共查询到20条相似文献,搜索用时 31 毫秒
1.
Mapping of QTL for downy mildew resistance in maize 总被引:4,自引:0,他引:4
H. A. Agrama M. E. Moussa M. E. Naser M. A. Tarek A. H. Ibrahim 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1999,99(3-4):519-523
Quantitative trait loci (QTLs) of maize involved in mediating resistance to Peronosclerospora sorghi, the causative agent of sorghum downy mildew (SDM), were detected in a population of recombinant inbred lines (RILs) derived
from the Zea mays L. cross between resistant (G62) and susceptible (G58) inbred lines. Field tests of 94 RILs were conducted over two growing
seasons using artificial inoculation. Heritability of the disease reaction was high (around 70%). The mapping population of
the RILs was also scored for restriction fragment length polymorphic (RFLP) markers. One hundred and six polymorphic RFLP
markers were assigned to ten chromosomes covering 1648 cM. Three QTLs were detected that significantly affected resistance
to SDM combined across seasons. Two of these mapped quite close together on chromosome 1, while the third one was on chromosome
9. The percentage of phenotypic variance explained by each QTL ranged from 12.4% to 23.8%. Collectively, the three QTLs identified
in this study explained 53.6% of the phenotypic variation in susceptibility to the infection. The three resistant QTLs appeared
to have additive effects. Increased susceptibility was contributed by the alleles of the susceptible parent. The detection
of more than one QTL supports the hypothesis that several qualitative and quantitative genes control resistance to P. sorghi. 相似文献
2.
H. C. LOHITHASWA K. JYOTHI K. R. SUNIL KUMAR PUTTARAMANAIK SHAILAJA HITTALMANI 《Journal of genetics》2015,94(4):741-748
Sorghum downy mildew caused by Peronosclerospora sorghi is a major disease of maize and resistance is under the control of polygenes which necessitated identification of quantitative-trait loci (QTLs) for initiating marker-assisted introgression of resistant QTLs in elite susceptible inbred lines. In the present study, QTLs for sorghum downy mildew (SDM) resistance in maize were identified based on cosegregation with linked simple sequence repeats in 185 F2 progeny from a cross between susceptible (CM500-19) and resistant (MAI105) parents. F3 families were screened in the National Sorghum Downy Mildew Screening Nursery during 2010 and 2011. High heritability was observed for the disease reaction. The final map generated using 87 SSR markers had 10 linkage groups, spanning a length of 1210.3 cM. Although, we used only 87 SSR markers for mapping, the per cent of genome within 20 cM to the nearest marker was 88.5. Three putative QTLs for SDM resistance were located on chromosomes 3 (bin 3.01), 6 (bin 6.01) and 2 (bin 2.02) using composite interval mapping. The locus on chromosome 3 had a major effect and explained up to 12.6% of the phenotypic variation. The other two QTLs on chromosomes 6 and 2 had minor effects with phenotypic variation of 7.1 and 2%. The three QTLs appeared to have additive effects on resistance. The QTLs on chromosomes 3 and 6 were successfully used in the marker-assisted selection programme for introgression of resistance to SDM in eight susceptible maize lines. 相似文献
3.
