• The Plant Pathology Journal
• /
• v.17 no.1
• /
• pp.1-8
• /
• 2001

The technique of plant transformation has started to show off its great power in the area of plant breeding by commercially successful introduction of transgenic varieties such as herbicide tolerant soybean and insect resistant corn in USA with an unimaginable speed. However, in contrast with the great success in the commercialization of herbicide tolerance and insect resistance, the transformation works on disease resistance has not yet reached the stage of full commercialization. This review surveys the current status of molecular breeding for plant disease resistance and their limits and problems. Some novel ideas and approaches in molecular breeding for disease resistance are introduced.

• The Plant Pathology Journal
• /
• v.32 no.2
• /
• pp.95-101
• /
• 2016

Inheritance of resistance to Fusarium wilt (FW) disease caused by Fusarium udum was investigated in pigeonpea using four different long duration FW resistant genotypes viz., BDN-2004-1, BDN-2001-9, BWR-133 and IPA-234. Based on the $F_2$ segregation pattern, FW resistance has been reported to be governed by one dominant gene in BDN-2004-1 and BDN-2001-9, two duplicate dominant genes in BWR-133 and two dominant complimentary genes in resistance source IPA-234. Further, the efficacy of six simple sequence repeat (SSR) markers namely, ASSR-1, ASSR-23, ASSR-148, ASSR-229, ASSR-363 and ASSR-366 reported to be associated with FW resistance were also tested and concluded that markers ASSR-1, ASSR-23, ASSR-148 will be used for screening of parental genotypes in pigeonpea FW resistance breeding programs. The information on genetics of FW resistance generated from this study would be used, to introgress FW resistance into susceptible but highly adopted cultivars through marker-assisted backcross breeding and in conventional breeding programs.

• Asian-Australasian Journal of Animal Sciences
• /
• v.16 no.9
• /
• pp.1247-1253
• /
• 2003

Selection for increased milk production in dairy cows has often resulted in a higher incidence of disease and thus incurred a greater health costs. Considerable interests have been shown in breeding dairy cattle for disease resistance in recent years. This paper discusses the limitations of breeding dairy cattle for genetic resistance in six parts: 1) complexity of disease resistance, 2) difficulty in estimating genetic parameters for planning breeding programs against disease, 3) undesirable relationship between production traits and disease, 4) disease as affected by recessive genes, 5) new mutation of the pathogens, and 6) variable environmental factors. The hidden problems of estimating genetic and phenotypic parameters involving disease incidence were examined in terms of categorical nature, non-independence, heterogeneity of error variance, non-randomness, and automatic relationship between disease and production traits. In light of these limitations, the prospect for increasing genetic resistance by conventional breeding methods would not be so bright as we like. Since the phenomenon of disease is the result of a joint interaction among host genotype, pathogen genotype and environment, it becomes essential to adopt an integrated approach of increasing genetic resistance of the host animals, manipulating the pathogen genotypes, developing effective vaccines and drugs, and improving the environmental conditions. The advances in DNA-based technology show considerable promise in directly manipulating host and pathogen genomes for genetic resistance and producing vaccines and drugs for prevention and medication to promote the wellbeing of the animals.

