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Author: Shitaye Homma Megerssa Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
Stem rust caused by Puccinia graminis f. sp. tritici Eriks. & Henn is the most destructive disease of durum and common wheat. The main focus of this study is to identify loci associated with stem rust resistance in durum wheat using association mapping and linkage mapping. A panel of 283 lines and 224 recombinant inbred lines (RILs) from a cross between 'Reichenbachii' and 'DAKIYE' developed by the durum wheat breeding program of the International Maize and Wheat Improvement Center (CIMMYT) were used for the study. The panel was evaluated against races TTKSK, TKTTF, JRCQC and TTRTF at the seedling stage and TKTTF and JRCQC in the field in Ethiopia from 2018 to 2019 for two seasons. The same panel was evaluated against bulk of multiple stem rust races prevalent in Ethiopia and Kenya from 2018 to 2019 in five environments. Genome-wide association study (GWAS) was conducted using 26,439 single nucleotide polymorphism (SNP) markers for seedling response (280 lines) and field response (283 lines) to stem rust. The RILs along with the two parents were evaluated for response to bulk of multiple stem rust races in Ethiopia and Kenya for two seasons from 2019 to 2020. Linkage analyses were conducted using 843 SNP markers for 175 lines. For GWAS of seedling response, a mixed linear model (MLM) identified 17 quantitative trait loci (QTL) of which eight were putatively novel while FarmCPU identified 20 QTL and 12 were likely novel. For field resistance to races TKTTF and JRCQC, MLM detected 19 QTL of which 12 were likely novel while FarmCPU detected 16 QTL and seven were putatively novel. For resistance to multiple Pgt races in East Africa, 160 significant marker-trait associations (MTAs) grouped into 42 QTL were identified using MLM and FarmCPU and 21 QTL were likely novel. From previously reported Sr genes, the regions of Sr7a, Sr8a, Sr8155B1, Sr11, Sr12, alleles of Sr13, Sr17, Sr22/Sr25, and Sr49 were identified. For the biparental population, composite interval mapping (CIM) identified three QTL on chromosomes 3B (QSr.cnl-3B), 4B (QSr.cnl-4B) and 7B (QSr.cnl-7B). These three QTL contributed by the resistant parent explained 4.7% to 15.3% of the phenotypic variation and all match previously reported loci. Lines with multiple-race stem rust resistance can be used as parents in durum wheat resistance breeding to stem rust and markers identified in the GWAS can be used in marker-assisted selection (MAS) once validated in a different population. Further study on the validation of allele specific markers and allelism tests in the Sr13 region of chromosome 6A is needed. Future evaluation of large numbers of durum wheat lines and searching for durable adult plant resistance gene is crucial in resistance breeding of durum wheat.
Author: Shitaye Homma Megerssa Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
Stem rust caused by Puccinia graminis f. sp. tritici Eriks. & Henn is the most destructive disease of durum and common wheat. The main focus of this study is to identify loci associated with stem rust resistance in durum wheat using association mapping and linkage mapping. A panel of 283 lines and 224 recombinant inbred lines (RILs) from a cross between 'Reichenbachii' and 'DAKIYE' developed by the durum wheat breeding program of the International Maize and Wheat Improvement Center (CIMMYT) were used for the study. The panel was evaluated against races TTKSK, TKTTF, JRCQC and TTRTF at the seedling stage and TKTTF and JRCQC in the field in Ethiopia from 2018 to 2019 for two seasons. The same panel was evaluated against bulk of multiple stem rust races prevalent in Ethiopia and Kenya from 2018 to 2019 in five environments. Genome-wide association study (GWAS) was conducted using 26,439 single nucleotide polymorphism (SNP) markers for seedling response (280 lines) and field response (283 lines) to stem rust. The RILs along with the two parents were evaluated for response to bulk of multiple stem rust races in Ethiopia and Kenya for two seasons from 2019 to 2020. Linkage analyses were conducted using 843 SNP markers for 175 lines. For GWAS of seedling response, a mixed linear model (MLM) identified 17 quantitative trait loci (QTL) of which eight were putatively novel while FarmCPU identified 20 QTL and 12 were likely novel. For field resistance to races TKTTF and JRCQC, MLM detected 19 QTL of which 12 were likely novel while FarmCPU detected 16 QTL and seven were putatively novel. For resistance to multiple Pgt races in East Africa, 160 significant marker-trait associations (MTAs) grouped into 42 QTL were identified using MLM and FarmCPU and 21 QTL were likely novel. From previously reported Sr genes, the regions of Sr7a, Sr8a, Sr8155B1, Sr11, Sr12, alleles of Sr13, Sr17, Sr22/Sr25, and Sr49 were identified. For the biparental population, composite interval mapping (CIM) identified three QTL on chromosomes 3B (QSr.cnl-3B), 4B (QSr.cnl-4B) and 7B (QSr.cnl-7B). These three QTL contributed by the resistant parent explained 4.7% to 15.3% of the phenotypic variation and all match previously reported loci. Lines with multiple-race stem rust resistance can be used as parents in durum wheat resistance breeding to stem rust and markers identified in the GWAS can be used in marker-assisted selection (MAS) once validated in a different population. Further study on the validation of allele specific markers and allelism tests in the Sr13 region of chromosome 6A is needed. Future evaluation of large numbers of durum wheat lines and searching for durable adult plant resistance gene is crucial in resistance breeding of durum wheat.
