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1.
Pei C Wang H Zhang J Wang Y Francis DM Yang W 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2012,124(3):533-542
Bacterial spot caused by Xanthomonas euvesicatoria, X. vesicatoria, X. perforans and X. gardneri is one of the most destructive diseases in tomatoes (Solanum lycopersicum L.) growing in tropical and subtropical regions. Exploring resistance genes from diverse germplasm and incorporating them
into cultivated varieties are critical for controlling this disease. The S. pimpinellifolium accession PI128216 was reported to carry the Rx4 gene on chromosome 11 conferring hypersensitivity and field resistance to race T3. To facilitate the use of marker-assisted
selection in breeding and map-based cloning of the gene, an F2 population derived from a cross between the susceptible variety OH88119 and the resistant accession PI128216 was created
for fine mapping of the Rx4 gene. Using 18 markers developed through various approaches, we mapped the gene to a 45.1-kb region between two markers pcc17
and pcc14 on chromosome 11. A NBS-LRR class of resistance gene was identified as the candidate for the Rx4 gene based on annotation results from the International Tomato Annotation Group. Comparison of the genomic DNA sequences
of the Rx4 alleles in PI128216 and OH88119 revealed a 6-bp insertion/deletion (InDel) and eight SNPs. The InDel marker was successfully
used to distinguish resistance and susceptibility in 12 tomato lines. These results will facilitate cloning the Rx4 gene and provide a useful tool for marker-assisted selection of this gene in tomato breeding programs. 相似文献
2.
3.
Mauricio Ulloa Robert B. Hutmacher Philip A. Roberts Steven D. Wright Robert L. Nichols R. Michael Davis 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2013,126(5):1405-1418
Diseases such as Fusarium wilt [Fusarium oxysporum f.sp. vasinfectum (FOV) Atk. Sny & Hans] represent expanding threats to cotton production. Integrating disease resistance into high-yielding, high-fiber quality cotton (Gossypium spp.) cultivars is one of the most important objectives in cotton breeding programs worldwide. In this study, we conducted a comprehensive analysis of gene action in cotton governing FOV race 4 resistance by combining conventional inheritance and quantitative trait loci (QTL) mapping with molecular markers. A set of diverse cotton populations was generated from crosses encompassing multiple genetic backgrounds. FOV race 4 resistance was investigated using seven parents and their derived populations: three intraspecific (G. hirsutum × G. hirsutum L. and G. barbadense × G. barbadense L.) F1 and F2; five interspecific (G. hirsutum × G. barbadense) F1 and F2; and one RIL. Parents and populations were evaluated for disease severity index (DSI) of leaves, and vascular stem and root staining (VRS) in four greenhouse and two field experiments. Initially, a single resistance gene (Fov4) model was observed in F2 populations based on inheritance of phenotypes. This single Fov4 gene had a major dominant gene action and conferred resistance to FOV race 4 in Pima-S6. The Fov4 gene appears to be located near a genome region on chromosome 14 marked with a QTL Fov4-C14 1 , which made the biggest contribution to the FOV race 4 resistance of the generated F2 progeny. Additional genetic and QTL analyses also identified a set of 11 SSR markers that indicated the involvement of more than one gene and gene interactions across six linkage groups/chromosomes (3, 6, 8, 14, 17, and 25) in the inheritance of FOV race 4 resistance. QTLs detected with minor effects in these populations explained 5–19 % of the DSI or VRS variation. Identified SSR markers for the resistance QTLs with major and minor effects will facilitate for the first time marker-assisted selection for the introgression of FOV race 4 resistance into elite cultivars during the breeding process. 相似文献
4.
DM Horvath RE Stall JB Jones MH Pauly GE Vallad D Dahlbeck BJ Staskawicz JW Scott 《PloS one》2012,7(8):e42036
We investigated whether lines of transgenic tomato (Solanum lycopersicum) expressing the Bs2 resistance gene from pepper, a close relative of tomato, demonstrate improved resistance to bacterial spot disease caused by Xanthomonas species in replicated multi-year field trials under commercial type growing conditions. We report that the presence of the Bs2 gene in the highly susceptible VF 36 background reduced disease to extremely low levels, and VF 36-Bs2 plants displayed the lowest disease severity amongst all tomato varieties tested, including commercial and breeding lines with host resistance. Yields of marketable fruit from transgenic lines were typically 2.5 times that of the non-transformed parent line, but varied between 1.5 and 11.5 fold depending on weather conditions and disease pressure. Trials were conducted without application of any copper-based bactericides, presently in wide use despite negative impacts on the environment. This is the first demonstration of effective field resistance in a transgenic genotype based on a plant R gene and provides an opportunity for control of a devastating pathogen while eliminating ineffective copper pesticides. 相似文献
5.
