plantlets of 30 to 35-day-old stem cuttings could be the best for production of 'Solara' potato tubers in an aeroponics system.

• Horticultural Science & Technology
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• v.33 no.4
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• pp.511-517
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• 2015

This research was conducted to evaluate the influence of root restriction materials and media on the growth of runner plantlets of 'Seolhyang' strawberry in a nursery field. To achieve this, the influence of three kinds of root media on the growth of runner plantlets was monitored when polyethylene film was used as the root restriction material. In addition, the influence of various root restriction materials (RRS) such as transparent polyethylene film (PE), non-woven fabric (NF), perforated polyethylene film (PP), and root proofing sheet (RPS) on the changes in volumetric water content (VWC) and temperature of root media as well as growth of runner plantlet were investigated when expanded rice hull (ERH) was used as the root medium. In the comparison of root media, growth parameters such as leaf area and crown thickness at 20 d after fixation as well as crown thickness and fresh weights of root and above-ground tissue at 40 d after runner plantlet fixation were higher in the ERH treatment than in sandy loam and loamy sand. When the influence of RRS was compared, the VWC of ERH was 55% just after irrigation, but decreased to 26% at just before irrigation. Ranges of the VWC as influenced by irrigation cycle were 16 to 10% in the PP and less than 10% in the NF and RPS. The soil temperature in the PE treatment was around $1^{\circ}C$ lower than in NF, PP, and RPS. The differences between day and night temperatures were also smaller in the PE treatment rather than those in NF, PP, and RPS. The growths of runner plantlet 50 d after fixation showed that plant heights as well as fresh weights of root and above-ground tissue were higher in the PE treatment than in NF, PP, and RPS. NF and PP did not effectively restrict roots inside the medium and the roots of runner plantlets penetrated through the root restriction materials resulting in the formation of root system below the restriction materials. The above results indicate that ERH is more effective than sandy loam or loamy sand as root medium. PE rather than NF, PP, or RPS as root restriction material resulted in better growth of runner plantlets in propagation of 'Seolhyang' strawberry. The results of this research will be used for production of high quality runner plantlets in strawberry propagation.

• Journal of Ginseng Research
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• v.20 no.4
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• pp.472-500
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• 1996

Researches on mineral nutrition, physiology and phyrsiological diseases, . cultivaction methods. brceding. pest control quality management and extension during 1976-1995 in Korea were reviewed Review in brceding and pest control was restricted to the researches directely related to cultivaction. Mineral nulrient up take. partion and varicos factors such as top dreasing. Light intersity etc. and interrelationship between minerals were investigated. Top dressing was not effective due to low minera1 requorement Physiological characteristics on tempelature light and water were well elucidated and applied to assess traditional cultivation method and its inovation. Photosyrnthetic pigments. light harvest proteins and activity of related enzymes were studied. In nitrogen metabolism arginine, praline, ammonium, threonine appeared to have important role in re growth of shoot Saponin metabolism was studied in relation to growth and new ginsenosides were found but physiological role of saponin was not clearly elucidated yet Endogenous growth regulators were reported and various erogenous growth regulators were studied for growth stimulation. short stem and seed pruning etc. Various physiological diseases were investigated for cause and control measures were established. Water culture was little studied Forest culture was studied but not retched the recommendable stage Drip irrigation straw mulching. seasonal shading and soil preparation method including soil fertility adjustment were established for practical application. Shading materials completely changed to polyethylene net and materials of polymers The research on ginseng cultivation in paddy field opened the way to establish the permanent ginseng cultivation plantation Ginseng harvester and seeder were developed in the late 1950s. Transplanted and many other machines were developed in the early 1990s. In ginseng breeding only pure line selection was of practical significance several verities were at the stage of seed propagation at ginseng plantations. Mutation breeding (${\gamma}$-ray. X-ray chemicals) was not successful. The research on plantlet formation through tissue culture was a little progressed but still far behind to vegetative propagation. Disease control research was concentrated in the isolation and identification of pathogans. their ecological charactelistics and biological control and soil humigation. Potato root rot nematodes was found and control method was established. Insect and small animal control research was greatly progresses in identification, ecological investigation, and ecological and physical control. Weed control was less important due to the development of mulching method of ridge and ditch. Quality factors of raw ginseng in relation to red ginseng process were extensively studied. Traditional quality measures were elucidated in accordance with modern analytical chemistry resulting in the importance of peptides in the centrat part rather than ginsenosides For large root production growth promoting rootzone micrcorganisms (PGPRM) were isolated and active compounds were identified. Field test on PGPRM was on going. Varictus methods formality improvement through cultivation were developed. Management research of ginseng production was rare Extension was active throuch official and private organizations and through workshop for the extension specialists, and direct lectures to grower's. Extension services made the researcher to understand the existing problems at grower's fields. Research environment for ginseng production was in prime time only for three years when Korea Ginseng Research Institute was established then gradually aggravated.

