Assessing wheat (Triticum aestivum) genotypes for "Yr" resistance genes using conserved regions and simple-sequence motifs

Analysis of DNA sequence variation among genotypes is useful for differentiation of wheat accessions, selection strategies and genetic development of crop plants. We screened molecular markers for yellow rust resistance genes (Yr7, Yr9, Yr15, Yr18, Yr26, and YrH52), which are in the gene-rich regions of wheat chromosomes 1B, 2B, and 7D, to investigate DNA sequence differences and repeat motifs and numbers between wheat cultivars resistant (Izgi2001, Sonmez2001, PI178383) and susceptible (Aytin98, ES14, Harmankaya99) to yellow rust. The F(2) individuals derived from the crosses were evaluated for yellow rust resistance at both the seedling and adult stages to identify DNA markers genetically linked to yellow rust resistance. The most repeated motif was found to be GA and the least repeated motif TAGA among the cultivars. When we examined DNA sequence differences (insertion, deletion and single nucleotide changes), the molecular markers Xgwm526 (Yr7) and Xgwm273 (YrH52) were found to have the most conserved regions and Yr15 (Xgwm413) the least conserved regions among the cultivars. This DNA sequence information can be used for selection of suitable parents, creating mapping populations and developing molecular markers associated with yellow rust resistance in plant breeding programs.     

Molecular markers for leaf rust resistance genes in wheat

Over 100 genes of resistance to rust fungi: Puccinia recondita f. sp. tritici, (47 Lr - leaf rust genes), P. striiformis (18 Yr - yellow rust genes) and P. graminis f. sp. tritici (41 Sr - stripe rust genes) have been identified in wheat (Triticum aestivum L.) and its wild relatives according to recent papers. Sixteen Lr resistance genes have been mapped using restriction fragments length polymorphism (RFLP) markers on wheat chromosomes. More than ten Lr genes can be identified in breeding materials by sequence tagged site (STS) specific markers. Gene Lrk 10, closely linked to gene Lr 10, has been cloned and its function recognized. Available markers are presented in this review. The STS, cleaved amplified polymorphic sequence (CAPS) and sequence characterized amplified regions (SCAR) markers found in the literature should be verified using Triticum spp. with different genetic background. Simple sequence repeats (SSR) markers for Lr resistance genes are now also available.     

Identification of molecular markers for the detection of the yellow rust resistance gene Yr17 in wheat

The Yr17 gene, which is present in many European wheat cultivars, displays yellow rust resistance at the seedling stage. The gene introduced into chromosome 2A from Aegilops ventricosa was previously found to be closely linked (0.5 cM) to leaf and stem rust resistance genes Lr37 and Sr38, respectively. The objective of this study was to identify molecular markers linked to the Yr17 gene. We screened with RAPD primers, for polymorphism, the DNAs of cv. Thatcher and the leaf rust-resistant near-isogenic line (NIL) RL 6081 of cv. Thatcher carrying the Lr37 gene. Using a F2 progeny of the cross between VPM1 (resistant) and Thésée (susceptible), the RAPD marker OP-Y15580 was found to be closely linked to the Yr17 gene. We converted the OP- Y15580 RAPD marker into a sequence characterized amplified region (SCAR). This SCAR marker (SC-Y15) was linked at 0.8 ± 0.7 cM to the Yr17 resistance gene. We tested the SC-Y15 marker over a survey of 37 wheat cultivars in order to verify its consistency in different genetic backgrounds and to explain the resistance of some cultivars against yellow rust. Moreover, we showed that the Xpsr150-2Mv locus marker of Lr gene described by Bonhomme et al. [6] which possesses A. ventricosa introgression on the 2A chromosome was also closely linked to the Yr17 gene. Both the SCAR SC-Y15 and Xpsr150-2Mv markers should be used in breeding programmes in order to detect the cluster of the three genes Yr17, Lr37 and Sr38 in cross progenies. This revised version was published online in June 2006 with corrections to the Cover Date.     

Nucleotide-binding site (NBS) profiling of genetic diversity in durum wheat.