QTL mapping of resistance to gray leaf spot in ryegrass 总被引:2,自引:0,他引:2
Curley J Sim SC Warnke S Leong S Barker R Jung G 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2005,111(6):1107-1117
Gray leaf spot (GLS) is a serious fungal disease caused by Magnaporthe grisea, recently reported on perennial ryegrass (Lolium perenne L.), an important turfgrass and forage species. This fungus also causes rice blast and many other grass diseases. Rice blast is usually controlled by host resistance, but durability of resistance is a problem. Little GLS resistance has been reported in perennial ryegrass. However, greenhouse inoculations in our lab using one ryegrass isolate and one rice-infecting lab strain suggest presence of partial resistance. A high density linkage map of a three generation Italian × perennial ryegrass mapping population was used to identify quantitative trait loci (QTL) for GLS resistance. Potential QTL of varying effect were detected on four linkage groups, and resistance to the ryegrass isolate and the lab strain appeared to be controlled by different QTL. Of three potential QTL detected using the ryegrass isolate, the one with strongest effect for resistance was located on linkage group 3 of the MFB parent, explaining between 20% and 37% of the phenotypic variance depending on experiment. Another QTL was detected on linkage group 6 of the MFA parent, explaining between 5% and 10% of the phenotypic variance. The two QTL with strongest effect for resistance to the lab strain were located on linkage groups MFA 2 and MFB 4, each explaining about 10% of the phenotypic variance. Further, the QTL on linkage groups 3 and 4 appear syntenic to blast resistance loci in rice. This work will likely benefit users and growers of perennial ryegrass, by setting the stage for improvement of GLS resistance in perennial ryegrass through marker-assisted selection. 相似文献
6.
Violeta Georgieva Sotirova Nevena Stojanova Bogatsevska 《Acta Physiologiae Plantarum》2000,22(3):256-259
Thirty six tomato wild species accessions of the subgenera Eulycopersicon and Eriopersicon of the genus Lycopersicon were inoculated with race T1 and T3 of Xanthomonas vesicatoria by vaccum infiltration method. Degree of diseases was evaluated by scale of 0 to 4. It was established that some accessions
showed low degree of disease to race T1 and others to race T3. LA 2623 indicated very low degree of disease to race T1 and
was immune in inoculation with T3. LA 386 and LA 1297 manifested hypersensitive reaction to both races and PI 127826 to race
T3 only. The accessions possessing low degree of disease or hypersensitive reaction to race T1 and race T3 are new promising
sources of resistance to Xanthomonas vesicatoria. 相似文献
7.
Identification of QTLs for Ralstonia solanacearum race 3-phylotype II resistance in tomato 总被引:1,自引:0,他引:1
Carmeille A Caranta C Dintinger J Prior P Luisetti J Besse P 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2006,113(1):110-121
Resistance against a Ralstonia solanacearum race 3-phylotype II strain JT516 was assessed in a F2:3 and a population of inbred lines (RIL), both derived from a cross between L. esculentum cv. Hawaii 7996 (partially resistant) and L. pimpinellifolium WVa700 (susceptible). Resistance criteria used were the percentage of wilted plants to calculate the AUDPC value, and bacterial colonization scores in roots and stem (hypocotyl and epicotyl) assessed in two independent greenhouse experiments conducted during the cool and hot seasons in Réunion Island, France. Symptoms were more severe during the cool season trials. Heritability estimates in individual seasons ranged from 0.82 to 0.88, depending on resistance criterion. A set of 76 molecular markers was used for quantitative trait loci (QTL) mapping using the single- and composite- interval mapping methods, as well as ANOVA. Four QTLs, named Bwr- followed by a number indicating their map location, were identified. They explained from 3.2 to 29.8% of the phenotypic variation, depending on the resistance criterion and the season. A major QTL, Bwr-6, and a minor one, Bwr-3, were detected in each season for all resistance criteria. Both QTLs showed stronger effects in the hot season than in the cool one. Their role in resistance to R. solanacearum race 3-phylotype II was subsequently confirmed in the RIL population derived from the same cross. Two other QTLs, Bwr-4 and Bwr-8, with intermediate and minor effects, respectively, were only detected in the hot season, demonstrating that environmental factors may strongly influence the expression of resistance against the race 3-phylotype II strain JT516. These QTLs were compared with those detected in the RIL population against race 1-phylotype I strain JT519 as well as those detected in other previous studies in the same genetic background against other race 1-phylotype I and II strains. This comparison revealed the possible occurrence of some phylotype-specific resistance QTLs in Hawaii 7996. 相似文献
8.
