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1.
Crown rust resistance is an important selection criterion in ryegrass breeding. The fungal disease caused by P. coronata causes yield loss and a reduced quality of the fodder crop. Molecular markers were used to unravel the genomic organization of crown rust resistance in a segregating L. perenne population. Two genomic regions involved in crown rust resistance were identified that together explained 35% of the phenotypic variance present. Bulked segregant analysis in combination with AFLP markers was a suitable method to identify DNA markers associated with genomic regions of major effect. One cluster of AFLP markers explained 6.1% of the variance and mapped to linkage group 2, a genomic region known to contain crown rust resistance genes. A second cluster of AFLP markers detected a novel genomic region of major effect that explained 27.7% of the phenotypic variance in crown rust resistance. This cluster was unlinked to the cluster on linkage group 2. Divergent selections performed within the segregating F1 population on the basis of genotype and phenotype revealed that the markers associated with crown rust resistance identified in this study have potential for marker assisted selection. Selection of plants on the basis of markers was more straightforward than the selection on the basis of phenotype.  相似文献   

2.
Bulked segregant analysis was utilized to identify random amplified polymorphic DNA (RAPD) markers linked to genes for specific resistance to a rust pathotype and indeterminate growth habit in an F2 population from the common bean cross PC-50 (resistant to rust and determinate growth habit) × Chichara 83-109 (susceptible to rust and indeterminate growth habit). Six RAPD markers were mapped in a coupling phase linkage with the gene ( Ur-9) for specific rust resistance. The linkage group spanned a distance of 41 cM. A RAPD marker OA4.1050 was the most closely linked to the Ur-9 gene at a distance of 8.6 cM. Twenty-eight RAPD markers were mapped in a coupling phase linkage with the gene ( Fin) for indeterminate growth habit. The linkage group spanned a distance of 77 cM. RAPD markers OQ3.450 and OA17.600 were linked to the Fin allele as flanking markers at a distance of 1.2 cM and 3.8 cM, respectively. The RAPD markers linked to the gene for specific rust resistance of Andean origin detected here, along with other independent rust resistance genes from other germplasm, could be utilized to pyramid the different genes into a bean cultivar for durable rust resistance.  相似文献   

3.
Development of molecular markers for different economically important traits in cultivated groundnut has progressed at slow pace. Although many genomic SSR markers were developed in both the wild and cultivated groundnut, the genetic linkage map in the species is still not saturated. Availability of a large number of ESTs in GenBank opened up the possibility of integrating new markers and to identify markers closely linked to agronomic traits. EST-SSR markers are also considered as genic molecular markers. In this study, 259 EST-SSR markers were developed by mining 5,184 Arachis hypogaea ESTs from NCBI database. These EST-SSRs and 34 resistance gene candidate markers were used for association and genetic mapping of rust resistance in cultivated groundnut. From these, Cer2, SSR_GO340445, SSR_HO115759, SSR_GO341324 and RGC 2 had a significant association with rust resistance based on locus-by-locus AMOVA and/or Kruskal?CWallis ANOVA. Some of these associated markers also had protein activity related to biotic stress responses. Through genetic mapping, EST-SSR markers SSR_GO340445 and SSR_HO115759 were found closely linked to a rust resistance gene at 1.9 and 3.8?cM distances, respectively. These markers are thus suitable candidates for marker assisted selection in groundnut. The tight linkage of SSR_GO340445 would be helpful to screen BAC clones and to isolate rust resistance gene in groundnut.  相似文献   

4.
B. Schejbel    L. B. Jensen    Y. Xing    T. Lübberstedt 《Plant Breeding》2007,126(4):347-352
Crown rust is an economically devastating disease of perennial ryegrass. Both artificial crown rust inoculations, with the possibility of several selection cycles in one year, as well as marker-assisted selection can be used for more efficient breeding of new resistant cultivars. The objective of this study was to map quantitative trait loci (QTL) for response to crown rust infection in perennial ryegrass. In order to identify relevant markers for response to crown rust infection, QTL mapping was performed on a ryegrass mapping population which was evaluated for resistance in the field for two years as well as by artificial pathogen inoculations using a detached leaf assessment. The broad sense heritability values for the field, detached leaf and combined assays were 0.42, 0.56, and 0.64, respectively, indicating a good potential for selection for crown rust resistance. A total of six QTLs were identified and mapped to linkage groups (LG) LG1, LG4 and LG5, explaining between 6.8% and 16.4% of the total phenotypic variation.  相似文献   