Author: Xianming Chen Publisher: Springer ISBN: 9402411119 Category : Science Languages : en Pages : 723
Book Description
This book comprehensively introduces stripe rust disease, its development and its integral control. Covering the biology, genetics, genome, and functional genomics of the pathogen, it also discusses host and non-host resistance, their interactions and the epidemiology of the disease. It is intended for scientists, postgraduates and undergraduate studying stripe rust, plant pathology, crop breeding, crop protection and agricultural science, but is also a valuable reference book for consultants and administrators in agricultural businesses and education.
Author: Katherine Gambone Publisher: ISBN: Category : Languages : en Pages :
Book Description
Stem rust, caused by the fungus Puccinia graminis f. sp. tritici, has historically been one of the most important diseases of wheat. Although losses have been much reduced in the last fifty years, new highly virulent races of the pathogen have recently emerged in East Africa. These new races are virulent on nearly all of the currently deployed resistance genes and therefore pose a serious threat to global wheat production. The spring wheat variety 'Kingbird' is thought to contain multiple quantitative trait loci (QTLs) that provide durable, adult-plant resistance against wheat stem rust. Stem rust-susceptible Kansas winter wheat line 'KS05HW14' was backcrossed to Kingbird and 379 recombinant lines were advanced to BC1F5 and then increased for testing. The lines were screened for stem rust resistance in the greenhouse and field in Kansas and in the field in Kenya over multiple years. We identified 16,237 single nucleotide polymorphisms (SNPs) with the Wheat 90K iSelect SNP Chip assay. After filtering for marker quality, linkage maps were constructed for each wheat chromosome. Composite interval mapping and multiple-QTL mapping identified seven QTLs on chromosome arms 2BL, 2DS, 3BS, 3BSc, 5DL, 7BL, and 7DS. Six QTLs were inherited from Kingbird and one QTL on 7BL was inherited from KS05HW14. The location of the QTL on 2BL is approximately at locus Sr9, 3BS is at Sr2, 3BSc is at Sr12, and 7DS is at Lr34/Yr18/Sr57. Although no QTL was found on 1BL, the presence of resistance gene Lr46/Yr29/Sr58 on 1BL in both parents was indicated by the gene-specific marker csLV46. QTLs on 2DS and 5DL may be related to photoperiod or vernalization genes. Pairwise interactions were only observed with race QFCSC, most notably occurring with QTLs 2BL and 3BSc. These results confirm that there are multiple QTLs present in Kingbird. Ultimately, the identification of the QTLs that make Kingbird resistant will aid in the understanding of durable, non-race-specific resistance to stem rust of wheat.
Author: Douglas R. Knott Publisher: Springer Science & Business Media ISBN: 3642836410 Category : Technology & Engineering Languages : en Pages : 213
Book Description
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.
Author: Izabela L. Ciechanowska Publisher: ISBN: Category : Wheat Languages : en Pages : 0
Book Description
Marker-assisted selection requires the identification of molecular markers associated with major genes and quantitative trait loci (QTL) using linkage analysis. In this study, we used 167 doubled haploid (DH) lines derived from two unregistered spring wheat (Triticum aestivum L.) parental lines that belong to the Canada Western Special Purpose (CWSP) class to map QTLs associated with five traits using inclusive composite interval mapping (ICIM). Using ICIM, least square means phenotype data across 3-4 environments, and a genetic map of 2,676 SNPs out of the wheat 90K SNP array, we identified ten QTLs associated with maturity (4A and 5B), plant lodging (4B, 5A, 5D, and 7D), grain yield (2D), leaf rust (4A) and stem rust (1A and 2B). Each QTL individually accounted for 6.0-22.3% of the phenotypic variance and together accounted for 8.6-38.2% of each trait. QTLs identified for rusts using ICIM had a minor effect (6.0-9.0%) or a major effect (22.3%). Our major effect QTL at 22.3% was discovered on chromosome 2B and contributed to stem rust response. Its physical location has been associated with disease response in previous studies. Results from this study provide additional valuable information to wheat researchers, in particular that the area on chromosome 2B should be considered for future analyses.