Bykova Irina V. Lashina Nina M. Efimov Vadim M. Afanasenko Olga S. Khlestkina Elena K. 《BMC plant biology》2017,17(2):250-103
Background
Spot blotch, caused by Cochliobolus sativus, is one of the most widespread and harmful diseases in barley. Identification of genetic loci associated with resistance to C. sativus is of importance for future marker-assisted selection. The goal of the current study was to identify loci conferring seedling resistance to two different pathotypes of C. sativus in the Siberian spring barley core collection.Results
A total of 96 spring barley cultivars and lines were phenotyped at the seedling stage with two C. sativus isolates (Kr2 and Ch3). According to the Fetch-Steffenson rating scale 16%/17% of genotypes were resistant and 26%/30% were moderate-resistant to the Kr2/Ch3 isolates respectively. A total of 94 genotypes were analyzed with the barley 50 K Illumina Infinium iSELECT assay. From 44,040 SNPs, 40,703 were scorable, from which 39,140 were polymorphic. 27,319 SNPs passed filtering threshold and were used for association mapping. Data analysis by GLM revealed 48 and 41 SNPs for Kr2 and Ch3 isolates, respectively. After application of 5% Bonferroni multiple test correction, only 3 and 27 SNPs were identified, respectively. A total of three genomic regions were associated with the resistance. The region on chromosome 3H associated with Ch3-resistance was expanded between markers SCRI_RS_97417 and JHI-Hv50k-2016-158003 and included 11 SNPs, from which JHI-Hv50k-2016-157070, JHI-Hv50k-2016-156842 had the lowest p-values. These two SNPs were also significant in case of Kr2 isolate. The region on chromosome 2H included 16 loci (7 of them with the lowest p-values were tightly linked to BOPA2_12_11504). Three loci corresponding to this region had suggestive p-values in case of Kr2 tests, so the locus on chromosome 2H may also contribute to resistance to Kr2 isolate. The third region with significant p-value in case of Kr2 tests was identified on chromosome 1H at the locus JHI-Hv50k-2016-33568.Conclusions
Three genomic regions associated with the resistance to one or both isolates of C. sativus were identified via screening of the Siberian spring barley core collection. Comparison of their location with QTLs revealed previously either with biparental mapping populations studies or with GWAS of distinct germplasm and other isolates, demonstrated that resistance to isolates Kr2 and Ch3 is conferred by known spot blotch resistance loci. Information on SNPs related can be used further for development of DNA-markers convenient for diagnostics of resistance-associated alleles in barley breeding programs.9.
R. Mizobuchi H. Sato S. Fukuoka S. Tsushima T. Imbe M. Yano 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2013,126(9):2417-2425
Bacterial seedling rot (BSR), a destructive disease of rice (Oryza sativa L.), is caused by the bacterial pathogen Burkholderia glumae. To identify QTLs for resistance to BSR, we conducted a QTL analysis using chromosome segment substitution lines (CSSLs) derived from a cross between Nona Bokra (resistant) and Koshihikari (susceptible). Comparison of the levels of BSR in the CSSLs and their recurrent parent, Koshihikari, revealed that a region on chromosome 10 was associated with resistance. Further genetic analyses using an F5 population derived from a cross between a resistant CSSL and Koshihikari confirmed that a QTL for BSR resistance was located on the short arm of chromosome 10. The Nona Bokra allele was associated with resistance to BSR. Substitution mapping in the Koshihikari genetic background demonstrated that the QTL, here designated as qRBS1 (quantitative trait locus for RESISTANCE TO BACTERIAL SEEDLING ROT 1), was located in a 393-kb interval (based on the Nipponbare reference genome sequence) defined by simple sequence repeat markers RM24930 and RM24944. 相似文献
10.
