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        검색결과 38

        21.
        2014.07 서비스 종료(열람 제한)
        Foxtail millet (Setaria italica L.) is the second most widely cultivated species of millet, especially in East Asia and is a tractable experimental model crop for studying functional genomics of millets. However, insufficient researches had been conducted about the foxtail millet germplasm and is significantly impeding its genetic improvement. We attempted to develop EST-derived-SSR (eSSR) markers and utilize them in genetic comparison of germplasm and transferability. A total of 66,027 foxtail millet EST sequences and 42,754 genomic sequence were deduced transcriptom. Approximately 42,000 single tone contigs were generated using DNAstar 5.0 software for redundancy minimization. Nearly 33% of the 14,012 unigenes contained SSRs, but primers were designed for a total of 314 microsatellites concentrating with more than 24 bp of repeats. A total of 314 primers were successfully designed with more than 24 bp of repeats. From these microsatellites, 56 primer pairs were showed polymorphism with over than 15 bp differences among 96 accessions collected from different countries. Polymorphic information content (PIC) value ranged from 0.020 to 0.700 with an average of 0.381 indicating moderate level of informativeness within these EST-SSRs markers. The EST-SSR markers developed in this study will serve as a useful source for genetic studies, such as genetic variability, transferability, association mapping, and molecular breeding
        22.
        2014.07 서비스 종료(열람 제한)
        Onion(Allium cepa L.) is one of the most important crops to the fresh vegetable spices and the food processing industry in Korea. To evaluate genetic variation in onion, major agricultural characteristics and biochemical characteristics such as flowering day, harvest day, brix and so on. Phenolic compound compositions were analyzed for 44 accessions. Accessions in white color was about 92% which is the largest one followed by standard criteria. The sweetness of juice ranged from 6.1 to 19.3(in brix), and Brix range of 117 accessions was from 10.1 to 14.0. High performance liquid chromatography(HPLC) was used to identify the phenolic profile and quantify phenolic content in bulbs: quercetin, quercetin 7, 4’-diglucoside, quercetin 3-glucoside and quercetin 4’-glucoside were detected as major components. The total Quercetin and Quercetin glycoside content ranged between 123.59 and 1155.84 mg/100mg bulb freeze dried weight. The quercetin contents was up to 16.7mg/100g, and 7.41mg/100g in average. It is expected that the result of this study can be used for breeding more competitive species with respect to contents in functional chemicals.
        23.
        2014.07 서비스 종료(열람 제한)
        Rice (Oryza sativa L.) is important crop as a staple carbohydrate sources and was regarded as domesticated in Asia region. The seed dormancy is one of the domesticated traits, and this character allows that plants survive in various environment. The degree of dormancy have been targeted for controling in breeding program while weak dormancy cause pre-harvest sprouting contrary to the nonuniform seed germination by strong dormancy. In this study, we surveyed the variation of germiability in diverse rice genetic resources including japonica and indica ecotype. Overall, the degree of seed dormancy of rice germplasm was distinguished into four groups and admixed types; first group(G-1) included accessions revealing high germiability, the accessions of second group(G-2) acquired the high germiability by after-ripening process, third group(G-3)’s accessions showed high germiability after dormancy breaking process and the accessions of last group(G-4) maintained the low germiability in spite of the dormancy breaking process. Among the 51 japonica accessions G-1, G-2, G-3 and G-4 included 15, 15, 11 and 10 accessions, respectively, and among 40 indica accessions, G-1, G-2, G-3 and G-4 groups included 15, 15, 9 and 1 accessions, respectively. Based on these primary test, we plan to detail examine the seed germiability and survey the genetic factors affecting the degree of germiability in representative accessions of each group
        24.
