• Korean Journal of Breeding Science
• /
• v.43 no.1
• /
• pp.42-49
• /
• 2011

QTL analysis for blast resistance was carried out using 140 $BC_3F_3$ lines derived from a cross between Ilpum as a recurrent parent and Moroberekan as a donor parent. 140 $BC_3F_3$ lines with the parents were inoculated with nine blast isolates. To identify QTLs for resistance to nine blast isolates, 134 SSR markers showing polymorphisms between the parents were genotyped for the 140 $BC_3F_3$ lines. A total of 17 resistance QTLs to nine isolates were detected on chromosomes 2, 3, 4, 6, 7, 9 and 10. The phenotypic variance explained by each QTL ranged from 8.2% to 26.4%. The Moroberekan alleles contributed the positive effect at these 17 QTL loci. In a previous study, the QTL, Pi45(t) for durable resistance to blast was identified using a sequential planting method. To know the relationship between Pi45(t) and the isolate-specific resistance gene, an $F_2$ population was developed from a cross between Ilpum and an introgression line harboring Pi45(t). $F_3$ lines segregating for the Pi45(t) were inoculated to three isolates. $F_3$ lines from the $F_2$ plants with the Moroberekan segment at the target region showed resistance to two isolates. This result seems to indicate that the Pi45(t) and the isolate-specific resistance gene are tightly linked or the resistance is controlled by the same gene(s). The markers linked to genes controlling blast resistance would be useful in developing blast resistance lines in the breeding program.

• Horticultural Science & Technology
• /
• v.34 no.5
• /
• pp.779-789
• /
• 2016

A total of 33 accessions of pepper (Capsicum spp.), including previously reported and newly discovered sources of resistance to bacterial spot caused by Xanthomonas euvesicatoria, were evaluated for their resistance to bacterial spot. The selected accessions were then grown and their horticultural characteristics were recorded. In a test for hypersensitive resistance (HR) to four races (P1, P3, P7, P8) of the pathogen found in Korea, KC00939 and Chilbok No.2, which carry the Bs2 gene, exhibited a hypersensitive response to all four races, as expected. Chilbok No.3, which carries the Bs3 gene, showed a hypersensitive reaction to race 1 and 7, as expected. KC00939 exhibited a high ASTA color value and tolerance to multiple infections from a viral complex of Cucumber mosaic virus (CMV) and Broad bean wilt virus (BBWV). Thus, this accession represents a promising genetic resource for breeding cultivars with multiple disease resistance and strong red coloration. KC01327, KC01617, KC01015, KC01760, KC01779, KC01137, KC01328, KC01006, KC00127, KC01704, and KC00995 did not exhibit hypersensitivity but showed a high level of general resistance when evaluated by spray inoculation. KC01617, KC01760, KC01779, KC01137, KC01704, and KC01777 are newly identified sources of resistance to bacterial spot. The previously and newly identified sources of resistance to bacterial spot evaluated in this study, including information about their resistance to CMV and BBWV complex in the field, the contents of pungent and sweet taste components, and the color values of dry fruits, will be useful for breeding pepper cultivars with resistance to bacterial spot.

• Korean Journal of Breeding Science
• /
• v.42 no.4
• /
• pp.390-396
• /
• 2010

A weedy rice, Ganghwaaengmi 11, shows high level of leaf blast resistance. The chromosomal number and locations of genes conferring the leaf blast resistance were detected by QTL (quantitative trait loci) analysis using SSR markers in the 120 RILs (recombinant inbred lines) derived from the cross between Nagdongbyeo and Ganghwaaengmi 11. Ganghwaaengmi 11 expressed compatibility with 20 of the 45 inoculated blast isolates, in contrast to Nagdongbyeo with 44 compatible isolates. To identify QTLs affecting partial resistance, RILs were assessed in upland blast nursery in three regions and inoculated with selected nine blast isolates. QTLs for resistance to blast isolates were identified on chromosomes 7, 11 and 12. Three QTLs associated with blast resistance in nursery test at three regions were also detected on chromosomes 7, 11 and 12. The QTL commonly detected on chromosome 12 was only increased blast resistance by Ganghwaaengmi 11 allele. This QTL accounted for 60.3~78.6% of the phenotypic variation in the blast nursery test. OSR32 and RM101 markers tightly linked to QTL for blast resistance on chromosome 12 might be useful for marker-assisted selection (MAS) and gene pyramiding to improve the blast resistance of japonica rice.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.23 no.2
• /
• pp.113-117
• /
• 1978

An attempt was made to establish a mass-screening technique for resistance to purple seed stain .disease in soybean. Seeds sterilized in 1 : 10000 'mercuric chloride for 1 minute and transffered to Petridishes containing 20ml water agar plus 50ppm of the sodium salt of 2,4-D were inoculated by placing a small agar cube containing fungal mycelium on the seed coat of each seed. A positive correlation between natural infection of purple seed :stain and purple discoloration by seed inoculation technique was highly significant and by this technique, some native soybean collections and introduced varieties were tested for resistance to the disease. Most of the soybean varieties tested were susceptible except for the varieties Hill, Harosoy and Sac, resistant comparatively.

