• Title/Summary/Keyword: resistance breeding

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Pathogenic Diversity of Ascochyta rabiei Isolates and Identification of Resistance Sources in Core Collection of Chickpea Germplasm

  • Farahani, Somayeh;Talebi, Reza;Maleki, Mojdeh;Mehrabi, Rahim;Kanouni, Homayoun
    • The Plant Pathology Journal
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    • v.35 no.4
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    • pp.321-329
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    • 2019
  • Ascochyta blight caused by Ascochyta rabiei (Pass.) Lab. (Telomorph: Didymella rabiei) (Kov.) is one of the most important fungal diseases in chickpea worldwide. Knowledge about pathogen aggressiveness and identification resistance sources to different pathotypes is very useful for proper decisions in breeding programs. In this study, virulence of 32 A. rabiei isolates from different part of Iran were analyzed on seven chickpea differentials and grouped into six races based on 0-9 rating scale and susceptibility/resistant pattern of chickpea differentials. The least and most frequent races were race V and race I, respectively. Race V and VI showed highly virulence on most of differential, while race I showed least aggressiveness. Resistance pattern of 165 chickpea genotypes also were tested against six different A. rabiei races. ANOVA analysis showed high significant difference for isolate, chickpea genotypes and their interactions. Overall $chickpea{\times}isolate$ (race) interactions, 259 resistance responses (disease severity ${\leq}4$) were identified. Resistance spectra of chickpea genotypes showed more resistance rate to race I (49.70%) and race III (35.15%), while there were no resistance genotypes to race VI. Cluster analysis based on disease severity rate, grouped chickpea genotypes into four distinct clusters. Interactions between isolates or races used in this study, showed the lack of a genotype with complete resistance. Our finding for virulence pattern of A. rabiei and newly identified resistance sources could be considerably important for integration of ascochyta blight resistance genes into chickpea breeding programs and proper decision in future for germplasm conservation and diseases management.

Evaluation of Tomato Genetic Resources for the Development of Resistance Breeding Lines against Late Blight (잎마름역병 저항성 육종을 위한 토마토 유전자원의 저항성 평가)

  • Kim, Byung-Sup
    • Research in Plant Disease
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    • v.18 no.1
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    • pp.35-39
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    • 2012
  • Occurrence of tomato late blight (Phytophthora infestans) has caused significant losses in tomato yield in all over the world. Evaluation of the level of resistance in tomato gene resources for main breeding and initiation of the resistance breeding program are important for control of this disease. Resistant assay of 78 tomato cultivars/lines to late blight in pots and field experiment was carried out under controlled and natural conditions in 2009. All commercial cultivars including 'Legend' were susceptible. However, 10 lines including KNU-2, KNU-6-1, KNU-11, KNU-13, KNU-14-1 lines distributed from University of California, Riverside and L3708, $AV107-4{\times}L3708$, $07-15{\times}L3708$, $BS67{\times}L3708$ lines which have resistant gene Ph-3 and $06-9-62A{\times}06-9-62A$ were highly resistant to late blight. These highly resistant lines can be used as resources of resistance to late blight in a tomato breeding program in future.

Development of a SCAR Marker Linked to Ph-3 in Solanum ssp.

  • Park, Pue Hee;Chae, Young;Kim, Hyun-Ran;Chung, Kyeong-Ho;Oh, Dae-Geun;Kim, Ki-Taek
    • Korean Journal of Breeding Science
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    • v.42 no.2
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    • pp.139-143
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    • 2010
  • Late blight caused by Phytophthora infestans is historically a serious epidemic disease in potato and tomato cultivations. Accession L3708 (Solanum pimpinellifolium), a new source for late blight resistance was identified in AVRDC, and carries the resistance gene, Ph-3, incompatible to P. infestans race 3. The AFLP markers linked to Ph-3 were previously developed from the L3708 accession (Chunwongse et al. 2002). To facilitate tomato breeding with the Ph-3 gene, an attempt was made to convert AFLP markers to sequence-characterized amplified region (SCAR) markers. Among 6 AFLP markers, only one AFLP marker, L87, was successfully converted to SCAR marker. The resistance-specific 230 bp AFLP fragment was cloned and sequenced, and the PCR primer amplifying a 123 bp fragment was designed. This SCAR marker could discriminate resistant and susceptible individuals with high stringency. The developed SCAR marker could be used for the marker assisted-selection in tomato breeding programs.

Application of Disease Resistance Markers for Developing Elite Tomato Varieties and Lines

  • Kim, Hyoun-Joung;Lee, Heung-Ryul;Hyun, Ji-Young;Won, Dong-Chan;Hong, Dong-Oh;Cho, Hwa-Jin;Lee, Kyung-Ah;Her, Nam-Han;Lee, Jang-Ha;Harn, Chee-Hark
    • Horticultural Science & Technology
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    • v.29 no.4
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    • pp.336-344
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    • 2011
  • Using the abundant available information about the tomato genome, we developed DNA markers that are linked to disease resistant loci and performed marker-assisted selection (MAS) to construct multi-disease resistant lines and varieties. Resistance markers of Ty-1, T2, and I2, which are linked to disease resistance to Tomato yellow leaf curl virus (TYLCV), Tomato mosaic virus (ToMV), and Fusarium wilt, respectively, were developed in a co-dominant fashion. DNA sequences near the resistance loci of TYLCV, ToMV, and Fusarium wilt were used for primer design. Reported candidate markers for powdery mildew-resistance were screened and the 32.5Cla marker was selected. All four markers (Ty-1, T2, I2, and 32.5Cla) were converted to cleavage amplification polymorphisms (CAPS) markers. Then, the CAPS markers were applied to 96 tomato lines to determine the phenetic relationships among the lines. This information yielded clusters of breeding lines illustrating the distribution of resistant and susceptible characters among lines. These data were utilized further in a MAS program for several generations, and a total of ten varieties and ten inbred lines were constructed. Among four traits, three were introduced to develop varieties and breeding lines through the MAS program; several cultivars possessed up to seven disease resistant traits. These resistant trait-related markers that were developed for the tomato MAS program could be used to select early stage seedlings, saving time and cost, and to construct multi-disease resistant lines and varieties.

