• KOREAN JOURNAL OF CROP SCIENCE
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• v.25 no.1
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• pp.47-53
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• 1980

Of 1, 428 entries examined to locate gene sources resistant to Septoria brown spot from the Korean native soybean collection, most lines were evaluated as highly susceptible, showing numerous leaf spots with surrounding yellowing tissue, while 136 lines of the entries showed the leaf spots without the yellowing. However, leaf defoliation was so much higher in inoculated soybean plants than those of uninoculated, regardless of leaf yellowing that resistance to Septoria brown spot could not be characterized by the lesion type. Various yield composing characters were negatively correlated to the leaf defoliation, suggesting that early defoliation incited by Septoria brown spot might result in significant yield reduction in soybean.

• Horticultural Science & Technology
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• v.32 no.6
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• pp.745-752
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• 2014

Chinese cabbage (Brassica rapa L. ssp. pekinensis) is an economically important vegetable crop as a source of the traditional food Kimchi in Korea. Although many varieties exhibiting desirable traits have been developed by the conventional selective breeding approach, breeding related to abiotic or biotic stresses, such as a particular pests or diseases, or tolerance to climatic conditions, is likely to be slow. This could be helped by an efficient method for selection from various, rapidly-evolved genetic resources on the basis of molecular markers. In particular, the Brassica genome sequencing project enables genome-wide discovery of genes or genetic variants associated with agricultural traits. We here discuss the recent progress in the field of Chinese cabbage breeding with regard to the application of molecular markers.

• Korean Journal of Breeding Science
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• v.40 no.4
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• pp.394-400
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• 2008

Blast resistance of one hundred and thirty-one rice cultivars bred in Korea was tested with thirty Korean isolates and twenty-two Philippines isolates using three screening methods. In the blast nursery conducted in Korea and in the Philippines, average disease index of rice cultivars were 4.6 and 2.2, respectively. Seventy-nine cultivars showed different resistance reaction in Korea and in the Philippines, and 19 cultivars showed the same resistant reaction in two locations. In the seedling test, Korean blast isolates displayed different levels of virulence. 93-093, a Korean isolate, was compatible with 90 cultivars whereas 97-057 showed a compatible reaction with 13 cultivars. Twenty-three cultivars showed high level of resistance against Korean and Philippines isolates but Chucheongbyeo, Heugnambyeo, and Manmibyeo showed susceptible reaction to all blast isolates. Through the sequential planting test in Korea and in the Philippines, Palgongbyeo and Seomjinbyeo displayed durable resistance, and Nagdongbyeo and Gihobyeo showed high level of disease infection over the planting time. These results indicate that blast isolates collected in two countries have different genetic background and number of compatible isolates should be considered in definition the durability of rice cultivar to rice blast.

• Korean Journal of Breeding Science
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• v.43 no.5
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• pp.413-421
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• 2011

The main objective of this study was to develop the multi-resistance lines to insects(brown planthopper; BPH, rice green leafhopper; GRH) and disease(blast; BL, bacterial blight; BB and rice stripe virus disease;RSV) with good grain quality and plant type by combining conventional breeding and marker assisted selection(MAS) and to eliminate the linkage drag effects between Bph1 gene and culm length, we conducted MAS of Bph1 gene in advanced backcross and double cross progenies. 'Nampyeong', 'Junam' and 'Milyang220' were used as the parent in this study. 'Milyang220' was used as the donor of brown planthopper resistance gene Bph1 with tall culm length. Two backcross progenies were developed using two recipients 'Nampyeong' carrying GRH resistance gene Grh3(t) with good grain appearance and 'Junam' harboring bacterial blight resistance gene Xa3 with short culm length. Two $BC_1$ generations were resulted from the backcrossing of the $F_1$ plants with recurrent parents 'Nampyeong' and 'Junam'. The second rounds of backcrossing($BC_2$) were derived from the cross of selected resistant $BC_1F_1$ plants based on heterozygous genotype of RM28493 linked to Bph1 gene. The double crossed population was constructed from the cross of between each heterozygous $BC_2F_1$ plants at RM28493 locus of '$Nampyeong^*3$ / Milyang220' and '$Junam^*3$ / Milyang220'., The homozygous alleles in Bph1 gene were selected using co-dominant DNA marker RM28493 in double crossed population. Eighty-five lines with multi-resistance to BL, BB, RSV, GRH and BPH were selected by bio-assay and MAS in generation of double crossing. The culm length, head rice ratio and yield of the selected multi resistance lines was ranged from 71 to 88 cm, from 51 to 93%, from 449 to 629 kg/10a. respectively. We can select a promising multi resistance line similar with 'Nampyeong' of major agronomic traits such as culm legnth, head rice ratio and yield. It was designated as Milyang265. Finally this study was developed the multi resistant varieties against to insects and diseases with the good grain quality 'Milyang265' by the advanced backcross and double cross combining MAS and it can be used as genetic resources of multi-resistance to insect and diseases in rice breeding programs.

• Korean Journal of Breeding Science
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• v.43 no.5
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• pp.464-469
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• 2011

Virus diseases often cause serious damage to rice production in Asia. The lack of information on virus resistance genes has been a major obstacle for the breeding of resistant varieties. In order to identify DNA marker associated with resistance against rice stripe virus (RSV), the quantitative trait locus (QTL) was carried out using advanced backcross population developed from a cross between RSV-resistant tongil type cultivar Shinkwang and susceptible japonica cultivar Ilpum. A RSV resistance QTL $qSTV11^{SG}$ explaining 44.2% of the phenotypic variation was identified on chromosome 11 of Tongil type rice cultivar 'Shingwang'. $qSTV11^{SG}$ was tightly linked to DNA marker RM6897. The RM6897 divided as resistance type allele and susceptible type alleles. Twenty seven resistant varieties showed the resistant-type allele and 23 susceptible varieties were susceptible-type allele to the marker of RM6897. This results and the molecular markers presented here may be useful in rice breeding for improving RSV resistance in japonica rice.