George ML Prasanna BM Rathore RS Setty TA Kasim F Azrai M Vasal S Balla O Hautea D Canama A Regalado E Vargas M Khairallah M Jeffers D Hoisington D 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2003,107(3):544-551
Downy mildew is one of the most destructive diseases of maize in subtropical and tropical regions in Asia. As a prerequisite for improving downy mildew resistance in maize, we analyzed quantitative trait loci (QTLs) involved in resistance to the important downy mildew pathogens--Peronosclerospora sorghi (sorghum downy mildew) and P. heteropogoni (Rajasthan downy mildew) in India, P. maydis (Java downy mildew) in Indonesia, P. zeae in Thailand and P. philippinensis in the Philippines--using a recombinant inbred line population derived from a cross between Ki3 (downy mildew resistant) and CML139 (susceptible). Resistance was evaluated as percentage disease incidence in replicated field trials at five downy mildew 'hotspots' in the four countries. Heritability estimates of individual environments ranged from 0.58 to 0.75 with an across environment heritability of 0.50. Composite interval mapping was applied for QTL detection using a previously constructed restriction fragment length polymorphism linkage map. The investigation resulted in the identification of six genomic regions on chromosomes 1, 2, 6, 7 and 10 involved in the resistance to the downy mildews under study, explaining, in total, 26-57% of the phenotypic variance for disease response. Most QTL alleles conferring resistance to the downy mildews were from Ki3. All QTLs showed significant QTL x environment interactions, suggesting that the expression of the QTL may be environment-dependent. A strong QTL on chromosome 6 was stable across environments, significantly affecting disease resistance at the five locations in four Asian countries. Simple-sequence repeat markers tightly linked to this QTL were identified for potential use in marker-assisted selection. 相似文献
4.
Nagabhushan H. C. Lohithaswa Anand S. Pandravada 《Molecular breeding : new strategies in plant improvement》2017,37(1):2
Sorghum downy mildew (SDM), caused by obligate biotrophic fungi Peronosclerospora sorghi, is an economically important disease of maize. The genetics of resistance was reported to be polygenic thereby necessitating identification of QTLs for resistance to SDM to initiate effective marker-assisted selection programs. During post-rainy and winter season of 2012, 645 F2:3 progeny families from the cross CML153 (susceptible) × CML226 (resistant) were screened for their reaction to SDM. Characterization of QTLs affecting resistance to SDM was undertaken using the genetic linkage map with 319 polymorphic SSR and SNP marker loci and the phenotypic data of F2:3 families. Three QTLs conferring resistance to SDM were consistently identified on chromosomes 2, 3 and 6 in both seasons. The resistant parent CML226 contributed all the QTL alleles conferring resistance to SDM. The major QTL located on chromosome 2 explained 38.68% of total phenotypic variation in the combined analysis with a LOD score of 9.12. All the three QTL showed partially dominant gene effects in combined analysis. The detection of more than one QTL supports the hypothesis that quantitative genes control resistance to P. sorghi. The generation was advanced to F6 using markers linked to major QTLs on chromosomes 2 and 3 to derive 33 SDM resistant maize inbred lines. 相似文献
5.
E. S. Jones C. J. Liu M. D. Gale C. T. Hash J. R. Witcombe 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1995,91(3):448-456
Quantitative trait loci (QTLs) for resistance to pathogen populations of Scelerospora graminicola from India, Nigeria, Niger and Senegal were mapped using a resistant x susceptible pearl millet cross. An RFLP map constructed using F2 plants was used to map QTLs for traits scored on F4 families. QTL analysis was carried out using the interval mapping programme Mapmaker/QTL. Independent inheritance of resistance to pathogen populations from India, Senegal, and populations from Niger and Nigeria was shown. These results demonstrate the existence of differing virulences in the pathogen populations from within Africa and between Africa and India. QTLs of large effect, contributing towards a large porportion of the variation in resistance, were consistently detected in repeated screens. QTLs of smaller and more variable effect were also detected. There was no QTLs that were effective against all four pathogen populations, demonstrating that pathotype-specific resistance is a major mechanism of downy mildew resistance in this cross. For all but one of the QTLs, resistance was inherited from the resistant parent and the inheritance of resistance tended to be the result of dominance or over-dominance. The implications of this research for pearl millet breeding are discussed. 相似文献
6.
Al-Chaarani GR Roustaee A Gentzbittel L Mokrani L Barrault G Dechamp-Guillaume G Sarrafi A 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2002,104(2-3):490-496
Partial resistance to downy mildew (Plasmopara halstedii) and to black stem (Phoma macdonaldii) in sunflower were investigated under natural field infection and a controlled growth chamber respectively. Genetic control
for resistance to the diseases was determined in recombinant inbred lines (RILs) and their two parents, ’PAC-2’ and ’RHA-266.’