Li Xu Yan He Deng-Feng Zhang Jing-Rui Dai Shou-Cai Wang 《Molecular breeding : new strategies in plant improvement》2009,23(4):709-718
Bacterial brown spot (BBS) in maize (Zea mays L.) is caused by Pseudomonas syringae pv. syringae Van Holl (Pss). In China, this disease is not prevalent in maize at present. Here, we report the identification and fine mapping of the
gene, referred to as Psy1, which confers resistance to BBS. An F2 population, derived from the cross P25/F349, was used for linkage analysis and mapping of the resistance gene Psy1. Analysis of a BC8F2 population, derived from the same parents, confirmed that Psy1 was located on chromosome 10L and inherited as a single dominant gene. For fine mapping of Psy1, two introgression lines, X41 and X44, homozygous at the resistant gene locus, were introduced to hybridize with the susceptible
parent P25 respectively, and developed a mixed BC1 population. We found the closest markers to Psy1 are EST1 and FG29-3, which located on two adjacent BACs respectively, based on the B73 BAC sequence. Sequence analysis of
these two BAC sequences (~300 kb) revealed the presence of a homologous sequence of receptor-like kinase. Also a co-segregation
marker was developed based on this homologous sequence. These results will be useful for cloning of Psy1 and for transferring or pyramiding Psy1 through MAS in maize breeding programs. 相似文献
11.
Tomato bacterial wilt (BW) incited by Ralstonia solanacearum is a constraint on tomato production in tropical, subtropical and humid regions of the world. In this paper, we present the
results of a research aimed at the identification of PCR-based markers amplified fragment length polymorphism (AFLP) linked
to the genes that confer resistance to tomato BW. To this purpose, bulked segregant analysis was applied to an F2 population segregating for the BW resistant gene and derived from the pair-cross between a BW resistant cultivar T51A and
the susceptible cultivar T9230. Genetic analysis indicated that tomato BW was conferred by two incomplete dominant genes.
A CTAB method for total DNA extraction, developed by Murray and Thompson with some modifications was used to isolation the
infected tomato leaves. Thirteen differential fragments were detected using 256 primer combinations, and two AFLP markers
were linked to the BW resistance. Subsequently, the AFLP markers were converted to co-dominant SCAR markers, named TSCARAAT/CGA and TSCARAAG/CAT. Linkage analysis showed that the two markers are on the contralateral side of TRSR-1. Genetic distance between TSCARAAT/CGA and TRS-1 was estimated to 4.6 cM, while 8.4 cM between TSCARAAG/CAT and TRS-1. 相似文献
12.
Identification of a new major QTL associated with resistance to soybean cyst nematode (Heterodera glycines) 总被引:4,自引:0,他引:4
I. Schuster R. V. Abdelnoor S. R. R. Marin V. P. Carvalho R. A. S. Kiihl J. F. V. Silva C. S. Sediyama E. G. Barros M. A. Moreira 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,102(1):91-96
Resistance of soybean [Glycine max (L.) Merr.] to cyst nematode (SCN) (Heterodera glycines Ichinohe), one of the most destructive pathogens affecting soybean, involves a complex genetic system. The identification
of QTLs associated with SCN resistance may contribute to the understanding of such system. The objective of this work was
to identify and map QTLs for resistance to SCN Race 14 with the aid of molecular markers. BC3F2:3 and F2:3 populations, both derived from an original cross between resistant cv. Hartwig and the susceptible line BR-92–31983 were
screened for resistance to SCN Race 14. Four microsatellite (Satt082, Sat_001, Satt574 and Satt301) and four RAPD markers
(OPAA-11795, OPAE-08837, OPR-07548 and OPY-072030) were identified in the BC3F2:3 population using the bulked segregant analysis (BSA) technique. These markers were amplified in 183 F2:3 families and mapped to a locus that accounts for more than 40% of the resistance to SCN Race 14. Selection efficiency based
on these markers was similar to that obtained with the conventional method. In the case of the microsalellite markers, which
identify homozygous resistant genotypes, the efficiency was even higher. This new QTL has been mapped to the soybean linkage
group D2 and, in conjunction with other QTLs already identified for SCN resistance, will certainly contribute to our understanding
of the genetic basis of resistance of this important disease in soybean.
Received: 12 October 1999 / Accepted: 14 April 2000 相似文献
13.