• Horticultural Science & Technology
• /
• v.32 no.2
• /
• pp.235-240
• /
• 2014

Cucumber mosaic virus (CMV) is one of the most important viral diseases in pepper (Capsicum annuum L.), and several genes for resistance were reported in Capsicum spp. In Korea, a single dominant gene that is resistant to $CMV_{Fny}$ and $CMV_{P0}$ has been used for breeding. Recently, a new strain ($CMV_{P1}$) was reported that could infect cultivars resistant to both $CMV_{Fny}$ and $CMV_{P0}$. Therefore, breeding of more robust CMV-resistant cultivars is required. In this study, we surveyed the inheritance of $CMV_{P1}$ resistance and analyzed the location of the resistance loci. After $CMV_{P1}$ inoculation of various germplasms and breeding lines, one accession (ICPN18-8) showed no visual symptoms at 15 dpi (days post inoculation) but was susceptible after 45 dpi, and one resistant line (I7339) showed resistance until at 45 dpi. The latter line was used for tests of resistance inheritance. A total of 189 $F_2$ plants were examined, with 42 individuals showing resistance at 15 dpi and a phenotype segregation ratio close to 1:3 (resistant:susceptible plants). In a lateral ELISA test at 45 dpi, 11 plants showed resistance, and the segregation ratio was changed to 1:15. These results indicate that resistance in C. annuum 'I7339' is controlled by two different recessive genes; we named these resistance genes 'cmr3E' and 'cmr3L,' respectively. To locate these two resistant loci in the pepper linkage map, various RAPD, SSR, and STS markers were screened; only nine markers were grouped into one linkage group (LG). Only one RAPD primer (OPAT16) was distantly linked with cmr3E (22.3 cM) and cmr3L (20.7 cM). To develop more accurate markers for marker-assisted breeding, enriching for molecular markers spanning two loci will be required.

• Korean journal of applied entomology
• /
• v.22 no.2 s.55
• /
• pp.74-83
• /
• 1983

Yield losses due to diseases and insect pests were mentioned and emphasized the efficiency of resistant cultivars in curving the yield losses and increasing chemical efficiency. Present status of resistance breeding for blast, bacterial leaf blight viruses, brown planthopper and white backed planthopper were introduced and the resistance sources for those are discussed. Breeding strategies for above items were presented. Specially for the blast resistance, discussions were made in some detail. With brief future prospects of resistance breeding in Korea, a suggestion was made for pathologists to make clear about whether the blast spores will be brought from mainland China as we see with Bph and Wbph or not.

• Plant Breeding and Biotechnology
• /
• v.7 no.3
• /
• pp.272-286
• /
• 2019

Developing elite hybrid rice varieties is one important objective of rice breeding programs. Several genes related to male sterilities, restores, and pollinators have been identified through map-based gene cloning within natural variations of rice. These identified genes are good targets for introducing genetic traits in molecular breeding. This study was conducted to breed elite hybrid lines with major genes related to hybrid traits and disease/insect resistance in 240 genetic resources and F₁ hybrid combinations of rice. Molecular markers were reset for three major hybrid genes (S5, Rf3, Rf4) and thirteen disease/insect resistant genes (rice bacterial blight resistance genes Xa3, Xa4, xa5, Xa7, xa13, Xa21; blast resistance genes Pita, Pib, Pi5, Pii; brown planthopper resistant genes Bph18(t) and tungro virus resistance gene tsv1). Genotypes were then analyzed using molecular marker-assisted selection (MAS). Biological assay was then performed at the Red River Delta region in Vietnam using eleven F₁ hybrid combinations and two control vatieties. Results showed that nine F₁ hybrid combinations were highly resistant to rice bacterial blight and blast. Finally, eight F₁ hybrid rice varieties with resistance to disease/insect were selected from eleven F₁ hybrid combinations. Their characteristics such as agricultural traits and yields were then investigated. These F₁ hybrid rice varieties developed with major genes related to hybrid traits and disease/insect resistant genes could be useful for hybrid breeding programs to achieve high yield with biotic and abiotic resistance.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2022.10a
• /
• pp.292-292
• /
• 2022