The experiments were undertaken in a randomized complete block design with two replications, in a field severely infected
by downy mildew and in a controlled growth chamber with plants inoculated with an agressive French isolate of P. macdonaldii. Each replication consisted of three rows, 4.6-m long, giving 48 plants per RIL or parent in the field and 15 plants in the
growth chamber. Genetic variability was observed among the RILs for resistance to both diseases. When 10% of the selected
RILs were compared with the mean of the two parents genetic gain was significant for partial resistance to the diseases. Four
putative QTLs for resistance to downy mildew on linkage groups 1, 9 and 17 were detected using composite interval mapping.
The QTLs explained 54.9% of the total phenotypic variance. Major QTLs (dmr1–1 and dmr1–2) for resistance were found on linkage group 1 with up to 31% of the phenotypic variability explained by two peaks. QTL analysis
of resistance to black stem showed seven QTLs on linkage groups 3, 6, 8, 9, 11, 15 and 17. The detected QTLs together explain
92% of the phenotypic variation of the trait. Crosses between RILs contrasted for their resistance to downy mildew and black
stem, and exhibiting molecular polymorphism in detected QTLs, will be made in order to focus more-precisely on the genomic
region of interest.
Received: 28 February 2001 / Accepted: 14 June 2001 相似文献
7.
Sabry A Jeffers D Vasal SK Frederiksen R Magill C 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2006,113(2):321-330
Quantitative trait loci (QTLs) for downy mildew resistance in maize were identified based on co-segregation with linked restriction fragment length polymorphisms or simple sequence repeats in 220 F2 progeny from a cross between susceptible and resistant parents. Disease response was assessed on F3 families in nurseries in Egypt, Thailand, and South Texas and after inoculation in a controlled greenhouse test. Heritability of the disease reaction was high (around 93% in Thailand). One hundred and thirty polymorphic markers were assigned to the ten chromosomes of maize with LOD scores exceeding 4.9 and covering about 1,265 cM with an average interval length between markers of 9.5 cM. About 90% of the genome is located within 10 cM of the nearest marker. Three putative QTLs were detected in association with resistance to downy mildew in different environments using composite interval mapping. Despite environmental and symptom differences, one locus on chromosome 2 had a major effect and explained up to 70% of the phenotypic variation in Thailand where disease pressure was the highest. The other two QTLs on chromosome 3 and chromosome 9 had minor effects; each explained no more than 4% of the phenotypic variation. The three QTLs appeared to have additive effects on resistance, identifying one major gene and two minor genes that contribute to downy mildew resistance. 相似文献
8.
Jeuken M Lindhout P 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2002,105(2-3):384-391
Lactuca sativa (lettuce) is susceptible to Bremia lactucae (downy mildew). In cultivated and wild Lactuca species, Dm genes have been identified that confer race-specific resistance. However, these genes were soon rendered ineffective by adaptation of the pathogen. Lactuca saligna (wild lettuce) is resistant to all downy mildew races and can be considered as a non-host. Therefore, L. saligna might be an alternative source for a more-durable resistance to downy mildew in lettuce. In order to analyze this resistance, we have developed an F(2) population based on a resistant L. saligna x susceptible L. sativa cross. This F(2) population was fingerprinted with AFLP markers and tested for resistance to two Bremia races NL14 and NL16. The F(2) population showed a wide and continuous range of resistance levels from completely resistant to completely susceptible. By comparison of disease tests, we observed a quantitative resistance against both Bremia races as well as a race-specific resistance to Bremia race NL16 and not to NL14. QTL mapping revealed a qualitative gene ( R39) involved in the race-specific resistance and three QTLs ( RBQ1, RBQ2 and RBQ3) involved in the quantitative resistance. The qualitative gene R39 is a dominant gene that gives nearly complete resistance to race NL16 in L. saligna CGN 5271 and therefore it showed features similar to Dm genes. The three QTLs explained 51% of the quantitative resistance against NL14, which indicated that probably only the major QTLs have been detected in this F(2) population. The perspectives for breeding for durable resistance are discussed. 相似文献
9.
