• Journal of Plant Biotechnology
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• v.37 no.4
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• pp.343-356
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• 2010

Plant micropropagation techniques include bud cultures using apical or axillary buds, organogenesis through callus culture or adventitious bud induction, and somatic embryogenesis. In Korea Forest Research Institute (KFRI), the first tissue culture trial in woody plant was initiated from the bud culture of hybrid poplars (Populus alba x P. glandulosa) in 1978. Since then several mass propagation techniques have developed from conifer and hardwood species, resulting in allowing practical application to Poplars, Birches and some oak species. In addition, useful micropropagation and genetic resources conservation techniques were established in some rare and endangered tree species including Abeliophyllum distichum. Among various in vitro propagation techniques, somatic embryogenesis is known to be the most efficient plant regeneration system. Since the first somatic embryo induction was reported in Tilia amurensis by KFRI in 1986, various protocols for direct or indirect somatic embryogenesis systems have developed in conifer and hardwood species including Larix leptolepis, Pinus rigida x P. taeda F1, Kalopanax septemlobus and Liliodendron tulipifera, etc. However, most of these technologies have been developed using juvenile tissues, i.e. immature zygotic embryos or mature embryos. Therefore it has been difficult to directly application to tree breeding program due to their unproven genetic background. Recently remarkable progresses and new approaches have been achieved in mature tree somatic embryogenesis. In this article we reviewed several micropropagation techniques, which have been mainly developed by KFRI and recent international progresses.

• Current Research on Agriculture and Life Sciences
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• v.11
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• pp.25-30
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• 1993

The buds of Hayward/Bruno tree were damaged from $-7^{\circ}C$ but serious damage was found on the buds treated at $-15^{\circ}C$ and $19^{\circ}C$. The bark tissue was more suceptible to low temperature than the bud. The trees were survived and bursted their at all on the top of the graft union and new shoots were formed from the rootstock of the tree. Yellowish area on the leaf surface was found, which is believed that as a result of low temperature. From these, the kiwifruit trees must be grafted with cold tolerant rootstocks will be clarified in future.

• Korean Journal of Plant Resources
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• v.10 no.2
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• pp.165-168
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• 1997

To establish the culture practices for mass propagation of Epimedium koreanum, root propagules were preserved with different methods. Bud emergence rate and number of multiple buds were the highest in root segments obtained from roots with buds which were preserved in open-burial. Plant height, leaf area, and number of new buds were the highest in root segments obtained from roots preserved with stratification.

• Journal of The Korean Society of Grassland and Forage Science
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• v.3 no.2
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• pp.58-66
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• 1983

This experiment was carried out to investigate the effects of the nitrogen rates and cutting heights on the appearance dry weight and death of new bud (branch and tiller) of sorghum-sudangrass hybrid (Sorghum bicolor (L.) Moench). The cultivar used in the present study was Pioneer 988. The experiment was arranged as a split plot design and undertaken in the Experimental Livestock Farm of Agriculture Coll., Seoul Nat'l Univ. in Suweon, 1981 and 1982. The results obtained are summarized as follows: 1. The appearance and death of branch and tiller were not influenced with high nitrogen fertilization. 2. The frequency of the branching was decreased as the low stubble height, and the rate of the tillering was decreased in the high stubble height. 3. The yield of forage mostly depended on the tiller regardless of cutting height, and minor portion of the yield was resulted from the branch. 4. The low cutting height resulted in the increased number of dead bud (p<0.05).