        2014.07 서비스 종료(열람 제한)
        Rice blast (Magnaporthe oryza B.) is one of the most widespread and devastating diseases of rice. Screening of valuable genetic resources harboring resistance genes is one of the most efficient approaches against blast disease. Because the bioassay to rice blast in the field shows high variations, this study has performed to provide DNA profiles in the accessions of diverse countries using major blast resistant genes linked markers, identified and mapped in different genotypes of rice. Because durable resistance to blast is controlled by a combination of major resistance genes, we surveyed the distribution of blast resistant genes in the 1,500 accessions using major 12 blast resistance genes linked markers. These resistant genes found that the frequency distribution of Pi-39 (66.9%), Pik-m (41.9%), Pit (40.5%), Pii (21%), Pib (19.3%), Pi-d(t)2 (12.7%), but Pita, Pita/Pita-2, Pik, Piz-t, Pi5 genes were identified in less than 10% frequency. Most of accessions contain from 1 to 4 different resistant genes. Pi39 and Pik-m genes amplified in the 69.1% and 51.7% among 356 Korean accessions, Pi39 (79.6%) and Pib (55.8%) in 113 China, Pit (80.6%) and Pib (32%) in 103 Philippines, respectively. In this study, we evaluated the blast resistance degree and the information about the distribution of rice blast resistant genes in rice germplasm. This study will help to develop effective strategies for managing rice blast disease in rice germplasm.
        25.
        2013.07 서비스 종료(열람 제한)
        Rice genetic resources are composed of various species and ecotypes, and each accession reveals different genetic and phenotypic characters. For the managenment of diverse rice genetic resources, seed integrity is important factor in that the individuals of one accession in self-pollinating crop might be homogeneous. To elevate the management efficiency of rice germplasm contrary to the phenotypic distinction, we focused on applicable microsatellite markers because this markers are widly used for genetic evaluation in diverse genetic resources with a character of high reproducibility and polymorphism. In this regard, we selected microsatellite markers based on genotypes; diversity set including 150 accessions using 249 SSR markers. As SSR loci with high PIC(polymorphism information content) values usually revealed multi bands in one accession, proper genotyping were difficult in these loci. Therefor, we checked the band clarity in addition to PIC values and chose 12 and 6 SSR markers finally. All accessions of rice diversity set were distinguished with the first marker set comprising 12 SSR markers, and only 3 combinations of tested accessions(0.03%, 3/11,175) showed same genotype with second marker set comprising 6 SSR markers. The tested 142 Korean bred varieties revealed 0.19%(19/10,011 combinations) and 0.69%(69/10,011 combinations) genotypic identity using first and second marker set, respectively. These newly selected markers might be useful for the analysis of genetic homogeneity and relationship in rice genetic resources.
        26.
        2012.12 KCI 등재 서비스 종료(열람 제한)
        The objective of this study was to analyze the genetic diversity using SSR marker and investigate the fatty acid composition of perilla (P. frutescens var. frutescens) germplasm. Genetic diversity among 95 accessions, which consisted of 29 weedy types and 66 landrace accessions, was evaluated based on 12 SSR markers carrying 91 alleles. The mean values of observed (HO) and expected heterozygosities (HE) were 0.574 and 0.640, respectively, indicating a considerable amount of polymorphism within this collection. A genetic distance-based phylogeny grouped into two distinct groups, which were the landrace, moderate and weedy type, genetic distance (GD) value was 0.609. The physicochemical traits about crude oil contents and fatty acid compositions were analyzed using GC. Among tested germplasm, the total average oil contents (%) showed a range from 28.57 to 49.67 %. Five fatty acids and their contents in the crude oils are as follows: α-linolenic acid (41.12%-51.81%), linoleic acid (15.38%-16.43%), oleic acid (18.93%-27.28%), stearic acid (2.56%-4.01%), and palmitic acid (7.38%-10.77%). The average oil content of wild types was lower than landrace, and the oil content of middle genotype accessions was higher than other germplasm, but no significant variation between landrace and wild types was shown. Nevertheless, IT117174, landrace of Korea, was highest in crude oil content (47.11%) and linolenic acid composition (64.58%) among the used germplasm. These traits of the selected accessions will be helped for new functional plant breeding in perilla crop.
