56个小麦品种（系）的苗期和成株抗叶锈鉴定

为了研究中国小麦品种中所携带的抗叶锈基因,对56个小麦品种（系）进行苗期接种推导其中所含有的抗叶锈基因,同时连续2年对供试材料进行田间成株抗叶锈鉴定。通过苗期基因推导结合分子标记辅助检测,结果表明,在36个小麦品种中共鉴定出Lr26、Lr34、Lr1、Lr2a、Lr11、Lr20、Lr30、Lr33和Lr44等9个抗叶锈基因,其中28个品种含有Lr26,Lr1和Lr20分别存在于6个品种中,4个品种含有Lr30,Lr11和Lr44各存在于2个品种中,Lr2a、Lr33和Lr34各自在1个品种中出现。经过2年的田间抗叶锈鉴定共筛选出46个慢锈品种。筛选到的这些苗期和成株抗病品种均可用于小麦持久抗叶锈品种的培育。     

兼抗型成株抗性小麦品系的培育、鉴定与分子检测

小麦条锈病、叶锈病和白粉病是我国小麦的重要真菌病害,培育兼抗型成株抗性品种是控制病害最为经济有效和持久安全的方法。本研究选用由成株抗性育种方法培育的21份冬小麦高代品系和96份春小麦高代品系,在多个环境下进行这3种病害的成株期抗性鉴定,并利用紧密连锁的分子标记检测了兼抗型基因Lr34/Yr18/Pm38、Lr46/Yr29/Pm39和Sr2/Yr30的分布。田间鉴定表明,21份冬小麦品系中有17份兼抗3种病害,占80.9%;96份春小麦品系中有85份兼抗3种病害,占88.5%。分子标记检测发现,21份冬小麦品系均含QPm.caas-4DL,其中7份还含QPm.caas-2BS,9份还含QPm.caas-2BL;96份春小麦品系中,18份含Lr34/Yr18/Pm38,37份含Lr46/Yr29/Pm39,29份含Sr2/Yr30。以上结果表明,分子标记与常规育种相结合,可有效培育兼抗型成株抗性品种,为我国小麦抗病育种提供了新思路。     

Cytogenetic studies in wheat XIX. Chromosome location and linkage studies of a gene for leaf rust resistance in the Australian cultivar 'Harrier'

Monosomic analysis indicated that a seedling leaf rust resistance gene present in the Australian wheat cultivar ‘Harrier’(tentatively designated LrH) is located on chromosome 2A. LrH segregated independently of the stripe rust resistance gene Yr1 located in the long arm of that chromosome, but failed to recombine with Lr17 located in the short arm. LrH was therefore designated Lr17b and the allele formerly known as Lr17 was redesignated as Lr17a. The genes Lr17b and Lr37 showed close repulsion linkage. Tests of allelism indicated that Lr1 7b is also present in the English wheats ‘Dwarf A’(‘Hobbit Sib’), ‘Maris Fundin’ and ‘Norman’. Virulence for Lr17b occurs in Australia, and pathogenicity studies have also demonstrated virulence in many western European isolates of the leaf rust pathogen. Despite this, it is possible that the gene may be of value in some regions if used in combination with other leaf rust resistance genes.     

Enhanced leaf rust resistance in wheat conditioned by resistance gene pairs with Lr13

Summary Leaf rust resistance gene Lr13 is present in many North American hard red spring wheat cultivars that have shown durable resistance to leaf rust. Fifteen pair-wise combinations of Lr13 and seedling leaf rust resistance genes were developed by intercrossing near isogenic Thatcher lines. In both seedling and adult plant tests, homozygous paired combinations of specific resistance genes with Lr13 had enhanced resistance relative to either parent to rust isolates that had intermediate avirulent infection types to the additional genes. In field tests, homozygous lines were more resistant than either parent if the additional leaf rust gene conditioned an effective level of resistance when present singly.     

Evaluation of seedling and adult plant resistance to leaf rust in European wheat cultivars

Summary A set of 105 European wheat cultivars, comprising 68 cultivars with known seedling resistance genes and 37 cultivars that had not been tested previously, was tested for resistance to selected Australian pathotypes of P. triticina in seedling greenhouse tests and adult plant field tests. Only 4% of the cultivars were susceptible at all growth stages. Twelve cultivars lacked detectable seedling resistance to leaf rust, and among the remaining cultivars, 10 designated genes were present either singly or in combination. Lr13 was the most frequently detected gene, present in 67 cultivars, followed by the rye-derived gene Lr26, present in 19 cultivars. Other genes present were Lr1, Lr3a, Lr3ka, Lr10, Lr14a, Lr17b, Lr20 and Lr37. There was evidence for unidentified seedling resistance in addition to known resistance genes in 11 cultivars. Field tests with known pathotypes of P. triticina demonstrated that 57% of the cultivars carried adult plant resistance (APR) to P. triticina. The genetic identity of the APR is largely unknown. Genetic studies on selected cultivars with unidentified seedling resistances as well as all of those identified to carry APR are required to determine the number and inheritance of the genes involved, to determine their relationships with previously designated rust resistance genes, and to assess their potential value in breeding for resistance to leaf rust.     

