DOCSLIB.ORG

Stem Rust on Wheat and Barley

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Stem Rust on Wheat and Barley Identification and Management of Stem Rust on Wheat and Barley Stem rust, leaf rust, and stripe rust comprise a production. The first of these races, known as ‘Ug99’, complex of diseases that reduces wheat and barley was originally detected in Uganda, Kenya, and grain production. These rust diseases occur in nearly Ethiopia. Since this initial detection, additional races all areas of the United States and Canada. The of the fungus have been reported and are further importance of any member of the complex at a given complicating efforts to contain the problem. location is determined by specific interactions with If these new races spread to North America, current wheat varieties, they may threaten wheat crop growth stage, and and barley production. weather conditions. Why does the genetic In preparation for the Stem rust has been resistance appear to fail? possible introduction of present in North America Currently genetic resistance is an effective these new races of stem for hundreds of years. means of managing the rust diseases of rust, a number of critical A series of particularly wheat and barley. Because the populations questions arise regarding severe outbreaks occurred the most effective ways during the early 1930s and of the fungi that cause rust diseases can to identify, monitor, and 1950s. These outbreaks change and adapt to the resistance genes of manage the disease. This caused serious yield loss in current varieties, the durability of this genetic publication answers these many parts of the United resistance has been problematic. These critical questions with the States and Canada with changes occur when naturally occurring best available information the greatest losses in the genetic changes allow members of the about the emerging threat. Great Plains. More local- fungal population to overcome the genetic ized outbreaks of wheat What is the regional stem rust occurred in the resistance of the plant. The rust fungi have a risk of stem rust southern Great Plains as tremendous reproduction potential and are epidemics? recently as 1986. Stem rust easily moved by wind; therefore, a new race If stem rust reemerges became a problem in barley of stem rust often increases rapidly, resulting as a serious problem in in the late 1980s and early in outbreaks of disease throughout a large North America, historical 1990s. In all these cases, geographical region. accounts of stem rust the increase in frequency outbreaks will provide and intensity of the disease important information was associated with about where the disease is changes in the population of the stem rust fungus, likely to be most severe and cause the largest reduc- which enabled it to overcome genetic resistance of tions in yield. Stem rust normally survives the winter common varieties. months in the southern United States and Mexico. After several decades of control with genetic The disease then becomes established near overwin- resistance, new genetic variants (races) of the stem tering locations in southern states and is subsequently rust fungus have emerged as a threat to wheat moved north by weather systems. Potential yield loss in northern states is strongly influenced by the varieties. The magnitude of this change in disease intensity of the disease outbreaks in southern states resistance depends on the diversity of the new and the timing of these northerly movements of the population of stem rust, specific combinations of disease, relative to crop resistance genes present development. Understanding the terminology within each variety, Based on the and interactions with historical accounts of of rust resistance genes affected the environment. stem rust outbreaks, it by ‘Ug99’ Until the exact appears that in most The populations of stem rust causing problems reactions to the new years the disease may in other parts of the world can be grouped by the races of stem rust can develop too late to resistance genes that they are able to overcome. be determined, it may cause much yield loss in These stem rust resistance genes are generally be useful to group Texas and Oklahoma. varieties based on the Moderate yield losses designated by an abbreviation for stem rust (Sr) stem rust resistance could occur in Kansas and a unique code of letters and numbers that genes they contain. If and Nebraska, but the help scientists communicate more effectively stem rust overcomes an greatest losses are most when breeding new varieties for disease resistance. important resistance likely to occur in South The original ‘Ug99’ is able to overcome the gene, all varieties Dakota, North Dakota, stem rust resistance gene Sr31. Since this initial protected by that gene Minnesota, Manitoba, discovery, additional types of the fungus have will likely experience and Saskatchewan significant reductions (Figure 1). Historical been discovered that are able to overcome the in stem rust resistance. reports of