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        검색결과 16

        3.
        2014.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Lilies are of great economic important floweringplant that belongs to the genus Lilium can be grown underdiverse climatic conditions. During the last decade the lilyhas gained popularity worldwide among cut flowers and pot-ted flowering plants. Seeing the great recognition of lilies ininternational flower trade, several breeding approacheshave been adopted on different Lilium sections/groups andmore than 10,000 lily cultivars have been bred. Innovativebreeding strategies and advancement in molecular and bio-technology techniques have made the assortment of liliesdramatically. Different DNA marker approaches have greatpotential to increase the precision and efficiency of conven-tional lily breeding via marker-assisted selection (MAS) anddifferent breeders used it for Lilium crop improvement. Inthis review, different approaches and techniques that lilybreeders have employed to develop novel cultivars are dis-cussed. It is imperative to recognize that there must be anenhanced integration and synchronization in different lilyobjective oriented breeding programs, so that current issues,barriers etc. can be well identified with their appropriatesolutions.
        4,000원
        4.
        2002.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        유전자 알고리즘은 적자 생존과 자연친화의 유전이론을 기초로 하여 이루어진 탐색기법이다. 유전자 알고리즘은 미분 정보 등과 같은 부가적인 정보없이 수렴함으로 전역적 최적값을 탐색하는 강인한 탐색기법으로 알려져 있다. 유전자 알고리즘은 연속형의 설계변수를 가지는 문제에서 세대가 계속 진행되어도 목적함수의 개선이 없이 조기에 수렴하는 경우가 있다. 또한 전역적 최적값 근처에서 수렴하지 못하고 목적함수값이 진동하여 수렴속도가 떨어지는 단점이 있다. 본 연구에서는 위와 같은 유전자 알고리즘의 단점을 보완하고자 재시동 조건과 엘리트 보존방법을 제안하였다. 수정된 유전자 알고리즘의 유용성을 검증하기 위해 3부재 트러스와 평면응력 외팔보에 적용하여 수렴 속도의 향상을 확인하였다.
        4,000원
        5.
        1995.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Genetic changes from improving female's reproductive rate through in vitro fertilization of large number of oocytes were studied. The breeding scheme employed was multiple ovulation and embryo transfer of juveniles and adults. Both balanced and unbalanced matings were examined for the four closed progeny population sizes, 10, 10, 105, 106. In balanced matings, all selected sires and dams were mated to each other(cross-classified mating) while unbalanced matings allowed selected dams and sires mated partially, eg. unbalanced matings allowed averages of .5 and .25 progeny per each mating. Various numbers of selected sires and dams were also examined in both balanced and unbalanced matings. In all mating schemes, selection of males and females was restricted to he one from each fullsib family to reduce the rate of inbreeding. The model calculations were deterministic and accounted for the effects of selection and inbreeding on loss of the genetic variation in succeeding generations. Balanced rectangular mating schemes, where more donors were selected than sires, resulted in larger selection responses than balanced square mating schemes, where equal numbers of sires and donors were selected, and unbalanced rectangular mating. The first round selection responses from the balanced rectangular matings of juvenile MOET, eg. number of progeny per mating equals 2 with 10 sires selected, were 1.192, 1.406, 1.580 and 1.735 times larger than the first round selection responses from the balanced square mating schemes for the given four progeny population sizes, 10, 10, 105 and 106, respectively. Similar results were obtained in adult MOET breeding schemes. However, balanced square matings gave greater selection responses than the unbalanced rectangular matings.
        4,300원
        6.