        27.
        2012.07 서비스 종료(열람 제한)
        The genus Rubus belongs to the Rosaceae family and is comprised of 600-800 species distributed worldwide. Understanding the genetic relationships and genetic structure in Rubus species is important for enabling efficient management, conservation, characterization and utilization of the species. However, as a minor crop, genetic research foundation was limited to explore genetic diversity and relationships in Rubus species. The present study shows the results of application SSR markers that were developed from SSR-enriched libraries of the one Rubus species (Rubus coreanus Mique.) in our previous study. We used 34 polymorphic microsatellite markers to analysis of genetic diversity within the Rubus species, including redraspberry, blackraspberry, blackberry and mountainberry. All the 34 SSR primers pairs produced 483 polymorphic and reproducible amplification fragments. The largest number of alleles per primer pair was confirmed at GB-RC-167, GB-RC-100, GB-RC-076 and GB-RC-245, which contained 26, 25, 23 and 21, respectively. An average value of polymorphic information contents (PIC) were 0.74 with a range of 0.36 to 0.92. Population structure and phylogenetic analyses showed that all Rubus species formed three largely distinct clusters, which were confirmed by principal coordinate analysis (PCoA). We obtained the results that the developed SSR markers showed a substantial degree of genetic diversity in the various Rubus species distributed in Korea.
        28.
        2012.07 서비스 종료(열람 제한)
        Soybean (Glycine max, 2n = 2x = 40) is broadly distributed throughout East and South East Asia, and important crop as a source of protein, oil, food and animal feed. In order to better understand the morphological differentiation of soybean germplasm collected from China, Japan, Korea, Philippines, America, we analyzed the morphological variabilities among 629 soybeans with 11 morphological traits, such as growth type, leaflet, flower color, trichome, seed coat color, color inside seed etc. and measured the fatty acid composition. The result of the principal coordinates analysis (PCoA) based on the 11 morphological traits revealed diversity among all accessions. The PCoA separated the accessions into two main groups, each group with distinctive features. Among tested germplasm, the contents of five fatty acids were as follows: linolenic acid (2.8%-16.23%), linoleic acid (27.4%-56.6%), oleic acid (9.2%-35.0%), stearic acid (2.9%-8.8%), and palmitic acid (8.7%-17.1%). The fatty acid composition has not shown significant variation among all accessions. IT 22268 was the highest linolenic acid composition (16.2%), while IT 154687 was the lowest (2.8%). Forty three of 629 accessions showed the arachidic acid (0.5%-3.6%), which is the saturated fatty acid with a 20 carbon chain and is as a minor constituent of peanut oil (1.1%-1.7%). This result of this characterization served as reliable resources for detailed description and new functional plant breeding of soybean varieties.
        29.
        2012.07 서비스 종료(열람 제한)
        The need to develop work on conservation of crop genetic diversity is emphasized in change of agricultural environment, such as climate change, turn of dietary habits, use of cereal to bioenergy production. To secure provide the germplasm and to derive improve quality, customers demands was surveyed in 2011 and the results are as follows. In the questionnaire on genetic resources necessary in the future, Korean landrace was the highest as 23.8%, followed by genetic resources of international agricultural research institutions as 21.4% and genetic resources of foreign countries of 21.4%. Followed by 42.8% for genetic resources from foreign countries, response ratio were 10.7%, 9.5% and 9.5% for wild or wild-relative species, advanced cultivar or breeders’ line from foreign countries, and advanced cultivar or breeders’ line from Korea, respectively. In addition, consumers desired different genetic resources according to their institutes. Satisfaction on seed purity, germination rate and expected characteristic expression with the genetic resources was higher than normal by 87.5%, 88.9%, 84.2% of respondents, respectively. In order to improve the quality of conserved resources, it is necessary to select the resources having useful characteristics from the time of introduction, and to facilitate the evaluation of the preserved accessions in the near future. Efforts for expansion and opening of information on genetic resources are required.