stem rust resistance genes Sr24, and Sr36. These resistance Varieties within other outbreaks indicate a genes are the basis for the genetic vulnerability groups, which have lower risk of yield loss that has scientists around the world concerned other resistance genes, east of the Mississippi about potential outbreaks of stem rust. may remain unaffected. River and in the Pacific Scientists around Northwest. the world are working Although this to incorporate new historical information provides some useful insights sources of resistance that will reduce the risk of into where stem rust is most likely to be a problem, regional disease outbreaks. Until these sources of recent changes in agricultural production may influ- resistance become widely available, farmers should ence the current risk of disease (Table 1). In most evaluate their regional risk of disease and carefully cases, current agricultural practices will diminish evaluate the sources of genetic resistance used on the risk of severe stem rust relative to historical their farm. Planting varieties with different sources outbreaks of disease. of resistance may help reduce the potential that any How will current wheat single race of stem rust will affect all varieties on a and barley varieties respond farm. Information regarding genetic resistance of to the new types of stem rust? many common wheat and barley varieties can be found on the USDA’s Cereal Disease Laboratory The introduction of one or more new races of website: www.ars.usda.gov/mwa/cdl. stem rust into North America might cause dramatic changes in the stem rust reaction of many wheat Table 1. Factors influencing the risk of stem rust and severe yield losses relative to historical outbreaks of the disease. Change to the production system Potential affect on stem rust outbreaks In many areas, less land is used for wheat and barley The distance between fields may cause the disease to production. These areas of cultivation are more spread more slowly and reduce the risk of movement isolated from each other. between regions. Areas away from main areas of production may escape severe disease. Wheat and barley production have moved to areas Growing wheat and barley in these drier climates with historically drier climates. may reduce the risk of disease development. Many wheat varieties mature earlier, relative to those Yield losses to stem rust are greatest when severe that were grown a few decades ago. disease develops during the early stages of grain development. Varieties that mature earlier may escape serious yield losses. Access to highly effective fungicides and application It may be possible to reduce the influence of the technologies disease on yield and slow regional spread of stem rust with fungicides. Figure 1. Estimated risk of yield losses caused by stem rust in North America based on historical records of disease outbreaks. Risk Map Legend High risk: disease outbreaks and severe yield losses are likely Moderate risk: disease outbreaks and moderate yield losses are possible Low risk: disease outbreaks causing moderate yield losses are rare No historical information Based on information summarized by Leonard, K. J. 2001. In P.D. Peterson (ed) Stem rust of wheat: from ancient enemy to modern foe. APS Press, St. Paul, MN. Figure 2. Key diagnostic features of stem rust. A B C D Leaf rust A. Stem rust commonly infects stems, leaves, Stem rust and leaf sheaths. B. Stem rust occasionally infects parts of the head including glumes and awns. C. Stem rust causes oval-shaped or elongated blister-like lesions. Tearing or ripping of the outer layers of the plant tissue is visible without magnification. D. Stem rust lesions tend to be larger and longer than those caused by leaf rust. How is stem rust identified? attention of disease specialists. The disease specialist Using several key diagnostic features, stem rust will make a preliminary evaluation of the sample and can be distinguished from other rust diseases of wheat. send suspect samples to the experts at the USDA’s When severe, stem rust can be differentiated from leaf Cereal Disease Laboratory in St. Paul, Minnesota or rust or stripe rust by the parts of the plant that are AAFC Cereal Disease Research Center in Winnipeg, infected. Stem rust is able to infect the stems, leaves, Manitoba to confirm the diagnosis. Disease specialists and leaf sheaths of the plant (Figure 2). This infec- in your state or province can be found through your tion of the stem helps separate it from the other rust local extension office or by contacting a diagnostic diseases. Leaf rust can infect the leaf sheath that wraps laboratory near you. Contact information is provided at around the stem, but not the stem itself. the end of this publication. When the disease is less severe and only a few How much yield loss can stem rust cause? lesions can be found, it is important to focus on specific characteristics of the lesions. Stem rust causes Stem rust is generally considered the most elongated or oval-shaped blister-like lesions.
