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1.
Kosman E Pardes E Anikster Y Manisterski J Yehuda PB Szabo LJ Sharon A 《Phytopathology》2004,94(6):632-640
ABSTRACT The genetic relationships between isolates of Puccinia triticina virulent on wheat with the Lr26 resistance gene were studied. The diversity within and between isolates of P. triticina from Israel, Europe, and the United States was determined by virulence on near-isogenic Thatcher lines and by random amplified polymorphic DNA. According to the molecular markers, isolates that were virulent on Lr26 had diversity levels similar to those of Lr26 nonpathogenic isolates. Distances between subpopulations of isolates virulent and avirulent on Lr26 varied and were unrelated to the Lr26 virulence phenotype. Cluster analysis suggested four groups, three of which were closely associated with the geographical origin of the isolates-Israel, the United States, and Europe. All four groups included both Lr26 virulent and avirulent pathotypes. The results showed that Lr26 virulent rust pathotypes are as genetically dissimilar as the rest of the population. The cluster analysis showed that the rust population in Israel includes at least two different subpopulations, both of which contain Lr26 virulent and Lr26 avirulent isolates. 相似文献
2.
ABSTRACT Collections of Puccinia triticina, the wheat leaf rust fungus, were obtained from Great Britain, Slovakia, Israel, Germany, Australia, Italy, Spain, Hungary, South Africa, Uruguay, New Zealand, Brazil, Pakistan, Nepal, and eastern and western Canada. All single-uredinial isolates derived from the collections were tested for virulence polymorphism on 22 Thatcher wheat lines that are near-isogenic for leaf rust resistance genes. Based on virulence phenotype, selected isolates were also tested for randomly amplified polymorphic DNA (RAPD) using 11 primers. The national collections were placed into 11 groups based on previously established epidemiological zones. Among the 131 single-uredinial isolates, 105 virulence phenotypes and 82 RAPD phenotypes were described. In a modified analysis of variance, 26% of the virulence variation was due to differences in isolates between groups, with the remainder attributable to differences within groups. Of the RAPD variation, 36% was due to differences in isolates between groups. Clustering based on the average virulence distance (simple distance coefficient) within and between groups resulted in eight groups that differed significantly. Collections from Australia-New Zealand, Spain, Italy, and Britain did not differ significantly for virulence. Clustering of RAPD marker differences (1 - Dice coefficient) distinguished nine groups that differed significantly. Collections from Spain and Italy did not differ significantly for RAPD variation, neither did collections from western Canada and South America. Groups of isolates distinguished by avirulent/virulent infection types to wheat lines with resistance genes Lr1, Lr2a, Lr2c, and Lr3 also differed significantly for RAPD distance, showing a general relationship between virulence and RAPD phenotype. The results indicated that on a worldwide level collections of P. triticina differ for virulence and molecular backgrounds. 相似文献
3.
ABSTRACT Isolates of Puccinia triticina collected from durum wheat from Argentina, Chile, Ethiopia, France, Mexico, Spain, and the United States were analyzed with 11 simple sequence repeat (SSR) markers in order to determine the genetic relationship among isolates. These isolates also were compared with P. triticina isolates from common wheat from North America, and an isolate collected from Aegilops speltoides from Israel, to determine genetic relationships among groups of P. triticina found on different telial hosts. The large majority of isolates from durum wheat were identical for SSR markers or had <8% genetic dissimilarity, except for isolates from Ethiopia, which had 55% dissimilarity with respect to the other durum isolates. Isolates from common wheat had >70% genetic dissimilarity from isolates from durum wheat, and the isolate from A. speltoides was >90% dissimilar from all isolates tested. Analysis of molecular variance tests showed significant levels (P = 0.001) of genetic differentiation among regions and among isolates within countries. Isolates of P. triticina from durum wheat from South America, North America, and Europe were closely related based on SSR genotypes, suggesting a recent common ancestor, whereas P. triticina from Ethiopia, common wheat, and A. speltoides each had distinct SSR genotypes, which suggested different origins. 相似文献
4.
