Download or read book Characterization of Stem Rust Resistance in Wheat Cultivar Gage written by Tadele Tadesse Kumssa and published by . This book was released on 2014 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wheat (Triticum spp.) stem rust, caused by Puccinia graminis f. sp. tritici Eriks. & E. Henn. (Pgt), re-emerged as a devastating disease of wheat because of virulent race Ug99 (TTKSK). Many modern bread wheat ( T. aestivum L.) cultivars grown in North America are susceptible to Ug99 or its derivative races with additional virulence. 'Gage', a USDA-University of Nebraska developed hard red winter wheat cultivar, was released in 1963 mainly for its excellent field resistance to leaf rust caused by Puccinia triticina Eriks and stem rust which was superior to another stem rust resistance cultivar, 'Scout66'. However, Gage's resistance has not been genetically characterized to facilitate its use in breeding programs. For molecular marker and genetic analysis, we created an F2 population and the corresponding F2:3 and F4:5 families from crosses between Gage and stem rust susceptible cultivar 'Bill Brown'. Inheritance of seedling resistance to Pgt race QFCSC and molecular marker analysis indicated that genes in addition to Sr2 explain the stem rust resistance of Gage. Using seedling plant infection types from the F2, F2:3 and F4:5 families, we confirmed that at least one dominant and most likely one recessive gene are involved in Gage's resistance. Seedling resistance genes acted independently of Sr2 since Sr2 is effective only at the adult plant stage. The relationship between adult plant resistance (APR) molecular marker gwm533 for Sr2 and adult plant disease response in the greenhouse indicated that Sr2 and at least one unknown resistance gene are involved in APR as plants without gwm533 indicative of Sr2 appeared resistant. We characterized the stem rust resistance in Gage and identified potential molecular markers linked to seedling resistance.

Download or read book Characterization of Stem Rust Resistance in US Wheat Germplasm written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In 1999 in Uganda a race of stem rust, Puccinia gramins f. sp. tritici was identified with virulence to Sr31. This race, designated as TTKS based on the North American nomenclature system, combined Sr31 virulence with virulence to the majority of Triticum aestivum L. derived stem rust resistance genes. The development of resistant cultivars is needed as TTKS may reach global dispersal due to its unique virulence to multiple known and unknown resistance genes and widespread cultivar susceptibility. The ability to detect the presence of specific stem rust resistance genes using molecular markers presents a viable method for identifying resistance to race TTKS in the absence of the pathogen itself. The frequency of DNA markers associated with resistance genes Sr24, Sr26, Sr36, and Sr1RSAmigo which confer resistance to TTKS was assessed in diverse wheat cultivars and breeding lines from breeding programs throughout the United States. The reliability of these markers in predicting the presence of the resistance genes in diverse germplasm was evaluated through comparison with phenotypic data. Introgression of undeployed seedling resistance genes is necessary to improve the availability of resistance to TTKS. The stem rust resistance gene Sr22 confers resistance to TTKS. Sr22 is present on a chromosomal translocation derived from Triticum boeoticum Boiss. which is homoeologous to the A genome of T. aesitivum Linkage analysis of SSR loci on 7AL was done to identify the loci most closely linked to Sr22. Individuals with reduced T. boeoticum segments due to recombination between wheat chromosome 7AL and the Sr22 introgression were identified with SSR markers in F2:3 populations of crosses between the germplasm stock Sr22Tb and the hard winter wheat lines 2174 and Lakin. From analysis of F3:4 populations derived from F2 recombinants, F3:4 individuals with further reduced translocation segments have been identified. Recombinant lines with reduced translocations will provide a m.

Download or read book Genetic Variation for Stem Rust Resistance in Spring Wheat written by Mahwish Ejaz and published by LAP Lambert Academic Publishing. This book was released on 2013 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stem rust is one of the major diseases of wheat round the world. New stem rust race; Ug99 and its variants as well as local stem rust races pose serious threat to wheat production in Pakistan. Stem rust can be controlled by identifying and incorporating resistant genes against the prevalent races into adapted wheat varieties. This study includes screening of 119 Pakistani wheat varieties with 18 DNA markers to detect the presence of various SR genes. Stem rust resistance genes Sr22, Sr24, Sr25 and Sr26 were absent in all varieties, whereas Sr2, Sr6, Sr9a, Sr31, Sr38 were present in various frequencies. However, frequency of APR gene Sr2 was quiet high. Results showed that Pakistani varieties are being protected by a few resistance genes and also lack potential resistance genes effective against new stem rust races. Thus, there is a need to incorporate stem rust resistance genes Sr22, Sr24, Sr25 and Sr26 into Pakistani wheat varieties, especially those possessing only Sr31. More reliable and efficient marker needs to be developed for Sr2 to assist MAS of this gene. Results of this study will help in pyramiding of SR genes in future wheat varieties to achieve durable rust resistance.