Load more

Recommended publications
  • Genome-Wide Association Study for Crown Rust (Puccinia Coronata F. Sp
    ORIGINAL RESEARCH ARTICLE published: 05 March 2015 doi: 10.3389/fpls.2015.00103 Genome-wide association study for crown rust (Puccinia coronata f. sp. avenae) and powdery mildew (Blumeria graminis f. sp. avenae) resistance in an oat (Avena sativa) collection of commercial varieties and landraces Gracia Montilla-Bascón1†, Nicolas Rispail 1†, Javier Sánchez-Martín1, Diego Rubiales1, Luis A. J. Mur 2 , Tim Langdon 2 , Catherine J. Howarth 2 and Elena Prats1* 1 Institute for Sustainable Agriculture – Consejo Superior de Investigaciones Científicas, Córdoba, Spain 2 Institute of Biological, Environmental and Rural Sciences, University of Aberystwyth, Aberystwyth, UK Edited by: Diseases caused by crown rust (Puccinia coronata f. sp. avenae) and powdery mildew Jaime Prohens, Universitat Politècnica (Blumeria graminis f. sp. avenae) are among the most important constraints for the oat de València, Spain crop. Breeding for resistance is one of the most effective, economical, and environmentally Reviewed by: friendly means to control these diseases. The purpose of this work was to identify elite Soren K. Rasmussen, University of Copenhagen, Denmark alleles for rust and powdery mildew resistance in oat by association mapping to aid Fernando Martinez, University of selection of resistant plants. To this aim, 177 oat accessions including white and red oat Seville, Spain cultivars and landraces were evaluated for disease resistance and further genotyped with Jason Wallace, Cornell University, USA 31 simple sequence repeat and 15,000 Diversity ArraysTechnology (DArT) markers to reveal association with disease resistance traits. After data curation, 1712 polymorphic markers *Correspondence: Elena Prats, Institute for Sustainable were considered for association analysis. Principal component analysis and a Bayesian Agriculture – Consejo Superior de clustering approach were applied to infer population structure.
    [Show full text]
  • Puccinia Sorghi), in Maize (Zea Mays
    Emirates Journal of Food and Agriculture. 2020. 32(1): 11-18 doi: 10.9755/ejfa.2020.v32.i1.2053 http://www.ejfa.me/ RESEARCH ARTICLE Induced resistance to common rust (Puccinia sorghi), in maize (Zea mays) Carmen Alicia Zúñiga-Silvestre1, Carlos De-León-García-de-Alba1*, Victoria Ayala-Escobar1, Víctor A. González-Hernández2 1Instituto de Fitosanidad, Colegio de Postgraduados, Carretera México-Texcoco Km 36.5, Montecillo, Texcoco, Estado de México, C.P. 56230, México, 2Instituto de Fisiología Vegetal, Colegio de Postgraduados, Carretera México-Texcoco Km 36.5, Montecillo, Texcoco, Estado de México, C.P. 56230, México ABSTRACT The common rust of maize (Zea mays L.), caused by Puccinia sorghi Schw., develops pustules on the leaves of maize plants, reducing the leaf area and production of the photoassimilates necessary for grain filling. The host possesses genes coding for different proteins related to the defense mechanisms that prevent the establishment of the pathogen. However, there are susceptible plants that are unable of preventing pathogen attack. This condition depend on biotic and abiotic factors known as inducers of resistance which are able of activating the physico-chemical or morphological defense processes to counteract the invasion of the pathogen. The Ceres XR21 maize hybrid is susceptible to P. sorghi. In this work, maize hybrid was evaluated under a split-split- plot design established in two spring-autumn cycles in the years 2016 and 2017, in which five commercial products of biological and chemical origin reported as inducers of resistance, plus a fungicide were compared. The results showed that trifloxystrobin + tebuconazole (Consist Max®), sprayed on the foliage with 1.5X the commercially recommended dose, showed significant better response in most evaluated variables, because it controlled better the pathogen P.
    [Show full text]
  • Stem Rust on Wheat and Barley
    Identification and Management of Stem Rust on Wheat and Barley Stem rust, leaf rust, and stripe rust comprise a production. The first of these races, known as ‘Ug99’, complex of diseases that reduces wheat and barley was originally detected in Uganda, Kenya, and grain production. These rust diseases occur in nearly Ethiopia. Since this initial detection, additional races all areas of the United States and Canada. The of the fungus have been reported and are further importance of any member of the complex at a given complicating efforts to contain the problem. location is determined by specific interactions with If these new races spread to North America, current wheat varieties, they may threaten wheat crop growth stage, and and barley production. weather conditions. Why does the genetic In preparation for the Stem rust has been resistance appear to fail? possible introduction of present in North America Currently genetic resistance is an effective these new races of stem for hundreds of years. means of managing the rust diseases of rust, a number of critical A series of particularly wheat and barley. Because the populations questions arise regarding severe outbreaks occurred the most effective ways during the early 1930s and of the fungi that cause rust diseases can to identify, monitor, and 1950s. These outbreaks change and adapt to the resistance genes of manage the disease. This caused serious yield loss in current varieties, the durability of this genetic publication answers these many parts of the United resistance has been problematic. These critical questions with the States and Canada with changes occur when naturally occurring best available information the greatest losses in the genetic changes allow members of the about the emerging threat.
