Genome-Wide Association Studies Combined with Genomic Selection as a Tool to Increase Fusarium Head Blight Resistance in Wheat and Its Wild Relatives PDF Download

Author: Sampurna Bartaula
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Fusarium head blight (FHB) is a devastating wheat (Triticum aestivum L.) disease worldwide. Presently, there is insufficient FHB resistance in the Canadian wheat germplasm. Genome-wide association study (GWAS) and genomic selection (GS) can be utilized to identify sources of resistance that could benefit wheat breeding. To define the genetic architecture of FHB resistance, association panels from a spring and a winter collection were evaluated using the Wheat Illumina Infinium 90K array. A total of 206 accessions from the spring panel and 73 from the winter panel were evaluated in field trials for 3-4 years at two locations, namely Morden (Manitoba) and Ottawa (Ontario). These accessions were phenotyped for FHB incidence (INC), severity (SEV), visual rating index (VRI), and deoxynivalenol (DON) content. Significant (p

Author: Cristiano Lemes Da Silva
Publisher:
ISBN:
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Languages : en
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Wheat diseases cause significant economic losses every year. To ensure global food security, newly released cultivars must possess increased levels of broadly-effective resistance against wheat pathogens, acceptable end-use quality, and high yield potential. Genetic host resistance stands out from other management strategies as the most viable option for controlling diseases. New genotyping platforms allow whole genome marker discovery at a relatively low cost, favoring the identification of novel loci underlying traits of interest. The work presented here describes genomic approaches for mapping and predicting the resistance to Fusarium head blight (FHB) and wheat rusts. The first study used biparental mapping to identify quantitative trait loci (QTL) associated with Fusarium head blight (FHB) resistance. A doubled haploid population (DH) was originated from a cross of Everest and WB-Cedar, which are widely grown wheat cultivars in Kansas with moderately resistant and moderately susceptible reactions to FHB, respectively. We confirmed that neither of the parents carry known large-effect QTLs, suggesting that FHB resistance is native. Eight small-effect QTLs were identified as associated with multiple mechanisms of FHB resistance. All QTLs had additive effects, providing significant improvements in levels of resistance when they were found in combinations within DH lines. In the second study, a genome-wide association mapping (GWAS) and genomic selection (GS) models were applied for FHB resistance in a panel of 962 elite lines from the K-State Wheat Breeding Program. Significant single nucleotide polymorphisms (SNPs) associated with the percentage of symptomatic spikelets were identified but not reproducible across breeding panels tested in each year. Accuracy of predictions ranged from 0.25 to 0.51 depending on GS model, indicating that it can be a useful tool to increase levels of FHB resistance. GWAS and GS approaches were also applied to a historical dataset to identify loci underlying resistance to leaf and stem rust at seedling stage in a panel of elite winter wheat lines. Infection types of multiple races of wheat rusts from the last sixteen years of the Southern Regional Performance Nursery (SRPN) were used in this study. A total of 533 elite lines originating from several breeding programs were tested in the SRPN during this period of time. GWAS identified significant SNP-trait associations for wheat rusts, confirming the effectiveness of already known genes and revealing potentially novel loci associated with resistance.

Author: Jared Howell Benson
Publisher:
ISBN:
Category :
Languages : en
Pages : 203

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Author: Sudheer Kumar
Publisher: CRC Press
ISBN: 0429894074
Category : Science
Languages : en
Pages : 157

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Wheat Blast provides systematic and practical information on wheat blast pathology, summarises research progress and discusses future perspectives based on current understanding of the existing issues. The book explores advance technologies that may help in deciding the path for future research and development for better strategies and techniques to manage the wheat blast disease. It equips readers with basic and applied understanding on the identification of disease, its distribution and chances of further spread in new areas, its potential to cause yield losses to wheat, the conditions that favour disease development, disease prediction modelling, resistance breeding methods and management strategies against wheat blast. Features: Provides comprehensive information on wheat blast pathogen and its management under a single umbrella Covers disease identification and diagnostics which will be helpful to check introduction in new areas Discusses methods and protocol to study the different aspects of the disease such as diagnostics, variability, resistance screening, epiphytotic creation etc. Gives deep insight on the past, present and future outlook of wheat blast research progress This book’s chapters are contributed by experts and pioneers in their respective fields and it provides comprehensive insight with updated findings on wheat blast research. It serves as a valuable reference for researchers, policy makers, students, teachers, farmers, seed growers, traders, and other stakeholders dealing with wheat.