• Korean Journal of Breeding Science
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• v.49 no.3
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• pp.235-244
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• 2017

'Manbaek' is a bacterial blight resistant mid-late maturing rice cultivar with high grain quality. 'Manbeak' was derived from anther culture using the backcross combination, $Hopum^*2/SR30075$. 'Hopum' is a mid-late maturing rice cultivar with high grain quality and 'SR30075' is a pyramid line carrying three bacterial blight resistance genes. 'Manbaek' was selected through the pedigree method, yield trials, and local adaptability tests. 'Manbeak' carrying two bacterial blight resistance gene Xa3 and xa5 showed high-level and broad-spectrum resistance against bacterial blight. 'Manbaek' was resistant to K3a, mostly virulent race in Korea, and exhibited resistance reaction against 16 Korean bacterial blight isolates. 'Manbaek' was a mid-late maturing rice. The heading date of 'Manbaek' was August 19th, which was 5 days later than that of 'Nampyeong'. Manbaek' was a lodging-tolerant rice with short culm and dark green leaf. Due to the low viviparous germination, 'Manbaek' could be a useful material to prevent pre-harvest sprouting. 'Mabeak' was resistant to bacterial blight and rice stripe virus, but susceptible to other virus diseases and insect pests. The yield of 'Manbaek' was similar to 'Nampyeong'. 'Manbaek' showed excellent grain appearance and good tastes of cooked rice, so that it could contribute to improving the quality of bacterial blight resistant cultivars. 'Manbaek', bacterial blight resistant cultivar with high grain quality, is suitable for the cultivation at bacterial blight prone area and has been utilized in the breeding programs for enhancing the resistance against bacterial blight (Registration No. 6069).

• Korean Journal of Breeding Science
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• v.41 no.3
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• pp.346-348
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• 2009

A golden double freesia (Freesia hybrida Hort.) "Golden Amor" was developed from a cross 'Golden Crown' and 'White Wing' followed by seedling and line selections at the National Horticultural Research Institute, Rural Development Administration (RDA) in 2005. Growth and flowering characteristic tests were conducted from 2000 to 2005. "Golden Amor" has large double type flower with bright golden color (RHS 12B). It have multiple florets, good flower shape, upright leaves and stalks. The average yield of "Golden Amor" was 6.0 cuttings per plant in greenhouse carried out from 2003 to 2005. It has good production of cormlets, vigorous growth and resistance to Fusarium and virus. "Golden Amor" would be cultured under greenhouse condition in Korea.

• Journal of Plant Biotechnology
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• v.42 no.4
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• pp.298-311
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• 2015

Grape is one of the important fruit crops around the world, and exposed to disease and pests, and internal or environmental stresses in the vineyards. Breeding and cultivation of new varieties of high quality-grapes resistant to diseases and pests and tolerant to stresses are the most important steps in the grape production. However, conventional breeding has laborious and time-consuming procedures in maintaining and selecting seedlings in the fields. Development of molecular breeding technology through understanding of molecular mechanism of useful traits can be used as an alternative strategy to improve the efficiency of grape breeding program by cross hybridization in grape development programs. The completion of the grape genome sequencing project provided the way to discover the novel genes and to analyze their functions. Comparative genomics, transcriptomic analysis, and the genome-wide identification and analysis of useful genes as well as development of molecular marker for valuable traits could provide novel insights into fruit quality and the responses to diseases and stresses, and can be used as important information in molecular breeding programs for grape development.

• Korean Journal of Breeding Science
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• v.40 no.1
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• pp.48-53
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• 2008

This study presents a case study designed to compare the selection efficiency between phenotypic selection (PS) and marker-assisted selection (MAS) in breeding of resistance lines to brown planthopper (BPH). The efficiency between PS and MAS were compared with four population such as the $F_2$, RILs ($F_6$), DH, and backcrosse ($BC_6F_5$) population, derived from a cross 'Samgang / Nagdong'. The resistance lines were selected using two markers, RM28493 and BpE18-3, related to BPH resistance were screened as resistance lines over 95% in PS. The costs required for BPH screening in the MAS system account for approximately 32% of the total costs of PS. The period needed to select the resistance plants was 30 days in PS and 7 days in MAS. Based on the results, we could establish the breeding system for selection of BPH resistance lines by MAS.

• Horticultural Science & Technology
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• v.31 no.6
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• pp.764-771
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• 2013

Recently, Cucumber mosaic virus (CMV)-P1 infection in pepper cultivation is very serious problem, which causes low marketability and yield. In this research, 56 domestic pepper cultivars including 20 PR (Phytophthora resistance) cultivars, 31 foreign pepper lines collected from USA and 112 genetic pepper resources form RDA Genebank were used for CMV-P1 resistance evaluation. Resistance evaluation was performed at 24 days and 51 days after artificial inoculation of peppers by enzyme-linked immunosorbent assay (ELISA). Among the 36 domestic cultivars 'Muhanjilju' were resistant to CMV-P1. All 20 PR cultivars and 29 foreign peppers except 'NuMex Twilight' and 'Chainese Giant' were susceptible. Among 112 pepper lines from RDA Genebank, nine pepper lines were resistant, and 17 pepper lines were moderately resistant, and 86 pepper lines were susceptible. Almost all domestic peppers on the market were highly susceptible to CMV-P1, whereas 17.2% of foreign pepper cultivars and genetic pepper lines from RDA Genebank were resistant or moderately resistant. Resistant pepper lines selected in this study can be used as genetic sources for breeding CMV-P1 resistant pepper.