Mildew In Wheat Research Articles

Dynamic QTL for adult plant resistance to powdery mildew in common wheat (Triticum aestivum L.).

Agriculture will benefit from a rigorous characterization of genes for adult plant resistance (APR) since this gene class was recognized to provide more durable protection from plant diseases. The present study reports the identification of APR loci to powdery mildew in German winter wheat cultivars Cortez and Atlantis. Cortez was previously shown to carry all-stage resistance gene Pm3e. To avoid interference of Pm3e in APR studies, line 6037 that lacked Pm3e but showed field resistance from doubled-haploid (DH) population Atlantis/Cortez was used in two backcrosses to Atlantis for the establishment of DH population 6037/Atlantis//Atlantis. APR was assessed in the greenhouse 10, 15, and 20days after inoculation (dai) from the 4-leaf stage onwards and combined with single-nucleotide polymorphism data in a genome-wide association study (GWAS) and a linkage map-based quantitative trait loci (QTL) analysis. In GWAS, two QTL were detected: one on chromosome 1BL 10dai, the other on chromosome 2BL 20dai. In conventional QTL analysis, both QTL were detected with all three disease ratings: the QTL on chromosome 1BL explained a maximum of 35.2% of the phenotypic variation 10dai, whereas the QTL on chromosome 2BL explained a maximum of 43.5% of the phenotypic variation 20dai. Compared with GWAS, linkage map-based QTL analysis allowed following the dynamics of QTL action. The two large-effect QTL for APR to powdery mildew with dynamic gene action can be useful for the enhancement of wheat germplasm.

Control of powdery mildew (Blumeria graminis spp.) in cereals by Serenade®ASO (Bacillus amyloliquefaciens (former subtilis) strain QST 713)

Powdery mildew (Blumeria graminis f.sp. tritici, f.sp. hordei, f.sp. avenae) is an important disease in cereal crops causing significant yield reductions, if not effectively controlled. The biofungicide Bacillus amyloliquefaciens (former subtilis) strain QST 713 suspension concentrate (Serenade®ASO) was investigated for its potential as a control agent against powdery mildew in winter wheat, spring barley, oats and triticale. Serenade®ASO reduced the severity of powdery mildew, providing moderate control in the range of 20–65%. The efficacy was highest at the earlier assessments and less pronounced at later assessments. With a few exceptions, no clear dose-response was seen between using 1, 2, 4, 6 or 8 L/ha Serenade®ASO applied four times at 8–10-day intervals. The efficacy was more variable compared with chemical references. Yield responses were positive following treatments. However, the yield increase by Serenade®ASO was insignificant and significantly inferior to that of prothioconazole. In a few cases, the use of Serenade®ASO in combination with the adjuvant Silwet®Gold improved the efficacy, but the results were inconsistent. The preventive and curative application of Serenade®ASO was tested at three dose rates in an artificially inoculated wheat and barley greenhouse pot trial. These trials confirmed the lack of a clear dose-response but confirmed that timing has a major impact on control, with the best control obtained when application took place on the day of inoculation in wheat and 0–2 days after inoculation in barley. This study revealed that powdery mildew challenges Serenade®ASO as a stand-alone control measure. The results show that further research is needed for the promotion of biofungicides as part of an integrated disease management approach in cereal diseases.

Interactions among Fungal Community, Fusarium Mycotoxins, and Components of Harvested Wheat under Simulated Storage Conditions.

Economic loss of postharvest wheat under poor storage conditions due to fungal spoilage and mycotoxin contamination is severe. In order to study the influencing factors of the aggravation of mildew in natural wheat during storage, we assessed changes in Fusarium mycotoxins by high performance liquid chromatography, changes in fungal communities by high-throughput sequencing, and changes in biochemical components in wheat stored under artificial simulation conditions. Deoxynivalenol was the dominant Fusarium mycotoxin, reaching 1103 μg/kg at 25 °C with 75% relative humidity after 30 weeks. Under these conditions, Fusarium dominated the fungal communities, and Fusarium graminearum was significantly negatively correlated with glutenin (p < 0.05). Low storage temperatures and low humidity result in lower levels of Fusarium mycotoxins. Different fungi tended to consume different wheat components, and the interaction between environmental and biological factors eventually leads to the deterioration of wheat quality. These findings might provide valuable information for control strategies of mildew occurrence during grain storage.