Improving wheat stripe rust resistance in Central Asia and the Caucasus

Wheat is the most important cereal in Central Asia (Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan and Uzbekistan) and the Caucasus (Armenia, Azerbaijan and Georgia). Stripe rust, caused by Puccinia striiformis f. sp. tritici is considered the most important disease of wheat in Central Asia and the Caucasus (CAC). Although stripe rust has been present in the region for a long time, it has become a serious constraint to wheat production in the past 10 years. This is reflected by the occurrence of five epidemics of stripe rust in the CAC region since 1999, the most recent in 2010. Several wheat varieties occupying substantial areas are either susceptible to stripe rust or possess a low level of resistance. Information on the stripe rust pathogen in terms of prevalent races and epidemiology is not readily available. Furthermore, there is an insufficient understanding of effective stripe rust resistance genes in the region, and little is known about the resistance genes present in the commercial varieties and advanced breeding lines. The deployment of resistant varieties is further complicated by putative changes in virulence in the pathogen population in different parts of the CAC. Twenty four out of 49 improved wheat lines received through international nurseries or other exchange programs showed high levels of resistance to stripe rust to local pathogen populations in 2009. Fifteen of the 24 stripe rust resistant lines also possessed resistance to powdery mildew. It is anticipated that this germplasm will play an important role in developing stripe rust resistant wheat varieties either through direct adoption or using them as parents in breeding programs.     

Molecular genetics of race non-specific rust resistance in wheat

Over 150 resistance genes that confer resistance to either leaf rust, stripe rust or stem rust have been catalogued in wheat or introgressed into wheat from related species. A few of these genes from the ‘slow-rusting’ adult plant resistance (APR) class confer partial resistance in a race non-specific manner to one or multiple rust diseases. The recent cloning of two of these genes, Lr34/Yr18, a dual APR for leaf rust and stripe rust, and Yr36, a stripe rust APR gene, showed that they differ from other classes of plant resistance genes. Currently, seven Lr34/Yr18 haplotypes have been identified from sequencing the encoding ATP Binding Cassette transporter gene from diverse wheat germplasm of which one haplotype is commonly associated with the resistance phenotype. The paucity of well characterised APR genes, particularly for stem rust, calls for a focused effort in developing critical genetic stocks to delineate quantitative trait loci, construct specific BAC libraries for targeted APR genes to facilitate robust marker development for breeding applications, and the eventual cloning of the encoding genes.     

Molecular markers for the identification of resistance genes and marker-assisted selection in breeding wheat for leaf rust resistance

The resistance genes Lr9, Lr24, Lr25, Lr29, Lr35 and Lr37, which were not previously utilised in Hungary, have been incorporated into four Martonvásár winter wheat cultivars using marker-assisted selection with PCR-based markers. In the course of a backcross programme, the genes were transferred into Martonvásár wheat varieties and various BC generations were produced. Work aimed at pyramiding resistance genes is currently underway in Martonvásár, and plants containing the gene combinations Lr9 + Lr24, Lr9 + Lr25 and Lr9 + Lr29 are now available. From the BC₂F₄ generation of the ‘Mv Emma’*3/’R.L.6010’ combination (‘R.L.6010’ is the donor of the Lr9 gene) 287 lines were tested for leaf rust resistance in an artificially inoculated nursery. A co-dominant primer combination was designed to identify both resistant and susceptible offsprings. The results of resistance tests and molecular marker detection agreed in most cases. Designated leaf rust resistance genes were identified with molecular markers in wheat varieties and breeding lines. The Lr26 and Lr34 resistance genes occur frequently in the Martonvásár gene pool, and the presence of the Lr37 gene has also been detected in a number of Hungarian genotypes.     