    [Show full text]
  • TCJP an Improved Method to Quantify <I>Puccinia Coronata</I> F
    CORE Metadata, citation and similar papers at core.ac.uk Provided by UNL | Libraries University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln U.S. Department of Agriculture: Agricultural Publications from USDA-ARS / UNL Faculty Research Service, Lincoln, Nebraska 2010 TCJP An improved method to quantify Puccinia coronata f. sp. avenae DNA in the host Avena sativa M. Acevedo USDA-ARS, [email protected] E. W. Jackson USDA-ARS A. Sturbaum USDA-ARS H. W. Ohm Purdue University J. M. Bonman USDA-ARS Follow this and additional works at: https://digitalcommons.unl.edu/usdaarsfacpub Part of the Agricultural Science Commons Acevedo, M.; Jackson, E. W.; Sturbaum, A.; Ohm, H. W.; and Bonman, J. M., "TCJP An improved method to quantify Puccinia coronata f. sp. avenae DNA in the host Avena sativa" (2010). Publications from USDA- ARS / UNL Faculty. 509. https://digitalcommons.unl.edu/usdaarsfacpub/509 This Article is brought to you for free and open access by the U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Publications from USDA-ARS / UNL Faculty by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Can. J. Plant Pathol. (2010), 32(2): 215–224 Genetics and resistance/Génétique et résistance AnTCJP improved method to quantify Puccinia coronata f. sp. avenae DNA in the host Avena sativa M.Crown rust of oat ACEVEDO1, E. W. JACKSON1, A. STURBAUM1, H. W. OHM2 AND J. M. BONMAN1 1USDA-ARS Small Grains and Potato Germplasm Research Unit, 1691 S. 2700 W., Aberdeen, ID 83210, USA 2Department of Agronomy, Purdue University, West Lafayette, IN 47907, USA (Accepted 1 March 2010) Abstract: Identification and genetic mapping of loci conferring resistance to polycyclic pathogens such as the rust fungi depends on accurate measurement of disease resistance.
    [Show full text]
  • EC1802 Reduce Black Stem Rust of Wheat, Oats, Barley, Rye J
    University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Historical Materials from University of Nebraska- Extension Lincoln Extension 5-1943 EC1802 Reduce Black Stem Rust of Wheat, Oats, Barley, Rye J. E. Livingston Follow this and additional works at: http://digitalcommons.unl.edu/extensionhist Livingston, J. E., "EC1802 Reduce Black Stem Rust of Wheat, Oats, Barley, Rye" (1943). Historical Materials from University of Nebraska-Lincoln Extension. 2732. http://digitalcommons.unl.edu/extensionhist/2732 This Article is brought to you for free and open access by the Extension at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Historical Materials from University of Nebraska-Lincoln Extension by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Reduce Black Stem Rust .;:t; of Wheat, Oats, Barley, Rye 180~ J E. Livingston ~ ) J Extension Plant Pathologist The University of Nebraska Agricultural College Extension Service and United States Department of Agriculture Cooperating W. H. Brokaw, Director, Lincoln, Nebraska Distributed in furtherance of Acts of May 8 and June 30, 1914 (5-43-20M) Acknowledgement is made to the Conference for the Pre­ vention of Grain Rust, Minneapolis, Minnesota, for assistance in preparation of illustrative material, and to the Division of Plant Disease Control, Bureau of Entomology and Plant Quar­ antine, Washington, D . C., for assistance in preparation of this circular. Two Important Sources of Stem Rust From Barberry rust organism is spread from the old straw, stubble 2. Blown in From Other Areas 1. and grasses of the past year to the green, growing In the spring, tiny stem rust spores become detached grain of the next year.