Intercropping cereals with faba bean reduces plant disease incidence regardless of fertilizer input; a meta-analysis

Ecological intensification of agriculture calls for ecological mechanisms to replace anthropogenic inputs. Cereal/legume intercropping increases yields due to species complementarities, it produces high protein food and feed, and it reduces the need for artificial N fertilizer because legumes fix N biologically. In addition, intercropping has the potential to suppress plant diseases, but its efficacy for disease suppression in cereal/legume mixtures has not been well characterized quantitatively. Here we conducted meta-analysis to quantify the disease suppressive effect of intercropping cereals with legumes at different levels of N fertilizer. Intercropping reduced disease incidence (measured by the odds ratio of disease occurrence) by 45% on average. This reduction was significant (P < 0.01) for four out of six studied pathogens: yellow rust (Puccinia striiformis f.sp. tritici) and mildew (Blumeria graminis) in wheat (Triticum aestivum), and chocolate spot (Botrytis fabae) and Fusarium wilt (Fusarium oxysporum) in faba bean (Vicia faba). Disease reduction was marginally significant for yellow rust in barley (Puccinia striiformis f.sp. hordei) (P < 0.10) and not significant for bean rust (Uromyces fabae). The reduction in disease incidence was greatest during the early stages of epidemics. N fertilizer strongly increased the incidence of powdery mildew of wheat, but it did not affect the incidence of the other diseases and it did not affect the effectiveness of intercropping as a management strategy for disease control. While nitrogen input increased powdery mildew incidence in both sole and intercropped wheat, the incidence was lower in the intercropped than sole wheat at all levels of N input. The disease suppressive effect of intercropping on wheat powdery mildew or any other disease was not affected by the amount of nitrogen fertilizer. The results show that intercropping has a substantial and consistent effect on disease incidence in cereal/faba bean mixtures across studies, but is not sufficient to provide complete disease control. Intercropping is therefore best used as a component in an integrated approach for managing plant diseases.

Study of Resistance of Common Winter Wheat Lines to the Fusarium Head Blight (Fusarium Culmorum)

The study includes 22 lines and varieties of common winter wheat, created in the crop breeding program in IPGR Sadovo and varieties Sadovo and Enola as standards. The trials were conducted during the period 2012-2015 in the infectious field of the Institute. A comparative variety trial was performed in three replicates of the infectious field at the Institute. The sowing was done using the Simson (1969) nesting method (circular sowing). The aim of the study was to investigate the resistance of the breeding materials to the fusarium head blight (Fusarium culmorum). The results showed that there are no immune varieties and lines to the studied phytopathogen. Two common winter wheat lines – PP 787 and BC 7, fall into the group of resistant genotypes. Into the medium sensitive breeding materials group refer the lines DB/A 458, DB 223 and the Fermer variety. The biggest group includes fifteen sensitive genotypes, representing 62.5% of the total number of the study materials. Highly sensitive genotypes to Fusarium culmorum were not reported. The correlation between the fusarium head blight (FHB) and the other economically important diseases (brown rust and powdery mildew) of common winter wheat has been established.

TaNAC6s are involved in the basal and broad-spectrum resistance to powdery mildew in wheat

NACs are important transcriptional factors involved in growth and development as well as responses to abiotic and biotic stresses in plants. In this study, TaNAC6 was identified as a differentially expressed gene between two lines with broad-spectrum resistance to powdery mildew, NAU9918 and OEStpk-V, and their corresponding susceptible isogenic lines, SM-1 and Yangmai158, after Bgt inoculation by transcriptome analysis. Then, three homoeologous genes of TaNAC6 were cloned and named as TaNAC6-A, TaNAC6-B and TaNAC6-D, respectively. Each member of TaNAC6s was subcellular localized to the nucleus and displayed the transcriptional activation activity. However, the responses of them to pathogens and phytohormones were different. Transient overexpression of each TaNAC6 reduced the haustorium index of Yangmai158, and stable transformation of TaNAC6-A enhanced its resistance against Bgt, implying that TaNAC6s play important roles in basal resistance. Silencing of TaNAC6s compromised the resistance of OEStpk-V and NAU9918 suggesting that TaNAC6s play positive roles in the broad-spectrum resistance against Bgt. TaNAC6s might be induced by JA and then feedback regulate the JA pathway leading to improved resistance to Bgt. The role of TaNAC6s and their orthologous genes HvNAC6 and ATAF1 in the powdery mildew resistance implied these NAC6 genes share a common signal pathway across species.