ABSTRACT Isolates of Puccinia triticina collected from common wheat in the Central Asia countries of Kazakhstan, Uzbekistan, Tajikistan, and Kyrgyzstan and the Caucasus countries of Azerbaijan, Georgia, and Armenia were tested for virulence to 20 isolines of Thatcher wheat with different leaf rust resistance genes and molecular genotype at 23 simple sequence repeat (SSR) loci. After clone correction within each country, 99 isolates were analyzed for measures of population diversity, variation at single SSR loci, and for genetic differentiation of virulence phenotypes and SSR genotypes. Isolates from Central Asia and the Caucasus were also compared with 16 P. triticina isolates collected from common wheat in North America that were representative of the virulence and molecular variation in this region and two isolates collected from durum wheat in France and the United States. Populations from the Caucasus, Uzbekistan, Tajikistan, and Kyrgyzstan were not significantly (P > 0.05) differentiated for SSR variation with F(st) and R(st) statistics. Populations from the Caucasus, Uzbekistan, Tajikistan, and Kyrgyzstan were significantly (P < 0.05) differentiated from the populations in South and North Kazakhstan for SSR variation. All populations from Central Asia and the Caucasus were significantly differentiated from the North American isolates and isolates from durum wheat for SSR variation and virulence phenotypes. There was a correlation between virulence phenotype and SSR genotype among individual isolates and at the population level. Mountain barriers may account for the differentiation of P. triticina geographic populations in Central Asia and the Caucasus. 相似文献
5.
由于地理生态条件、叶锈菌群体结构、研究历史和研究方法等的差异,不同国家和地区采用相应的小麦叶锈菌鉴别寄主和小种命名方法。美洲、中国、欧洲、埃及、南非等国家和地区均采用以Thatcher为遗传背景的分别含有Lr1、Lr2 a、Lr2 c、Lr3、Lr9、Lr16、Lr24、Lr26、Lr3 ka、Lr11、Lr17和Lr30基因的近等基因系或单基因系作为小麦叶锈菌鉴别寄主,但附加的辅助鉴别品种不尽相同;澳大拉西亚和印度的鉴别寄主自成体系。这种格局不利于国家间研究结果的对比和交流。因此,建立一套国际通用鉴别体系实属当务之急。 相似文献
6.
A pathogenicity survey of Puccinia recondita f.sp. tritici ( Prt ) was conducted in western Europe in 1995. Random urediospore isolates (850) of Prt were collected from the air by means of a jet spore sampler in wheat-growing regions of Austria, Belgium, France, Germany, northern Italy, Switzerland and the UK. Pathogenicity of the isolates was determined in tests of detached primary leaf segments maintained on water agar supplemented with benzimidazole (35 p.p.m.). The differential genotypes used were Thatcher, 20 near-isogenic Thatcher lines each with a single leaf rust resistance gene, and five cultivars/lines with additional resistance genes. All isolates were avirulent for the genes Lr9, Lr19, Lr21, Lr24, Lr25 and Lr29 , and both virulence and avirulence were detected for the remaining 19 genes. Fifty-three pathotypes were identified, four of which predominated (64% of isolates) and were widespread throughout western Europe. Three of the four predominant pathotypes were also identified in collections of wheat leaf rust collected in Poland, Hungary, Estonia and Finland. One pathotype, which comprised 35% of isolates in the south of France, was not detected in any other region. This pathotype was indistinguishable from several isolates obtained from Morocco, which suggested that it may have originated from northern Africa. Comparisons with previously published data suggested that the four predominant pathotypes were very similar and possibly the same as pathotypes present in the former Czechoslovakia for up to 20 years. The results obtained provide evidence of migration of Prt over considerable distances in western Europe, stressing the need for a co-ordinated approach for genetical control of the disease in this region. 相似文献
7.