Molecular markers are effective tools to investigate genetic diversity for resistance to pathogens. NBS (nucleotide-binding site) profiling is a PCR (polymerase chain reaction)-based approach to studying genetic variability that specifically targets chromosome regions containing R-genes and R-gene analogues. We used NBS profiling to measure genetic diversity among 58 accessions of durum wheat. Mean polymorphism rates detected using MseI and AluI as restriction enzymes were 34% and 22%, respectively. Mean number of polymorphisms per enzyme-primer combination was equal to 23.8 +/- 5.9, ranging from 13 to 31 polymorphic bands. In total, 96 markers over 190 indicated a good capacity to discriminate between accessions (the polymorphic index content ranging from 0.30 to 0.50). The results obtained with NBS profiling were compared with simple sequence repeat (SSR) and amplified fragment length polymorphism (AFLP) data of the same set of accessions. The genetic distances computed with 190 NBS profiling markers were in close agreement with those obtained with AFLP and SSR markers (r = 0.73 and 0.76, respectively). Our results indicate that NBS profiling provides an effective means to investigate genetic diversity in durum wheat.     

Leaf tip necrosis, molecular markers and β1-proteasome subunits associated with the slow rusting resistance genes Lr46/Yr29

Resistance based on slow-rusting genes has proven to be a useful strategy to develop wheat cultivars with durable resistance to rust diseases in wheat. However this type of resistance is often difficult to incorporate into a single genetic background due to the polygenic and additive nature of the genes involved. Therefore, markers, both molecular and phenotypic, are useful tools to facilitate the use of this type of resistance in wheat breeding programs. We have used field assays to score for both leaf and yellow rust in an Avocet-YrA × Attila population that segregates for several slow-rusting leaf and yellow rust resistance genes. This population was analyzed with the AFLP technique and the slow-rusting resistance locus Lr46/Yr29 was identified. A common set of AFLP and SSR markers linked to the Lr46/Yr29 locus was identified and validated in other recombinant inbred families developed from single chromosome recombinant populations that segregated for Lr46. These populations segregated for leaf tip necrosis (LTN) in the field, a trait that had previously been associated with Lr34/Yr18. We show that LTN is also pleiotropic or closely linked to the Lr46/Yr29 locus and suggest that a new Ltn gene designation should be given to this locus, in addition to the one that already exists for Lr34/Yr18. Coincidentally, members of a small gene family encoding β-1 proteasome subunits located on group 1L and 7S chromosomes implicated in plant defense were linked to the Lr34/Yr18 and Lr46/Yr29 loci.     

Strong linkage disequilibrium near the selected Yr17 resistance gene in a wheat experimental population

Dynamic management (DM) is a method of genetic resources conservation that aims at maintaining evolutionary process in subdivided populations cultivated in contrasted environments. Such populations are often submitted to strong natural selection as it was the case for experimental wheat populations maintained under DM. Understanding impacts of selection on genetic diversity around selected genes is necessary for the middle-term maintenance of genetic variability in DM populations. Evolution of diversity at six neutral markers located near the yellow rust resistance gene Yr17 has been studied for the parental lines and for generations 1, 5, 10 and 17 in one of the DM populations. Yr17 provided complete resistance to yellow rust in France until 1997 and thus was suspected to be under strong selection. The gene is located on a fragment introgressed in winter wheat from a wild species. The presence of the gene was estimated using a marker closely related to the gene. We showed that the Yr17 gene has been selected between generations 5 and 10. Generally, selection tends to reduce diversity around selected genes, generating linkage disequilibrium (LD) between a gene and adjacent markers. Here, the major effect of the Yr17 gene selection was a reduction of multilocus diversity and the maintenance of strong pre-existing LD in the zone surrounding the gene for a distance of 20 cM. As expected, the presence of the exogenous introgression was responsible for restrictions to recombination which contributed to the maintenance of strong correlations between loci. However, we found a noticeable number of recombinations around the gene indicating a progressive incorporation of the fragment into the wheat genome.     