5.
Eucalypts are susceptible to a wide range of diseases. One of the most important diseases that affect Eucalyptus plantations worldwide is caused by the rust fungus Puccinia psidii. Here, we provide evidence on the complex genetic control of rust resistance in Eucalyptus inter-specific hybrids, by analyzing a number of full-sib families that display different patterns of segregation for rust resistance. These families are totally unrelated to those previously used in other inheritance studies of rust resistance. By using a full genome scan with 114 genetic markers (microsatellites and expressed sequence tag derived microsatellites) we also corroborated the existence and segregation of a resistance locus, explaining 11.5% of the phenotypic variation, on linkage group 3, corresponding to Ppr1. This find represents an additional validation of this locus in totally unrelated pedigree. We have also detected significant additive × additive digenic interactions with LOD >10.0 on several linkage groups. The additive and epistatic QTLs identified explain between 29.8 and 44.8% of the phenotypic variability for rust resistance. The recognition that both additive and non-additive genetic variation (epistasis) are important contributors to rust resistance in eucalypts reveals the complexity of this host-pathogen interaction and helps explain the success that breeding has achieved by selecting rust-resistant clones, where all the additive and non-additive effects are readily captured. The positioning of epistatic QTLs also provides starting points to look for the underlying genes or genomic regions controlling this phenotype on the upcoming E. grandis genome sequence.  相似文献   

6.
由黑顶柄锈菌(Puccinia melanocephala H. Sydow ＆ P. Sydow)引起的甘蔗褐锈病是危害中国甘蔗生产的主要病害之一。为了鉴定和发掘抗褐锈病新基因,防止褐锈病爆发流行和保证甘蔗安全生产,本研究以杂交组合‘粤糖03-393’× ‘ROC 24’抗感分离真实性F1代群体为材料,构建抗感基因池,合成449对引物对抗感亲本及抗感基因池进行抗、感连锁SSR分子标记筛选。结果表明,25对引物在抗感亲本间有多态性,其中4对引物(SMC236CG、SCESSR0928、SCESSR0636、SCESSR2551)在抗感亲本及抗感池间有多态性,初步判定这4个SSR标记在染色体上的位点可能与抗褐锈病新基因存在连锁关系。研究结果为后续开展抗褐锈病新基因定位、为中国甘蔗褐锈病防控及抗病育种奠定了良好的基础。  相似文献   

7.
Summary Molecular mapping is a promising strategy for studying and understanding traits with complex genetic control, such as partial resistance to oat crown rust. The objectives of this research were to develop molecular maps from the progenies of the cross UFRGS7 (susceptible) × UFRGS910906 (partially resistant) and to identify QTLs (quantitative trait loci) associated to partial resistance to oat crown rust in two generations of that population.DNA of 86 genotypes of the F2 and 90 genotypes of the F6 UFRGS7 × UFRGS910906 population were used to generate AFLP markers. Molecular maps were constructed using Mapmaker Exp. 3.0 and QTLs for partial resistance to oat crown rust were identified with Mapmaker/QTL software. Five hundred and fifty seven markers in the F2 and 243 markers in the F6 generations were identified. The F2 map integrated 250 markers in 37 linkage groups. The F6 map integrated 86 markers in 17 linkage groups.Five QTLs were identified for partial resistance to oat crown rust in the F2 generation and three QTLs in the F6. The QTL identified on F6 through the PaaaMctt340 AFLP marker showed consistency across two environments and two generations (F4 and F6), and appear to have potential for marker-assisted selection in oat.  相似文献   

8.
小麦叶锈病（leaf rust）是对小麦危害最严重的真菌病害之一,原菌群体中新致病菌类型的不断出现导致部分抗叶锈病基因的抗性功能逐步丧失,不断发掘和研究利用新抗源基因、培育种植抗病品种是控制该病害最有效的方法。周麦22在田间成株期对叶锈病表现出良好的抗性,为解析周麦22成株期抗叶锈病的遗传基础,将周麦22与铭贤169杂交构建遗传群体,获得255个F2:3家系群体,经2个年度的大田成株期抗叶锈病鉴定,并利用复合区间作图法对该群体的抗叶锈病QTL进行定位分析。结果显示,该群体成株期检测到2个抗叶锈病QTL位点,分别位于1BL和2BS染色体上,命名为QLr.hebau-1BL和QLr.hebau-2BS,分别解释9.62%~11.88%和16.89%~20.99%的表型变异,该位点对叶锈病抗性表现稳定,均来自抗病品种周麦22。初步的遗传定位结果显示,QLr.hebau-2BS可能为已知抗叶锈病基因LrZH22,而QLr.hebau-1BL是新的抗病QTL。  相似文献   