ABSTRACT Alsen is a recently released spring wheat cultivar that has been widely grown in the United States because it has resistance to Fusarium head blight and leaf rust caused by Puccinia triticina. Norm is a high yielding wheat cultivar that has been very resistant to leaf rust since it was released. Alsen and Norm were genetically examined to determine the number and identity of the leaf rust resistance genes present in both wheats. The two cultivars were crossed with leaf rust susceptible cv. Thatcher and F(1) plants were backcrossed to Thatcher. Eighty one and seventy three BCF(1) of Thatcher times; Alsen and Thatcher x Norm respectively, were selfed to obtain BCF(2) families. The BCF(2) families were tested as seedlings with different isolates of P. triticina that differed for virulence to specific leaf rust resistance genes. The BCF(2) families that lacked seedling resistance were also tested as adult plants in greenhouse tests and in a field rust nursery plot. Segregation of BCF(2) families indicated that Alsen had seedling genes Lr2a, Lr10, and Lr23 and adult plant genes Lr13 and Lr34. Norm was determined to have seedling genes Lr1, Lr10, Lr16, and Lr23 and adult plant genes Lr13 and Lr34. The characterization of Lr23 in the segregating populations was complicated by the presence of a suppressor gene in Thatcher and the high temperature sensitivity of resistance expression for this gene. The effective leaf rust resistance in Alsen is due to the interaction of Lr13 and Lr23, with Lr34; and the effective leaf rust resistance in Norm is due to the interaction of Lr13, Lr16, and Lr23, with Lr34. 相似文献
8.
1999年我国小麦叶锈菌毒性监测 总被引：7，自引：1，他引：7
采用国际通用的小麦叶锈菌鉴别寄主和辅助鉴别寄主分析了来自1999年我国不同地区小麦叶锈菌的毒性基因,479个叶锈菌株共划分为162个毒性类型,其中23个为主要毒性类型.毒性类型中出现频率最高的为FHB、PHT、FHG、THT,它们对抗叶锈基因Lr2a、Lr2b、Lr3、Lr10、Lr14b、Lr16、 Lr26的平均毒性频率高于80%,而对Lr3ka、Lr25、Lr19、Lr24、Lr30、Lr15、Lr35的平均毒性频率低于30%;发现对Lr35有毒力的菌株,出现频率为1.04%;至今尚未发现对Lr38、Lr45抗性基因有毒力的菌株.研究同时发现,不同地区小麦叶锈菌的毒性类型不同,毒性频率存在一定的差异.Lr9、Lr15、Lr19、Lr24、Lr35、Lr38、Lr45为小麦抗叶锈育种可利用的有效抗病基因. 相似文献
9.
Leaf rust of wheat, caused by Puccinia triticina, is a common and widespread disease in the Middle East. The objective of this study was to determine whether genetically differentiated groups of P. triticina are present in the Middle East region and to compare the population from the Middle East with the previously characterized population from Central Asia to determine whether genetically similar groups of isolates are found in the two regions. In total, 118 isolates of P. triticina collected from common wheat and durum wheat in Egypt, Israel, Turkey, Ethiopia, and Kenya were tested for virulence on 20 lines of wheat with single genes for leaf rust resistance and for molecular genotypes with 23 simple-sequence repeat (SSR) markers. After removal of isolates with identical virulence and SSR genotype in each country, 103 isolates were retained for further analysis. Clustering of SSR genotypes based on two-dimensional principal coordinates and virulence to wheat differential lines grouped the isolates into four Middle East (ME) groups. The two largest ME groups had virulence phenotypes typical of isolates collected from common wheat and two smaller ME groups had virulence typical of isolates collected from durum wheat. All pairs of ME groups were significantly differentiated for SSR genotype based on R(ST) and F(ST) statistics, and for virulence phenotype based on Φ(PT). All ME groups had observed values of heterozygosity greater than expected and significant fixation indices that indicated the clonal reproduction of urediniospores in the overall population. Linkage disequilibria for SSR genotypes was high across the entire population. The overall values of R(ST) and F(ST) were lower when isolates were grouped by country of origin that indicated the likely migration of isolates within the region. Although the two ME groups with virulence typical of isolates from common wheat were not differentiated for SSR genotype from groups of isolates from Central Asia based on R(ST), there was no direct evidence for migration between the two regions because all ME isolates differed from the Central Asia isolates for SSR genotypes. 相似文献
10.