Molecular mapping of two quantitative trait loci for adult-plant resistance to powdery mildew in common wheat (Triticum aestivum L.)

Powdery mildew is one of the major wheat diseases in regions with maritime or semi-continental climate and can strongly affect grain yield. Breeding wheat varieties with quantitative resistance to powdery mildew would be relatively more durable and promising than varieties with only major resistance genes (Pm genes). The chief aim of the present study is to map the quantitative trait loci (QTLs) for adult plant resistance (APR) to powdery mildew. A population of 176 recombinant inbred lines was developed from a cross of “Shannong 0431 × Lumai 21” (SN0431 × LM21) and evaluated for disease severity of powdery mildew under two cropping seasons. Two major QTLs (QPm.sdau-2A and QPm.sdau-2B) for APR to powdery mildew were mapped on chromosomes 2A and 2B, which were contributed by LM21 and SN0431. The molecular markers associated with the QTLs will be useful for selecting partial and potentially durable resistance genes against powdery mildew.

Proteomic analysis of the impacts of powdery mildew on wheat grain

Powdery mildew of wheat is one of the major foliar diseases, causing significant yield loss and flour quality change. In this study, grain protein and starch response to powdery mildew infection were investigated. Total protein, glutenin and gliadin exhibited a greater increase in grains from infected wheat, while the content of total starch and amylopectin was decreased. Comparative proteomic analysis demonstrated that the overabundant protein synthesis-related proteins might facilitate the accumulation of storage proteins in grains from infected plants. The significant increase in triticin, serpin and HMW-GS in grains from infected wheat might relate to the superior gluten quality. In addition, overabundant carbohydrate metabolism-related proteins in grains from infected wheat were conducive to the depletion of starch, whereas the decreased abundance of ADP glucose pyrophosphorylase might be related to the deficiency of starch synthesis. These results provide a deeper understanding on the change of wheat quality under powdery mildew infection.

TaEDS1 genes positively regulate resistance to powdery mildew in wheat.

Three EDS1 genes were cloned from common wheat and were demonstrated to positively regulate resistance to powdery mildew in wheat. The EDS1 proteins play important roles in plant basal resistance and TIR-NB-LRR protein-triggered resistance in dicots. Until now, there have been very few studies on EDS1 in monocots, and none in wheat. Here, we report on three common wheat orthologous genes of EDS1 family (TaEDS1-5A, 5B and 5D) and their function in powdery mildew resistance. Comparisons of these genes with their orthologs in diploid ancestors revealed that EDS1 is a conserved gene family in Triticeae. The cDNA sequence similarity among the three TaEDS1 genes was greater than 96.5%, and they shared sequence similarities of more than 99.6% with the respective orthologs from diploid ancestors. The phylogenetic analysis revealed that the EDS1 family originated prior to the differentiation of monocots and dicots, and EDS1 members have since undergone clear structural differentiation. The transcriptional levels of TaEDS1 genes in the leaves were obviously higher than those of the other organs, and they were induced by Blumeria graminis f. sp. tritici (Bgt) infection and salicylic acid (SA) treatment. The BSMV-VIGS experiments indicated that knock-down the transcriptional levels of the TaEDS1 genes in a powdery mildew-resistant variety of common wheat compromised resistance. Contrarily, transient overexpression of TaEDS1 genes in a susceptible common wheat variety significantly reduced the haustorium index and attenuated the growth of Bgt. Furthermore, the expression of TaEDS1 genes in the Arabidopsis mutant eds1-1 complemented its susceptible phenotype to powdery mildew. The above evidences strongly suggest that TaEDS1 acts as a positive regulator and confers resistance against powdery mildew in common wheat.