Nannan Yang Gregory Reighard David Ritchie William Okie Ksenija Gasic 《Tree Genetics & Genomes》2013,9(2):573-586
Bacterial spot, caused by Xanthomonas arboricola pv. pruni (Xap), is a serious disease that can affect peach fruit quality and production worldwide. This disease causes severe defoliation and blemishing of fruit, particularly in areas with high rainfall, strong winds, high humidity, and sandy soil. The molecular basis of its tolerance and susceptibility in peach is yet to be understood. An F2 population of 63 genotypes derived from a cross between peaches “O’Henry” (susceptible) and “Clayton” (resistant) has been used for linkage map construction and quantitative trait loci (QTL) mapping. Phenotypic data for leaf and fruit response to Xap infection were collected over 2 years at two locations. A high-density genetic linkage map that covers a genetic distance of 421.4 cM with an average spacing between markers of 1.6 cM was developed using the International Peach Single Nucleotide Polymorphism Consortium (IPSC) 9K array v1. Fourteen QTLs with an additive effect on Xap resistance were detected, including four major QTLs on linkage groups (LG) 1, 4, 5, and 6. Major QTLs, Xap.Pp.OC-4.1 and Xap.Pp.OC-4.2, on LG4 were associated with Xap resistance in leaf; Xap.Pp.OC-5.1 on LG5 was associated with Xap resistance in both leaf and fruit, while Xap.Pp.OC-1.2 and Xap.Pp.OC-6.1 on LG1 and LG6, respectively, were associated with Xap resistance in fruit. This suggested separate regulation of leaf and fruit resistance for Xap in peach as well as participation of genes involved in general plant response to biotic stress. The potential for marker-assisted selection for Xap resistance in peach is discussed. 相似文献
14.
15.
Identification of a molecular marker tightly linked to bacterial wilt resistance in tomato by genome-wide SNP analysis 总被引:1,自引:0,他引:1
Boyoung Kim In Sun Hwang Hyung Jin Lee Je Min Lee Eunyoung Seo Doil Choi Chang-Sik Oh 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2018,131(5):1017-1030
Key message
Genotyping of disease resistance to bacterial wilt in tomato by a genome-wide SNP analysisAbstract
Bacterial wilt caused by Ralstonia pseudosolanacearum is one of the destructive diseases in tomato. The previous studies have identified Bwr-6 (chromosome 6) and Bwr-12 (chromosome 12) loci as the major quantitative trait loci (QTLs) contributing to resistance against bacterial wilt in tomato cultivar ‘Hawaii7996’. However, the genetic identities of two QTLs have not been uncovered yet. In this study, using whole-genome resequencing, we analyzed genome-wide single-nucleotide polymorphisms (SNPs) that can distinguish a resistant group, including seven tomato varieties resistant to bacterial wilt, from a susceptible group, including two susceptible to the same disease. In total, 5259 non-synonymous SNPs were found between the two groups. Among them, only 265 SNPs were located in the coding DNA sequences, and the majority of these SNPs were located on chromosomes 6 and 12. The genes that both carry SNP(s) and are near Bwr-6 and Bwr-12 were selected. In particular, four genes in chromosome 12 encode putative leucine-rich repeat (LRR) receptor-like proteins. SNPs within these four genes were used to develop SNP markers, and each SNP marker was validated by a high-resolution melting method. Consequently, one SNP marker, including a functional SNP in a gene, Solyc12g009690.1, could efficiently distinguish tomato varieties resistant to bacterial wilt from susceptible varieties. These results indicate that Solyc12g009690.1, the gene encoding a putative LRR receptor-like protein, might be tightly linked to Bwr-12, and the SNP marker developed in this study will be useful for selection of tomato cultivars resistant to bacterial wilt.16.