为明确春小麦品种沈免2063所含抗叶锈病基因的对数、身份、显隐性和互作关系,以沈免2063为父本,分别与感病品种Thatcher及小麦抗叶锈病近等基因系Lr9、Lr19、Lr24、Lr25、Lr28、Lr42和Lr43的载体品系杂交,获得F1、F2和F3代群体后,分别在苗期和成株期进行抗病性测定。结果表明:沈免2063含有3对显性遗传且相互独立作用的抗叶锈病基因Lr9、Lr19和Lr25,在苗期,沈免2063对致病类型CBG/QQ的抗病性由Lr9和Lr25控制,对PHT/RP的抗病性由上述3对抗叶锈病基因控制;在成株期,沈免2063对优势致病类型PHT/RP和THT/TP等比混合菌种的抗病性由上述3对抗叶锈病基因控制。Lr9、Lr19和Lr25在育成品种中出现频率很低,目前尚很有效,但这3个基因均为典型的垂直抗病性基因,应进行基因布局、基因轮换等科学组配,才能延长其使用寿命。 相似文献
11.
J. A. Kolmer Z. Mert K. Akan L. Demir R. Ünsal C. Şermet M. Keser B. Akin A. Morgounov 《European journal of plant pathology / European Foundation for Plant Pathology》2013,135(4):703-716
Leaf rust caused by Puccinia triticina is a common disease on wheat in the coastal regions of Turkey. Collections of P. triticina from infected wheat leaves were obtained from the main wheat production zones of Turkey in 2009 and 2010. A total of 104 single uredinial isolates were tested for virulence on 20 lines of Thatcher wheat that differ for single leaf rust resistance genes. Forty-four different virulence phenotypes were identified over both years. Four phenotypes were found in both years. Phenotype FHPTQ found in 2009, with virulence to genes Lr2c, Lr3, Lr16, Lr26, Lr3ka, Lr17a, Lr30, LrB, Lr10, Lr14a, Lr18, Lr3bg, and Lr14b, was the most common phenotype at 15.4 % of the total isolates. Forty-three winter and spring wheat cultivars from Turkey were tested as seedlings with 13 different P. triticina virulence phenotypes from Canada, the US and Turkey. The infection types on the cultivars were compared with infection types on the Thatcher near isogenic lines to postulate the presence of seedling leaf rust resistance genes in the cultivars. Resistance genes Lr1, Lr3a, Lr10, Lr14a, Lr17a, Lr20, Lr23, and Lr26 were postulated to be present in the Turkish wheat cultivars. DNA of the wheat cultivars was tested with PCR markers to determine the presence of the adult plant resistance genes Lr34 and Lr37. Marker data indicated the presence of Lr34 in 20 cultivars and Lr37 in three cultivars. Field plot evaluations of the wheat cultivars indicated that no single Lr gene conditioned highly effective leaf rust resistance. Resistant cultivars varied for combinations of seedling and adult plant resistance genes. 相似文献
12.
冬小麦品种北京837抗叶锈病基因的染色体定位研究 总被引：2，自引：0，他引：2
1990~1993年间,引用中国春全套单体系列和抗叶锈病小麦近等基因系(或单基因系)为材料,采用单体遗传分析和基因推导相结合的方法,对冬小麦品种北京837抗叶锈病基因进行染色体定位研究,明确其对生理小种叶中1号的抗性系由分别位于染色体1B和6B上的两个显性互补基因所控制。位于1B染色体上的基因可能是Lr26,位于6B上的可能是Lr3a,二者可抵抗我国小麦叶锈菌群体中的部分生理小种(或毒性基因组合)。 相似文献
13.