Download or read book Characterisation of Stem Rust Resistance Genes Effective Against Race Ug99 on Wheat Chromosome 7l written by Vincent Pujol and published by . This book was released on 2014 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wheat is one the most important food crops in the world, grown on more acreage than any other. Puccinia graminis f. sp. tritici, the causal agent of wheat and barley stem rust, is responsible for major production losses around the world. The development of resistant cultivars is an effective way to manage the disease, but outbreaks can occur when new pathogen races overcome the existing resistances. This happened with Ug99 (TTKSK), a highly virulent race now spreading in Africa and the Middle East and dangerously threatening worldwide food security. Thus, constant efforts to find new sources of resistance must remain a priority. The hexaploid wheat cultivar Canthatch has long been known for carrying a suppressor of stem rust resistance on chromosome 7DL. This suppressor is now of particular interest, as the genes it inhibits were found to be strongly effective against Ug99. Because the 7DL suppressor seems to be common in wheat cultivars, cloning it would be the first step toward unlocking the masked resistance genes, as well as providing new information about the nature of action of a previously unstudied class of negative regulators of plant defence responses. This study first aimed to genetically map the 7DL suppressor. A F2:3 mapping population was developed from the cross between the susceptible line Columbus, thought to possess the 7DL suppressor, with the resistant line Columbus-NS, a near-isogenic line in which a mutated allele of the suppressor was inferred to have been transferred into the Columbus genetic background. The mapping population was phenotyped using two stem rust races, Ug99 and #313, for which results were similar, indicating a common resistance against both races. Molecular markers were found using two recently developed techniques: i) genotyping of nearly 9,000 putative single nucleotide polymorphisms (SNP) using the wheat 9k SNP chip and ii) genotyping by sequencing using the restriction-site associated DNA sequencing (RAD-Seq) method in association with bulked segregant analysis. This led to the rapid identification of thousands of markers putatively linked to the stem rust resistance in Columbus-NS. Surprisingly, genetic mapping revealed the resistance to be located on 7AL, not 7DL, indicating that it was due to a new resistance locus rather than a non-suppressor. This locus is most likely part of the resistance complex repressed by the 7DL suppressor. Although segregation ratios in the F2:3 population indicated monogenic segregation (1:2:1), phenotypic observations and genomic studies indicated the possible involvement of multiple genes in the resistance, notably on chromosome 6A. The 7AL locus seemed to be essential but not sufficient for full resistance. The resistance response was also investigated at a microscopic level, which showed the involvement of cell death during the rust penetration through the stoma, at two days post-inoculation. Transcriptome analysis using RNA-Seq revealed 353 genes differentially expressed between Columbus and two independent Columbus-NS lines. Notably, several genes coding for cysteine-rich receptor-like kinases were found to be good candidates for involvement in the defence response.

Download or read book Wheat Rusts written by RA McIntosh and published by CSIRO PUBLISHING. This book was released on 1995-01-01 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt: Although stem rust has been controlled by means of resistant cultivars, leaf and stripe rust continue as problems for many growing areas of the world. Wheat Rusts: An Atlas of Resistance Genes has been prepared by specialists from one of the leading international laboratories, and illustrates with colour photographs typical resistance phenotypes associated with most known genes for resistance to the three rust diseases of wheat. Relevant details for each gene include chromosome location, aspects of genetics and pathogen variation, the effects of environment on expression, origin, availability in genetic and breeding stocks, and use in agriculture. This atlas includes an introduction to host:pathogen genetics, methodologies for wheat rust research and breeding for resistance.

Download or read book Characterization of Two Different Genetic Mechanisms Involved in the Rust Resistance Defense Response in Wheat written by Mina Rachelle Talajoor and published by . This book was released on 2013 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wheat leaf rust, stem rust, and stripe rust are major fungal diseases of wheat caused by Puccinia triticina, P. graminis f. sp. tritici, and P. striiformis f. sp. tritici, respectively. Development of wheat varieties with genetic resistance to pathogens is a common strategy to protect against significant yield loss. However, incorporating resistance is not always straightforward, and understanding the mechanisms responsible for triggering host resistance is key. Here, were characterized two different genetic mechanisms involved in the rust resistance defense response in wheat. Two spring wheat cultivars and their respective EMS mutants, which displayed enhanced resistance to leaf, stem, and/or stripe rust, were studied. The cultivar Canthatch possesses a stem rust resistance suppressor on chromosome 7DL. We characterized the spectrum of resistance of Canthatch and the mutant CTH-NS, confirming the specificity of this suppressor is stem rust-specific. The cultivar Alpowa mutant MNR220 displays broad-spectrum resistance to a number of wheat rust races at the seedling stage. We characterized the functional resistance of MNR220 to a race of leaf rust by sampling inoculated tissues at various time points and tracking the disease progress microscopically. The mutant MNR220 confers resistance at the pre-haustorial stage; formation of haustoria is delayed or inhibited in MNR220 relative to the wild type Alpowa.