Molecular markers linked to papaya ring spot virus resistance and Fusarium race 2 resistance in melon 总被引:6,自引:0,他引:6
Brotman Y Kovalski I Dogimont C Pitrat M Portnoy V Katzir N Perl-Treves R 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2005,110(2):337-345
In melon, the Fom-1 gene confers monogenic resistance against the soil-borne fungus Fusarium oxysporum f. sp. melonis, races 0 and 2, while the closely linked Prv gene specifies resistance against the papaya ring spot virus. Markers linked to these resistance (R) genes were identified using two recombinant inbred line populations, derived from crosses between Cucumis melo Védrantais and C. melo PI 161375, and between C. melo Védrantais and C. melo PI 414723, respectively. Using bulked segregant analysis, as well as systematic scoring of the mapping populations, we developed two amplified fragment length polymorphism markers, two random amplified polymorphic DNA markers and five restriction fragment length polymorphism (RFLP) markers linked to this locus. Four of the RFLP sequences bear homology to nucleotide-binding site–leucine-rich repeat R genes, indicating the presence of a significant R-gene cluster in this locus. Our study provides the most closely linked markers published so far for these important traits. It also improves the resolution of the whole linkage group IX, which was difficult to order in our previous studies. Two of the markers were converted to cleaved amplified polymorphic sequence markers to facilitate their application in marker-assisted selection. Testing these two markers in several melon lines revealed different marker haplotypes in the melon germplasm and supported multiple, independent origin of the Fusarium races 0 and 2 resistance trait. 相似文献
17.
Identification of novel QTL contributing resistance to aflatoxin accumulation in maize 总被引:1,自引:0,他引:1
Marilyn L. Warburton Thomas D. Brooks Gary L. Windham W. Paul Williams 《Molecular breeding : new strategies in plant improvement》2011,27(4):491-499
The toxic metabolic product aflatoxin produced by the opportunistic fungus Aspergillus flavus (Link:Fr) in maize (Zea mays L.) can cause disease and economic harm when levels exceed very minute quantities. The selection of resistant germplasm has
great potential to reduce the problem, but the highly quantitative nature of the trait makes this a difficult endeavor. The
identification of aflatoxin accumulation resistance quantitative trait loci (QTL) from resistant donor lines and the discovery
of linked markers could speed this task. To identify marker–trait associations for marker-assisted breeding, a genetic mapping
population of F2:3 families was developed from Mp715, a maize inbred line resistant to aflatoxin accumulation, and T173, a susceptible, southern-adapted
maize inbred line. QTL, some with large phenotypic effects, were identified in multiple years on chromosomes 1, 3, 5, and
10, and smaller QTL identified in only 1 year were found on chromosomes 4 and 9. The phenotypic effect of each QTL ranged
from 2.7 to 18.5%, and models created with multiple QTL could explain up to 45.7% of the phenotypic variation across years,
indicating that the variation associated with the trait can be manipulated using molecular markers. 相似文献
18.
Li Ning Zhang Xiaofei Yang Wencai 《Molecular breeding : new strategies in plant improvement》2019,39(12):1-11
Molecular Breeding - Stigma exsertion is a plant trait wherein stigmas emerge from flower buds before anthesis. It is a key determinant of the ornamental kale mating system, greatly increases the... 相似文献
19.
Genetics of resistance to bacterial speck of tomato caused by Pseudomonas syringae pv. tomato 总被引:1,自引:0,他引:1
Two tomato cultivars, Ontario 7710 and Rehovot 13, and their F1, F2, F3 and backcross progenies were screened for resistance to bacterial speck (Pseudomonas syringae pv. tomato) of tomato. The results support the hypothesis that the resistance factors contained in the two parents are non-allelic and controlled by two different genes. 相似文献
20.
QTL analysis of quantitative resistance to Phytophthora infestans (late blight) in tomato and comparisons with potato. 总被引:6,自引:0,他引:6
Quantitative trait loci (QTLs) for resistance to Phytophthora infestans (late blight) were mapped in tomato. Reciprocal backcross populations derived from cultivated Lycopersicon esculentum x wild Lycopersicon hirsutum (BC-E, backcross to L. esculentum; BC-H, backcross to L. hirsutum) were phenotyped in three types of replicated disease assays (detached-leaflet, whole-plant, and field). Linkage maps were constructed for each BC population with RFLPs. Resistance QTLs were identified on all 12 tomato chromosomes using composite interval mapping. Six QTLs in BC-E (lb1a, lb2a, lb3, lb4, lb5b, and lb11b) and two QTLs in BC-H (lb5ab and lb6ab) were most consistently detected in replicated experiments or across assay methods. Lycopersicon hirsutum alleles conferred resistance at all QTLs except lb2a. Resistance QTLs coincided with QTLs for inoculum droplet dispersal on leaves, a trait in L. hirsutum that may contribute to resistance, and dispersal was mainly associated with leaf resistance. Some P. infestans resistance QTLs detected in tomato coincided with chromosomal locations of previously mapped R genes and QTLs for resistance to P. infestans in potato, suggesting functional conservation of resistance within the Solanaceae. 相似文献