Author: Jemanesh Kifetew Haile Publisher: Cuvillier Verlag ISBN: 3736943253 Category : Science Languages : en Pages : 134
Book Description
Ethiopia is the second largest wheat producer in the sub-Saharan Africa. The country is rich in genetic resources of tetraploid wheat and has suitable environments for wheat production. However, the country is a net importer of wheat particularly durum wheat (hard wheat). The demand for durum wheat is continuously increasing because of the new emerging food processing industries. But the productivity of wheat in Ethiopia is low due to biotic and abiotic stresses. Among the biotic factors, diseases particularly stem rust play a significant role in yield reduction. As a result of a recent spread of a new and highly virulent race of Puccinia graminis f. sp. tritici (Pgt), Ug99, stem rust is becoming a serious threat to wheat production in Ethiopia as well as in other East African and wheat producing countries. Therefore, it is important to identify new resistance sources and to apply marker assisted selection for sustainable and efficient control stem rust. The aims of the studies included in this thesis were (i) identification of QTL and test for epistatic effects in a segregating population for resistance to stem rust, (ii) identification of stem rust resistance (Sr) genes that are present in durum wheat (Triticum durum Desf.) varieties that were released in Ethiopia during the period 1966–2009 and tetraploid wheat landraces using linked/diagnostic molecular markers and (iii) Evaluation of genetic diversity and relationship pattern within and among these tetraploid wheat landraces and improved varieties based on SSR/STS markers including those linked with reported stem rust resistance genes and QTL. Across all the three experiments, our study demonstrates that there exist potential germplasm and strategies to combat the threat posed by Ug99 and its derivatives. These results provide useful information to wheat breeders in Ethiopia and other national and international programs, regarding the use of available landraces and released varieties for the enhancement of the genetic base of wheat germplsm. Particularly it will give an alarm for Ethiopian wheat breeders to broaden the genetic base of the varieties that will be released in the future since most of the varieties released for the last five decades have a narrow genetic base. In addition, our research provides a base of knowledge for future QTL and gene mapping conferring resistance to stem rust and the use of the linked markers in marker assisted selection.
Author: RA McIntosh Publisher: CSIRO PUBLISHING ISBN: 0643103023 Category : Technology & Engineering Languages : en Pages : 308
Book Description
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.
Author: Shabir H Wani Publisher: Springer Nature ISBN: 3030595773 Category : Technology & Engineering Languages : en Pages : 296
Book Description
World population is growing at an alarming rate and may exceed 9.7 billion by 2050, whereas agricultural productivity has been negatively affected due to yield limiting factors such as biotic and abiotic stresses as a result of global climate change. Wheat is a staple crop for ~20% of the world population and its yield needs be augmented correspondingly in order to satisfy the demands of our increasing world population. “Green revolution”, the introduction of semi-dwarf, high yielding wheat varieties along with improved agronomic management practices, gave rise to a substantial increase in wheat production and self-sufficiency in developing countries that include Mexico, India and other south Asian countries. Since the late 1980’s, however, wheat yield is at a standoff with little fluctuation. The current trend is thus insufficient to meet the demands of an increasing world population. Therefore, while conventional breeding has had a great impact on wheat yield, with climate change becoming a reality, newer molecular breeding and management tools are needed to meet the goal of improving wheat yield for the future. With the advance in our understanding of the wheat genome and more importantly, the role of environmental interactions on productivity, the idea of genomic selection has been proposed to select for multi-genic quantitative traits early in the breeding cycle. Accordingly genomic selection may remodel wheat breeding with gain that is predicted to be 3 to 5 times that of crossbreeding. Phenomics (high-throughput phenotyping) is another fairly recent advancement using contemporary sensors for wheat germplasm screening and as a selection tool. Lastly, CRISPR/Cas9 ribonucleoprotein mediated genome editing technology has been successfully utilized for efficient and specific genome editing of hexaploid bread wheat. In summary, there has been exciting progresses in the development of non-GM wheat plants resistant to biotic and abiotic stress and/or wheat with improved nutritional quality. We believe it is important to highlight these novel research accomplishments for a broader audience, with the hope that our readers will ultimately adopt these powerful technologies for crops improvement in order to meet the demands of an expanding world population.
Author: Shitaye Homma Megerssa
Author: Shitaye Homma Megerssa
Author: Xianming Chen
Author: Katherine Gambone
Author: Douglas R. Knott
Author: Izabela L. Ciechanowska
Author: Jemanesh Kifetew Haile
Author: RA McIntosh
Author: Julia Xiuling Zhang
Author: Alan P. Roelfs
Author: Shabir H Wani