Registration of Two Wheat Germplasm Lines Fixed for Pm58

Powdery mildew is a persistent threat to global wheat (Triticum aestivum L.) production. To broaden the genetic base for resistance to powdery mildew in wheat, germplasm lines U6714‐A‐011 (Reg. No. GP‐1023, PI 682090) and U6714‐B‐056 (Reg. No. GP‐1022, PI 682089) were developed at Michigan State University and are fixed for the novel powdery mildew resistance gene Pm58. This gene was identified in Aegilops tauschii Coss. accession TA1662, introgressed, and mapped to wheat chromosome 2DS. The two germplasm lines described are BC2F4–derived inbred backcrossed lines from a direct cross between TA1662 and the recurrent wheat parent KS05HW14, a hard white winter wheat line adapted to western Kansas. In addition to exhibiting resistant reactions to multiple Bgt isolates with broad virulence profiles, both lines have moderate yield potential and good agronomic characteristics, making them suitable as breeding germplasm. The availability of these lines will enable the incorporation of Pm58 into wheat breeding programs, providing additional genetic variation for resistance to powdery mildew.

Silencing of copine genes confers common wheat enhanced resistance to powdery mildew.

Powdery mildew, caused by the biotrophic fungal pathogen Blumeria graminis f. sp. tritici (Bgt), is a major threat to the production of wheat (Triticum aestivum). It is of great importance to identify new resistance genes for the generation of Bgt-resistant or Bgt-tolerant wheat varieties. Here, we show that the wheat copine genes TaBON1 and TaBON3 negatively regulate wheat disease resistance to Bgt. Two copies of TaBON1 and three copies of TaBON3, located on chromosomes 6AS, 6BL, 1AL, 1BL and 1DL, respectively, were identified from the current common wheat genome sequences. The expression of TaBON1 and TaBON3 is responsive to both pathogen infection and temperature changes. Knocking down of TaBON1 or TaBON3 by virus-induced gene silencing (VIGS) induces the up-regulation of defence responses in wheat. These TaBON1- or TaBON3-silenced plants exhibit enhanced wheat disease resistance to Bgt, accompanied by greater accumulation of hydrogen peroxide and heightened cell death. In addition, high temperature has little effect on the up-regulation of defence response genes conferred by the silencing of TaBON1 or TaBON3. Our study shows a conserved function of plant copine genes in plant immunity and provides new genetic resources for the improvement of resistance to powdery mildew in wheat.

Virulence Differences in Blumeria graminis f. sp. tritici from the Central and Eastern United States.

Wheat powdery mildew is a disease of global importance that occurs across a wide geographic area in the United States. A virulence survey of Blumeria graminis f. sp. tritici, the causal agent, was conducted by sampling 36 wheat fields in 15 U.S. states in the years 2013 and 2014. Using a hierarchical sampling protocol, isolates were derived from three separated plants at each of five separated sites within each field in order to assess the spatial distribution of pathotypes. In total, 1,017 isolates from those fields were tested individually on single-gene differential cultivars containing a total of 21 powdery mildew resistance (Pm) genes. Several recently introgressed mildew resistance genes from wild wheat relatives (Pm37, Pm53, MlAG12, NCAG13, and MlUM15) exhibited complete or nearly complete resistance to all local B. graminis f. sp. tritici populations from across the sampled area. One older gene, Pm4b, also retained at least some efficacy across the sampled area. The B. graminis f. sp. tritici population sampled from Arkansas and Missouri, on the western edge of the eastern soft red winter wheat region, had virulence profiles more similar to other soft wheat mildew populations than to the geographically closer population from hard wheat fields in the Plains states of Oklahoma, Nebraska, and Kansas. The Plains population differed in that it was avirulent to several Pm genes long defeated in the soft-wheat-growing areas. Virulence complexity was greatest east of the Mississippi River, and diminished toward the west. Several recently introgressed Pm genes (Pm25, Pm34, Pm35, and NCA6) that are highly effective against mildew in the field in North Carolina were unexpectedly susceptible to eastern-U.S. B. graminis f. sp. tritici populations in detached-leaf tests. Sampled fields displayed a wide range of pathotype diversity and spatial distribution, suggesting that epidemics are caused by varying numbers of pathotypes in all regions. The research confirmed that most long-used Pm genes are defeated in the eastern United States, and the U.S. B. graminis f. sp. tritici population has different virulence profiles in the hard- and soft-wheat regions, which are likely maintained by host selection, isolation by distance, and west-to-east gene flow.