Resistance to leaf rust in cultivars of bread wheat and durum wheat grown in Spain

A set of bread wheat and durum wheat cultivars adapted to Spanish conditions was tested for resistance against leaf rust caused by different pathotypes of Puccinia triticina in field trials and in growth chamber studies. Lower levels of resistance were found in durum wheat than in bread wheat. The most frequent Lr genes found in bread wheat were Lr1, Lr10, Lr13, Lr20, Lr26 and Lr28. In durum wheat, additional resistance genes that differed from the known Lr genes were identified. The level of partial resistance to leaf rust was in general low, although significant levels were identified in some bread wheat and durum wheat cultivars.     

Specific resistance to leaf rust expressed at the seedling stage in cultivars grown in France from 1983 to 2007

Host resistance is the most economical means to reduce yield losses caused by wheat leaf rust. Knowledge of the effective specific resistance genes is a prerequisite for analysis of the non-specific components of resistance, assumed to be more durable than specific resistance. Lr genes were inferred from seedling response phenotype of 275 wheat cultivars and 21 standard isolates of Puccinia triticina. Enough cultivars were selected for analysis so that findings would account for at least two-thirds of the French agricultural land dedicated to wheat from 1983 to 2007. In this paper, genes Lr13, Lr37, Lr10, Lr14a, Lr3, Lr26, Lr1, Lr24, Lr20 are postulated, alone or in combinations, in, respectively, 67%, 45%, 34%, 20%, 8%, 7%, 6%, 1%, and 1% of the cultivars. Forty five phenotypic arrays were found, the most frequent being (Lr10, Lr13, Lr37) and (Lr13) in 45 and 37 cultivars, respectively. Over the period, the combinations became increasingly complex. Isolates with virulence corresponding to most of the Lr gene combinations were identified in the pathogen population, except for combinations involving Lr24 and some unidentified genes. These findings will help breeders and extension service staff (Arvalis) in diversifying sources of resistance to wheat leaf rust. This information is also crucial for research programs aiming, on the one hand, to identify sources of quantitative resistance, and, on the other hand, to quantify selection pressure exerted on pathogen populations.     

28个小麦微核心种质抗叶锈性分析

选取在成株期表现高、中、低抗叶锈的28个小麦微核心种质,利用39个以Thatcher为背景的近等基因系(或单基因系)作为已知基因的鉴别寄主,接种8个小麦叶锈菌致病型进行苗期抗叶锈基因推导,结合成株期抗病鉴定,初步明确了这些品种(系)的抗性和可能携带的抗病基因。利用19个与Lr基因紧密连锁或共分离的分子标记,对28个微核心种质进行抗叶锈病基因的进一步鉴定,推测新克旱9号可能含有Lr17、Lr2b、Lr14a和Lr33;兴义4号可能含有Lr26、Lr36和Lr37;紫皮可能含有Lr2b和Lr34;大白皮含有Lr1;毕红穗含有Lr1、Lr10和Lr34;中优9507含有Lr10;小白麦、红粒当年老、老麦、蝉不吱、苏麦3号和车锏子含有Lr1和Lr34;红花早可能含有Lr1、Lr34、Lr14a和Lr2b;江西早、泡子麦、三月黄、有芒扫谷旦、阜阳红、成都光头和酱麦可能含有Lr34;敦化春麦和甘肃96可能含有Lr28;欧柔可能含有Lr34、Lr16、Lr11、Lr3bg和Lr33;此外,新克旱9号、兴义4号、红花早、红粒当年老、欧柔、有芒扫谷旦、成都光头、甘肃96、小红皮、定兴寨、中优9507和红冬麦中可能含有未知抗病基因;在这28份种质中,不含Lr9、Lr19、Lr20、Lr21、Lr24、Lr29、Lr35、Lr38和Lr47基因。研究结果表明,测试的微核心种质中含有比较丰富的抗叶锈病基因,可为育种提供丰富的抗源。     

The role of Lr34 in imparting durable resistance to wheat leaf rust through gene interaction

Summary The leaf rust responses of wheat lines carrying the complementary genes Lr27 and Lr31 and the same genes in a Chinese Spring background which contains Lr34, indicate that Lr34 interacts with the complementary genes to give enhanced levels of field resistance to leaf rust. Lr34, particularly in combination with other genes, is considered to be an important gene for imparting a high degree of durable resistance to leaf rust. Its similarity to Sr2, an adult plant gene for resistance to stem rust and its association with adult plant resistances to stem and stripe rusts are discussed.     

Development of a PCR assay and marker-assisted transfer of leaf rust resistance gene <Emphasis Type="Italic">Lr58</Emphasis> into adapted winter wheats

Leaf rust resistance gene Lr58 derived from Aegilops triuncialis L. was transferred to the hard red winter wheat (HRWW) cultivars Jagger and Overley by standard backcrossing and marker-assisted selection (MAS). A co-dominant PCR-based sequence tagged site (STS) marker was developed based on the sequence information of the RFLP marker (XksuH16) diagnostically detecting the alien segment in T2BS·2BL-2^tL(0.95). STS marker Xncw-Lr58-1 was used to select backcross F₁ plants with rust resistance. The co-dominant marker polymorphism detected by primer pair NCW-Lr58-1 efficiently identified the homozygous BC₃F₂ plants with rust resistance gene Lr58. The STS marker Xncw-Lr58-1 showed consistent diagnostic polymorphism between the resistant source and the wheat cultivars selected by the US Wheat Coordinated Agricultural Project. The utility and compatibility of the STS marker in MAS programs involving robust genotyping platforms was demonstrated in both agarose-based and capillary-based platforms. Screening backcross derivatives carrying Lr58 with various rust races at seedling stage suggested the transferred rust resistance in adapted winter wheats is stable in both cultivar backgrounds. Lr58 in adapted winter wheat backgrounds could be used in combination with other resistance genes in wheat rust resistance breeding.     

Inheritance of seedling and adult plant resistance to leaf rust of selected Australian spring and English winter wheat varieties

Genetic studies were conducted to gain an understanding of the inheritance of adult plant resistance (APR) to leaf rust in six common wheat varieties. The Australian varieties ‘Cranbrook’ and ‘Harrier’ each carry two genes for APR to leaf rust. These genes are genetically independent of the seedling resistance genes Lr23 and Lrl7b, carried by the respective varieties. Adult plant resistance in ‘Suneca’ was conferred by at least two genes, in addition to the seedling genes Lr1 and Lrli. It is likely that the APRs in ‘Cranbrook’, ‘Harrier’ and ‘Suneca’ are conferred by uncharacterized gene(s). Tests of allelism confirmed that seedling resistances in the varieties ‘Avocet R’, ‘Hereward’, ‘Moulin’ and ‘Pastiche’ are conferred by Lrli. Adult plant resistance in the variety ‘Hereward’ was inherited monogenically, whereas varieties ‘Moulin’ and ‘Pastiche’ each carried two dominant genes. On the basis of rust specificity and pedigree analysis, it would seem likely that the APR genes in ‘Hereward’, ‘Moulin’ and ‘Pastiche’ are also currently uncharacterized.     

Genetics of leaf rust resistance in three Americano landrace-derived wheat cultivars from Uruguay

A genetic analysis of the landrace‐derived wheat accessions Americano 25e, Americano 26n, and Americano 44d, from Uruguay was conducted to identify the leaf rust resistance genes present in these early wheat cultivars. The three cultivars were crossed with the leaf rust susceptible cultivar ‘Thatcher’ and approximately 80 backcross (BC1) F₂ families were derived for each cross. The BC1F₂ families and selected BC1F₄ lines were tested for seedling and adult plant leaf rust resistance with selected isolates of leaf rust, Puccinia triticina. The segregation and infection type data indicated that Americano 25e had seedling resistance genes Lr3, Lr16, an additional unidentified seedling gene, and one adult plant resistance gene that was neither Lr12 nor Lr13, and did not phenotypically resemble Lr34. Americano 26n was postulated to have genes Lr11, Lr12, Lr13, and Lr14a. Americano 44d appeared to have two possibly unique adult plant leaf rust resistance genes.     

山西省小麦主栽品种抗叶锈病研究

选用14个具有不同毒性基因组合的叶锈菌系，推导分析了来自山西省6个育种单位和种子部门的24个重要小麦品种所携带的抗叶锈病基因状况。在供试的44个已知抗叶锈病基因(或基因组合)中，推导出了Lr1，Lr3，Lr13，Lr23，Lr26，Lr30等6个抗叶锈病基因，以单基因或基因组合形式分别分布在19个小麦品种中，其中Lr1，Lr3，Lr26是供试材料的主要已知抗叶锈病基因。成株期抗病性鉴定结果表明，在24个供试品种中，仅有晋麦62号和鲁麦14号两个品种表现出对叶锈病良好的抗性，晋麦31号、晋麦56号和晋麦61号3个品种表现为中抗至中感(杂合类型)，晋春9号、晋春13号、晋偃746—9等12个品种具有慢叶锈病特征。     

Inheritance and QTL mapping of leaf rust resistance in the European winter wheat cultivar ‘Beaver’

Genetic studies were conducted on an European winter wheat cultivar, Beaver, to determine the mode of inheritance of leaf rust resistance at seedling and adult plant growth stages using a recombinant doubled haploid population, Beaver/Soissons. Greenhouse studies indicated the involvement of genes Lr13 and Lr26 in governing leaf rust resistance at seedling growth stages, whereas, adult plant resistance (APR) in the field with pathotypes carrying virulence individually for Lr13 and Lr26 showed trigenic inheritance for the population. Marker regression analysis of adult plant field data indicated the involvement of six significant QTLs (chromosomes 1B, 3B, 3D, 4B, 4D and 5A) in year 2005, four QTLs (1B, 3B, 4B and 5A) in 2006, and six QTLs (1A, 1B, 3B, 4A, 4B and 5A) in 2007 for reducing leaf rust severity. QTLs on chromosomes 1B, 4B and 5A were considered the most important because of their detection across years, whereas QTLs on chromosomes 1A, 3B, 3D and 4A were either inconsistent or non-significant and unexplained. Based on an association of closely linked markers with phenotypic data, putative single gene stocks were identified for each consistent QTL and crossing was initiated to develop populations segregating for each to permit fine mapping of the identified regions.     

小麦新品种“山农20”抗病基因的分子检测

山农20是2011年和2012年分别通过国家黄淮南、北片审定的小麦高产多抗新品种,在国家区试抗病性鉴定和生产中都表现出良好的抗黄淮麦区主要病害的特性。本研究利用与小麦抗白粉病、条锈病、叶锈病、纹枯病基因和抗赤霉病主效QTL紧密连锁的SSR、SCAR、STS等标记对该品种进行了分子检测,发现山农20含有6个抗白粉病基因(Pm12、Pm24、Pm30、Pm31、Pm35和Pm36),6个抗条锈病基因(Yr5、Yr9、Yr15、Yr24、Yr26和YrTp1),2个抗叶锈病基因(Lr21和Lr26),1个抗纹枯病基因(Ses1),但未检测到抗赤霉病主效QTL。分子检测结果部分解释了山农20的优良抗病性,也为利用分子标记辅助选择培育抗病稳产小麦新品种提供参考。     

Development and Validation of SCAR Markers Co-Segregating with an Agropyron Elongatum Derived Leaf Rust Resistance Gene Lr24 in Wheat

Summary An Agropyron elongatum-derived leaf rust resistance gene Lr24 located on chromosome 3DL of wheat was tagged with six random amplified polymorphic DNA (RAPD) markers which co-segregated with the gene. The markers were identified in homozygous resistant F₂ plants taken from a population segregating for leaf rust resistance generated from a cross between two near-isogenic lines (NILs) differing only for Lr24. Phenotyping was done by inoculating the plants with pathotype 77-5 of Puccinia triticina. To enable gene-specific selection, three RAPD markers (S1302₆₀₉, S1326₆₁₅ and OPAB-1₃₈₈) were successfully converted to polymorphic sequence characterized amplified region (SCAR) markers, amplifying only the critical DNA fragments co-segregating with Lr24. The SCAR markers were validated for specificity to the gene Lr24 in wheat NILs possessing Lr24 in 10 additional genetic backgrounds including the Thatcher NIL, but not to 43 Thatcher NILs possessing designated leaf rust resistance genes other than Lr24. This indicated the potential usefulness of these SCAR markers in marker assisted selection (MAS) and for pyramiding leaf rust resistance genes in wheat.     

‘CPAN 1842’: a new source of adult plant leaf rust resistance in bread wheat

There is worldwide interest in adult plant resistance (APR) because of greater durability of APR to the cereal rusts. Peruvian bread wheat genotype ‘CPAN (Coordinated Project Accession Number) 1842’ (LM 50–53) has shown leaf rust resistance in disease screening nurseries since its introduction in 1977. However, it is susceptible at the seedling stage to several Puccinia triticina (Pt) pathotypes including the widely prevalent 77‐5 (121R63‐1) that infects bread wheat. Inheritance studies showed that CPAN 1842 carried a dominant gene for APR to pathotype 77‐5, which was different from Lr12, Lr13, Lr22a, Lr34, Lr35, Lr37, Lr46, Lr48, Lr49 and Lr68, based on the tests of allelism; and from Lr67, based on genotyping with the closely linked SSR marker cfd71. This gene should also be different from Lr22b as the latter is totally ineffective against pathotype 77‐5. CPAN 1842 therefore appears to be a new promising source of leaf rust resistance. Also having resistance to stem rust and stripe rust, this line can contribute to breeding for multiple rust resistances in wheat.