Download or read book Characterization of Stem Rust Resistance in US Wheat Germplasm written by Eric Leonard Olson and published by . This book was released on 2009 with total page 109 pages. Available in PDF, EPUB and Kindle. Book excerpt: Keywords: stem rust, simple sequence repeat, marker assisted selection, resistance genes.

Download or read book The Wheat Rusts Breeding for Resistance written by Douglas R. Knott and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 213 pages. Available in PDF, EPUB and Kindle. Book excerpt: The idea for this book was conceived by the late Dr. Irvine A. Watson of the University of Sydney, and he developed the first outline. I was then invited by Dr. Watson to share in its writing. Unfortunately, shortly there after, recurring heart problems forced him to curtail his activities and with draw from the project. He died before the book could be completed. Dr. Watson's intention was to produce a very practical book that would provide wheat breeders with all of the information necessary to breed success fully for resistance to the three wheat rusts: leaf rust, stem rust, and yellow rust. It was intended to be very specific in describing procedures to be used and at the same time provide all of the necessary theoretical background. I hope that I have been successful in meeting these objectives. The book assumes that the reader has some knowledge of plant pathology, genetics, and plant breeding. Extensive use has been made of the literature, but it was not possible to cite all of the papers on a given topic. In making a choice, an attempt was made to choose key papers or more recent papers that provided references to the earlier literature. Acknowledgements This book was written partly at the University of Saskatchewan and partly at the University of California, Davis, while I was on a sabbatical leave.

Download or read book Genetic Validation and its Role in Crop Improvement written by Ahmed Sallam and published by Frontiers Media SA. This book was released on 2022-11-08 with total page 253 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Molecular Mapping of Stem Rust Resistance Genes in Wheat written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Stem rust, caused by Puccinia graminis f. sp. tritici, has successfully prevented rust epidemics by Deployment of resistant cultivars in the past several decades. Unfortunately, race TTKS (termed Ug99) has defeated most stem rust resistance genes existing in commercial cultivars. Sr40, a stem rust resistance gene from Triticum timopheevii ssp. araraticum, was transferred to wheat and provides effective levels of seedling and adult plant resistance against Ug99. To characterize Sr40 in wheat, two mapping populations were developed from the crosses RL6088 / Lakin and RL6088 / 2174. RL6088 is an Ug99-resistant parent with Sr40. Since race TTKS is a quarantined pathogen, a US stem rust isolate RKQQ that is avirulent to Sr40 was used to evaluate the rust resistance in the F[subscript]2 and F[subscript]2:3 populations at the seedling stage. A total of 83 simple sequence repeats (SSR) primers on chromosome 2B were used to screen the parents for polymorphism. Each F[subscript]2 population was analyzed with the markers polymorphic between two parents. Marker Xwmc344 was the most closely linked to Sr40, at 0.7 cM proximal, in the linkage map constructed from the population RL6088 / Lakin, while Xwmc474 and Xgwm374 were also tightly linked. Xwmc474 was mapped 2.5 cM proximal to Sr40 in the RL6088 / 2174 population. Xwmc474 and Xwmc661 were flanking markers for Sr40 in both populations. Markers linked to Sr40 will be useful for marker-assisted integration of Sr40 into elite wheat breeding lines. In addition, a unknown stem rust resistance gene from another source, OK01307, a breeding line from Oklahoma State University shows partial resistance to Ug99, and was characterized using SSRs in this study. Two mapping populations were developed from cross OK01307 / Chinese Spring and OK01307 / LMPG-6. A total of 1300 SSR primers were screened for polymorphism between OK01307 and Chinese spring, and 1000 SSR primers were screened for polymorphism between OK01307 and LMPG-6. Polymorphic primers between parents and between bulks were used to screen the corresponding population. One Sr gene in OK01307 was mapped on chromosome 1BS of the both populations, which was closely linked to Sr24. Whether the gene is Sr24 per se or a new Sr gene that closely linked to Sr24 needs further investigation.