Detection and discrimination of pests and diseases in winter wheat based on spectral indices and kernel discriminant analysis

Kernel discriminant analysis (KDA) can be used as a feasible strategy for identifying plant stresses, especially for detection of pests and diseases, considering the highly nonlinear distribution of hyperspectral absorption features that respond to biophysical variations in plants caused by foliar lesions. However, traditional computation of the kernel projection features produced by hyperspectral data is always affected by redundant information among the numerous wavelengths, subsequently leading to dimension disaster. In order to alleviate this problem, the aim of this study is to propose a spectral vegetation indices-based kernel discriminant approach (SVIKDA) for the detection and classification of yellow rust, aphid, and powdery mildew in winter wheat at the leaf and canopy level. Leaf and canopy level hyperspectral reflectance datasets were measured with a total of 314 and 187 samples, respectively. Fourteen Spectral Vegetation Indices (SVIs) related to foliar biophysical variations were employed as the input sample space; then, by using correlation analysis and independent t-tests, redundant information among SVIs was removed. Subsequently, a Gaussian kernel function was utilized to cast discriminant analysis into a nonlinear framework. Finally, using 5-fold cross validation, performance and transferability of this approach were evaluated. Our results revealed that the SVIKDA outperformed conventional linear discriminant approach on detection and classification among healthy wheat leaves and leaves infected with yellow rust, aphids, and powdery mildew. At the leaf level, the classification returned the overall accuracies (OA) of 82.9%, 89.2%, 87.9% for three occurrence levels, i.e. slight, moderate, and severe (Kappa>0.85). Depending on the types and severities of infestations, the classification accuracy was between 76% and 95%; At the canopy level, the multiple classifications between healthy leaves and leaves with damages from the three different infestations still achieved an accuracy greater than 87% (Kappa=0.84). In addition, this approach was also successfully applied in disease index (DI) estimation for a specific infestation at the leaf level, and optimal DI estimation returned high coefficients of determination (R2>0.7). Furthermore, compared with the commonly used automatic classification algorithm, the SVIKDA achieved an accurate classification without losing the pathological basis of input variables. The results suggest that this method has reliable transferability and great robustness in detecting and discriminating pests and diseases for guiding precision plant protection.

Development and comparative genomic mapping of Dasypyrum villosum 6V#4S-specific PCR markers using transcriptome data

Twenty-five Dasypyrum villosum 6V#4S-specific PCR markers were developed using transcriptome data and further assigned to comparative genomic maps of wheat chromosome 6A, 6B, and 6D and barley chromosome 6H contrasting their homologous genes in these genomes. Two Dasypyrum villosum accessions, D.v#2 and No. 1026 from England and Russia, respectively, contain Pm21 on chromosome 6V#2S and PmV on chromosome 6V#4S. Both genes confer high resistance to powdery mildew (PM) in wheat. Even though several molecular markers have been developed to detect Pm21 and PmV, only the MBH1 marker can simultaneously detect both Pm21 and PmV. In this study, we first used a high-throughput sequencing technique to obtain the transcriptome sequences of a wheat-D. villosum translocation line, Pm97033-which contains chromosome 6V#4S carrying the PmV locus, under wheat PM pathogen induction. Twenty-five 6V#4S chromosome-specific markers were developed. Three of them were able to clearly distinguish chromosomes 6V#4S and 6V#2S by product size, four amplified the product specific for chromosome 6V#4S only, and the remaining 18 markers identified chromosome 6VS in wheat backgrounds. Two different D. villosum accessions, their derived translocation lines and wheat varieties carrying different chromosome 6VS were identified using these specific markers. The 25 newly developed markers together with the known PM resistance gene Stpk-V were used to construct comparative genomic maps with the homoeologous chromosome arms of wheat and barley. The colinearity of the identified gene sequences amplified by the 25 markers among wheat chromosomes 6A, 6B, and 6D and barley chromosome 6H was not very conserved and interrupted frequently by inversion and insertion. Our markers have potential in marker assisted selection for PM resistance breeding, and for locating other potential important genes and cloning the PmV gene on chromosome 6V#4S.

