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        검색결과 95

        82.
        2014.07 서비스 종료(열람 제한)
        With the economy development, people have an increasing demand for meat and eggs. Hence the market demand for cereal crop keeps increasing. maize is the major crop to meet the conditions of market demand. As a part of the Golden Seed Project, we are planning to develop maize varieties for adaptation in Southern Asia, especially in India. This project was started at 2013 and has been collaborated with Nongwoo Bio Co. Our project is based on overseas maize breeding in Bangalore, India. At first year, we tested 40 maize hybrids to investigate adaptability, yield capacity, and growing characteristics. Planting materials for this test were developed and selected in Cambodia by researchers of Maize Research Institute. Growing performance is usually quite different by the growing area and seasons, but some of our materials have shown good adaptability and yield at dry season in Southern India. 13IN07 was selected by yield and grain color, 13IN39 was selected by yield and plant type. These two selected hybrids were applied to regional test controled by Indian Council of Agricultural Research in India. We will see how our hybrids adapt in various regions in India, assess how other tested hybrids perform in those regions, and compare each other. We may also expect one of the selected hybrids can be a candidate variety for some regions in India and we will continuously select good hybrids and develop new varieties in India.
        83.
        2014.07 서비스 종료(열람 제한)
        Maize breeding is mainly divided by two steps; line development and hybrid selection. Line development is very important procedure to make good hybrids and this line development in Korea is fully depend upon conventional methods like pedigree selection, back-cross, etc. For development of pure line, we have to do self-pollination for at least seven cycles. This line development system is tedious, labor-intensive, and time-consuming procedure. Doubled Haploid technology for maize is a new system to develop inbred lines within short period and many maize research institutes in foreign advanced countries have been actively using this technology. Using Doubled Haploid technology, we can greatly reduce the period of line development and strengthen maize research ability in Korea. Key requisite for Doubled Haploid breeding is possession of inducer lines which can produce haploid when source population is crossed with them. Maize Research Institute in Gangwon Province secures the right of using inducer lines and is trying to introduce Doubled Haploid breeding in Korea. Doubled Haploid breeding system is as follows; crossing between population and inducer, separation haploid seeds from F1 seeds, chromosome doubling, doubled plant management, self-pollination, seed multiplication, and assessment. We expect our breeding capacity will be progressed by introduction of Doubled Haploid technology. When this technology comes to combine with marker assisted selection, we can increase competitiveness against global institutes.
        86.
        2013.07 서비스 종료(열람 제한)
        FLOWERING LOCUS T (FT) is major determinant of the length of the vegetative phase in plants. To understand the role of FT homologs in flowering time control of soybean, we identified ten soybean FT genes and named GmFTs. Expression analysis of GmFT homologs showed that the transcripts of most FT clade genes are mainly expressed in leaves. The expression of GmFT2a, GmFT2b, GmFT5a, and GmFT6 strongly induced in response to floral inductive short-day condition, but GmFT4 and GmFT6 exhibited opposite expression pattern. To understand the biological function of each GmFT/TFL1 genes in flowering time control, we ectopically expressed GmFT cDNAs in Arabidopsis under the control of CaMV 35S promoter. Interestingly, while 35S:GmFT2a and 35S:GmFT5a transgenic plant showed extremely early flowering phenotype, overexpression of GmFT4 delayed flowering. Furthermore we analyzed expression patterns GmFT genes in the leaves of Korean soybean landraces showing various flowering time. The results showed that the transcript level of two FT homologs, GmFT2a and GmFT5a, was high in early flowering landraces, but low in late flowering landraces. In contrast, GmFT4 exhibited opposite expression pattern to those of GmFT2a and GmFT5a, suggesting that GmFT4 may function antagonistically to GmFT2a and GmFT5a in flowering time control of soybean. These results demonstrated that soybean FT homologs have both unique and conserved functions in the photoperiodic control of flowering compared with those in Arabidopsis.
        87.
        2013.07 서비스 종료(열람 제한)
        We are importing corn grains more than eight million tons every year, and self-sufficiency rate of corn is less than one percent. It is not easy to increase field corn production in Korea because of limited arable land. For this reason, many companies have been interesting overseas agriculture for corn production. But they don’t have enough suitable variety for the target area. Our objective is to develop field corn varieties for adaptation in Primorsky Krai which is the southeasternmost region of Russia. This project has been collaborated with Dr. Huk-Ha Lee in Seoul National Univ. and planted three times in Primorsky Krai since 2011. Planting materials for this project were developed in Maize Research Institute. 74 hybrids in 2011, 76 in 2012, and 80 in 2013 were planted for regional performance test. Primorsky Krai is a colder area and has less frost-free days than Korea. Several hybrids have shown good performance, but lots of materials developed in Korea could not fully ripened in 2011 because of late planting and early frost. In 2012, we mainly selected early flowering materials as well as picked materials from first year. The silking date of our materials was later than local commercial varieties, but some our hybrids had good characteristics and high yield. Among them, we picked two hybrids and planted them in Ussuriysk in Primorsky Krai for field demonstration test. We expect some of the selected hybrids can be candidate varieties for improvement of corn production at overseas agricultural production base.