Author: Philomin Juliana
Publisher:
ISBN:
Category :
Languages : en
Pages : 400

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Wheat (Triticum aestivum L.) is one of the major food crops in the world that is grown on more land area than any other commercial crop. The demand for wheat is expected to increase by 60% by 2050 which cannot be met with the current yield gain of 1%. Hence, it is important to evaluate different strategies for increasing the genetic gain in wheat. With this focus, we evaluated two strategies, genomic prediction and genome-wide association studies (GWAS) for disease resistance in CIMMYT’s international bread wheat screening nurseries (IBWSN). Our objective was to compare different prediction models for resistance to leaf rust (LR), stem rust (SR), stripe rust (STR), Septoria tritici blotch (STB), Stagonospora nodorum blotch (SNB) and tan spot (TS) in the 45th and 46th IBWSN entries. The prediction models tested include: Least-squares (LS), genomic-BLUP (G-BLUP), Bayesian ridge regression (BRR), Bayes A (BA), Bayes B (BB), Bayes C (BC), Bayesian least absolute shrinkage and selection operator (BL), reproducing kernel Hilbert spaces (RKHS) markers (RKHS-M), RKHS pedigree (RKHS-P) and RKHS markers and pedigree (RKHS-MP). The 333 lines in the 45th IBWSN and the 313 lines in the 46th IBWSN were genotyped using genotyping-by-sequencing markers. For the rusts, the mean prediction accuracies were 0.74 for LR seedling, 0.56 for LR APR, 0.65 for SR APR, 0.78 for YR seedling and 0.71 for YR APR. For the leaf spotting diseases, the mean genomic prediction accuracies were 0.45 for STB APR, 0.55 for SNB seedling, 0.66 for TS seedling and 0.48 for TS APR. Using genome-wide marker based models resulted in an average of 42-48% increase in accuracy over LS. Overall, the RKHS-MP model gave the highest accuracies, while LS gave the lowest. GWAS was also performed on these traits and several significant markers and candidate genes were identified. We conclude that implementing GWAS and genomic selection in breeding for these diseases would help to achieve higher accuracies and rapid gains from selection. ...

Author: Harwinder Sidhu
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Fusarium Head Blight (FHB) is a devastating disease of Wheat (Triticum aestivum L.) caused primarily by Fusarium graminearum Schwabe in Canada. Wheat FHB results in yield and produce quality losses. The clearest symptoms of FHB are premature bleaching of spikelets in the field, and fusarium damaged kernels in the harvested seed. Insufficient and costly disease control strategies make breeding for FHB resistance in wheat an ideal choice. There is a lack of FHB resistance sources in the Canadian wheat germplasm and Genome Wide Association Studies (GWAS) can be utilized to identify such sources. Furthermore, as no Quantitative Trait Loci (QTL) provides absolute resistance to FHB, identification of novel sources of resistance is desired. Genomic Selection (GS) has great potential in crop improvement, specifically for quantitative traits. A diversity panel that represents the genetic diversity of the Canadian, i.e., high latitude North American winter wheat was assembled for this thesis and the genetic diversity, population structure, and linkage disequilibrium of the germplasm was studied. To identify QTL associated with FHB, a GWAS study was conducted using the phenotypic data collected at three locations over two years. For understanding the role of number of genotypic markers, population structure, and choice of model in trait prediction modelling, a GS study was conducted. The Canadian Winter Wheat Diversity Panel is a diverse collection of winter wheat capturing diversity both in time and geography from Canada. The panel comprises of seven subpopulations with different LD, allele frequencies, and genetic diversity parameters. Multiple QTL associated with FHB related traits were identified on 13 chromosomes which may harbor genes involved in plant defense and stress response mechanisms. For FHB resistance improvement, the GS study demonstrated that the modelling parameters can be determined based upon the genotypic information available. Deoxynivalenol contamination was one of the traits with the highest prediction accuracy. GS can account for minor effect QTL, which is beneficial when breeding for quantitative traits. FHB resistant varieties are needed for an effective and economical disease control strategy in wheat and GS can complement current breeding efforts to develop FHB resistant wheat varieties.

Author: Fizza Fatima
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Wheat is the most widely grown crop in the world and as such, is an essential source of energy and nutrition. The challenges that breeders presently face is to increase production to feed the rising population of the world, while also accounting for climate change, pollution, water and environmental stresses. As genetic uniformity of modern cultivars has increased vulnerability to pests and diseases, the wild relatives of wheat offer a rich source of genetic diversity and stress tolerance traits, that can be harnessed and transferred in to modern wheat. In this study, we used array-based genotyping to explore genetic diversity in 385 domesticated and non-domesticated lines of wheat and their wild relatives. Genetic characterization using the wheat 90K array, and subsequent filtering and validation mapped 9,570 single nucleotide polymorphic markers onto the wheat reference genome. Phylogenetic analyses illustrated four major clades, clearly separating the wild species from the domesticated, and the ancient Triticum turgidum species from modern T. turgidum cultivars. Using this diverse germplasm, a genome-wide association study (GWAS) was performed for leaf rust, the most widespread rust disease of wheat. Identification of novel sources of resistance is necessary to maintain disease resistance and stay ahead in the plant-pathogen evolutionary arms race. GWAS was conducted using eight statistical models for infection types against six leaf rust isolates and leaf rust severity rated in field trials for 3-4 years at 2-3 locations in Canada. Functional annotation of genes containing significant quantitative trait nucleotides (QTNs) identified 96 disease-related nucleotide associated with leaf rust resistance. A total of 21 QTNs were in haplotype blocks or within flanking markers of at least 16 known leaf rust (Lr) resistance genes. The remaining significant QTNs were considered loci that putatively harbor new Lr resistance genes. Future efforts to validate these loci will help understand their role in disease resistance and promote their utility for marker-assisted selection in pre-breeding.