    [Show full text]
  • Integrated Management of Southern Corn Rust and Northern Corn
    INTEGRATED MANAGEMENT OF SOUTHERN CORN RUST AND NORTHERN CORN LEAF BLIGHT USING HYBRIDS AND FUNGICIDES by SUZETTE MAGDALENE SEÑEREZ ARCIBAL (Under the Direction of Robert C. Kemerait, Jr.) ABSTRACT Southern corn rust (SCR) caused by Puccinia polysora and northern corn leaf blight (NCLB) caused by Exserohilum turcicum are important foliar diseases of corn in the southern United States. Field experiments were conducted to determine the effect of hybrid, fungicide and timing of fungicide application on NCLB and SCR epidemics and corn yield. The Rpp9-virulent and Rpp9-avirulent races of P. polysora were characterized in the field. Onset of SCR in Pioneer 33M52 was delayed in early-planted trials but not in later-planted trials. Area under the disease progress curves (AUDPC) for SCR were lower and yields were higher in Pioneer 33M52 than in Pioneer 33M57 when this disease was severe. Fungicides were usually most effective when applied near disease onset. When both diseases were severe, multiple fungicide applications improved disease management and yield. In vitro sensitivity assays indicated a range of EC50 values from 0.008 to 0.155 μg/ml. These results can be used to further develop management guidelines for SCR and NCLB. INDEX WORDS: Southern corn rust, Puccinia polysora, Rpp9-virulent race, northern corn leaf blight, Exserohilum turcicum, pyraclostrobin, metconazole, fluxapyroxad, fungicide timing, area under the disease progress curve, severity, incidence, necrosis, yield, fungicide sensitivity INTEGRATED MANAGEMENT OF SOUTHERN CORN
    [Show full text]
  • Ug99 Factsheet Updated: May 2010 • Ug99 Is a Single Race of the Fungal Disease Wheat Stem Rust (Puccinia Graminis F
    UG99 FACTSHEET Updated: May 2010 • Ug99 is a single race of the fungal disease wheat stem rust (Puccinia graminis f. sp. tritici). • First identified from samples collected in Uganda in 1999, hence the popu- lar name Ug99. Scientifically, using North American nomenclature, the race is termed TTKSK. • Wheat stem rust is historically the most feared and devasting disease af- fecting wheat. Under suitable conditions, yield losses of 70% or more are possible. • Stem rust is highly mobile, spreading over large distances by wind or via accidental human transmission (infected clothing or plant material). • For over 30 years, wheat stem rust has largely been under control prima- rily due to the widespread use of wheat cultivars carrying resistance to the disease. • Ug99 is a special cause for concern because it has overcome the resistance in most wheat cultivars. An estimated 80-90% of all global wheat cultivars growing in farmer’s fields are now susceptible to Ug99 or variants. • Ug99 is the only known race of wheat stem rust that has virulence for an extremely important resistance gene - Sr31. In addition, Ug99 has virulence against most of the resistance genes of wheat origin and other resistance genes from related species. • Six additional races have now been identified in the Ug99 lineage. These all have an identical DNA fingerprint to Ug99, but they show different viru- lence patterns. • Additional key resistance genes have been defeated by these variants, nota- bly; Sr24 (races TTKST and PTKST) and Sr36 (race TTTSK). • Ug99 (race TTKSK) has spread throughout East Africa. In 2006 it was con- firmed in Sudan and Yemen, and in 2007 Ug99 was confirmed in Iran.
    [Show full text]
  • Rust Diseases of Brambles
    University of Kentucky College of Agriculture, Food & Environment Extension Plant Pathology College of Agriculture, Food and Environment Cooperative Extension Service Plant Pathology Fact Sheet PPFS-FR-S-06 Rust Diseases of Brambles Nicole Gauthier Jessica Sayre Plant Pathology Horticulture Extension Specialist Extension Agent Importance Cane & Leaf Rust The three most important rust diseases occurring Symptoms & Signs on brambles in Kentucky are cane and leaf rust, late The first evidence of cane and leaf rust is the presence rust, and orange rust. The most destructive of these of elongated, bright yellow pustules appearing on diseases is orange rust, which is ultimately lethal to infected floricanes (year-old canes that will produce plants. Once infected, entire plants must be removed fruit) in spring (Figure 1). Pustules rupture through and destroyed. In contrast, cane and leaf rust, along the bark and result in brittle canes that break easily. with late rust, are not lethal to plants and can be Small yellow pustules may also appear on undersides managed using cultural practices and fungicides. of leaves (Figure 2) and less frequently on fruit Distinguishing between these rust diseases is critical (Figure 3). Fungal signs (pustules of powdery yellow for proper management. rust spores) may be evident in mid-April and extend through summer. Premature defoliation, which results in stress and loss of plant vigor, can occur if 1a leaf infections are severe. Hosts Blackberry is susceptible; raspberry infections are rare. 1a Figure 1. (A) Cane and leaf rust pustules erupt through the bark of floricanes in spring. (B) Close-up of cane and leaf rust pustule containing abundant powdery yellow spores.