        88.
        2011.09 KCI 등재 서비스 종료(열람 제한)
        The immature embryos during seed development were examined to predict the suitable embryos for an efficient regeneration system. Five spring wheat genotypes and five winter wheat genotypes were tested using immature embryos as explants. Spring wheat genotypes showed much higher levels of plant regeneration than those of winter wheat genotypes. The highest frequencies of embryogenesis and regeneration were obtained when embryos at 13-14 days after anthesis (DAA) were used as explant and decreased using embryos at 21-22 DAA during seed development. Significant differences were also found for callus induction and regeneration as affected by immature embryo size. The regeneration efficiency was drastically decreased in spring and winter wheat genotypes when embryos larger than 2.0 mm of length were used. The optimum developmental stage and embryo length for regeneration efficiency were at 13-14 DAA and 1.0-1.5 mm, respectively. The selection of suitable embryos for the high frequencies of embryogenesis and regeneration leads us to efficient genetic improvement of wheat.
        89.
        2009.09 KCI 등재 서비스 종료(열람 제한)
        Mature dry seeds of Korean cultivars, Daepungkong, Muhankong, Myeongjunamulkong, Somyeongkong, Sowonkong, Jinpumkong, and Pungsannamulkong were used. The influence of antibiotics on elimination of Agrobacterium growth and shoot regeneration was estimated with cotyledonary node. Cefotaxime and timentin at the concentration of 250 and 500 mg/l suppressed Agrobacterium, especially cefotaxime was an efficient antibiotic to suppress Agrobacterium in all cultivars. While carbenicillin and timentin at the concentration of 50 and 100 mg/l were not sufficient to control the development of Agrobacterium, respectively. Cefotaxime and timentin represented high shoot formation rates compared with carbenicillin. Carbenicillin at low concentrations did not effectively suppress Agrobacterium and also had no effect on shoot development. Cefotaxime at the concentration of 250 mg/l showed maximum frequency of shoot regeneration in cvs. Somyeongkong and Sowonkong. Furthermore, on medium containing cefotaxime, shoot was more quickly formed than the other antibiotics. The use of cefotaxime was very useful for elimination of Agrobacterium growth with cotyledonary node of Korean soybean cultivars.
        90.
        2008.10 KCI 등재 서비스 종료(열람 제한)
        The puroindoline genes (Pina and Pinb) losely linked on the short arm of the 5D chromosome (Hardness locus (Ha)) of hexaploid wheat (Triticum aestivum L.) are of great importance to wheat and product quality. In this study, the barley cultivar Harrington was transformed with wheat gene pina and pinb by particle bombardment and performed in order to develop softer barley lines. The result, an efficiency of 3.9% of the bombarded calli regenerated transgenic plants. Each transgenic event was obtained from the callus of a different immature embryo. They showed the multiple shoots compared with control (no bombardment). Two plants from T0 lines were PCR positive for only the 'soft type' pinb transgene, 10 plants were positive for the 'soft type' pina transgene only, whereas they did not show both 'soft type' pina and pinb transgene. These results supply more evidence to support the hypothesis that puroindolines are potential genes for barley grain hardness and used to be suitable target for the production of transgenic barley plants to their availability biolistic transformation system.
        91.
        2005.12 KCI 등재 서비스 종료(열람 제한)
        Mature embryos were aseptically excised with a scalpel and sliced in fragments measuring 0.5 mm in diameter (sliced mature embryo fragment; 4 ~~ 5 fragments/one embryo). Sliced mature embryo fragments of six wheat cultivars were cultured to develop an efficient method of callus induction and plant regeneration. Callus derived from sliced mature embryo fragments showed a good capacity to embryogenesis and regeneration. Furthermore sliced mature embryo fragments decreased contamination from fungi and bacteria. The high efficiency of callus induction were obtained Keumkangmil and Bob­white. For plant regeneration, selected embryogenic calli were transferred to two types regeneration media. An average number of green spots per callus was 4 to 5 in regeneration media after about one week. Percentage of plant regeneration showed high in regeneration medium containing 0.1 mg/l 2,4-D and 5 mg/l zeatin. Especially, Keumkangmil (27.5~% ) and Bobwhite (33.3~% ) showed high regeneration efficiency. This regeneration system from sliced mature embryo fragments may provide an effective and convenient explant for plant transformation studies
        92.