• Horticultural Science & Technology
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• v.28 no.5
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• pp.845-849
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• 2010

This study was conducted to compare various culture methods and evaluate economic feasibility of each method for mass propagation of new ever-bearing strawberry 'Goha'. Four different methods such as semi-solid culture, solid culture, liquid suspension culture and bioreactor culture were compared. The solid culture and bioreactor culture showed the shortest and longest root length, such as 3.6 cm and 8.3 cm, respectively. Fresh weights of plants cultured in bioreactor were 2,261 mg, which were heavier than those of cultures. Dry weights of plants cultured in bioreactor were the heavier compared to those in other cultures. The number of axillary bud developed in bioreactor was seven, but axillary bud was not developed in other cultures. Production cost through bioreactor culture was calculated to be 303 won per plant which was 542 won less than that of solid culture. As a result, we found that the bioreactor culture was the most cost effective culture method for in vitro mass propagation in new ever-bearing strawberry 'Goha'.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.1
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• pp.69-89
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• 1981

Stevia (Stevia rebaudiana Bertoni) is a perennial herb widely distributed in the mountainous area of Paraguay. It belongs to the family Compositae and contains 6 to 12 percent stevioside in the leaves. Stevioside is a glucoside having similar sweetening character to surgar and the degree of sweetness is approximately 300 times of sugar. Since Korea does not produce any sugar crops, and the synthetic sweetenings are potentially hazardous for health, it is rather urgent to develop an economical new sweetener. Consequently, the current experiments are conducted to establish cultural practices of stevia, a new sweetening herbs, introduced into Korea in 1973 and the results are summarized as followings: 1. Days from transplanting of cuttings to the flower bud formation of 6 stevia lines were similar among daylengths of 8, 10 and 12 hours, but it was much greater at daylengths of 14 or 24 hour and varietal differences were noticable. All lines were photosensitive, but a line, 77013, was the most sensitive and 77067 and Suweon 2 were less sensitive to daylength. 2. Critical daylength of all lines seemed to be approximately 12 hours. Growth of plants was severely retarded at daylengths less than 12 hours. 3. Cutting were responded to short daylength before rooting. Number of days from transplanting to flower bud formation of 40-day old cuttings in the nursery bed was 20 days and it was delayed as duration of nursery were shorter. 4. Number of days from emergence to flower bud formation was shortest at short day treatment from 20 days after emergence. It was became longer as initiation of short day treatment was earlier or later than 20 days. 5. Plant height, number of branches, and top dry weight of stevia were reduced as cutting date was delayed from March 20 to May 20. The highest yield of dry leaf was obtained at nursery duration of 40-50 days in march 20 cutting, 30-40 days in April 20 cutting, and 30 days in May 20 cutting. 6. An asymptotic relationship was observed between plant population and leaf dry weight. Yield of dry leaf increased rapidly as plant population increased from 5,000 to 10,000 plants/10a with a reduced increasing rate from 10,000 to 20,000 plants/l0a, and levelled off at the plant population higher than 20,000 plants/l0a. 7. Stevia was adaptable in Suweon, Chengju, Mokpo and Jeju and drought was one of the main factors reducing yield of dry leaf. Yield of dry leaf was reduced significantly (approximately 30%) at June 20 transplanting compared to optimum transplanting. 8. Yield of dry leaf was higher in a vinyl house compared to unprotected control at long daylength or natural daylength except at short day treatment at March 20. Higher temperature ill a vinyl house does not have benefital effects at April 20 transplanting. 9. The highest content of stevioside was noted at the upper leaves of the plant but the lowest was measured at the plant parts of 20cm above ground. Leaf dry weight and stevioside yield was mainly contributed by the plant parts of 60 to 120cm above ground but the varietal differences were also significant. 10. Delayed harvest by the time of flower bud formation increased leaf dry weight remarkably. However, there were insignificant changes of yield as harvests were made at any time after flower bud formation. Content of stevioside was highest at the time of flower bud formation and earlier or later harvest than this time was low in its content. The optimum harvesting time determined by leaf dry weight and stevioside content was the periods from flower bud formation to right before flowering that would be the period from September 10 to September 15 in Suweon area. 11. Stevioside and rebaudioside content in the leaves of Stevia varieties were ranged from 5.4% to 14.3% and 1.5% to 8.3% respectively. However, no definit relationships between stevioside and rebaudioside were observed in these particular experiments.