    [Show full text]
  • The Emergence of Ug99 Races of the Stem Rust Fungus Is a Threat to World Wheat Production
    PY49CH22-Singh ARI 4 July 2011 16:27 The Emergence of Ug99 Races of the Stem Rust Fungus is a Threat to World Wheat Production Ravi P. Singh,1 David P. Hodson,2 Julio Huerta-Espino,3 Yue Jin,4 Sridhar Bhavani,5 Peter Njau,6 Sybil Herrera-Foessel,1 Pawan K. Singh,1 Sukhwinder Singh,1 and Velu Govindan1 1International Maize and Wheat Improvement Center (CIMMYT), 06600, Mexico, DF, Mexico; email: [email protected] 2FAO, Viale delle Terme di Caracalla, 00153, Rome, Italy 3INIFAP-CEVAMEX, 56230, Chapingo, Mexico 4USDA-ARS, Cereal Disease Laboratory, St. Paul, Minnesota 55108 5CIMMYT, ICRAF House, United Nations Avenue, Gigiri, Village Market-00621, Nairobi, Kenya 6Kenya Agricultural Research Institute, Njoro Plant Breeding Research Center (KARI-NPBRC), P.O. Njoro, Kenya Annu. Rev. Phytopathol. 2011. 49:465–81 Keywords The Annual Review of Phytopathology is online at Triticum aestivum, Puccinia graminis, resistance, epidemiology phyto.annualreviews.org This article’s doi: Abstract 10.1146/annurev-phyto-072910-095423 Race Ug99 of the fungus Puccinia graminis tritici that causes stem or Copyright c 2011 by Annual Reviews. black rust disease on wheat was first detected in Uganda in 1998. Seven All rights reserved races belonging to the Ug99 lineage are now known and have spread 0066-4286/11/0908/0465$20.00 to various wheat-growing countries in the eastern African highlands, as well as Zimbabwe, South Africa, Sudan, Yemen, and Iran. Because of the susceptibility of 90% of the wheat varieties grown worldwide, the Ug99 Annu. Rev. Phytopathol. 2011.49:465-481. Downloaded from www.annualreviews.org group of races was recognized as a major threat to wheat production by University of Minnesota - Twin Cities Wilson Library on 08/15/11.
    [Show full text]
  • Evaluation of Resistance to Wheat Stem Rust and Identification of Resistance Genes in Wheat Lines from Heilongjiang Province
    Evaluation of resistance to wheat stem rust and identification of resistance genes in wheat lines from Heilongjiang province Qiujun Lin*, Yue Gao*, Xianxin Wu, Xinyu Ni, Rongzhen Chen, Yuanhu Xuan and Tianya Li College of Plant Protection, Shenyang Agricultural University, Shenyang, China * These authors contributed equally to this work. ABSTRACT Wheat stem rust, caused by Puccinia graminis f. sp. tritici,(Pgt) is a devastating disease in wheat production. The disease has been effectively controlled since the 1970s due to the widespread use of the Sr31 resistance gene. However, Sr31 has lost its effectiveness following the emergence and spread of the Ug99 race variants. Therefore, there is an urgent global effort to identify new germplasm resources effective against those races. In this study, the resistance to Pgt of 95 wheat advance lines from Heilongjiang Province was evaluated using three predominant races of Pgt, 21C3CTTTM, 34C0MKGSM, and 34C3MTGQM, in China at the seedling and adult plant stage. The presence of 6 Sr genes (Sr2, Sr24, Sr25, Sr26, Sr31, and Sr38) was evaluated using linked molecular markers. The results showed that 86 (90.5%) wheat lines had plant stage resistance to all three races. Molecular marker analysis showed that 24 wheat lines likely carried Sr38, 15 wheat lines likely carried Sr2, 11 wheat lines likely carried Sr31, while none of the wheat lines carried Sr24, Sr25, or Sr26. Furthermore, six out of the 95 wheat lines tested carried both Sr2 and Sr38, three contained both Sr31 and Sr38, and two wheat lines contained both Sr2 and Sr31. Wheat lines with known Sr genes may be used as donor parents for further breeding programs to provide resistance to stem rust.