• Journal of Bio-Environment Control
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• v.22 no.4
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• pp.421-426
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• 2013

This study was conducted to investigate the effects of timing of nutrient starvation during transplant production on growth of runner plants and yield of strawberry 'Seolhyang' (Fragaria ${\times}$ ananassa). Nutrient solution supply at the level of EC (electrical conductivity) 0.8 $dS{\cdot}m^{-1}$ was terminated at interval about 10 days between July 25 and September 5. As a result, the growth of above-ground part was inhibited while root growth increased when the nutrient starvation treatment had been brought forward to July 25. It also reduced the T/R ratio significantly and chlorophyll content was tended to be lower than the other treatment. In addition, it significantly promoted the budding, flowering and harvest of first flower cluster. On the other hand, the period of harvest was delayed more than two weeks when the nutrients were continuously supplied after the middle of August. An accumulated marketable fruit yield per plant until the end of January and February was 169 and 266g, respectively in the treatment of nutrient starvation on July 25, which was 71 and 12% increase, respectively, as compared with those in the treatment of September 5. Therefore, the appropriate nutrient starvation in the late season of strawberry nursery period could be expected the increase in yield and income during the winter season by promoting the flower bud differentiation as reducing the endogenous nitrate level of the plantlet.

• Korean Journal of Plant Tissue Culture
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• v.27 no.1
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• pp.71-75
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• 2000

To clarify the possibility of plant production under red, green. blue, and red+blue using light emitting diodes (LEDs) and fluorescent lamps (control), the effects of light quality on the growth and morphogenesis of in vitro seedlings in Piatycodon grandiflorum were examined. The plantlets grown under the LEDs resulted in taller plants with greater stem than fluorescent lamps. The shortest shoot length, 3.8 cm, was observed in the control and the longest one, 13.4 cm, in the red light. But the shoot length was 5.6 cm under red LED with supplemental blue(red+blue light). This results indicate that red LED may be suitable, in proper combination with other wavelengths of light. The root length under red light was significantly smaller among the treatments. The plantlets grown under red+blue light had lower shoot dry weight, higher dry matter than other lights-grown plantlets. Among the various growth parameters measered, there was an indication that leaf area was controlled by the LEDs. Leaf area of a plantlets developing under green light was about 2.4 times wider than that of plantlets grown under red LED (10.1 $\textrm{cm}^2$ in area). The dry matter rate per plantlet among the treatments was greater in plantlets grown under the red/blue LEDs in comparison with that grown under other LEDs. Chlorophyll contents in plantlets grown under the red, green, blue and red/blue LEDs were 2%, 7% 20% and 10% lower, respectively, than those in plant grown under fluorescent lamps.

• Journal of Bio-Environment Control
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• v.21 no.4
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• pp.385-391
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• 2012

This study was conducted to investigate the effects of the runner cutting time on the growth and yield of strawberry (Fragaria ${\times}$ ananassa cv. Maehyang and Seolhyang) during nursery period of two consecutive years (2009 and 2010). Strawberry runners which connected from mother plants to daughter plants were cut 30, 20, 10 and 5 days before transplanting day (11 Sep. 2009 and 10 Sep. 2010). When runner cutting time delayed, more nutrition was supplied to the daughter plant until late nursery period. It showed that there was a tendency to increase the fresh weight, crown diameter and leaf chlorophyll content. On the other hand, when the runner was cut earlier, the growth of underground part such as root weight was improved. Irrigation demand increased to 29.7% in case of runner cutting from mother plant compared with runner non-cutting treatment. In addition, infection ratio of anthracnose through runner part was 37.6% higher in case of runner cutting than that of runner non-cutting treatment. After transplanting, budding and flowering period were delayed up to 2 or 3 days because of late runner cutting. But there was no significant difference in marketable fruit yield among runner cutting times. It is recommended to conduct runner cutting 5 or 10 days before transplanting for reducing the occurrence of anthracnose.