Evaluation of wavelet spectral features in pathological detection and discrimination of yellow rust and powdery mildew in winter wheat with hyperspectral reflectance data

Hyperspectral absorption features are important indicators of characterizing plant biophysical variables for the automatic diagnosis of crop diseases. Continuous wavelet analysis has proven to be an advanced hyperspectral analysis technique for extracting absorption features; however, specific wavelet features (WFs) and their relationship with pathological characteristics induced by different infestations have rarely been summarized. The aim of this research is to determine the most sensitive WFs for identifying specific pathological lesions from yellow rust and powdery mildew in winter wheat, based on 314 hyperspectral samples measured in field experiments in China in 2002, 2003, 2005, and 2012. The resultant WFs could be used as proxies to capture the major spectral absorption features caused by infestation of yellow rust or powdery mildew. Multivariate regression analysis based on these WFs outperformed conventional spectral features in disease detection; meanwhile, a Fisher discrimination model exhibited considerable potential for generating separable clusters for each infestation. Optimal classification returned an overall accuracy of 91.9% with a Kappa of 0.89. This paper also emphasizes the WFs and their relationship with pathological characteristics in order to provide a foundation for the further application of this approach in monitoring winter wheat diseases at the regional scale.

Vacuum and Co-cultivation Agroinfiltration of (Germinated) Seeds Results in Tobacco Rattle Virus (TRV) Mediated Whole-Plant Virus-Induced Gene Silencing (VIGS) in Wheat and Maize.

Tobacco rattle virus (TRV)-mediated virus-induced gene silencing (VIGS) has been frequently used in dicots. Here we show that it can also be used in monocots, by presenting a system involving use of a novel infiltration solution (containing acetosyringone, cysteine, and Tween 20) that enables whole-plant level VIGS of (germinated) seeds in wheat and maize. Using the established system, phytoene desaturase (PDS) genes were successfully silenced, resulting in typical photo-bleaching symptoms in the leaves of treated wheat and maize. In addition, three wheat homoeoalleles of MLO, a key gene repressing defense responses to powdery mildew in wheat, were simultaneously silenced in susceptible wheat with this system, resulting in it becoming resistant to powdery mildew. The system has the advantages generally associated with TRV-mediated VIGS systems (e.g., high-efficiency, mild virus infection symptoms, and effectiveness in different organs). However, it also has the following further advantages: (germinated) seed-stage agroinfiltration; greater rapidity and convenience; whole-plant level gene silencing; adequately stable transformation; and suitability for studying functions of genes involved in seed germination and early plant development stages.

Progression of powdery mildew on different varieties of wheat and triticale in relation to environmental conditions

Six varieties of wheat and triticale (DDK1029, TL2934, PBW174, DPW 621-50, PBW343 and PBW590) were sown in the field of Indian Institute of Wheat and Barley Research, Karnal, Haryana (IIWBR) and Regional Research Station, Dhaulakuan under Himachal Pradesh Krishi Vishvavidyalaya, H.P during seasons 2012-13 and 2013-14 to study the role of environmental factors on the development of powdery mildew of wheat (Erysiphe graminis f.sp. tritici). The disease development was positively correlated with temperatures and negatively correlated with evening relative humidity and rainfall under field conditions. Best fit regression model was developed with maximum temperature, evening relative humidity and rainfall across the varieties and locations which explains 64% variation in powdery mildew disease.

利用成像高光谱区分冬小麦白粉病与条锈病

利用成像高光谱区分冬小麦白粉病与条锈病

利用成像高光谱区分冬小麦白粉病与条锈病

利用成像高光谱区分冬小麦白粉病与条锈病

Identification of Novel Powdery Mildew Resistance Sources in Wheat

Genetic resistance plays an important role in managing powdery mildew of wheat (Triticum aestivum L.), a disease of global importance. The objectives of this study were to evaluate powdery mildew resistance and the underlying genes in US wheat breeding lines and identify novel resistance sources from a worldwide collection of winter wheat germplasm. Our results suggested that 37.5% of powdery mildew resistant breeding lines recently developed in the United States carry the Pm3a gene, indicating the abundance of Pm3a in US cultivars. Among a worldwide collection of 1,297 landraces and 874 early cultivars or breeding lines, 59 and 68 accessions showed high (HR) and moderate resistance (MR), respectively. In addition, highly resistant plants were identified in 41 heterogeneous accessions. These resistant accessions were further screened for the presence of Pm3a, Pm3b, Pm3c, Pm3d, and Pm3f genes as well as the 1RS translocation segment. Among them, 13 accessions had a Pm3 allele, and another seven accessions possessed the 1BL/1RS translocation fragment with the Pm8 gene. Genetic diversity analysis based on a set of 5,011 single‐nucleotide polymorphism (SNP) markers identified genetically similar accessions. The deployment of resistance sources identified in this study in wheat breeding may greatly broaden the genetic base of powdery mildew resistance.