    [Show full text]
  • Western Gall Rust Management
    Insect and Disease Forest Health Protection and State Forestry Organizations Management Series 14.1 WEB 2011 Western Gall Rust Management James Hoffman and Endocronartium harknessii (J.P.Moore)Y. Hiratsuka Susan Hagle Forest Pathologists Forest Health Protection Hosts: USDA Forest Service Lodgepole pine Western gall rust is the most common Ponderosa pine stem rust found on “hard pines” Ornamental pines (2-3 needled pines) in the Northern and (Austrian, Mugo, Intermountain Regions. Scots) Topics Damage Lodgepole and ponderosa pines Stem cankers on pole or larger Damage 1 are the principal hosts in the western trees rarely kill the trees directly but Life History 2 United States; however, ornamental often contribute to stem breakage. Impact 2 plantings of Austrian, Mugo, and The rust infects pines of all ages, Scots pines in proximity to forested causing the most severe damage to Management 2 areas can become infected. Unlike seedlings/saplings in tree nurseries, Other Reading 3 other stem rusts, western gall rust Christmas tree plantations, and/or doesn’t require an alternate host to progeny test areas. Infected trees are complete its life cycle. more commonly found in drainage Perennial infections of the bottoms or near bodies of water. Key Points cambial tissues in branches and twigs cause globose swellings called galls. Trees of all ages Galls that develop on the main stems are affected. can cause somewhat concentric WHERE GALL RUST IS SEVERE: ridges in the stem sapwood called Infections in "hip" cankers which affect form, Promote tree species diversity and young trees are lumber content, and growth rate. control tree density most damaging.
    [Show full text]
  • Population Genetics of Phragmidium Violaceum
    Population genetics of Phrugmidium violaceum Don R. Gomez B. Ag. Sc. (Hons), The University of Adelaide Thesis submitted for the degree of Doctor of Philosophy tn The University of Adelaide Discipline of Plant and Pest Science School of Agriculture and \Mine Faculty of Sciences July 2005 I dedicøte this thesis to my pørents, Rosølio and Rosølie for their untiring love ønd support Table of contents Abstract t Declaration tv Acknowledgements v Publications and conference proceedings vl Abbreviations vii Glossary of terms vul I Introduction I 2.1 Introduction 4 2.2 The weed: Rubus fruticosus tggregate 5 2.2.I History of introduction and spread 5 2.2.2 Impact on Australian environment and economy 5 2.2.3 Morphology and growth habit 6 2.2.4 Taxonomy 6 2.2.5 Distribution and ecology 8 2.2.6 Integrated weed management 10 2.3 The biocontrol agent: Phragmídium violaceum 11 2.3.7 Host specificity and mode of action 11 2.3.2 History of P. violaceum in Australia 72 2.3.3 Life history of P. violaceum 13 2.3.3.I Uredinales rust fungi and their spore states 13 2.3.3.2 Life history of P. violaceum inrelation to host phenology I6 2.3.4 Disease signs and symptoms I7 2.3.5 Disease epidemiology 18 2.3.51 Weather and climate 18 2.3.5.2 Disease impact in Australia I9 2.4 Host-pathogen interactions 2t 2.5 Population genetics of rust fungi in relation to biological control 23 2.5.1 Evolution in natural versus agricultural ecosystems 24 2.5.2 Metapopulation theory: populations within a population 25 2.5.3 Gene flow 28 2.5.4 Reproductive mode 29 2.5.5 Selection of molecular markers for population genetic studies 31 2.5.5.1 The issue of dominance 31 2.5.5.2 Isozymes and RFLPs 32 2.5.5.3 PCR-based markers JJ Arbitrarily-primed PCR 34 Sequence-tagged sites 36 2.5.6 Application of molecular markers in population studies of P.
    [Show full text]