9.
Heterogeneous inbred families segregating for rust resistance were identified from the two crosses involving susceptible (TAG 24 and TG 26) and resistant (GPBD 4) varieties of peanut. Rust‐resistant (less than score 5) and rust‐susceptible (more than score 5) plants were identified in each HIF and evaluated under rust epiphytotic conditions. The set of plants belonging to the same HIF, but differing significantly in rust resistance, not in other morphological and productivity traits, was regarded as near‐isogenic lines (NILs). Largely, rust‐resistant NILs had GPBD 4‐type allele, and susceptible NILs carried either TAG 24 or TG 26‐type allele at the three SSR loci (IPAHM103, GM1536 and GM2301) linked to a major genomic region governing rust resistance. Comparison of the remaining genomic regions between the NILs originating from each of the HIFs using transposon markers indicated a considerably high similarity of 86.4% and 83.1% in TAG 24 × GPPBD 4 and TG 26 × GPBD 4, respectively. These NILs are useful for fine mapping and expression analysis of rust resistance.  相似文献   

10.
Groundnut rust (Puccinia arachidis Speg.) is an important air borne pathogen, which causes substantial losses in groundnut yield and quality. Although large numbers of accessions were identified as rust resistant in wild, interspecific derivative and cultivated groundnut species, transfer of resistance to well-adapted cultivars is limited due to linkage drag, which worsens yield potential and market acceptance. A F2 mapping population comprising 117 individuals was developed from a cross between the rust resistant parent VG 9514 and rust susceptible parent TAG 24. Rust resistance was governed by single dominant gene in this cross. We identified 11 (out of 160) RAPD primers that exhibited polymorphism between these two parents. Using a modified bulk segregant analysis, primer J7 (5′CCTCTCGACA3′) produced a single coupling phase marker (J71350) and a repulsion phase marker (J71300) linked to rust resistance. Screening of the entire F2 population using primer J7 revealed that the coupling phase marker J71350 was linked with the rust resistance gene at a distance of 18.5 cM. On the other hand, the repulsion phase marker J71300 was completely linked with rust resistance. Additionally, both J71300 (P = 0.00075) and J71350 (P < 0.00001) were significantly associated with the rust resistance. Marker J71300 identified all homozygous rust resistant genotypes in the F2 population and was present in all the eight susceptible genotypes tested for validation. Thus, J71300 should be applicable for marker-assisted selection (MAS) in the groundnut rust resistance breeding programme in India. To the best of our knowledge this is the first report on the identification of RAPD markers linked to rust resistance in groundnut.  相似文献   

11.
Many stem rust resistance genes have been formally named in wheat. Adult plant stem rust resistance gene Sr2 was mapped in the short‐arm of chromosome 3B. Stripe rust resistance gene Yr57, identified in Aus91463, was mapped about 5 cM away from Sr2 based on its linkage with Sr2‐linked marker gwm533. The objective of this study was to combine Sr2 and Yr57 in a single genotype. A mapping population containing 107 recombinant inbred lines was developed from a cross between Aus91463‐Yr57 and Hartog‐Sr2. This population was tested at the seedling stage in the glasshouse for variation in stripe rust response, and high temperature induced Sr2‐linked seedling chlorosis. The RIL population was screened for Sr2‐linked pseudo black chaff phenotype at the adult plant stage in field. Five recombinants carrying Sr2 and Yr57 in coupling were detected using phenotypic and marker data. Four recombinants also carried leaf rust resistance gene Lr23 from Aus91463. These recombinants are being used as triple rust resistance source in the Australian Cereal Rust Control Program.  相似文献   

12.
Genetic mapping for resistance to gray leaf spot in maize   总被引：1，自引：0，他引：1  
The molecular marker technology has been used on mapping of quantitative trait loci (QTLs) associated with plant resistance. The objectives of this research were to estimate genetic parameters and to map genomic regions involved in the resistance to gray leaf spot in maize. Ninety F3 families from the BS03 (susceptible) and BS04 (resistant) cross were used. Field trials were performed using a 10 × 10 square lattice design with three replications. Data from 62 SSR markers were used for linkage analysis. The locations of the QTLs on the linkage groups were determined by composite interval mapping method and the phenotypic variance explained by each marker was determined by regression analysis. Several QTLs associated to disease resistance were identified in the population BS03 × BS04. Some QTLs showed significant effects over the different environments studied. The existence of significant QTLs in common among different environments indicates these genomic regions as possible new tools for marker-assisted selection in maize breeding programs.  相似文献   