• The Journal of the Korean bone and joint tumor society
• /
• v.15 no.1
• /
• pp.13-25
• /
• 2009

Purpose: The DNA repair protein, $O^6$-methylguanine-DNA methyltransferase (MGMT), removes alkyl adducts from the $O^6$ position of guanine. Epigenetic inactivation of MGMT has been found in human neoplasia and considered one of the implicated factors in chemoresistance. Materials and Methods: Sixty-two patiensts with soft tissue sarcomas (STS) were analyzed for the status of MGMT protein expression by immunohistochemistry and the promoter hypermethylation of the MGMT gene using methylation-specific PCR. Result: The loss of MGMT expression was found in 20 cases (32.3%) of total 62 STS. MGMT promoter hypermethylation rate was 25.0% (11/44 cases). The loss of MGMT expression showed significant association with high AJCC stage, high FNCLCC grade, and aggressive behavior. However,when the group who received chemotherapy was analyzed (n=27), loss of MGMT expression was correlated with worse survival in multivariate analysis (p=0.024). MGMT promoter hypermethylation is associated with high FNCLCC grade. MGMT promoter hypermethylation status had a strong correlation with loss of MGMT expression (p=0.000). Conclusion: Our results suggest that MGMT promoter hypermethylation and loss of MGMT expression had a tendency to be associated with poor prognosis and that loss of MGMT protein expression is frequently occurs via MGMT promoter hypermethylation.

• Horticultural Science & Technology
• /
• v.30 no.1
• /
• pp.64-72
• /
• 2012

Phytophthora root rot has been causing a serious yield loss in pepper production. Since 2004, the year in which commercial cultivars resistant to the disease were firstly commercialized, it has been necessary to introduce the resistance into domestic pepper cultivars for dried red pepper. Therefore, developing molecular markers linked to the resistance is required for an accurate selection of resistant plants and increasing breeding efficiency. Until now, several markers associated with the major dominant gene resistant to Phytophthora root rot have been reported but they have some serious limitations for their usage. In this study, we aimed to develop molecular markers linked to the major dominant gene that can be used for almost of all genetic resources resistant to Phytophthora root rot. Two segregating $F_2$ populations derived from a 'Subicho' ${\times}$ 'CM334' combination and a commercial cultivar 'Dokyacheongcheong' were used to develop molecular markers associated with the resistance. After screening 1,024 AFLP primer combinations with bulked segregant analysis, three AFLP (AFLP1, AFLP2, and AFLP3) markers were identified and converted into three CAPS markers (M1-CAPS, M2-CAPS, and M3-CAPS), respectively. Among them, M3-CAPS marker was further studied in ten resistants, fourteen susceptibles, five hybrids and 53 commercial cultivars. As a result, M3-CAPS marker was more fitted to identify Phytophthora resistance than previously reported P5-SNAP and Phyto5.2-SCAR markers. The result indicated that the M3-CAPS marker will be useful for resistance breeding to Phytophthora root rot in chili pepper.

• Research in Plant Disease
• /
• v.9 no.3
• /
• pp.166-169
• /
• 2003

Occurrence of cercospora leaf spot by Cercospora capsici is assamed to remarkbly cause the yield reduction through the leaf spot, yellowing of leaves and early defoliation in pepper cultivation. To develop resistant cultivar, optimal screening conditions of pepper against cercospora leaf spot were studied. Optimal screening conditions were 3.4 ${\times}$ $10^5$ conidia/ml conidial suspension were sprayed on to the leaves of 30~40 days old pepper seedlings, incubated at 15~$20^{\circ}C$/20~$25^{\circ}C$(day/night) and examined 20 days after inoculation.