Investigation of Defense and Vegetative Growth Related Traits of Recombinant Inbred Lines of Brassica rapa

  • Kwon, Soon-Tae;Yeam, Inhwa;Shin, Jong Hwa
    • Korean Journal of Plant Resources
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    • v.33 no.6
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    • pp.615-623
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    • 2020
  • Brassica rapa is one of the most valuable vegetable crops worldwide. Cultivated varieties of B. rapa exhibit diverse developmental and morphological appearances, which includes important vegetables, oilseeds, and fodder crops. In this study, various phenotypes of recombinant inbred lines (RILs) of B. rapa were investigated, including their responses to five different pathogenic Botrytis cinerea isolates, responses to aphid and thrips during flowering stages, days to flowering, and plant heights. Responses of 113 RILs to five different B. cinerea isolates showed variations, suggesting that genetic factors controlling resistance or tolerance against each isolate were dependent on isolate/genotype pairs. Correlation analysis was performed to understand the nature of genetic factors and the relationship among these phenotypes. Although high levels of correlation were not detected between phenotypes assessed in this study, statistically significant correlation was detected for several combinations. Significant positive correlations were found for different B. cinerea isolates, supporting that certain levels of commonality could exist in genetic components controlling resistance against different B. cinerea isolates. Based on correlation analysis using numbers of insects counted on plants, it was speculated that genetic factors responsible for aphid tolerance or repellence might be also involved in the response against thrips. Relationship between vegetative growth and tolerance against B. cinereal or insects is rather more complicated. However, it was observed that shorter plants appeared to have a certain level of tolerance or repellence against both aphids and thrips. Data presented in this study could be used to assist further genetic studies and breeding efforts to obtain Botritis and insect resistance for B. rapa.

Detection of Blackleg Resistance Gene Rlm1 in Double-Low Rapeseed Accessions from Sichuan Province, by Kompetitive Allele-Specific PCR

  • Chai, Liang;Zhang, Jinfang;Dilantha Fernando, Wannakuwattewaduge Gerard;Li, Haojie;Huang, Xiaoqin;Cui, Cheng;Jiang, Jun;Zheng, Benchuan;Liu, Yong;Jiang, Liangcai
    • The Plant Pathology Journal
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    • v.37 no.2
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    • pp.194-199
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    • 2021
  • Blackleg is a serious disease in Brassica plants, causing moderate to severe yield losses in rapeseed worldwide. Although China has not suffered from this disease yet (more aggressive Leptosphaeria maculans is not present yet), it is crucial to take provisions in breeding for disease resistance to have excellent blackleg-resistant cultivars already in the fields or in the breeding pipeline. The most efficient strategy for controlling this disease is breeding plants with identified resistance genes. We selected 135 rapeseed accessions in Sichuan, including 30 parental materials and 105 hybrids, and we determined their glucosinolate and erucic acid content and confirmed 17 double-low materials. A recently developed single-nucleotide polymorphism (SNP) marker, SNP_208, was used to genotype allelic Rlm1/rlm1 on chromosome A07, and 87 AvrLm1-resistant materials. Combined with the above-mentioned seed quality data, we identified 11 AvrLm1-resistant double-low rapeseed accessions, including nine parental materials and two hybrids. This study lays the foundation of specific R gene-oriented breeding, in the case that the aggressive Leptosphaeria maculans invades and establishes in China in the future and a robust and less labor consuming method to identify resistance in canola germplasm.

Near-Isogenic Lines for Genes Conferring Hypersensitive Resistance to Bacterial Spot in Chili Pepper

  • Kim, Byung-Soo;Kim, Young-Chun;Shin, Kwang-Sik;Kim, Jeong-Hoon
    • The Plant Pathology Journal
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    • v.23 no.3
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    • pp.155-160
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    • 2007
  • In order to develop chili pepper bacterial spot resistant cultivars and near-isogenic lines (NILs) to prompt the molecular mapping of the resistance gene, we have run backcross breeding program since 1994. Two resistance genes against Xanthomonas axonopodis pv. vesicatoria Bs2 from Fla. XVR 3-25 and Bs3 from our breeding line 25-11-3-2, were introduced into a land race, Chilseongcho (abbreviated to Chilseong hereafter) with good fruit guality. We report here the testing of $BC_4F_3\;to\;BC_4F_5$. We found that $BC_4F_5$ lines of the crosses were homozygous with respect to the respective genes of introduction. The lines, in which Bs2 gene was introduced, were hypersensitively resistant to both race 1 and race 3 of X. axonopodis pv. vesicatoria, whereas, those in which Bs3 was introduced were resistant to race 1.