Author: Colin W Wrigley
Publisher: Academic Press
ISBN: 0123947863
Category : Technology & Engineering
Languages : en
Pages : 1956

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Book Description
The Encyclopedia of Food Grains, Four Volume Set is an in-depth and authoritative reference covering all areas of grain science. Coverage includes everything from the genetics of grains to the commercial, economic and social aspects of this important food source. Also covered are the biology and chemistry of grains, the applied aspects of grain production and the processing of grains into various food and beverage products. With the paramount role of cereals as a global food source, this Encyclopedia is sure to become the standard reference work in the field of science. Also available online via ScienceDirect – featuring extensive browsing, searching, and internal cross-referencing between articles in the work, plus dynamic linking to journal articles and abstract databases, making navigation flexible and easy. For more information, pricing options and availability visit www.info.sciencedirect.com. Written from an international perspective the Encyclopedia concentrates on the food uses of grains, but details are also provided about the wider roles of grains Well organized and accessible, it is the ideal resource for students, researchers and professionals seeking an authoritative overview on any particular aspect of grain science This second edition has four print volumes which provides over 200 articles on food grains Includes extensive cross-referencing and "Further Reading" lists at the end of each article for deeper exploration into the topic This edition also includes useful items for students and teachers alike, with Topic Highlights, Learning objectives, Exercises for Revision and exercises to explore the topic further

Author: John E. Bradshaw
Publisher: Springer
ISBN: 3319232851
Category : Science
Languages : en
Pages : 710

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Book Description
This book aims to help plant breeders by reviewing past achievements, currently successful practices, and emerging methods and techniques. Theoretical considerations are also presented to strike the right balance between being as simple as possible but as complex as necessary. The United Nations predicts that the global human population will continue rising to 9.0 billion by 2050. World food production will need to increase between 70-100 per cent in just 40 years. First generation bio-fuels are also using crops and cropland to produce energy rather than food. In addition, land area used for agriculture may remain static or even decrease as a result of degradation and climate change, despite more land being theoretically available, unless crops can be bred which tolerate associated abiotic stresses. Lastly, it is unlikely that steps can be taken to mitigate all of the climate change predicted to occur by 2050, and beyond, and hence adaptation of farming systems and crop production will be required to reduce predicted negative effects on yields that will occur without crop adaptation. Substantial progress will therefore be required in bridging the yield gap between what is currently achieved per unit of land and what should be possible in future, with the best farming methods and best storage and transportation of food, given the availability of suitably adapted cultivars, including adaptation to climate change. My book is divided into four parts: Part I is an historical introduction; Part II deals with the origin of genetic variation by mutation and recombination of DNA; Part III explains how the mating system of a crop species determines the genetic structure of its landraces; Part IV considers the three complementary options for future progress: use of sexual reproduction in further conventional breeding, base broadening and introgression; mutation breeding; and genetically modified crops.

Author: Yasunari Ogihara
Publisher: Springer
ISBN: 4431556753
Category : Science
Languages : en
Pages : 421

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Book Description
This proceedings is a collection of 46 selected papers that were presented at the 12th International Wheat Genetics Symposium (IWGS). Since the launch of the wheat genome sequencing project in 2005, the arrival of draft genome sequences has marked a new era in wheat genetics and genomics, catalyzing rapid advancement in the field. This book provides a comprehensive review of the forefront of wheat research, across various important topics such as germplasm and genetic diversity, cytogenetics and allopolyploid evolution, genome sequencing, structural and functional genomics, gene function and molecular biology, biotic stress, abiotic stress, grain quality, and classical and molecular breeding. Following an introduction, 9 parts of the book are dedicated to each of these topics. A final, 11th part entitled “Toward Sustainable Wheat Production” contains 7 excellent papers that were presented in the 12th IWGS Special Session supported by the OECD. With rapid population growth and radical climate changes, the world faces a global food crisis and is in need of another Green Revolution to boost yields of wheat and other widely grown staple crops. Although this book focuses on wheat, many of the newly developed techniques and results presented here can be applied to other plant species with large and complex genomes. As such, this volume is highly recommended for all students and researchers in wheat sciences and related plant sciences and for those who are interested in stable food production and food security.