Evaluation of Pakistan wheat germplasms for stripe rust resistance using molecular markers

Wheat production in Pakistan is seriously constrained due to rust diseases and stripe rust (yellow) caused by Puccinia striiformis f. sp. tritici, which could limit yields. Thus development and cultivation of genetically diverse and resistant varieties is the most sustainable solution to overcome these diseases. The first objective of the present study was to evaluate 100 Pakistan wheat cultivars that have been grown over the past 60 years. These cultivars were inoculated at the seedling stage with two virulent stripe rust isolates from the United States and two from Pakistan. None of the wheat cultivars were resistant to all tested stripe rust isolates, and 16% of cultivars were susceptible to the four isolates at the seedling stage. The data indicated that none of the Pakistan wheat cultivars contained either Yr5 or Yr15 genes that were considered to be effective against most P. striiformis f. sp. tritici isolates from around the world. Several Pakistan wheat cultivars may have gene Yr10, which is effective against isolate PST-127 but ineffective against PST-116. It is also possible that these cultivars may have other previously unidentified genes or gene combinations. The second objective was to evaluate the 100 Pakistan wheat cultivars for stripe rust resistance during natural epidemics in Pakistan and Washington State, USA. It was found that a higher frequency of resistance was present under field conditions compared with greenhouse conditions. Thirty genotypes (30% of germplasms) were found to have a potentially high temperature adult plant (HTAP) resistance. The third objective was to determine the genetic diversity in Pakistan wheat germplasms using molecular markers. This study was based on DNA fingerprinting using resistance gene analog polymorphism (RGAP) marker analysis. The highest polymorphism detected with RGAP primer pairs was 40%, 50% and 57% with a mean polymorphism of 36%. A total of 22 RGAP markers were obtained in this study. RGAP, simple sequence repeat (SSR) and sequence tagged site (STS) markers were used to determine the presence and absence of some important stripe rust resistance genes, such as Yr5, Yr8, Yr9, Yr15 and Yr18. Of the 60 cultivars analyzed, 17% of cultivars showed a RGAP marker band for Yr9 and 12% of cultivars exhibited the Yr18 marker band. No marker band was detected for Yr5, Yr8 and Yr15, indicating a likely absence of these genes in the tested Pakistan wheat cultivars. Cluster analysis based on molecular and stripe rust reaction data is useful in identifying considerable genetic diversity among Pakistan wheat cultivars. The resistant germplasms identified with 22 RGAP markers and from the resistance evaluations should be useful in developing new wheat cultivars with stripe rust resistance.     

Characterization of genetic loci conferring adult plant resistance to leaf rust and stripe rust in spring wheat.

Leaf (brown) and stripe (yellow) rusts, caused by Puccinia triticina and Puccinia striiformis, respectively, are fungal diseases of wheat (Triticum aestivum) that cause significant yield losses annually in many wheat-growing regions of the world. The objectives of our study were to characterize genetic loci associated with resistance to leaf and stripe rusts using molecular markers in a population derived from a cross between the rust-susceptible cultivar 'Avocet S' and the resistant cultivar 'Pavon76'. Using bulked segregant analysis and partial linkage mapping with AFLPs, SSRs and RFLPs, we identified 6 independent loci that contributed to slow rusting or adult plant resistance (APR) to the 2 rust diseases. Using marker information available from existing linkage maps, we have identified additional markers associated with resistance to these 2 diseases and established several linkage groups in the 'Avocet S' x 'Pavon76' population. The putative loci identified on chromosomes 1BL, 4BL, and 6AL influenced resistance to both stripe and leaf rust. The loci on chromosomes 3BS and 6BL had significant effects only on stripe rust, whereas another locus, characterized by AFLP markers, had minor effects on leaf rust only. Data derived from Interval mapping indicated that the loci identified explained 53% of the total phenotypic variation (R2) for stripe rust and 57% for leaf rust averaged across 3 sets of field data. A single chromosome recombinant line population segregating for chromosome 1B was used to map Lr46/Yr29 as a single Mendelian locus. Characterization of slow-rusting genes for leaf and stripe rust in improved wheat germplasm would enable wheat breeders to combine these additional loci with known slow-rusting loci to generate wheat cultivars with higher levels of slow-rusting resistance.     

小麦抗条锈基因Yr69的连锁标记开发

抗条锈病基因Yr69对我国小麦条锈菌(Puccinia striiformis f. sp. tritici)小种具有广谱抗性,在小麦抗条锈病育种中具有重要价值。为提高分子标记辅助选择育种的效率,加快Yr69在小麦抗病育种中的应用,本研究利用条锈菌小种CYR34对包含340个小麦家系的‘Taichung29/CH7086’F9代RIL(Recombinant inbred line)群体进行接种鉴定,并利用BSA-SNP(Bulked segregant analysis-single nucleotide polymorphism)技术对其抗条锈病基因进行了重新定位。抗病鉴定结果显示,RIL群体中抗感病家系的数量呈双峰分布,‘CH7086’的条锈病抗性受一个主效位点控制。BSA-SNP基因分型结果表明,多态性SNP主要集中于小麦2AS染色体末端0～30Mb的染色体区段。在该基因组区段开发了208个SSR分子标记,利用抗感病小群体从中筛选到14个与Yr69连锁的分子标记。利用14个标记对340个RIL家系进行PCR扩增和分子作图,将Yr69定位于2AS111和2AS171之间约7.76...     