• Journal of the Korean Professional Engineers Association
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• v.27 no.2
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• pp.42-54
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• 1994

Nowadays communication network is steadily changing from a main body of telephone to a network which is creating new services such as multimedia etc. Jhis article introduces a bud of new service and new network which are able to sustain the above service. Including Korea, world advanced countries have been digitatizing their network with N-ISDN (narrowband ISDN) by e.g. 64K b/s and 1.5M b/s. New service by N-ISDN are extraordinary, though it can not solve all kinds of services. To solve these problems, a solving platform should be constituted. B-ISDN(broadband ISDN), as a platform has to be built to deal with almost all uinds of services, whatever the communication speed, communication mode or communication quality may be. Korea Telecommunication Authority(KTA) opened the narrowband ISDN(N-ISDN) at the end of 1993. This was one step previous opening of the broadband ISDN(B-ISDN) service scheduled to be rendered in 2001. B-ISDN, receiving and transmitting by far more information with high speed than the N-NSDN does, is one of G-7 Progects which the Korean government is driving foreward to raise the national scientific power to seven advan ced countries. This is also linked with an extremely high speed information network scheduled to be built by the Ministry of Communications in 2015.

• Journal of Ginseng Research
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• v.40 no.4
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• pp.409-414
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• 2016

Background: The low survival rate of in vitro regenerated Panax ginseng plantlets after transfer to soil is the main obstacle for their successful micropropagation and molecular breeding. In most cases, young plantlets converted from somatic embryos are transferred to soil. Methods: In vitro thickened taproots, which were produced after prolonged culture of ginseng plantlets, were transferred to soil. Results: Taproot thickening of plantlets occurred near hypocotyl and primary roots. Elevated concentration of sucrose in the medium stimulated the root thickening of plantlets. Senescence of shoots occurred following the prolonged culture of plantlets. Once the leaves of plantlets senesced, the buds on taproots developed a dormant tendency. Gibberellic acid treatment was required for dormancy breaking of the buds. Analysis of endogenous abscisic acid revealed that the content of abscisic acid in taproots with senescent shoots was comparatively higher than that of taproots with green shoots. Thickened taproots were transferred to soil, followed by exposure to gibberellic acid or a cold temperature of $2^{\circ}C$ for 4 mo. Cold treatment of roots at $2^{\circ}C$ for 4 mo resulted in bud sprouting in 84% of roots. Spraying of 100 mg/L gibberellic acid also induced the bud sprouting in 81% roots. Conclusion: Soil transfer of dormant taproots of P. ginseng has advantages since they do not require an acclimatization procedure, humidity control of plants, and photoautotrophic growth, and a high soil survival rate was attained.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.2
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• pp.111-115
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• 1982

The trials were carried out for improvement of early maturing wheat varieties, desease resistant and good quality through transfering good characters of barley to the wheat, during 1980-'81. For these purpose, Chinese Spring, a wheat variety was used as male and Manker 16 a barley variety, as female parents. EACA($\varepsilon$-Amino Caprolic Acid) known as an inhibitor of blood coagulation was injected to all barley from 14 days until heading with 1$m\ell$ per culm at the level of 500ppM. $GA_3$ solution which accelerates pollen activity was also used with 75ppM concentration after pollination for two days including check to determine the single effect of EACA. Two different methods of the cross were used. One was bud-pollination, another was post-pollination. The result indicated that the post-pollination was better than bud-pollination in terms of pollination rate, even though formation rate of normal embryo was seemingly adversed. The new plant derived from barley-wheat cross was similar in phenotype to the wheat.

• Proceedings of the Korean Society of Sericultural Science Conference
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• 2003.10a
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• pp.28-33
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• 2003

Over 100 million people worldwide are chronic carriers of hepatitis C virus (HCV)(1). Chronic viral infections of the liver can prouess to cirrhosis, which may ultimately lead to hepatic failure or the development of hepatocellular carcinoma. There are a limited number of antiviral drugs on the market approved fur clinical management of chronic HCV infections; interferon-alpha (IFN$\alpha$) and the nucleoside analog ribavirin. However, whether used as monotherapy or in combination, adverse side-effects are associated with each drug and better therapeutic regimens are needed. (omitted)