Flavia M. Moreira Alberto Madini Rosanna Marino Luca Zulini Marco Stefanini Riccardo Velasco Pal Kozma M. Stella Grando 《Tree Genetics & Genomes》2011,7(1):153-167
Two populations (Pop) segregating quantitatively for resistance to downy mildew (DM), caused by Plasmopara viticola, were used to construct genetic maps and to carry out quantitative trait locus (QTL) analysis. Pop1 comprised of 174 F1 individuals from a cross of ‘Moscato Bianco’, a susceptible Vitis vinifera cultivar, and a resistant individual of Vitis riparia. Pop2 consisted of 94 progeny from a cross of two interspecific hybrids, ‘VRH3082 1-42’ and ‘SK77 5/3’, with resistance traits
inherited from Vitis rotundifolia and Vitis amurensis, respectively. Resistance of progeny was measured in field and greenhouse conditions by visual evaluation of disease symptoms
on leaves. Linkage maps of 1037.2 and 651 cM were built essentially with simple sequence repeat markers and were enriched
with gene-derived single-strand conformational polymorphism and single-nucleotide polymorphism markers. Simple interval mapping
and Kruskall–Wallis analysis detected a stable QTL involved in field resistance to DM on linkage group (LG) 7 of the Pop1
integrated map co-localized with a putative Caffeoyl-CoA O-methyltransferase-derived marker. Additional QTLs were detected on LGs 8, 12 and 17. We were able to identify genetic factors
correlated with resistance to P. viticola with lower statistical significance on LGs 1, 6 and 7 of the Pop2 map. Finally, no common QTLs were found between the two
crosses analyzed. A search of the grapevine genome sequence revealed either homologues to non-host-, host- or defense-signalling
genes within the QTL intervals. These positional candidate genes may provide new information about chromosomal regions hosting
phenotypic loci. 相似文献
10.
Shuancang Yu Tongbing Su Shenghua Zhi Fenglan Zhang Weihong Wang Deshuang Zhang Xiuyun Zhao Yangjun Yu 《Molecular breeding : new strategies in plant improvement》2016,36(4):44
Specific-locus amplified fragment sequencing is a high-resolution method for genetic mapping, genotyping, and single nucleotide polymorphism (SNP) marker discovery. Previously, a major QTL for downy mildew resistance, BraDM, was mapped to linkage group A08 in a doubled-haploid population derived from Chinese cabbage lines 91–112 and T12–19. The aim of the present study was to improve the linkage map and identify the genetic factors involved in downy mildew resistance. We detected 53,692 high quality SLAFs, of which 7230 were polymorphic, and 3482 of the polymorphic markers were used in genetic map construction. The final map included 1064 bins on ten linkage groups and was 858.98 cM in length, with an average inter-locus distance of 0.81 cM. We identified six QTLs that are involved in downy mildew resistance. The four major QTLs, sBrDM8, yBrDM8, rBrDM8, and hBrDM8, for resistance at the seedling, young plant, rosette, and heading stages were mapped to A08, and are identical to BraDM. The two minor resistance QTLs, rBrDM6 (A06) and hBrDM4 (A04), were active at the rosette and heading stages. The major QTL sBrDM8 defined a physical interval of ~228 Kb on A08, and a serine/threonine kinase family gene, Bra016457, was identified as the possible candidate gene. We report here the first high-density bin map for Chinese cabbage, which will facilitate mapping QTLs for economically important traits and SNP marker development. Our results also expand knowledge of downy mildew resistance in Chinese cabbage and provide three SNP markers (A08-709, A08-028, and A08-018) that we showed to be effective when used in MAS to breed for downy mildew resistance in B. rapa. 相似文献
11.
