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: 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: Jameel M. Al-Khayri Publisher: Springer ISBN: 3319225219 Category : Technology & Engineering Languages : en Pages : 656
Book Description
The basic concept of this book is to examine the use of innovative methods augmenting traditional plant breeding towards the development of new crop varieties under different environmental conditions to achieve sustainable food production. This book consists of two volumes: Volume 1 subtitled Breeding, Biotechnology and Molecular Tools and Volume 2 subtitled Agronomic, Abiotic and Biotic Stress Traits. This is Volume 1 which consists of 21 chapters covering domestication and germplasm utilization, conventional breeding techniques and the role of biotechnology. In addition to various biotechnological applications in plant breeding, it includes functional genomics, mutations and methods of detection, and molecular markers. In vitro techniques and their applications in plant breeding are discussed with an emphasis on embryo rescue, somatic cell hybridization and somaclonal variation. Other chapters cover haploid breeding, transgenics, cryogenics and bioinformatics.
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: 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: Andrew H. Paterson Publisher: CRC Press ISBN: 9781420049381 Category : Science Languages : en Pages : 328
Book Description
In the past 10 years, contemporary geneticists using new molecular tools have been able to resolve complex traits into individual genetic components and describe each such component in detail. Molecular Dissection of Complex Traits summarizes the state of the art in molecular analysis of complex traits (QTL mapping), placing new developments in thi
Author: Sudheer Kumar Publisher: CRC Press ISBN: 0429894074 Category : Science Languages : en Pages : 157
Book Description
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: Shitaye Homma Megerssa
Author: Xianming Chen
Author: Alan P. Roelfs
Author: Jemanesh Kifetew Haile
Author: Jameel M. Al-Khayri
Author: Katherine Gambone
Author: Izabela L. Ciechanowska
Author: Ingo Potrykus
Author: Andrew H. Paterson
Author: Sudheer Kumar