ABSTRACT A leaf rust attacking Aegilops speltoides in its natural habitat is reported for the first time. It was found in two locations in northern and central Israel. The two collections from A. speltoides resemble wheat leaf rust, Puccinia triticina, in most spore dimensions, in the morphology of the substomatal vesicle of the urediniospore, and in DNA content in pycniospore nuclei. Similarly to P. triticina isolates from wheat, isolates taken from A. speltoides are compatible with Thalictrum speciosissimum as an aecial host and they are crossed easily with wheat leaf rust isolates. However, isolates from A. speltoides differ from wheat leaf rust in their telial host range. They are avirulent to cultivated wheat cultivars, but attack hundreds of A. speltoides accessions that were immune to wheat leaf rust. This distinct host preference justifies delineation of the newly found leaf rust as a forma specialis (f. sp. speltoides) within P. triticina. 相似文献
14.
ABSTRACT Isolates of wheat leaf rust collected from durum and bread wheat cultivars in France during 1999-2002 were analyzed for virulence on 18 Thatcher lines with single genes for leaf rust resistance (Lr genes). Sampling focused on the five most widely grown bread wheat cultivars (two susceptible and three resistant) to allow statistical comparison of diversity indexes between the cultivars. Leaf rust populations from durum and bread wheats were different. The diversity of the bread wheat leaf rust pathotypes, as measured by the Shannon index, ranged from 2.43 to 2.76 over the 4 years. Diversity for wheat leaf rust resistance was limited in the host since we postulated only seven seedling resistance genes in the 35 cultivars most widely grown during 1999-2002. Leaf rust populations were strongly differentiated for virulence within bread wheat cultivars, and diversity was higher on those that were resistant, mainly due to a more even distribution of virulence phenotypes than on susceptible cultivars. The pathogen population on the susceptible cv. Soissons was largely dominated by a single pathotype (073100), whereas all other pathotypes virulent on cv. Soissons either decreased in frequency or remained at a low frequency during the period studied. Several pathotypes including the most complex one were found only on resistant cultivars, even though most of them were virulent on the susceptible cv. Soissons. Specific interactions were necessary, but not always sufficient, to account for pathotype distribution and frequencies on the cultivars, suggesting that selection for virulence to host resistance genes is balanced by other selective forces including selection for aggressiveness. 相似文献
15.
No internationally agreed differential set is available for characterization of virulences in populations of Puccinia triticina causing wheat leaf rust on durum wheat. In a first step, 73 potentially differential host genotypes were tested with 96 durum leaf rust isolates collected in France. A differential set, adapted to the local epidemiological context and useful for comparison with international studies was selected, including French commercial cultivars, Thatcher lines with Lr genes, and international cultivars. In the second step, a sample of 310 isolates collected in France from 1999 to 2009 was characterized on this set. Diversity was very low, as only five pathotypes were distinguished. Genotyping of a subset of 76 isolates according to 20 SSR markers confirmed this low diversity, with 73 isolates belonging to a single dominant genotype. Population was strongly shaped by cultivars, and the findings explain the successive breakdown of resistance sources deployed in French durum wheat cultivars. The gene Lr14a, suggested to be an efficient source of resistance in several European and American countries, was overcome by pathotypes frequent in France since 2000. Postulation of resistance genes in the commercial cultivars led to a proposed simplified version of the differential set. This study, providing new information about leaf rust resistance genes present in the French durum wheat germplasm, highlights the need to diversify sources of resistance to P. triticina in this germplasm. The results are also discussed in terms of relatedness and intercontinental migration of P. triticina on durum wheat. 相似文献
16.