Mohammad H. Borhan Edemar Brose Jim L. Beynon Eric B. Holub 《Molecular Plant Pathology》2001,2(2):87-95
Two accessions of Arabidopsis thaliana (Ksk-1 and Ksk-2) were used to identify and map three loci ( RAC1 , RAC2 and RAC3 ) of genes that confer R esistance to A lbugo c andida (white rust). The phenotypes associated with these genes were classified as either FN (necrotic f lecks on upper surface of cotyledons and n o blisters) for RAC2 and RAC3, or FYN ( f lecks surrounded by y ellowing and n o blisters) for RAC1 . Both phenotypes exhibited rapid death of host cells penetrated by the parasite (hypersensitive response), with callose deposition commonly encasing the haustorium. F6 recombinant inbred lines were produced specifically for the purpose of mapping each RAC locus relative to molecular markers. Dominant resistance at the locus RAC1 in Ksk-1 was previously mapped to chromosome 1 between RFLP markers m253 and m254, and co-segregating with a downy mildew resistance specificity RPP9 in the accession Wei-0. We report here a fine-scale map interval and co-segregating markers for this locus, which in turn enabled mapping of a previously unnoticed source of resistance in Ksk-1 designated RAC3 that exhibits an FN phenotype hyperstatic to the FYN phenotype of RAC1. RAC3 is closely linked to the RPP8/HRT on chromosome 5, a locus which contains specificities for resistance to downy mildew and turnip crinkle virus. Recombinant inbreds also enabled mapping of recessive resistance at RAC2 in Ksk-2 to the bottom arm of chromosome 3, in the 6 cM interval between two downy mildew resistance loci ( RPP1 and RPP13 ) . 相似文献
12.
13.
Genetic dissection of sex determinism, inflorescence morphology and downy mildew resistance in grapevine 总被引:1,自引:0,他引:1
Elisa Marguerit Christophe Boury Aurélie Manicki Martine Donnart Gisèle Butterlin Alice Némorin Sabine Wiedemann-Merdinoglu Didier Merdinoglu Nathalie Ollat Stéphane Decroocq 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2009,118(7):1261-1278
A genetic linkage map of grapevine was constructed using a pseudo-testcross strategy based upon 138 individuals derived from
a cross of Vitis vinifera Cabernet Sauvignon × Vitis riparia Gloire de Montpellier. A total of 212 DNA markers including 199 single sequence repeats (SSRs), 11 single strand conformation
polymorphisms (SSCPs) and two morphological markers were mapped onto 19 linkage groups (LG) which covered 1,249 cM with an
average of 6.7 cM between markers. The position of SSR loci in the maps presented here is consistent with the genome sequence.
Quantitative traits loci (QTLs) for several traits of inflorescence and flower morphology, and downy mildew resistance were
investigated. Two novel QTLs for downy mildew resistance were mapped on linkage groups 9 and 12, they explain 26.0–34.4 and
28.9–31.5% of total variance, respectively. QTLs for inflorescence morphology with a large effect (14–70% of total variance
explained) were detected close to the Sex locus on LG 2. The gene of the enzyme 1-aminocyclopropane-1-carboxylic acid synthase, involved in melon male organ development
and located in the confidence interval of all QTLs detected on the LG 2, could be considered as a putative candidate gene
for the control of sexual traits in grapevine. Co-localisations were found between four QTLs, detected on linkage groups 1,
14, 17 and 18, and the position of the floral organ development genes GIBBERELLIN INSENSITIVE1, FRUITFULL, LEAFY and AGAMOUS. Our results demonstrate that the sex determinism locus also determines both flower and inflorescence morphological traits. 相似文献
14.