        30.
        2012.07 서비스 종료(열람 제한)
        During the last decade, considerable progress has been made to understand the molecular mechanisms of M. grisea infection in rice plants and 10 rice blast R genes have been identified and characterized via map-based cloning methods. In case of rice germplasm, the genetic backgrounds of each germplasm accessions are not uniform and the evaluation for pathogenicity is difficult. To solve these problems, we applied the single resistance gene markers to rice germplasm accessions. A molecular survey was conducted to identify the presence of major blast resistance (R) gene in 363 accessions of Korea landrace rice germplasm. The results revealed that the resistance gene Pik-p (100%), Pib (98%), Pi-d(t)2 (98%) and Piz (76%) were widely observed in tested rice germplasm, but Pita-2, Pik and Pi39 gene were identified in less than 10 accessions. Most of landrace contain the four or five different resistant genes, but these results was not consist of field nursery screening. 13 accessions were shown the blast resistance in field nursery screening and Pik-p, Pib, Pi-d(t)2 and Piz genes were observed in these accessions. The evaluation results of blast resistance genes in rice germplasm will help in breeding of multi disease resistant varieties.
        31.
        2011.12 KCI 등재 서비스 종료(열람 제한)
        Buckwheat (Fagopyrum esculentum Moench), one of the minor crops grown in Korea belonging to the Polygonaceae family, is an annual crop widely cultivated in Asia, Europe, and America and has a character of outcrossing and self-incompatibility. The objective of this study was to analyze the genetic variability, phylogenetic relationships and population structure of buckwheat landraces of Korea using SSR markers. Ten microsatellite markers have been detected from a total of 79 alleles among the 179 buckwheat accessions were collected from Korea. The number of allele per marker locus (NA) ranged from 2 (GB-FE-001, GB-FE-043 and GB-FE-055) to 31 (GB-FE-035) with an average of 7.9 alleles. GB-FE-035 was the most polymorphic with the highest PIC value 0.93. Major allele frequencies (MAF) for the 10 polymorphic loci varied from 0.12 to 0.97 with a mean allele frequency of 0.57. The expected heterozygosity (HE) values ranged from 0.05 to 0.94 with an average of 0.53. The observed heterozygosity (HO) ranged from 0.06 to 0.92 with an average of 0.42. The overall polymorphic information contents (PIC) values ranged from 0.05 to 0.93 with an average of 0.48. The landrace accessions of buckwheat used in the present study were not distinctly grouped according to geographic distribution. The study concludes that the results revealed genetic differentiation was low according to the geographic region because of outcrossing and self-incompatibility. We reported that our analyses on the genetic diversity of common buckwheat cultivars of Korea were performed by using of microsatellite markers.
        32.
        2010.04 KCI 등재 서비스 종료(열람 제한)
        Fusarium head blight (FHB) is the most important disease of wheat that may cause serious yield and quality losses and leads to harmful contamination of the grain with fungal toxins. Korean wheat cultivars showed much less resistant to FHB than Sumai3, which known as resistance to FHB, evaluated by spray inoculation in our companion report. Many DNA-marker studies, including sequence tagged site (STS) and simple sequence repeat (SSR) markers and qualitative trait loci (QTL) associated with FHB resistance have been identified and mapped on the specific chromosome, especially 3BS, by many previous studies. However, there was no application of DNA-markers to select FHB resistance lines in Korean wheat breeding programs. 3 SSR markers and 6 STS markers linked to major QTL on chromosome arms 3BS found in Sumai3 and its derivatives were used to screen FHB resistance in Korean wheat cultivars. All markers known to be most significant markers based on previous research (Liu and Anderson 2003). There was general lack of marker polymorphism for Korean wheat cultivars used in this study. However, STS3B-138 marker only showed the polymorphism in Korean wheat cultivars. Allele size of STS3B-138 is 355 bp in Sumai 3 and 12 of 24 cultivar showed this allele. The range in Type II resistance rating was 1-5 and average of these 12 cultivars have 355bp allele was grade 2.4. The most resistant cultivars under the 2 grade, Gobun, Jinpoom, Milseong and Namhae also showed 355bp allele. Therefore, These results provide potential for development of wheat cultivars with improved Fusarium head blight resistance through use of effective FHB screen methods and marker - assisted selection.
        33.
        2010.04 KCI 등재 서비스 종료(열람 제한)
        Fusarium head blight (FHB), also known as head scab of wheat causes serious yield losses and deteriorated grain and may also contaminate the grain with mycotoxins. Many researches have been conducted to minimize damage caused by FHB and to improve resistance to FHB in many countries. However, little information of FHB in Korean wheats is available. In this study, 23 Korean wheat cultivars and F8 population were evaluated FHB symptoms infected two types of inoculations, both spray and point inoculation. Grain properties of Korean wheat cultivars, including grain morphology, antioxidant activity and ion content, were also evaluated to elucidated the relationship to the degree of infection of FHB. Anbaek, Eunpa and Milsung showed lower degree of infection by spray inoculation than any other cultivars, in spite of higher infection degree than Sumai3, which have been known as resistant to FHB. The degree of infection by point inoculation of Milsung, Gobun and Olgeuru was comparable to that of Sumai3. Poly phenol oxidase activity and total polyphenol content negatively correlated with the degree of infection by spray inoculation (r = -0.388, r = -0.466* respectively). Roundness of grain positively correlated with the degree of infection by point inoculation (r = 0.419*). In F8 population of 234 lines derived from the cross between Sumai3 and Korean wheat cultivar, 33 lines (14.1%) showed lower degree of infection by spray inoculation than parental cultivars, although there was no line comparable resistance of FHB to Sumai3. Fourteen lines (6.0%) showed lower degree of infection by point inoculation than Sumai3 and 135 lines (57.6%) were comparable to Sumai3 and parental cultivars.
        34.
        2010.04 KCI 등재 서비스 종료(열람 제한)
        The SSR markers were generally used to analysis the plant genetic diversity, but it have been rarely reported in case of castor bean. We constructed the microsatellite-enriched genomic library and sequenced totally 775 clones to obtain the microsatellite sequence information of the castor bean. Among the sequenced clones, one hundred fifty clones (19.3%) were redundant and four hundred twenty (67.2%) were found to contain microsatellite sequences within the remaining 625 unique clones. A total of 237 primer pairs were designed based on the sequenced microsatellite clones information and evaluated for polymorphism in ten castor bean accessions. Twenty-eight SSR markers produced reproducible polymorphic bands and were further characterized using a diverse set of 25 castor bean accessions. The majority of unique SSRs revealed dinucleotide motives (84%) on the other hand the ratio of trinucleotide motives was 15%. A microsatellite enriched library from the Ricinus communis L. was mainly consisted of [(AG), (GA)/(CT), (TC)] and [(CTT)/(AAG)] microsatellite motifs. The length of dinucleotide SSRs ranged from 4 to 50 repeats with an average 12.4, and that of trinucleotide SSRs from 4 to 56 with an average of 7.35 repeats. These newly developed microsatellite markers will be useful for breeding system and classification of Ricinus communis L.
        35.
        2010.04 KCI 등재 서비스 종료(열람 제한)
        The genus Allium which is one of the biggest plant genera comprises around 750 species that show the various morphological and ecological diversity with various taxonomic and geographical groups. The species of genus Allium has not been clearly distinguished because of extraordinary large amount of variation. We developed 8 simple sequence repeat markers (SSRs) which showed polymorphism within A. sativum accessions, but it was insufficient in transferability analysis of other Allium species. In this regard, we finally selected 50 primer pairs which was applicable to other Allium species adding to 8 primer pairs. According to results from application of 50 SSR markers to 9 Allium species, the average number of alleles ranged from 1.400 (A. porrum) to 1.889 (A. tuberrosum) and A. tuberosum (2n=32) has maximum 9 alleles. The lowest transferability value was 42.0% ( A. cepa and A. chinense) while A. sativum showed 96.7%. The A. porrum conceived to be close relationship to A. sativum as Allium subgenera revealed higher transferability (73%) rather than other Allium species. According to PCA analysis, three groups were divergent, and the A. fistulosum and A. sativum revealed the distinct groups and the rest 7 species formed another group.
        36.
        2008.12 KCI 등재 서비스 종료(열람 제한)
        Over 7 individual rice (Oryza sativa L.) plants per a line were sowed and sampled by pooled sampling method for genomic DNA extraction. The 5,400 flanking sequence tags (FSTs) were analysed by adaptor PCR and direct sequencing. FST analysis showed that the intragenic FSTs, the intergenic FSTs, and the original insertional sequences including hot spot covered 48.1% (2,597), 25.6% (1,383), and 25% (1,350), respectively. The 2,597 intragenic FSTs were used for genotyping to determine whether they are heterozygous or homozygous, and 1,393 core lines were selected. Among them, 422 knockout genes were distributed on chromosome 3, while 56 - 157 intragenic FSTs scattered on other chromosomes. Among 1,393 FSTs, known genes such as transcription factor covered 59.4% (827), while unknown genes such as expressed protein covered 40.6% (566). RT-PCR indicated that some core lines had no expression or decreased expression level in their knockout genes. It means that core lines are very useful knockout lines for functional genomic studies.
        37.
        2008.03 KCI 등재 서비스 종료(열람 제한)
        1. Ds 삽입변이체 3,000계통으로부터 제초제 저항성 1,874계통을 선발하고 농업적 주요 특성으로서 출수일수, 간장, 수수, 수장, 엽장 등 5가지 형질에 대하여 조사한 바, 조사된 5가지 형질에 대하여 원품종인 동진벼에 비하여 매우 다양한 변이폭을 보여주었다. 2. 농업적 유용성과 관련된 수장이 길고, 조기출수, 수수가 많은 변이체 뿐만 아니라 형태학적 변이를 보이는 twin seedling, dwarf, early heading, strip albino, liguleless 등 변이체가 다수 발견됨으로서 육종적 이용 및 유전자 기능해석을 위한 유용한 집단으로서 유용성을 보여주었다. 3. 서던분석 결과, 벼 게놈상에서 Ds는 평균 2 copy로 전이되었으며 조직부위별로 GUS의 발현을 조사한 결과 잎, 뿌리 및 화기관등에서 약 3.9%가 발현되었다. 이 삽입변이체에서 나타난 다양한 변이형질의 주요 농업적 특성과 GUS 발현의 재현성을 위해 다음 세대의 전개를 통한 후대분석이 필요하다.
        38.
        2007.12 KCI 등재 서비스 종료(열람 제한)
        It has been hypothesized that efficient exclusion of methylated retrotransposons and repeated DNA region is one of the rapid and cost-effective approaches for comprehensive gene discovery in large genome size of maize. Three kinds of methylation-sensitive restriction enzymes, HapII, MspI and McrBC, were used to identify the restriction frequency of cytosine methylation sites in maize genome. Roughly 60% of total maize genomic DNA was restricted less than 500bp by McrBC, and the most of restricted small size fraction was composed retrotransposon. In order to validate the efficient construction of gene-rich shotgun library, we compare two gene-rich methyl-filtration shotgun libraries using in vivo and in vitro methyl-filtration system. The size selected DNA fraction by Sau3A-McrBC enzyme treated was very stable and has not appeared modification in E. coli, but most insert DNA size of partially digested with Sau3A were decrease less than 500bp by bacterial methylation-modification system. In compare of retroelements portion, A 44.6% of the sequences were retroelement in unmethyl-filtered library, and the most of them was Copia type, such as Prem, Opie and Ji. The portion of retroelement was drastically decreased to 25% and 20% by in vivo and in vitro filtration system, respectively.
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