        2015.07 서비스 종료(열람 제한)
        Next generation sequencing (NGS) technologies provide a fast and easy way to understand the plant genomes, transcriptomes, regulatory elements and their interactions. About a decade ago, rice was the only crop that whole genome sequence information was publicly available but today many agricultural crops including maize, soybean, tomato, potato, cotton have been sequenced and many more will be available. Moreover newly developed method such as Genotyping-By-Sequencing (GBS) allows efficiently collecting sequence information from hundreds of individuals in population to identify genetic variations, detect quantitative trait loci (QTLs) and develop molecular markers. Coupled with high-throughput phenotyping, the accumulated genomic information will be effectively utilized in crop improvement by genomics-assisted breeding, genome-wide association mapping (GWAS) and genomic selection (GS). Rice is one of the important staple crops providing daily nutrition to more than a half of the world population. The genus Oryza consists of 23 species including two domesticated rice and it has been classified into 10 distinct genome types, represented by six diploids (A, B, C, E, F, and G) and four allotetraploids (BBCC, CCDD, HHJJ, and HHKK). It shows wide ranges of phenotypic variations to biotic and abiotic stress thus is considered a genetic reservoir of unique allelic variation for rice improvement. International collaborative efforts have been focused on generating the Oryza genomics resources including reference genome, transcriptome, smallRNAs, methylome and resequencing of many accessions to collect genetic variations and better understand the 15 MY evolution of Oryza. The Oryza genomic resources will be a backbone to layer various omics data to catalogue more genetic variations within and between Oryza species and the untapped genetic diversities existing in wild Oryza species will be finally translated to crop improvement.
        7.
        2014.06 KCI 등재 서비스 종료(열람 제한)
        Maize is one of the most important food and feed crops in the world including Southeast Asia. In spite of numberous efforts with conventional breeding, the maize productions remain low and the loss of yields by drought and downy mildew are still severe in Asia. Genetic improvement of maize has been performed with molecular marker and genetic engineering. Because maize is one of the most widely studied crop for its own genome and has tremendous diversity and variant, maize is considered as a forefront crop in development and estimation of molecular markers for agricultural useful trait in genetics and breeding. Using QTL (Quantitative Trait Loci) and MAS (Marker Assisted Breeding), molecular breeders are able to accelerate the development of drought tolerance or downy mildew resistance maize genotype. The present paper overviews QTL/MAS approaches towards improvement of maize production against drought and downy mildew. We also discuss here the trends and importance of molecular marker and mapping population in maize breeding.
        8.
        2013.07 서비스 종료(열람 제한)
        In U.S.A. maize breeding, exotic germplasm is considered as high-risk and usually introduced by backcrossing specific traits into elite lines. The U.S.A. maize germplasm base is narrow. Only a few open-pollinated varieties are well represented in current programs. Currently, the barrier in using of exotic germplasm in the U.S.A is less formidable than in the 1980s. The major reason is that U.S.A materials are now used in tropical breeding to accelerate earlier maturity and lodging resistance. These exotic materials, developed with U.S.A germplasm, are being introduced back into the U.S.A.Since1994, the ARS-led Germplasm Enhancement of Maize (GEM) project has sought to help broaden the genetic base of America’s corn crop by promising exotic germplasm and crossing it with domestic lines. New hybrids derived from such crosses have provided corn researchers and the producers. These may include improved or alternative native source of resistance to insect pests such as corn rootworms and diseases like northern leaf blight. GEM’s aim is to provide source of useful genetic maize diversity to help the producers to reduce risks from new or evolving insect and disease threats or changes in the environment or respond to new marketing opportunities and demand. During the 2009 growing season, the Ames (Iowa) and Raleigh (North Carolina) locations managed or coordinated evaluations on 17,200 nursery plots as well as 14,000 yield trial plots in Ames and 12,000 in Raleigh. A new “allelicdiversity” study is devoted to exploring and capturing the genetic variation represented by over 300 exotic corn races. Since 2001, GEM has released 221 new corn lines to cooperators for further development into elite commercial new hybrids. GEM has already identified about 50%-tropical, 50%-temperate families tracing primarily to tropical hybrids that are competitive with commercial checks. In North Carolina State University program, they have examined the potential of tropical inbredand hybrids for U.S.A. breeding by crossing temperate-adapted, 100%-tropical lines to U.S.A hybrids. There should be favorably unique alleles or genomic regions in temperate germplasm that can be helpful in tropical maize improvement as well as utilization of tropical lines in temperate areas.