Download or read book Molecular Mapping and Characterization of Stripe Rust Resistance Genes in Important Winter Wheat Cultivars in the U S Pacific Northwest written by Lu Liu and published by . This book was released on 2018 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stripe rust, caused by Puccinia striiformis Westend. f. sp. tritici Erikss. (Pst), is one of the most devastating and economically important diseases across major wheat growing regions in the world. Growing resistant cultivars is the most effective and environmentally sound method for controlling the disease. This study was conducted to identify resistance genes/QTL in three winter wheat cultivars Madsen, Skiles and Eltan and develop molecular markers for marker-assisted selection. Madsen has shown high-level and durable resistance since its release in 1988 and was identified to have both all-stage resistance (ASR) and high-temperature adult-plant (HTAP) resistance. Two major effect ASR QTL on chromosome arms 1AS and 2AS, one minor ASR QTL on 1BS and two HTAP resistance QTL on 3BS and 6BS were identified in Madsen. Skiles is susceptible to all tested Pst races at seedling stage but shows strong resistance at adult-plant stage with higher resistance level expressed at high temperature, indicating that Skiles has only HTAP resistance against the tested Pst races. Six HTAP resistance QTL were mapped in Skiles, with two major QTL mapped on 3BS and 4BL and four minor QTL on 1BL, 5AL, 6B and 7DL. Markers linked to the QTL were used to select highly resistant breeding lines derived from crosses with Skiles. Eltan has shown variable reactions from moderate susceptibility to resistance in different years since its release in 1990. Five QTL were detected in Eltan, with two major ASR QTL on 2BS and 4BL, one minor ASR on 5BS and two minor HTAP resistance QTL on 6AS and 7BL. The two major ASR QTL became less effective due to the fact that the Pst population has changed to virulent, leading to the resistance reduction in Eltan. By studying these three wheat cultivars with different genes for different types of resistance, it is concluded that the best strategy to achieve high-level and durable resistance is to combine several genes for effective ASR and adequate HTAP resistance. These studies provide the information of useful genes and molecular markers for improving resistance to stripe rust in wheat cultivars.

Download or read book Molecular Genetic Characterisation of Stem Rust Resistance in Wheat written by Sambasivam K. Periyannan and published by . This book was released on 2011 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Molecular Markers to Deploy and Characterize Stem Rust Resistance in Wheat written by Emma Leigh Flemmig and published by . This book was released on 2012 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Genetics of Stem Rust Resistance in the Spring Wheat Cultivar Thather and the Effect of Lr34 on Stem Rust Resistance written by Carmen Denise Gavin Vanegas and published by . This book was released on 2006 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book AN ANALYSIS OF THE GROWTH AND DEGENERATION OF PHYSIOLOGICAL RACES OF WHEAT STEM RUST IN 1964 written by and published by . This book was released on 1967 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: According to the analysis of the trend of growth and decline from 1962 to 1964, the dominance of the physiological racial group of wheat stem rust No. 21 declined year after year while that of the physiological racial group No. 34 rose year after year; therefore, with regard to the work of breeding stem rust resistant wheat varieties, both physiological racial groups should be given attention and the rust resistant varieties kept in reserve must be those varieties that are resistant to both physiological racial groups so that the danger of a sudden loss of rust resistance may be prevented.

Download or read book Molecular Characterization of Effective Sources of Stripe Rust Resistance in Tetraploid Wheat written by Weizhen Liu and published by . This book was released on 2016 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is a globally devastating disease of wheat. New Pst races overcoming the currently resistant wheat varieties and more frequent stripe rust-favorable weather conditions threaten the global wheat crops. The most economically and environmentally friendly approach to control stripe rust is to grow highly resistant cultivars with durable resistance. However, development of varieties with high levels of durable resistance has been limited by the small number of well-characterized and effective resistance genes available and technical difficulties in pyramiding several resistance genes in one plant. In order to identify more resistance genes and provide more marker-trait association information for marker-assisted selection and wheat improvement, genome-wide association mapping was conducted in cultivated emmer wheat (Triticum turgidum ssp. dicoccum), elite durum wheat (Triticum turgidum ssp. durum) and Ethiopian durum wheat landrace populations using the wheat 90,000 Illumina iSelect single nucleotide polymorphism array. In emmer wheat population, we identified thirty-eight loci significantly associated (P

Download or read book Genetic Analysis of Leaf Rust and Stem Rust Resistance Gene s in Interspecifie Derivatvies of Wheat Triticum Aestivum L written by P. M. Dhakate and published by . This book was released on 2002 with total page 93 pages. Available in PDF, EPUB and Kindle. Book excerpt: