DOCSLIB.ORG

Environmental Conditions Associated with Stripe Rust and Leaf Rust Epidemics in Kansas Winter Wheat

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Environmental Conditions Associated with Stripe Rust and Leaf Rust Epidemics in Kansas Winter Wheat ENVIRONMENTAL CONDITIONS ASSOCIATED WITH STRIPE RUST AND LEAF RUST EPIDEMICS IN KANSAS WINTER WHEAT by BETHANY GRABOW B.S., Arizona State University, 2006 M.S., Kansas State University, 2010 AN ABSTRACT OF A DISSERTATION submitted in partial fulfillment of the requirements for the degree DOCTOR OF PHILOSOPHY Department of Plant Pathology College of Agriculture KANSAS STATE UNIVERSITY Manhattan, Kansas 2016 Abstract Stripe rust (caused by Puccinia striiformis f. sp. tritici) and leaf rust (caused by Puccinia triticina) are the top two diseases of winter wheat (Triticum aestivum) with a 20-year average yield loss of 4.9% in Kansas. Due to the significant yield losses caused by these diseases, the overall objective of this research was to identify environmental variables that favor stripe and leaf rust epidemics. The first objective was to verify the environmental conditions that favor P. triticina infections in an outdoor field environment. Wheat was inoculated with P. triticina and exposed to ambient weather conditions for 16 hours. Number of hours with temperature between 5 to 25°C and relative humidity >87% were highly correlated and predicted leaf rust infections with 89% accuracy. The results of this outdoor assay were used to develop variables to evaluate the association of environment with regional leaf rust epidemics. Before regional disease models can be developed for a forecast system, suitable predictors need to be identified. Objectives two and three of this research were to identify environmental variables associated with leaf rust and stripe rust epidemics and to evaluate these predictors in models. Mean yield loss on susceptible varieties was estimated for nine Kansas crop reporting districts (CRD’s). Monthly environmental variables were evaluated for association with stripe rust epidemics (>1% yield loss), leaf rust epidemics (>1% yield loss), severe stripe rust epidemics (>14% yield loss) and severe leaf rust epidemics (>7% yield loss) at the CRD scale. Stripe rust and leaf rust epidemics were both strongly associated with soil moisture conditions; however, the timing differed between these diseases. Stripe rust epidemics were associated with soil moisture in fall and winter, and leaf rust epidemics during winter and spring. Severe stripe rust and leaf rust epidemics were associated with favorable temperature (7 to 12°C) and temperature (15 to 20°C) with relative humidity (>87%) or precipitation in May using tree-based methods of classification, respectively. The preliminary models developed in this research could be coupled with disease observations and varietal resistance information to advise growers about the need for foliar fungicides against these rusts in Kansas winter wheat. ENVIRONMENTAL CONDITIONS ASSOCIATED WITH STRIPE RUST AND LEAF RUST EPIDEMICS IN KANSAS WINTER WHEAT by BETHANY GRABOW B.S., Arizona State University, 2006 M.S., Kansas State University, 2010 A DISSERTATION submitted in partial fulfillment of the requirements for the degree DOCTOR OF PHILOSOPHY Department of Plant Pathology College of Agriculture KANSAS STATE UNIVERSITY Manhattan, Kansas 2016 Approved by: Major Professor Erick DeWolf Copyright BETHANY GRABOW 2016 Abstract Stripe rust (caused by Puccinia striiformis f. sp. tritici) and leaf rust (caused by Puccinia triticina) are the top two diseases of winter wheat (Triticum aestivum) with a 20-year average yield loss of 4.9% in Kansas. Due to the significant yield losses caused by these diseases, the overall objective of this research was to identify environmental variables that favor stripe and leaf rust epidemics. The first objective was to verify the environmental conditions that favor P. triticina infections in an outdoor field environment. Wheat was inoculated with P. triticina and exposed to ambient weather conditions for 16 hours. Number of hours with temperature between 5 to 25°C and relative humidity >87% were highly correlated and predicted leaf rust infections with 89% accuracy. The results of this outdoor assay were used to develop variables to evaluate the association of environment with regional leaf rust epidemics. Before regional disease models can be developed for a forecast system, suitable predictors need to be identified. Objectives two and three of this research were to identify environmental variables associated with leaf rust and stripe rust epidemics and to evaluate these predictors in models. Mean yield loss on susceptible varieties was estimated for nine Kansas crop reporting districts (CRD’s). Monthly environmental variables were evaluated for association with stripe rust epidemics (>1% yield loss), leaf rust epidemics (>1% yield loss), severe stripe rust epidemics (>14% yield loss) and severe leaf rust epidemics (>7% yield loss) at the CRD scale. Stripe rust and leaf rust epidemics were both strongly associated with soil moisture conditions; however, the timing differed between these diseases. Stripe rust epidemics were associated with soil moisture in fall and winter, and leaf rust epidemics during winter and spring. Severe stripe rust and leaf rust epidemics were associated with favorable temperature (7 to 12°C) and temperature (15 to 20°C) with relative humidity (>87%) or precipitation in May using tree-based methods of classification, respectively. The preliminary models developed in this research could be coupled with disease observations and varietal resistance information to advise growers about the need for foliar fungicides against these rusts in Kansas winter wheat. Table of Contents List of Figures ................................................................................................................................ xi List of Tables ............................................................................................................................... xiii Acknowledgements ...................................................................................................................... xiv Dedication ..................................................................................................................................... xv Chapter 1 - Literature Review ......................................................................................................... 1 Introduction ................................................................................................................................. 1 Leaf Rust ..................................................................................................................................... 2 Stripe Rust ................................................................................................................................... 7 Research Objectives .................................................................................................................. 11 Literature Cited ......................................................................................................................... 12 Chapter 2 - Effect of temperature and moisture on infection of wheat by Puccinia triticina under field conditions in Kansas. ..................................................................................................... 20 Abstract ..................................................................................................................................... 20 Introduction ............................................................................................................................... 21 Methods .................................................................................................................................... 23 Wheat leaf rust spore increase .............................................................................................. 23 Plant production .................................................................................................................... 24 Wheat leaf rust inoculation procedure .................................................................................. 25 Bioassay ................................................................................................................................ 25 Weather conditions ............................................................................................................... 26 Data analysis ......................................................................................................................... 26 Results ....................................................................................................................................... 29 Variable selection .................................................................................................................. 30 Model fit ................................................................................................................................ 30 Discussion ................................................................................................................................. 31 Literature Cited ......................................................................................................................... 34 Figures and Tables .................................................................................................................... 39 Chapter 3 - Environmental conditions associated with stripe rust in Kansas winter wheat ......... 44 Abstract ..................................................................................................................................... 44 viii Introduction ..............................................................................................................................
Load more

Recommended publications
  • Induced Resistance in Wheat
    https://doi.org/10.35662/unine-thesis-2819 Induced resistance in wheat A dissertation submitted to the University of Neuchâtel for the degree of Doctor in Naturel Science by Fares BELLAMECHE Thesis direction Prof. Brigitte Mauch-Mani Dr. Fabio Mascher Thesis committee Prof. Brigitte Mauch-Mani, University of Neuchâtel, Switzerland Prof. Daniel Croll, University of Neuchâtel, Switzerland Dr. Fabio Mascher, Agroscope, Changins, Switzerland Prof. Victor Flors, University of Jaume I, Castellon, Spain Defense on the 6th of March 2020 University of Neuchâtel Summary During evolution, plants have developed a variety of chemical and physical defences to protect themselves from stressors. In addition to constitutive defences, plants possess inducible mechanisms that are activated in the presence of the pathogen. Also, plants are capable of enhancing their defensive level once they are properly stimulated with non-pathogenic organisms or chemical stimuli. This phenomenon is called induced resistance (IR) and it was widely reported in studies with dicotyledonous plants. However, mechanisms governing IR in monocots are still poorly investigated. Hence, the aim of this thesis was to study the efficacy of IR to control wheat diseases such leaf rust and Septoria tritici blotch. In this thesis histological and transcriptomic analysis were conducted in order to better understand mechanisms related to IR in monocots and more specifically in wheat plants. Successful use of beneficial rhizobacteria requires their presence and activity at the appropriate level without any harmful effect to host plant. In a first step, the interaction between Pseudomonas protegens CHA0 (CHA0) and wheat was assessed. Our results demonstrated that CHA0 did not affect wheat seed germination and was able to colonize and persist on wheat roots with a beneficial effect on plant growth.
    [Show full text]
  • Image-Based Wheat Fungi Diseases Identification by Deep
    plants Article Image-Based Wheat Fungi Diseases Identification by Deep Learning Mikhail A. Genaev 1,2,3, Ekaterina S. Skolotneva 1,2, Elena I. Gultyaeva 4 , Elena A. Orlova 5, Nina P. Bechtold 5 and Dmitry A. Afonnikov 1,2,3,* 1 Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia; [email protected] (M.A.G.); [email protected] (E.S.S.) 2 Faculty of Natural Sciences, Novosibirsk State University, 630090 Novosibirsk, Russia 3 Kurchatov Genomics Center, Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia 4 All Russian Institute of Plant Protection, Pushkin, 196608 St. Petersburg, Russia; [email protected] 5 Siberian Research Institute of Plant Production and Breeding, Branch of the Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, 630501 Krasnoobsk, Russia; [email protected] (E.A.O.); [email protected] (N.P.B.) * Correspondence: [email protected]; Tel.: +7-(383)-363-49-63 Abstract: Diseases of cereals caused by pathogenic fungi can significantly reduce crop yields. Many cultures are exposed to them. The disease is difficult to control on a large scale; thus, one of the relevant approaches is the crop field monitoring, which helps to identify the disease at an early stage and take measures to prevent its spread. One of the effective control methods is disease identification based on the analysis of digital images, with the possibility of obtaining them in field conditions, Citation: Genaev, M.A.; Skolotneva, using mobile devices. In this work, we propose a method for the recognition of five fungal diseases E.S.; Gultyaeva, E.I.; Orlova, E.A.; of wheat shoots (leaf rust, stem rust, yellow rust, powdery mildew, and septoria), both separately Bechtold, N.P.; Afonnikov, D.A.
    [Show full text]
  • Wheat Leaf Rust
    Marcia McMullen Jack Rasmussen Plant Pathologist Plant Pathologist PP589 (Revised) NDSU Extension Service Agricultural Experiment Station WHEAT LEAF RUST Wheat leaf rust, caused by the fungus Puccinia triticina (formerly recondita f. sp. tritici), reduces wheat yields in susceptible varieties when weather conditions favor rust development and spread. The most notable signs of leaf rust infection are the reddish-orange spore masses of the fungus breaking through the leaf surface (Figure 1). These spore masses, called pus- tules or uredinia, are first detected on wheat in North Dakota in late May or early June, generally in the Figure 1. Top: Resistant reaction; Center: Moderately resistant reac- southern-most counties. Normally, tion; Bottom: Susceptible reaction. only a few pustules are visible on susceptible varieties in early June because spore numbers are still low. The disease develops prior to this period on susceptible winter or spring wheat crops grown in states farther south. The leaf rust spores are carried by wind currents, and the disease advances progressively northward across the Great Plains as the wheat crops develop (Figure 2). The leaf rust pathogen has only occasionally over-wintered in North Dakota, during a mild winter or when protected by deep snow. Figure 2. Leaf rust disease cycle. North Dakota State University, Fargo, North Dakota 58105 JULY 2002 The Disease The following factors must be present for wheat leaf rust infection to occur: viable spores; susceptible or moder- ately susceptible wheat plants; moisture on the leaves (six to eight hours of dew); and favorable temperatures (60 to 80 degrees Fahrenheit). Relatively cool nights combined with warm days are excellent conditions for disease development.
    [Show full text]
  • Cereal Rye Section 9 Diseases
    SOUTHERN SEPTEMBER 2018 CEREAL RYE SECTION 9 DISEASES TOOLS FOR DIAGNOSING CEREAL DISEASE | ERGOT | TAKE-ALL | RUSTS | YELLOW LEAF SPOT (TAN SPOT) | FUSARIUM: CROWN ROT AND FHB | COMMON ROOT ROT | SMUT | RHIZOCTONIA ROOT ROT | CEREAL FUNGICIDES | DISEASE FOLLOWING EXTREME WEATHER EVENTS SOUTHERN JANUARY 2018 SECTION 9 CEREAL rye Diseases Key messages • Rye has good tolerance to cereal root diseases. • The most important disease of rye is ergot (Claviceps purpurea). It is important to realise that feeding stock with ergot infested grain can result in serious losses. Grain with three ergots per 1,000 kernels can be toxic. 1 • Stem and leaf rusts can usually be seen on cereal rye in most years, but they are only occasionally a serious problem. 2 • All commercial cereal rye varieties have resistance to the current pathotypes of stripe rust. However, the out-crossing nature of the species will mean that under high disease pressure, a proportion of the crop (approaching 15–20% of the plant population) may show evidence of the disease. Other diseases are usually insignificant. • Cereal rye has tolerance to take-all, making it a useful break crop following grassy pastures. 3 • Bevy is a host for the root disease take-all and this should be carefully monitored. 4 General disease management strategies: • Use resistant or partially resistant varieties. • Use disease-free seed. • Use fungicidal seed treatments to kill fungi carried on the seed coat or in the seed. • Have a planned in-crop fungicide regime. • Conduct in-crop disease audits to determine the severity of the disease. This can be used as a tool to determine what crop is grown in what paddock the following year.
    [Show full text]
  • Virulence of Puccinia Triticina on Wheat in Iran
    African Journal of Plant Science Vol. 4 (2), pp. 026-031, February 2010 Available online at http://www.academicjournals.org/ajps ISSN 1996-0824 © 2010 Academic Journals Full Length Research Paper Virulence of Puccinia triticina on wheat in Iran S. Elyasi-Gomari Azad Islamic University, Shoushtar Branch, Faculty of Agriculture, Shoushtar, Iran. E-mail: [email protected]. Accepted 12 January, 2010 Wheat leaf rust is controlled mainly by race-specific resistance. To be effective, breeding wheat for resistance to leaf rust requires knowledge of virulence diversity in local populations of the pathogen. Collections of Puccinia triticina were made from rust-infected wheat leaves on the territory of Khuzestan province (south-west) in Iran during 2008 - 2009. In 2009, up to 20 isolates each of the seven most common leaf rust races plus 8 -10 isolates of unnamed races were tested for virulence to 35 near- isogenic wheat lines with different single Lr genes for leaf rust resistance. The lines with Lr9, Lr25, Lr28 and Lr29 gene were resistant to all of the isolates. Few isolates of known races but most isolates of the new, unnamed races were virulent on Lr19. The 35 Lr gene lines were also exposed to mixed race inoculum in field plots to tests effectiveness of their resistance. No leaf rust damage occurred on Lr9, Lr25, Lr28 and Lr29 in the field, and lines with Lr19, Lr16, Lr18, Lr35, Lr36, Lr37 and the combination Lr27 + Lr31 showed less than 15% severity. A total of 500 isolates of P. triticina obtained from five commercial varieties of wheat at two locations in the eastern and northern parts of the Khuzestan region were identified to race using the eight standard leaf rust differential varieties of Johnson and Browder.
    [Show full text]
  • Status of Wheat Rust Research and Control in China
    Status of wheat rust research and control in China Zhensheng Kang*, Jie Zhao, Dejun Han, Hongchang Zhang, Xiaojie Wang, Chenfang Wang, Qingmei Han, Jun Guo & Lili Huang *College of Plant Protection and Shaanxi Key Laboratory of Molecular Biology for Agriculture, Northwest A&F University, Yangling, Shaanxi 712100, P. R. China e-mail: [email protected] Abstract In China, wheat is grown on approximately 24 million hectares with an annual yield of 100 million tonnes. Stem rust, caused by Puccinia graminis f. sp. tritici, is a threat mainly to spring wheat in northeastern China. Leaf rust, caused by P. triticina, occurs on crops in the late growth stages in the Yellow-Huai-Hai River regions. Stripe rust, caused by P. striiformis f. sp. tritici (Pst), is destructive in all winter wheat regions and is considered the most important disease of wheat in China. During the last 20 years, widespread stripe rust epidemics occurred in 2002, 2003, and 2009, and localized epidemics occurred in many other years. In recent years, major yield losses were prevented by widespread and timely applications of fungicides based on accurate monitoring and prediction of disease epidemics. A total of 68 Pst races or pathotypes have been identified using a set of 19 differential wheat genotypes. At present, races CYR32 and CYR33 virulent to resistance genes Yr9, Yr3b, Yr4b, YrSu and some other resistance genes are predominant. Moreover, these races are virulent on many cultivars grown in recent years. Of 501 recent cultivars and breeding lines 71.9% were susceptible, 7.0% had effective all-stage resistance, mostly Yr26 (= Yr24), and 21.2% had adult-plant resistance.
    [Show full text]
  • Monitoring Wheat Leaf Rust and Stripe Rust in Winter Wheat Using High-Resolution UAV-Based Red-Green-Blue Imagery
    remote sensing Article Monitoring Wheat Leaf Rust and Stripe Rust in Winter Wheat Using High-Resolution UAV-Based Red-Green-Blue Imagery Ramin Heidarian Dehkordi 1,* , Moussa El Jarroudi 2 , Louis Kouadio 3 , Jeroen Meersmans 1 and Marco Beyer 4 1 TERRA Teaching and Research Centre, Gembloux Agro-Bio Tech, University of Liège, 5030 Gembloux, Belgium; [email protected] 2 Department of Environmental Sciences and Management, University of Liège, 6700 Arlon, Belgium; [email protected] 3 Centre for Applied Climate Sciences, University of Southern Queensland, West Street, Toowoomba, QLD 4350, Australia; [email protected] 4 Luxembourg Institute of Science and Technology, 41 Rue du Brill, L-4422 Belvaux, Luxembourg; [email protected] * Correspondence: [email protected]; Tel.: +32-81-622-189 Received: 28 September 2020; Accepted: 7 November 2020; Published: 11 November 2020 Abstract: During the past decade, imagery data acquired from unmanned aerial vehicles (UAVs), thanks to their high spatial, spectral, and temporal resolutions, have attracted increasing attention for discriminating healthy from diseased plants and monitoring the progress of such plant diseases in fields. Despite the well-documented usage of UAV-based hyperspectral remote sensing for discriminating healthy and diseased plant areas, employing red-green-blue (RGB) imagery for a similar purpose has yet to be fully investigated. This study aims at evaluating UAV-based RGB imagery to discriminate healthy plants from those infected by stripe and wheat leaf rusts in winter wheat (Triticum aestivum L.), with a focus on implementing an expert system to assist growers in improved disease management. RGB images were acquired at four representative wheat-producing sites in the Grand Duchy of Luxembourg.
    [Show full text]
  • Early Molecular Signatures of Responses of Wheat to Zymoseptoria Tritici in Compatible and Incompatible Interactions
    Plant Pathology (2016) Doi: 10.1111/ppa.12633 Early molecular signatures of responses of wheat to Zymoseptoria tritici in compatible and incompatible interactions E. S. Ortona, J. J.Ruddb and J. K. M. Browna* aJohn Innes Centre, Norwich Research Park, Norwich NR4 7UH; and bRothamsted Research, Harpenden AL5 2JQ, UK Zymoseptoria tritici, the causal agent of septoria tritici blotch, a serious foliar disease of wheat, is a necrotrophic pathogen that undergoes a long latent period. Emergence of insensitivity to fungicides, and pesticide reduction policies, mean there is a pressing need to understand septoria and control it through greater varietal resistance. Stb6 and Stb15, the most common qualitative resistance genes in modern wheat cultivars, determine specific resistance to avirulent fun- gal genotypes following a gene-for-gene relationship. This study investigated compatible and incompatible interactions of wheat with Z. tritici using eight combinations of cultivars and isolates, with the aim of identifying molecular responses that could be used as markers for disease resistance during the early, symptomless phase of colonization. The accumulation of TaMPK3 was estimated using western blotting, and the expression of genes implicated in gene-for- gene interactions of plants with a wide range of other pathogens was measured by qRT-PCR during the presymp- tomatic stages of infection. Production of TaMPK3 and expression of most of the genes responded to inoculation with Z. tritici but varied considerably between experimental replicates. However, there was no significant difference between compatible and incompatible interactions in any of the responses tested. These results demonstrate that the molecular biology of the gene-for-gene interaction between wheat and Zymoseptoria is unlike that in many other plant diseases, indicate that environmental conditions may strongly influence early responses of wheat to infection by Z.
    [Show full text]
  • Evaluation of Winter Wheat Germplasm for Resistance To
    EVALUATION OF WINTER WHEAT GERMPLASM FOR RESISTANCE TO STRIPE RUST AND LEAF RUST A Thesis Submitted to the Graduate Faculty of the North Dakota State University of Agriculture and Applied Science By ALBERT OKABA KERTHO In Partial Fulfillment of the Requirements for the Degree of MASTER OF SCIENCE Major Department: Plant Pathology August 2014 Fargo, North Dakota North Dakota State University Graduate School Title EVALUATION OF WINTER WHEAT GERMPLASM FOR RESISTANCE TO STRIPE RUST AND LEAF RUST By ALBERT OKABA KERTHO The Supervisory Committee certifies that this disquisition complies with North Dakota State University’s regulations and meets the accepted standards for the degree of MASTER OF SCIENCE SUPERVISORY COMMITTEE: Dr. Maricelis Acevedo Chair Dr. Francois Marais Dr. Liu Zhaohui Dr. Phil McClean Approved: 09/29/2014 Dr. Jack Rasmussen Date Department Chair ABSTRACT Wheat leaf rust, caused by Puccinia triticina (Pt), and wheat stripe rust caused by P. striiformis f. sp. tritici (Pst) are important foliar diseases of wheat (Triticum aestivum L.) worldwide. Breeding for disease resistance is the preferred strategy of managing both diseases. The continued emergence of new races of Pt and Pst requires a constant search for new sources of resistance. Winter wheat accessions were evaluated at seedling stage in the greenhouse with races of Pt and Pst that are predominant in the North Central US. Association mapping approach was performed on landrace accessions to identify new or underutilized sources of resistance to Pt and Pst. The majority of the accessions were susceptible to all the five races of Pt and one race of Pst. Association mapping studies identified 29 and two SNP markers associated with seedling resistance to leaf rust and stripe rust, respectively.
    [Show full text]
  • [Puccinia Striiformis F. Sp. Tritici] on Wheat
    314 Review / Synthèse Epidemiology and control of stripe rust [Puccinia striiformis f. sp. tritici ] on wheat X.M. Chen Abstract: Stripe rust of wheat, caused by Puccinia striiformis f. sp. tritici, is one of the most important diseases of wheat worldwide. This review presents basic and recent information on the epidemiology of stripe rust, changes in pathogen virulence and population structure, and movement of the pathogen in the United States and around the world. The impact and causes of recent epidemics in the United States and other countries are discussed. Research on plant resistance to disease, including types of resistance, genes, and molecular markers, and on the use of fungicides are summarized, and strategies for more effective control of the disease are discussed. Key words: disease control, epidemiology, formae speciales, races, Puccinia striiformis, resistance, stripe rust, wheat, yellow rust. Résumé : Mondialement, la rouille jaune du blé, causée par le Puccinia striiformis f. sp. tritici, est une des plus importantes maladies du blé. La présente synthèse contient des informations générales et récentes sur l’épidémiologie de la rouille jaune, sur les changements dans la virulence de l’agent pathogène et dans la structure de la population et sur les déplacements de l’agent pathogène aux États-Unis et autour de la planète. L’impact et les causes des dernières épidémies qui ont sévi aux États-Unis et ailleurs sont examinés. La synthèse contient un résumé de la recherche sur la résistance des plantes à la maladie, y compris les types de résistance, les gènes et les marqueurs moléculaires, et sur l’emploi des fongicides, et un examen des stratégies pour une lutte plus efficace contre la maladie.
    [Show full text]
  • Rapid Global Spread of Two Aggressive Strains of a Wheat Rust Fungus
    Molecular Ecology (2008) doi: 10.1111/j.1365-294X.2008.03886.x RapidBlackwell Publishing Ltd global spread of two aggressive strains of a wheat rust fungus MOGENS S. HOVMØLLER,* AMOR H. YAHYAOUI,† EUGENE A. MILUS‡ and ANNEMARIE F. JUSTESEN* *Department of Integrated Pest Management, Faculty of Agricultural Sciences, University of Aarhus, Flakkebjerg, 4200 Slagelse, Denmark, †International Center for Agricultural Development in the Dry Areas, PO Box 5466, Aleppo, Syria, ‡Department of Plant Pathology, University of Arkansas, Fayetteville, AR 72701, USA Abstract Rust fungi can overcome the effect of host resistance genes rapidly, and spores can disperse long distance by wind. Here we demonstrate a foreign incursion of similar strains of the wheat yellow rust fungus, Puccinia striiformis f. sp. tritici, in North America, Australia and Europe in less than 3 years. One strain defined by identity at 15 virulence loci and 130 amplified fragment length polymorphism (AFLP) fragments was exclusive to North America (present since 2000) and Australia (since 2002). Another strain of the same virulence phenotype, but differing in two AFLP fragments, was exclusive to Europe (present since 2000–2001) as well as Western and Central Asia and the Red Sea Area (first appearance unknown). This may be the most rapid spread of an important crop pathogen on the global scale. The limited divergence between the two strains and their derivatives, and the temporal–spatial occurrence pattern confirmed a recent spread. The data gave evidence for additional intercontinental dispersal events in the past, that is, many isolates sampled before 2000 in Europe, North America and Australia had similar AFLP fingerprints, and isolates from South Africa, which showed no divergence in AFLP, differed by only two fragments from particular isolates from Central Asia, West Asia and South Europe, respectively.
    [Show full text]
  • Achievements and Prospects of Wheat Breeding for Disease Resistance
    Czech J. Genet. Plant Breed., 38, 2002 (1): 16–28 Achievements and Prospects of Wheat Breeding for Disease Resistance PAVEL BARTOŠ, VÁCLAV ŠÍP, JANA CHRPOVÁ, JOSEF VACKE, EVA STUCHLÍKOVÁ, VERONIKA BLAŽKOVÁ, JANA ŠÁROVÁ and ALENA HANZALOVÁ Research Institute of Crop Production – Division of Genetics and Plant Breeding, Prague-Ruzyně, Czech Republic Abstract: Achievements and prospects of wheat breeding for disease resistance in the world and in the Czech Republic are reviewed. Attention is paid to rusts, powdery mildew, leaf blotch, glume blotch, tan spot, fusarium head blight, common and dwarf bunt, eyespot, barley yellow dwarf virus on wheat and wheat dwarf virus. Genes for resistance to rusts and powdery mildew in the cultivars registered in the Czech Republic are listed. Promising resistance genes and sources of resistance to the above mentioned diseases are reviewed. Prospects of resistance breeding including application of methods of molecular genetics and development of synthetic hexaploids are outlined. Keywords: wheat; resistance breeding; fungal diseases; virus diseases; Czech Republic The development of disease resistance breeding is (defined by JOHNSON [1981]) attracted attention par- closely linked with the development of genetics, plant ticularly in the last decade when several conferences pathology and the progress of plant breeding methods. were devoted to this aspect of resistance. Finally, recent First crosses of wheat based on Mendels genetic princi- development of molecular biology opened many new ples, aiming to transfer disease resistance, were carried prospects for the resistance breeding. out by BIFFEN (1905). He found monogenic inheritance of yellow rust resistance in wheat. Such inheritance has been later confirmed in other crops and pathogens.
    [Show full text]