        9.
        2013.07 서비스 종료(열람 제한)
        In the past half century, production of major food crops in the world has kept pace with the population increase. The yields of major cereals such as maize, rice and wheat have been more than doubled in most parts of the world and even tripled in certain countries. However, food production is facing even greater challenges in the next half century because of high demands in both quantity and quality, and ever increasing pressures on resources and environments. At the same time, advances in genomics, biotechnology and genetic studies have brought about unprecedented opportunities for crop genetic improvement. Rice is a major food crop feeding approximately half of the world’s population, and has provided a model system for cereal research. In my presentation, I will describe the demands for increased production for future needs, address the main issues that we have encountered as challenges, present current progress in rice functional genomics research, and provide prospect on how the advance in research can be translated into technologies and activities for rice genetic improvement.
        10.
        2012.07 서비스 종료(열람 제한)
        Korean soybean variety Kwangan was transformed with ORE7 gene using highly efficient soybean transformation system. The gene is known to exhibit a delayed leaf senescence phenotype in Arabidopsis. To confirm phenotypic characterization of leaf senescence for non-transgenic (NT) and transgenic plants, we transplanted T1 transgenic lines 7, 9, 14 and 15 together with two negative controls (NT and EV) in greenhouse. As a result, line 15 showed dramatic phenotypic characterization of yield increase and senescence delay. In addition, to investigate the agriculture traits for transgenic plants with leaf senescence delaying, T2 transgenic lines and two negative controls were transplanted on GMO fields in Ochang and harvested T3 seeds (2010). Most transgenic lines showed higher total seed weigh than NT. Especially, total seed weight of line 15 was increased by about 180% and 120% compared with the NT and EV, respectively. Therefore, we carried out the second field experiments with T3 transgenic line 15 and NT in Ochang (2011). A total of 117 transgenic plants were divided into two groups, senescence delaying (64 out of 117 plants) and increased yield (53 out of 117 plants), by transcript level of ORE7 gene. Interestingly, among increased yield plants, total seed weight of each 7 plants were increased by more than 200% compared with NT.
        11.
        2005.06 KCI 등재 서비스 종료(열람 제한)
        Proper choice of source populations contributes to the ultimate success of selection for genetic improvement. The source population should possess the most desirable alleles at as many loci as possible for intra population improvement. Such desirable alleles can be intensified by introgression of exotic germ plasm into locally adapted ones through hybridization followed by selection. The objectives of this study were to determine the mean performance, genetic variability (~sigma2G) and heritability of fresh ear yield and other important traits within two sweet corn source populations, BC1-10~timesSyn-II and BC2-10. One hundred selfed progenies from each of the two source populations were evaluated in a 10~times10 lattice design, at the Institute of Bioscience (IBS) Farm, University of Putra Malaysia (UPM) following the recommended cultural practices. Significant differences among selfed progenies within BC1-10~timesSyn-II were observed for all traits, while differences among selfed progenies within BC2-10 were noted for fresh ear yield, ear length, ear diameter, number of kernels per row, ear height, days to tasseling and days to silking. Progenies developed from BC1-10~timesSyn-II population had higher estimates of ~sigma2G than did progenies from BC2-10 population for number of kernel rows per ear, total soluble solids, plant height, days to tasseling and days to silking, showing that selection to improve these traits would be more effective in selfed progenies of BC1-10~timesSyn-II than that in BC2-10. On the other hand, progenies developed from BC2-10 population had higher estimates of ~sigma2G for ear length, ear diameter and ear height, indicating that progenies from this population would have better genetic gain than BC1-10~timesSyn-II . Comparable estimates of genetic variance were found for fresh ear yield, and number of kernels per row, indicating that genetic improvement of the two source populations is expected to produce similar genetic gains for these two traits. Therefore, selfed progenies developed from both source populations could be used to improve the two populations for various traits and thereby develop superior genotypes for immediate use in the production system.