13.
Marker-trait associations identified in diverse germplasm can be exploited in crop improvement programs. An attempt to establish such associations was made by evaluating 205 wheat landraces for stripe rust, leaf rust and stem rust responses in the field over three crop seasons. Diversity arrays technology was used to genotype the landraces and associations were identified using a single-marker scan. Sixty-eight markers were significantly associated with rust resistance. Several significantly associated loci coincided with the presence of known major genes or QTL for rust resistance. In contrast, many marker-rust response associations identified in this analysis for each of the three rust diseases uncovered new loci. Dual associations; stripe rust-leaf rust (1AL, 2BS, 2BL, 3DL, 5BS, 6BS and 7DL), leaf rust-stem rust (5BL) and stripe rust-stem rust (4BL and 6AS) resistance were also observed. These associations could enable a cost-effective targeted mapping of dual rust resistance. Some marker-trait associations identified in this study have been validated through genetic analyses and formal naming of resistance loci.  相似文献   

14.
Stripe rust is a devastating disease in common wheat (Triticum aestivum) worldwide. Growing cultivars with adult-plant resistance (APR) is an environmental friendly approach that provides long-term protection to wheat from this disease. Wheat cultivar Yaco“S” showed a high level of APR to stripe rust in the field from 2008 to 2014. The objective of this study was to detect the major quantitative trait loci (QTL) for APR to stripe rust in Yaco“S”. One hundred and eighty-four F2:3 lines were developed from a cross between Yaco“S” and susceptible cultivar Mingxian169. Illumina 90K and 660K single nucleotide polymorphism (SNP) chips were implemented to bulked pools and their parents to identify SNPs associated with the major QTL. A high-density linkage map was constructed using simple sequence repeat (SSR) and SNP markers. Inclusive composite interval mapping detected a major effect QTL Qyryac.nwafu-2BS conferring stable resistance to stripe rust in all tested environments. Qyryac.nwafu-2BS were mapped to a 1.3 cm interval and explained 17.3–51.9% of the phenotypic variation. Compared with stripe rust resistance genes previously mapped to chromosome 2B, Qyryac.nwafu-2BS is likely a new APR gene to stripe rust. Combining SNP iSelect assay and kompetitive allele specific PCR technology, we found that the APR gene could be rapidly and accurately mapped and it is useful for improving stripe rust resistance in wheat breeding.  相似文献   

15.
While studying powdery mildew resistance in a recombinant line (code 81882) derived from a Hordeum vulgare (cv. ‘Vada’) ×Hordeum bulbosum hybrid, a low infection type of resistance to leaf rust was observed. To determine the mode of inheritance of the leaf rust resistance and whether there was linkage between the two resistances, F2 and F3 progenies from crosses between 81882 and ‘Vada’ were inoculated with the leaf rust and powdery mildew pathogens. Southern blots were prepared using restricted DNA extracted from leaves of 82 F2 plants and four chromosome 2HS sequences were hybridized with the blots to define the length of the introgression. The leaf rust resistance appears to be inherited as a single dominant gene on chromosome 2HS, which co-segregates with the powdery mildew resistance. There was an almost complete association between the resistances and the respective molecular markers, but it is likely that the strong linkage results from the frequent inheritance of the introgressed H. bulbosum DNA as an intact segment of chromatin with only low levels of recombination within the segment.  相似文献   

16.
郑麦103是一个高抗条锈病的小麦新品种,为明确其携带的抗病基因,用郑麦103与感条锈病品种农大399杂交构建分离群体,用条锈菌CYR32、CYR33和CRY34(V26)混合菌系进行田间接种和成株期抗性鉴定,对214个F2:3家系的条锈病抗性进行遗传分析,初步确定郑麦103的抗条锈性由单个主效基因控制,定名为Yr ZM103。通过BSR-Seq技术开发了6个与Yr ZM103紧密连锁的分子标记,将Yr ZM103定位于染色体臂7BL分子标记ZM215和ZM221之间,遗传距离分别为11.8 c M和6.9 c M。利用7BL染色体上与其他已知抗条锈病基因紧密连锁的分子标记进行比较作图,发现Yr ZM103是不同于7BL末端其他抗条锈病基因的新基因。  相似文献   