普通小麦Qz180中一个抗条锈病基因的分子作图(英文)

普通小麦(Triticum aestivum L.)材料Qz180具有良好的抗条锈病特性,经基因推导发现其含有一个优良的抗条锈病的基因,暂定名为YrQz。用Qz180与感病材料铭贤169和WL1分别杂交构建了两个F_2群体,用条中30号条锈菌小种对这两个群体进行的抗性测验表明,YrQz为显性单基因遗传。通过SSR和AFLP结合BSA的方法对这个基因进行了分子作图,结果鉴定出与YrQz连锁的2个SSR标记和2个AFLP标记。根据SSR标记的染色体位置,该基因被定位在2B染色体的长臂上,位于两个SSR位点Xgwm388和Xgwm526之间;两个AFLP标记P35M48(452)和P36M61(163)分别位于该基因的两侧,遗传距离分别为3.4cM和4.1cM。     

普通小麦Qz180中一个抗条锈病基因的分子作图

普通小麦(Triticum aestivum L.)材料Qz180具有良好的抗条锈病特性,经基因推导发现其含有一个优良的抗条锈病的基因,暂定名为YrQz.用Qz180与感病材料铭贤169和WL1分别杂交构建了两个F2群体,用条中30号条锈菌小种对这两个群体进行的抗性测验表明,YrQz为显性单基因遗传.通过SSR和AFLP结合BSA的方法对这个基因进行了分子作图,结果鉴定出与YrQz连锁的2个SSR标记和2个AFLP标记.根据SSR标记的染色体位置,该基因被定位在2B染色体的长臂上,位于两个SSR位点Xgwm388和Xgwm526之间;两个AFLP标记P35M48(452)和P36M61(163)分别位于该基因的两侧,遗传距离分别为3.4 cM和4.1cM.     

Mapping a stripe rust resistance gene YrC591 in wheat variety C591 with SSR and AFLP markers

Stripe rust, caused by Puccinia striiformis Westend. f. sp. tritici (PST), is one of the most destructive diseases of common wheat (Triticum aestivum L.). To determine inheritance of stripe rust resistance and map the resistance gene(s) in wheat variety C591, F₁, F_2, and F₃ progenies derived from the Taichung 29 × C591 cross were inoculated with Chinese PST race CY32 in the greenhouse. Genetic analysis identified a single dominant gene, temporarily designated YrC591. A total of 178 SSR and 130 AFLP markers were used to test the parents and resistant and susceptible bulks. From the bulk segregant analysis, seven polymorphic SSR and two AFLP markers were selected for genotyping the F₂ population. SSR marker Xcfa2040-7B, and SCAR marker SC-P35M48 derived from AFLP marker P35M48 ₃₇₃ were identified to be closely linked to the resistance gene with genetic distances of 8.0 and 11.7 cM, respectively. The SSR markers mapped the resistance gene on chromosome arm 7BL. In the seedling test with five PST races, the reaction patterns of C591 were different from wheat cultivars or lines carrying Yr2 or Yr6 that also are found on chromosome 7B. The results indicate that YrC591 is probably a novel stripe rust resistance gene.     

Identification and characterization of stripe rust resistance gene Yr34 in common wheat