T. G. Terefe B. Visser L. Herselman R. Prins T. Negussie J. A. Kolmer Z. A. Pretorius 《European journal of plant pathology / European Foundation for Plant Pathology》2014,139(1):95-105
Samples of wheat and triticale infected with leaf rust were collected from 2008 to 2010 in South Africa to identify Puccinia triticina races. Races were identified based on their virulence profile on standard differential lines. Eight races were identified from 362 isolates. The dominant races were 3SA133 (syn. PDRS) in 2008 (78 %) and 2009 (34 %), and 3SA145 (47 %) in 2010. Race 3SA145 (CCPS) identified in 2009 was a new race in South Africa with virulence for the adult plant resistance gene Lr37. Another new race, 3SA146 (MCDS), was identified in 2010. Race 3SA146 is also virulent for Lr37 but unlike 3SA145, it is virulent for Lr1 and Lr23 and avirulent for Lr3ka and Lr30. Microsatellite analysis showed that 3SA145 and 3SA146 shared 70 % genetic similarity with each other, but only 30 % similarity with other races in South Africa, suggesting that both represent foreign introductions. In seedling tests of 98 South African winter and spring cultivars and advanced breeding lines, 27 % were susceptible to 3SA145 and 3SA146 but resistant to 3SA133. In greenhouse studies of 59 spring wheat adult plants, 19 % of breeding lines and 46 % of cultivars were susceptible to 3SA145, whereas 29 % of the lines and 53 % of cultivars were susceptible to 3SA146. The cssfr6 gene-specific DNA marker confirmed the presence of Lr34 gene for leaf rust resistance in a homozygous condition in 28 wheat entries. Five entries were heterogeneous for Lr34. Several entries which were susceptible as seedlings to the new races carried Lr34. These lines are expected to show lower levels of leaf rust as adult plants. Results of these studies indicate a continued vulnerability of South African wheat cultivars to new races and emphasise the importance of regular rust monitoring and the need to incorporate genes for durable resistance. 相似文献
17.
小麦抗叶锈基因Lr19来源于长穗偃麦草,表现优良的抗叶锈性,国内外发现对Lr19有毒性的小麦叶锈菌菌株的报道较少。本研究以TcLr19和Thatcher亲本以及TcLr19×Thatcher F2代单株构建的分离群体为材料,建立了与Lr19共分离的稳定的SCAR分子标记,命名为Y19SCAR982。对49个小麦抗叶锈近等基因系材料的稳定性检测结果表明,其重复性好且为Lr19特异的分子标记。对120个小麦品种检测的结果表明,该标记可有效应用于小麦抗叶锈分子辅助选择育种。 相似文献
18.
中国三麦区小麦抗叶锈基因部署研究 总被引：3，自引：1，他引：3
利用已知抗叶锈基因的小麦近等基因系(或单基因系),推导了来自中国3大麦区(东北春麦区、华北平原冬麦区、江淮半冬麦区)的主要小麦品种,待推广品种(系)和抗源材料中可能含有的抗叶锈基因,分析了3大麦区小麦叶锈菌群体的毒性基因。研究结果表明,东北春麦区的小麦品种可能含有的抗叶锈基因主要有Lr16、Lr20、Lr17等11个;华北平原冬麦区的小麦品种,可能含有的抗叶锈基因主要是Lr26等7个,江淮麦区的小麦品种可能含有的抗叶锈基因主要是Lr3Bg、Lr10、Lr26等9个。对3大麦区小麦叶锈菌群体的毒性基因分析表明,V1、V2d、V3、V10、V26、V33等13个基因是3大麦区的优势毒性基因,但个别毒性基因在3大麦区的出现频率仍有较大差别。根据基因对基因概念,在基因部署上建议,东北麦区减少含单个无效抗病基因的品种如90-05744、91-1179、东农88-5797等的种植面积,适当控制含Lr20、17、15、30、3Ka的品种,增加沈免系统及小冰麦系统的种植面积;华北麦区增加含Lr14a、14ab、15的品种的种植面积,如CA9069、CA8646、CA9070、C489和冀87-5108等,减少含单个Lr26的品种的种植面积,江淮麦区适当减少肖农12(Lr3Bg)、偃师9号(Lr26)、8870(Lr26)等含单个无效抗病基因的品种,适当增加含Lr2b、3Ka、30的品种如内乡5号、宁8931等的种植面积。本文初步讨论了不同生态区小麦叶锈菌的基因鉴定系统。 相似文献
19.