Erik den Boer Koen T. B. Pelgrom Ningwen W. Zhang Richard G. F. Visser Rients E. Niks Marieke J. W. Jeuken 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2014,127(8):1805-1816
Key message
In a stacking study of eight resistance QTLs in lettuce against downy mildew, only three out of ten double combinations showed an increased resistance effect under field conditions.Abstract
Complete race nonspecific resistance to lettuce downy mildew, as observed for the nonhost wild lettuce species Lactuca saligna, is desired in lettuce cultivation. Genetic dissection of L. saligna’s complete resistance has revealed several quantitative loci (QTL) for resistance with field infection reductions of 30–50 %. To test the effect of stacking these QTL, we analyzed interactions between homozygous L. saligna CGN05271 chromosome segments introgressed into the genetic background of L. sativa cv. Olof. Eight different backcross inbred lines (BILs) with single introgressions of 30–70 cM and selected predominately for quantitative resistance in field situations were intercrossed. Ten developed homozygous lines with stacked introgression segments (double combinations) were evaluated for resistance in the field. Seven double combinations showed a similar infection as the individual most resistant parental BIL, revealing epistatic interactions with ‘less-than-additive’ effects. Three double combinations showed an increased resistance level compared to their parental BILs and their interactions were additive, ‘less-than-additive’ epistatic and ‘more-than-additive’ epistatic, respectively. The additive interaction reduced field infection by 73 %. The double combination with a ‘more-than-additive’ epistatic effect, derived from a combination between a susceptible and a resistant BIL with 0 and 30 % infection reduction, respectively, showed an average field infection reduction of 52 %. For the latter line, an attempt to genetically dissect its underlying epistatic loci by substitution mapping did not result in smaller mapping intervals as none of the 22 substitution lines reached a similar high resistance level. Implications for breeding and the inheritance of L. saligna’s complete resistance are discussed. 相似文献15.
Małgorzata Karbarz Mirosław Tyrka Anna Woźniak-Strzembicka Grzegorz Czajowski Agnieszka Wardyńska Dorota Tyrka Mirosław Pojmaj Maria Wędzony 《The Annals of applied biology》2020,177(2):223-231
Powdery mildew (PM) is a common disease caused by Blumeria graminis, which affects cereals and has recently adapted to triticale. Adult-plant resistance (APR) genes provide durable protection of crops from the disease. Quantitative trait loci corresponding to the APR effects were mapped in an F2 population of “Lamberto” (susceptible) × “Moderto” (resistant). A genetic map of winter triticale was constructed based on the segregation of 863 DArT, 38 microsatellite and 10 resistance gene analogue markers. Composite interval mapping (CIM) was applied to identify three QTLs for maximum disease severity (MDS) and two for the area under disease progress curve (AUDPC) conferring resistance to the powdery mildew on chromosomes: 6A, 7A, 1B and 4R. The 39% variation in AUDPC was explained by the main QTL localised on chromosome 4R. Genes coding TRIUR3 proteins, serine/threonine protein kinase and cell wall associated kinases were localised in silico within the QTL and alternative DNA markers were proposed for flexible use in laboratories of diversified throughput. 相似文献
16.
Genetic mapping and localization of a major QTL for seedling resistance to downy mildew in Chinese cabbage (Brassica rapa ssp. pekinensis) 总被引:1,自引:0,他引:1
Shuancang Yu Fenglan Zhang Renbo Yu Yanmin Zou Jiani Qi Xiuyun Zhao Yangjun Yu Deshuang Zhang Li Li 《Molecular breeding : new strategies in plant improvement》2009,23(4):573-590
Downy mildew caused by the fungus Peronospora parisitica is a serious threat to members of the Brassicaceae family. Annually, a substantial loss of yield is caused by the widespread
presence of this disease in warm and humid climates. The aim of this study was to localize the genetic factors affecting downy
mildew resistance in Chinese cabbage (Brassica rapa ssp. pekinensis). To achieve this goal, we improved a preexisting genetic map of a doubled-haploid population derived from a cross between
two diverse Chinese cabbage lines, 91-112 and T12-19, via microspore culture. Microsatellite simple sequence repeat (SSR)
markers, isozyme markers, sequence-related amplified polymorphism markers, sequence-characterized amplified region markers
and sequence-tagged-site markers were integrated into the previously published map to construct a composite Chinese cabbage
map. In this way, the identities of linkage groups corresponding to the Brassica A genome reference map were established. The new map contains 519 markers and covers a total length of 1,070 cM, with an
average distance between markers of 2.06 cM. All markers were designated as A1–A10 through alignment and orientation using
55 markers anchored to previously published B. rapa or B. napus reference maps. Of the 89 SSR markers mapped, 15 were newly developed from express sequence tags in Genbank. The phenotypic
assay indicated that a single major gene controls seedling resistance to downy mildew, and that a major QTL was detected on
linkage group A8 by both interval and MQM mapping methods. The RAPD marker K14-1030 and isozyme marker PGM flanked this major
QTL in a region spanning 2.9 cM, and the SSR marker Ol12G04 was linked to this QTL by a distance of 4.36 cM. This study identified
a potential chromosomal segment and tightly linked markers for use in marker-assisted selection to improve downy mildew resistance
in Chinese cabbage. 相似文献
17.