An uncharacterized source of seedling resistance to Puccinia striiformis f.sp. tritici was identified in an advanced wheat breeding line WAWHT2046. Genetic analysis based on a WAWHT2046/Carnamah-derived double haploid (DH) population demonstrated monogenic inheritance of seedling stripe rust resistance in WAWHT2046. The gene controlling stripe rust resistance in line WAWHT2046 was tentatively designated YrWA. The chromosome 5AL located awn inhibitor gene B1, possessed by WAWHT2046, also showed monogenic inheritance when the DH population was scored for the presence and absence of awns. Joint segregation analysis at the B1 and YrWA loci indicated genetic linkage between the two loci. A recombination value of 12.2 cM was computed using Mapmanager. This association located YrWA in the chromosome arm 5AL. Molecular mapping using microsatellite markers placed YrWA distal to B1. All molecular markers mapped proximal to the awn inhibitor locus B1. As no other stripe rust resistance gene is reported to be located in the chromosome arm 5AL, YrWA was permanently designated as Yr34. Yr34 produced an intermediate (23C) seedling infection type and expressed very low stripe rust response (10R-MR) on adult plants in the field, similar to the resistance gene Yr17. In addition to Yr34, this mapping population segregated for three genetically independent adult plant stripe rust resistance genes. The detection of DH lines with completely susceptible response, higher than that shown by the Yr34-lacking parent Carnamah, suggested that both parents contributed adult plant resistance. The use of WAWHT2046 as a parent in breeding programs would also contribute APR in addition to Yr34.     

Development of resistance gene analog polymorphism markers for the Yr9 gene resistance to wheat stripe rust.

The Yr9 gene, which confers resistance to stripe rust caused by Puccinia striiformis f.sp. tritici (P. s. tritici) and originated from rye, is present in many wheat cultivars. To develop molecular markers for Yr9, a Yr9 near-isogenic line, near-isogenic lines with nine other Yr genes, and the recurrent wheat parent 'Avocet Susceptible' were evaluated for resistance in the seedling stage to North American P s. tritici races under controlled temperature in the greenhouse. The resistance gene analog polymorphism (RGAP) technique was used to identify molecular markers for Yr9. The BC7:F, and BC7:F3 progeny, which were developed by backcrossing the Yr9 donor wheat cultivar Clement with 'Avocet Susceptible', were evaluated for resistance to stripe rust races. Genomic DNA was extracted from 203 BC7:F2 plants and used for cosegregation analysis. Of 16 RGAP markers confirmed by cosegregation analysis, 4 were coincident with Yr9 and 12 were closely linked to Yr9 with a genetic distance ranging from 1 to 18 cM. Analyses of nullitetrasomic 'Chinese Spring' lines with the codominant RGAP marker Xwgp13 confirmed that the markers and Yr9 were located on chromosome 1B. Six wheat cultivars reported to have 1B/1R wheat-rye translocations and, presumably, Yr9, and two rye cultivars were inoculated with four races of P. s. tritici and tested with 9 of the 16 RGAP markers. Results of these tests indicate that 'Clement', 'Aurora', 'Lovrin 10', 'Lovrin 13', and 'Riebesel 47/51' have Yr9 and that 'Weique' does not have Yr9. The genetic information and molecular markers obtained from this study should be useful in cloning Yr9, in identifying germplasm that may have Yr9, and in using marker-assisted selection for combining Yr9 with other stripe rust resistance genes.     

Gene-specific markers for the wheat gene Lr34/Yr18/Pm38 which confers resistance to multiple fungal pathogens

The locus Lr34/Yr18/Pm38 confers partial and durable resistance against the devastating fungal pathogens leaf rust, stripe rust, and powdery mildew. In previous studies, this broad-spectrum resistance was shown to be controlled by a single gene which encodes a putative ATP-binding cassette transporter. Alleles of resistant and susceptible cultivars differed by only three sequence polymorphisms and the same resistance haplotype was found in the three independent breeding lineages of Lr34/Yr18/Pm38. Hence, we used these conserved sequence polymorphisms as templates to develop diagnostic molecular markers that will assist selection for durable multi-pathogen resistance in breeding programs. Five allele-specific markers (cssfr1–cssfr5) were developed based on a 3 bp deletion in exon 11 of the Lr34-gene, and one marker (cssfr6) was derived from a single nucleotide polymorphism in exon 12. Validation of reference genotypes, well characterized for the presence or absence of the Lr34/Yr18/Pm38 resistance locus, demonstrated perfect diagnostic values for the newly developed markers. By testing the new markers on a larger set of wheat cultivars, a third Lr34 haplotype, not described so far, was discovered in some European winter wheat and spelt material. Some cultivars with uncertain Lr34 status were re-assessed using the newly derived markers. Unambiguous identification of the Lr34 gene aided by the new markers has revealed that some wheat cultivars incorrectly postulated as having Lr34 may possess as yet uncharacterised loci for adult plant leaf and stripe rust resistance. E. S. Lagudah and S. G. Krattinger contributed equally to the work.     