Since 1992, the Rural Development Administration (RDA), Republic of Korea in collaboration with International Rice Research Institute (IRRI) has developed 6 japonica rice varieties(MS11, Japonica 1, 2, 6, 7 and Cordillera 4) that are adaptable to tropical regions. However, these varieties show moderate resistance or susceptibility to certain biotic and abiotic stress. The development of varieties with more stable forms of resistance is highly desirable, and this could be possibly achieved through rapid introgression of known biotic and abiotic resistant genes. In this study, we analyzed the allele types of major biotic stress resistant genes including Xa5, Xa13, Xa21 and Xa25 for bacterial leaf blight, Pi5, Pi40, Pish and Pita2 for blast, tsv1 for rice tungro spherical virus, and Bph6, Bph9, Bph17, Bph18 and Bph32 for brown planthopper by using gene-specific molecular markers. In addition, seed quality related genes Sdr4 for preharvest sprouting and qLG-9 for seed longevity were also analyzed. The results revealed that2h5 and Xa25 resistance alleles showed in all varieties while Pi5 resistance allele showed only in MS11. The Pish resistance allele were present in five varieties except for Japonica 1. Meanwhile, for the rest of the genes, no presence of resistance alleles found in six varieties. In conclusions, most of tropical japonica varieties are lack of the major biotic stress resistant genes and seed quality genes (Sdr4 and qLG-9). Moreover, the results indicated that rapid deployment of a few major genes in the current tropical japonica rice varieties is urgent to increase durability and spectrum of biotic stress resistance and also seed dormancy/longevity which are essential traits for tropical environments.

• Plant Resources
• /
• v.7 no.2
• /
• pp.127-135
• /
• 2004

We characterized the resistances such as to waterlogging, Phytophythora and viruses in hybrids between Italian and Korean mother lines and screened them for complex resistances and agronomic traits to select elite multi-resistant lines for hybrid breeding. Resistance to waterlogging was selectable due to diversity of the resistance. Phytophythora resistance introduced from Italian lines could also be combined with resistance to other diseases and restoration abilities from cytoplasmic male sterility that has been maintained in Korean varieties.

• The Plant Pathology Journal
• /
• v.28 no.4
• /
• pp.418-422
• /
• 2012

Eleven hot pepper accessions collected in Vietnam showed stable resistance to bacterial wilt as well-known resistance sources, MC4 and MC5, in repeated inoculation tests with different Ralstonia solanacearum isolates conducted from 2004 to 2010. Seven of these accessions (specifically KC981, KC1006, KC1021, KC1027, KC1045, KC1050, and KC1055) resulted in stable male sterile F1 plants in the crosses with a cytoplasmically male sterile (CMS) Chilseong (CMS-A, Srfrf ), and therefore, they were maintainers (CMS-B) with a genotype of Nrfrf. The rest (KC980, KC995, KC999, and KC1009) produced stable male fertile F1 plants in the crosses, and therefore, were restorers (CMS-C) with a genotype of N(S)RfRf. Therefore, the maintainer and restorer sources of resistance may be used in preference in breeding maternal (CMS and their maintainers) and paternal parents (restorers) for resistance to bacterial wilt, respectively, in the hybrid breeding system utilizing cytoplasmic male sterility.

• The Plant Pathology Journal
• /
• v.38 no.4
• /
• pp.296-303
• /
• 2022

The cucurbit powdery mildew (CPM) caused by different fungal species is a major concern for cucurbit crops around the world. In Argentina CPM constitutes the most common and damaging disease for cucurbits, especially for squash crops (Cucurbita moschata). The present study displays initial insights into the knowledge of the disease in western Argentina, including the determination of the prevalent species causing CPM, as well as the evaluation of the resistance of squash cultivars and breeding lines. Fungal colonies were isolated from samples collected in Mendoza province, Argentina. A field trial was also performed to assess the resistance of five squash accessions, including commercial cultivars and breeding lines. The severity of CPM was analyzed and epidemiological models were built based on empirical data. The morphological determinations and analysis with specific molecular markers confirmed Podosphaera xanthi as the prevalent causal agent of CPM in Mendoza. The results od the field trial showed differences in the resistance trait among the squash accessions. The advanced breeding line BL717/1 showed promising results as source of CPM resistance for the future development of open pollinated resistant cultivars, a crucial tool for an integrative control of the disease.