• Horticultural Science & Technology
• /
• v.32 no.2
• /
• pp.217-226
• /
• 2014

Root-knot symptoms were found on a commercial tomato cultivar carrying Mi, a resistance gene to root-knot nematodes including Meloidogyne incognita, M. arenaria, and M. javanica in 2012 at Buyeo, Chungnam Province in Korea. The isolate was identified as M. incognita based on molecular analyses using two species-specific primer sets. Pathogenicity of the isolate on one susceptible and three resistant tomato cultivars to the root-knot nematodes was tested. The nematode isolate showed strong pathogenicity on all the tested cultivars at all tested incubation temperatures. In addition, resistance degree of 33 commercial tomato cultivars, 8 susceptible and 25 resistant cultivars to root-knot nematodes, was also tested. Plants were determined as resistant when they suppressed the nematode reproduction. All the cultivars demonstrated strong susceptibility to the nematode regardless of resistance of the tomato cultivars. To our knowledge, this is the first report on the occurrence of Mi infecting M. incognita isolate in Korea. On the other hand, to construct an efficient screening method for selecting resistant breeding source to the nematode isolate, root-knot development of M. incognita on four tomato cultivars according to several conditions such as inoculum concentration, plant growth stage, and incubation period after transplant was investigated. Reproduction of the nematode on all the tested cultivars according to inoculum concentration increased in a dose-dependent manner. Except for inoculum concentration, there was no significant difference in reproduction level of the cultivars according to the other tested conditions. On the basis of the results, we suggest an efficient screening method for new resistant tomato to the nematode isolate.

• Korean Journal of Breeding Science
• /
• v.51 no.4
• /
• pp.395-403
• /
• 2019

Rice blast caused by the fungus Magnaporthe grisea (anamorphic: Pyricularia oryzae) is an important disease in rice and development of resistant varieties to blast is one of the most important goals in rice breeding programs. A japonica rice variety, Palgong, has shown resistance to the Korean blast pathogen since it was developed in 1996. Nine blast resistance quantitative trait loci (QTLs) in Palgong alleles were identified on chromosomes 2, 4, 7, and 11. Four QTLs of qBn2.3, qBn4.2, qBn11.1, and qBn11.2 explained 28-56.7% of total phenotypic variation, while five QTLs of qBn2.2, qBn2.4, qBn4.1, qBn7.1, and qBn7.2 explained 9.7-18.8%. In a previous study, one to four resistance genes were located on the loci qBn2.2, qBn2.3, qBn4.2, qBn11.1, and qBn11.2, however, resistance genes were not located on the loci qBn2.4, qBn4.1, and qBn7.1. A major QTL, qBn11.2, explaining 56.7% of total phenotypic variation was related to the durable resistance of Palgong. Additionally, rice stripe virus resistance of Palgong was assumed to be based on the Stvb-i gene, which is located on a major QTL qBn11.2.

• Proceedings of the Korean Society of Tobacco Science Conference
• /
• 2001.05a
• /
• pp.35-43
• /
• 2001

일대잡종육종이란 현대의 다양한 육종기술 중 하나로 교배 제1세대의 잡종강세현상을 곧바로 이용하는 것으로 여러 작물에서 실용적으로 이용되고 있다. F$_1$잡종종자를 생산하려면 자가수분을 통제해야 하는데 웅성불임을 이용하면 자친의 화분제거 노력이 생력되어 경제적인 종자생산이 가능하다. 연초는 자식성 작물로 잡종강세는 높지 않으나 종간 교잡에 의한 cms가 만들어진 이후 버어리종 등에서는 60년대부터 직적형질에 가깝게 유전되는 우성 단일유전자의 지배를 받는 N. logniflora의 역병(race 0)저항성을 도입한 웅성불임(cms) F$_1$잡종이 활발하게 이용되어 왔다. 최근에는 cms F$_1$잡종의 이용영역이 넓어져 우리나라의 경우 N. glutinosa에서 유래한 우성 단일인자 TMV저항성을 도입한 황색종 cms F$_1$잡종 KF 114가 주 재배품종이 되었고 버어리종에서는 VAM에서 유래한 열성단일유전자의 지배를 받는 PVY저항성이 도입된 KB 111의 확대재배가 예상되고 있다. 본 글에서는 cms F$_1$잡종의 국내외 이용 사례를 살펴보고 cms F$_1$잡종의 육성과 이용방향, cms F$_1$잡종 종자생산에 관하여 기술하였다. 그리고 병저항성뿐 아니라 알칼로이드함량, 염록소함량, DVT나 챤-abienol 및 SE함량 등 질적형질에 가깝게 유전되고 유전양식이 명확하게 밝혀진 화학성분에 대해서도 F$_1$잡종 육성의 대상 형질로 논의하였다.