        2005.06 KCI 등재 서비스 종료(열람 제한)
        Thirty-two germplasms of Korean adlay landraces were examined to analyse the genetic relationship through the amplified fragment length polymorphism (AFLP) approach. Total number of AFLP products generated by 12 selective primer combinations was 882. The number of polymorphic fragments by each primer combination greatly varied from 4 to 51 with a mean of 20.3, bands visible on the polyacrylamide gel. A genetic similarity coefficient was used for cluster analysis following UPGMA (unweighted pair grouping method of averages) method. The resulting clusters were represented in the form of a dendrogram. The clustering was not tight in the dendrogram. There was generally no clear grouping of the adlay according to the geographic regions in which germplasms were collected. The present AFLP analysis imply that although Korean adlay displayed a larger amount of AFLP variation within germplasms, the variation was shown independently without reflecting a clinal variation. This study demonstrated that AFLP method can be used to examine the genetic relationships among different germplasms of adlay.
        93.
        2004.09 KCI 등재 서비스 종료(열람 제한)
        Mature embryo and leaf base segment of Korean oat were used as materials in an experiment to check plant regeneration efficiency. MS media supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D), kinetin, and picloram were used for callus induction from mature embryos and leaf base segments. Three mg/l of 2,4­D and 3 mg/l of picloram in callus induction medium showed high frequency for plant regeneration from mature embryos. Leaf base segments were transferred to callus induction medium and incubated at 25~circC in 16/8 hr light/dark cycle for 3 weeks. Callus induction from leaf base segments of Malgwiri showed high efficiency in medium containing 3 mg/l of 2,4-D and 1 mg/l of kinetin (91.8~%) . In case of Samhangwiri, the combinations of phytohormones did not show significant difference. Regeneration from leaf base segments showed high frequency in shoot medium containing 1 mg/l of antiauxin, tri-iodobenzoic acid (TIBA) and 1 mg/l of 6-benzyladenine (BA). Calli induced from leaf base segments of Samhangwiri and Malgwiri in media containing 3 mg/l of 2,4-D and 3 mg/l of picloram showed high regeneration frequency. It appears that the callus initiation medium may be an important factor for subsequent plant regeneration.
        94.
        2003.03 KCI 등재 서비스 종료(열람 제한)
        Immature and mature embryos of 18 Korean wheat genotypes were cultured in vitro to develop an efficient method of callus formation and plant regeneration, and to compare the responses of both embryo cultures. Immature and mature embryos were placed on a solid agar medium containing the MS salts and vitamins, 30g/l maltose, 2 mg/l 2,4-dichlorophenoxyacetic acid (2,4-D), and amino acids. The developed calli were maintained on regeneration medium containing MS salts and B5 vitamins, 20 g/l sucrose, and the combination of two plant growth regulators, 6-benzylaminopurine (BAP) and indole-3-acetic acid (IAA). Immature embryos in most genotypes showed high efficiency of callus induction except three genotypes; Eunpamil, Chunggemil, and Namhaemil, and significant differences among the genotypes. Plant regeneration of calli induced from immature embryos showed high efficiency in Geurumil (56.5%), Tapdongmil (50.5%), Gobunmil (45.5%), and Urimil(42.2%). The analysis of variance showed significant differences for regeneration frequency among the genotypes. Mature embryos showed low callus induction frequency compared with that in immature embryos, and significant differences among the genotypes. Plant regeneration of calli induced from mature embryos showed high efficiency in Keumkangmil (33.33%), Tapdongmil(28.13%), and Geurumil (27.78%). The analysis of variance showed significant differences for plant regeneration frequency among the genotypes.
        95.
        2002.12 KCI 등재 서비스 종료(열람 제한)
        Mature embryos of five oat genotypes were cultured to develop an efficient method of callus induction and plant regeneration. Murashige and Skoog(MS) and N6 media supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D) and kinetin were used for callus induction. Percentage of callus induction showed significant among the combinations of plant growth regulators. Callus induction showed high efficiency in medium containing 3 mg/~ell of 2,4-D. The high frequency of callus induction was obtained in Gwiri37. For plant regeneration, calli induced from mature embryos were transferred onto MS and N6 media supplemented with combinations of 6-benzyladenine (BA) and naphthaleneacetic acid (NAA) for 5 weeks. Percentage of plant regeneration showed high in MS medium containing 0.2 mg/~ell of NAA and 1 mg/~ell of BA. The callus initiation medium affected the subsequent plant regeneration. Treatment with 3 mg/~ell of 2,4-D, and 3 mg/~ell of 2,4-D and 3 mg/~ell of kinetin in callus induction media showed high frequency for plant regeneration. Plant regeneration frequency among the genotypes showed significant. Especially, Gwiri37 showed high regeneration frequency. Regenerated shoots were treated with 200, 350 and 500 mg/~ell of indole-3-butyric acid (IBA) transferred onto half-strength MS medium without plant growth regulators. Treatment of shoots with IBA induced root formation rapidly
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