17.
We developed 178 recombinant inbred lines from a southern‐by‐spring oat population designated as “TxH.” These lines were genotyped to generate a high‐quality linkage map that resolved 6,902 markers into 21 linkage groups that matched closely with the latest hexaploid oat consensus map. Three major quantitative trait loci (QTLs) affecting heading date were found in locations that are consistent with known QTLs and candidate genes, and two other QTLs affecting heading date were found in novel locations. Five QTLs affecting plant height were found. Both sets of QTLs are responsible for transgressive segregation observed for these two traits. Four QTLs affecting resistance to crown rust, caused by the pathogen Puccinia coronata f. sp. avenae, were identified. Two of these QTLs are consistent with known clusters of rust resistance genes, while two may represent new locations of novel rust resistance genes. A complete set of SNP sequences suitable for generating markers for molecular selection is provided.  相似文献   

18.
G. Wricke    P. Dill  P. Senft 《Plant Breeding》1996,115(1):71-73
DNA samples from an F2 progeny which segregated for resistance to powdery mildew were bulked for resistant and susceptible individuals. In a segregant analysis, genomic rye probes which had been localized previously in a linkage map of rye were systematically screened for polymorphisms between these bulks. An RFLP marker located on linkage group 1RS was found to be tightly linked to a dominant mildew resistance gene. This is the first publication mapping a major gene for mildew resistance in rye.  相似文献   

19.
Hop with powdery mildew [HPM: caused by Podosphaera macularis (Wallr.) U. Braun & S. Takam.] results in significant losses in hop production by reducing yield and quality. One means of increasing yield and quality is the production of resistant hop lines. Breeding for resistance can be significantly improved and accelerated by use of marker-assisted selection. The objective of this preliminary study was to identify QTLs and markers for genetic resistance to HPM. A bi-parental mapping population between the resistant line “Newport” and susceptible line ‘21110M’. Phenotypic data was scored under controlled greenhouse conditions. Significant differences among offspring were observed and disease resistance did not follow a distinct binomial distribution, suggesting quantitative genetic control. Genotyping-by-sequencing resulted in approximately 375 K SNP markers, which were filtered down to 2263 markers mapped to 10 linkage groups. Interval Mapping identified four QTLs with one on linkage group 1 and three located on linkage group 6. Composite interval mapping identified three QTLs, all located on linkage group 6. Mixed linear models identified 15 markers associated with expression of resistance to HPM. Three of these 15 SNPs were also identified in QTL-CIM analysis. Evaluation of the scaffolds containing the significant SNP markers identified seven putative genes—several of which appear involved in disease resistance in other plant species. The SNP markers identified in this study still require validation in unrelated populations prior to implementation in breeding programs.  相似文献   

20.
由Puccinia triticina引起的叶锈病是小麦主要病害之一, 引进种质C615具有叶锈病成株期抗性, 但其抗病性遗传机制尚不清楚。本研究以抗病亲本C615与高感叶锈病亲本宁麦18构建的F2:7代重组自交系群体为材料, 利用337对多态性SSR标记构建遗传连锁图谱, 结合2016、2017连续两年的叶锈病鉴定结果进行复合区间作图, 结果在1BL、2DS、3BS、4DL和6BS染色体上共发现了5个抗性QTL, 暂命名为QLr.njau-1BL、QLr.njau-2DS、QLr.njau-3BS、QLr.njau-4DL和QLr.njau-6BS。其中, QLr.njau-1BL、QLr.njau-3BS和QLr.njau-4DL在两年均被检测到, 分别解释10.1%~15.7%、10.9%~13.5%和8.2%~9.0%的表型变异; 另2个QTL只在一年被检测到, 解释6.2%和9.2%的表型变异。除QLr.njau-2DS外的4个抗性QTL均来源于抗病亲本C615。QLr.njau-1BL和QLr.njau-4DL分别与已报道的慢病性基因Lr46、Lr67在同一区域, QLr.njau-3B可能为一个新的抗叶锈病QTL。此外, 本研究在C615/扬麦13 (轮回亲本)BC4F5回交群体中选出了15个农艺性状优良且抗叶锈病的株系, 利用与C615所含抗性QTL紧密连锁的7个SSR标记对其进行基因型检测, 结果显示所有这15个株系均含有来自C615的抗性QTL, 且有3个株系聚合了全部抗性位点, 表明C615可作为抗源亲本用于高产、抗病育种。本研究结果将为分子标记选育抗叶锈品种提供材料和技术支撑。  相似文献   

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