Characterization and molecular mapping of stripe rust resistance gene Yr61 in winter wheat cultivar Pindong 34

Key message

We report a new stripe rust resistance gene on chromosome 7AS in wheat and molecular markers useful for transferring it to other wheat genotypes.

Abstract

Several new races of the stripe rust pathogen have established throughout the wheat growing regions of China in recent years. These new races are virulent to most of the designated seedling resistance genes limiting the resistance sources. It is necessary to identify new genes for diversification and for pyramiding different resistance genes in order to achieve more durable resistance. We report here the identification of a new resistance gene, designated as Yr61, in Chinese wheat cultivar Pindong 34. A mapping population of 208 F₂ plants and 128 derived F_2:3 lines in a cross between Mingxian 169 and Pindong 34 was evaluated for seedling stripe rust response. A genetic map consisting of eight resistance gene analog polymorphism (RGAP), two sequence-tagged site (STS) and four simple sequence repeat (SSR) markers was constructed. Yr61 was located on the short arm of chromosome 7A and flanked by RGAP markers Xwgp5467 and Xwgp5765 about 1.9 and 3.9 cM in distance, which were successfully converted into STS markers STS5467 and STS5765b, respectively. The flanking STS markers could be used for marker-assisted selection of Yr61 in breeding programs.     

Resistance gene analogs within an introgressed chromosomal segment derived from Triticum ventricosum that confers resistance to nematode and rust pathogens in wheat

A resistance (R) gene-rich 2S chromosomal segment from Triticum ventricosum contains a cereal cyst nematode (CCN; Heterodera avenae) R gene locus CreX and a closely linked group of genes (Sr38, Yr17, and Lr37) that confer resistance to stem rust (Puccinia graminis f. sp. tritici), stripe rust (P. striiformis f. sp. tritici), and leaf rust (P. recondita f. sp. tritici) when introgressed into wheat. The 2S chromosomal segment from T. ventricosum is further delineated in translocations onto chromosome 2A of bread wheat, where the rust genes are retained but not the CreX gene. Using these critical genetic stocks, we have isolated family members of R gene analogs that are associated with either the 2S segment from T. ventricosum carrying the CreX locus or the rust genes. Derivatives of the Cre3 candidate R gene sequence and a rice (Oryza sativa) R gene analog that mapped to the 2S homologous chromosome groups in wheat were used to isolate related gene sequences from T. ventricosum that contain a nucleotide binding site-leucine rich repeat domain. The potential of these gene sequences as entry points for isolating candidate genes or gene family members of the CreX or rust genes and their further applications to plant breeding are discussed.     

Effective and ineffective resistance genes to wheat yellow rust during six years monitoring in Ardabil

Stripe (yellow) rust caused by Puccinia striiformis f. sp. tritici is the most devastating disease of bread wheat (Triticum aestivum) in the cool winter areas. This rust disease represents a constant threat to wheat production in several countries in Central and Western Asia. A wide range of virulent yellow rust pathotypes is evolving in this region causing the breakdown of widely utilised sources of resistance in wheat. Hence, the knowledge of effective resistance genes in the region will enable breeders to target those useful genes in their breeding programmes. From 2006 to 2012, in order to determine of effective resistance genes in Ardabil, north-west of Iran, virulence patterns of wheat yellow rust were studied under the field conditions by planting of differential sets and isogenic lines. The results showed that yellow rust resistance genes Yr1,Yr2⁺ , Yr3V, Yr3a, Yr4a, Yr4, Yr5, Yr7⁺ , Yr10, Yr15,Yr16, YrCV, YrSD and YrND were effective and race-nonspecific resistance genes YrA3, YrA4, Yr18 and Yr29 were partially effective during study periods. Genes Yr2, Yr6, Yr7, Yr9, Yr17, Yr20, Yr21,Yr22, Yr23, Yr24, Yr25, Yr26, Yr27, YrSU, YrSP and YrA were found ineffective. The Genes found effective against yellow rust under natural conditions may be deployed singly or in combinations with durable resistance genes to develop high yielding resistant wheat cultivars in wheat-growing areas in where yellow rust races have the same virulence profile to the prevalent race/s of Ardabil.