二倍体及四倍体中抗叶锈病基因在双二倍体中的表达与抑制 总被引：2，自引：0，他引：2
通过杂交将近缘植物中的抗病基因导入普通小麦是抗病育种的常用方法。在利用二倍体和四倍体杂交合成双二倍体小麦过程中, 二倍体或四倍体携带的抗叶锈病基因在双二倍体中大多数情况下可以完全表达或部分表达其固有的抗病性, 但部分抗叶锈病基因则不能表达。四倍体波斯小麦Ps5、Ps8和野生二粒小麦D s3含有相同的抗叶锈病基因LrPs (暂定名), 在双二倍体Am1、Am2、Am3、Am5和Am7中可以表达其抗病性, 但在Am4中不能表达;二倍体粗山羊草Ae37含有Lr41和未知基因, 但Lr41在双二倍体Am2中不能表达;四倍体硬粒小麦Dr147携带Lr23和未知基因, 在双二倍体Am6中不能充分表达。抑制基因的存在是导致抗病基因不能表达或部分表达的主要原因之-。抑制基因位于AB染色体组或D染色体组上, 其抑制作用对抗病基因和病菌致病类型具有专化性, 还可能受温度等环境条件和寄主遗传背景等因素的影响。遗传分析结果表明, 在常温下, 双二倍体Am1、Am2、Am3和Am5对叶锈菌致病类型DGS/HB的抗病性均由1对相同的隐性抗病基因LrPs (暂定名)控制, 与它们具有共同的四倍体亲本Ps5有关。Am4不具有苗期抗叶锈病基因, 但含有来自粗山羊草A e39的1对隐性抑制基因SuLrPs (暂定名), 可抑制Am1、Am2、Am3和Am5中隐性抗叶锈病基因的表达。对抗病抑制基因存在原因和遗传分析验证方法等进行了讨论。 相似文献
20.
ABSTRACT Host plant resistance is an economical and environmentally sound method of control of leaf rust caused by the fungus Puccinia triticina, which is one of the most serious diseases of wheat (Triticum aestivum) worldwide. Wild relatives of wheat, including the tetraploid T. timopheevii subsp. armeniacum, represent an important source of genes for resistance to leaf rust. The objectives of this study were to (i) evaluate the performance of leaf rust resistance genes previously transferred to wheat from three accessions of T. timopheevii subsp. armeniacum, (ii) determine inheritance and allelic relationship of the new leaf rust resistance genes, and (iii) determine the genetic map location of one of the T. timopheevii subsp. armeniacum-derived genes using microsatellite markers. The leaf rust resistance gene transferred to hexaploid wheat from accession TA 28 of T. timopheevii subsp. armeniacum exhibited slightly different infection types (ITs) to diverse races of leaf rust in inoculated tests of seedlings compared with the gene transferred from TA 870 and TA 874. High ITs were exhibited when seedlings of all the germ plasm lines were inoculated with P. triticina races MBRL and PNMQ. However, low ITs were observed on adult plants of all lines having the T. timopheevii subsp. armeniacum-derived genes for resistance in the field at locations in Kansas and Texas. Analysis of crosses between resistant germ plasm lines showed that accessions TA 870 and TA 874 donated the same gene for resistance to leaf rust and TA 28 donated an independent resistance gene. The gene donated to germ plasm line KS96WGRC36 from TA 870 of T. timopheevii subsp. armeniacum was linked to microsatellite markers Xgwm382 (6.7 cM) and Xgdm87 (9.4 cM) on wheat chromosome arm 2B long. This new leaf rust resistance gene is designated Lr50. It is the first named gene for leaf rust resistance transferred from wild timopheevi wheat and is the only Lr gene located on the long arm of wheat homoeologous group 2 chromosomes. 相似文献