Sakata Y Kubo N Morishita M Kitadani E Sugiyama M Hirai M 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2006,112(2):243-250
A population of F7 recombinant inbred lines (RILs) was made from a cross between susceptible (‘Santou’) and resistant (PI197088-1) lines of
cucumber in order to study powdery mildew resistance loci. Susceptibility to powdery mildew in the F7 RIL individuals showed a continuous distribution from susceptible to resistant, suggesting that powdery mildew resistance
is controlled by quantitative trait loci (QTLs). A QTL analysis identified two and three loci for powdery mildew resistance
under 26 and 20°C conditions, respectively. One QTL was found in the same position under both temperature conditions. Therefore,
it is more likely that one major QTL acts under both temperature conditions and that other QTLs are specific to the two temperature
conditions. The above results suggest that the four QTLs are controlled in a different temperature manner, and that their
combination played an important role in expressing a high level of resistance to powdery mildew in this cucumber population.
Sequence-tagged site (STS) markers associated with each QTL were developed and would be useful for breeding a cucumber line
with a high level of powdery mildew resistance.
Y. Sakata and N. Kubo contributed equally to this work and are considered as first authors. 相似文献
18.
Khin Thanda Win Juan Vegas Chunying Zhang Kihwan Song Sanghyeob Lee 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2017,130(1):199-211
Key message
QTL mapping using NGS-assisted BSA was successfully applied to an F 2 population for downy mildew resistance in cucumber. QTLs detected by NGS-assisted BSA were confirmed by conventional QTL analysis.Abstract
Downy mildew (DM), caused by Pseudoperonospora cubensis, is one of the most destructive foliar diseases in cucumber. QTL mapping is a fundamental approach for understanding the genetic inheritance of DM resistance in cucumber. Recently, many studies have reported that a combination of bulked segregant analysis (BSA) and next-generation sequencing (NGS) can be a rapid and cost-effective way of mapping QTLs. In this study, we applied NGS-assisted BSA to QTL mapping of DM resistance in cucumber and confirmed the results by conventional QTL analysis. By sequencing two DNA pools each consisting of ten individuals showing high resistance and susceptibility to DM from a F2 population, we identified single nucleotide polymorphisms (SNPs) between the two pools. We employed a statistical method for QTL mapping based on these SNPs. Five QTLs, dm2.2, dm4.1, dm5.1, dm5.2, and dm6.1, were detected and dm2.2 showed the largest effect on DM resistance. Conventional QTL analysis using the F2 confirmed dm2.2 (R 2 = 10.8–24 %) and dm5.2 (R 2 = 14–27.2 %) as major QTLs and dm4.1 (R 2 = 8 %) as two minor QTLs, but could not detect dm5.1 and dm6.1. A new QTL on chromosome 2, dm2.1 (R 2 = 28.2 %) was detected by the conventional QTL method using an F3 population. This study demonstrated the effectiveness of NGS-assisted BSA for mapping QTLs conferring DM resistance in cucumber and revealed the unique genetic inheritance of DM resistance in this population through two distinct major QTLs on chromosome 2 that mainly harbor DM resistance.19.
Konstantin Divilov Paola Barba Lance Cadle-Davidson Bruce I. Reisch 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2018,131(5):1133-1143