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Author : Matthew L. Ramage
Publisher :
ISBN 13 :
Total Pages : 106 pages
Book Rating : 4.:/5 (522 download)
Download or read book Quantitative Trait Loci Identification of Gray Leaf Spot Resistance in Maize written by Matthew L. Ramage and published by . This book was released on 2000 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Michael Phillip Jines
Publisher :
ISBN 13 :
Total Pages : 153 pages
Book Rating : 4.:/5 (592 download)
Download or read book Identification of Quantitative Trait Loci for Gray Leaf Spot Resistance, Maturity, and Grain Yield in a Semi-tropical Recombinant Inbred Population of Maize written by Michael Phillip Jines and published by . This book was released on 2004 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt: Keywords: qtl, maturity, gls resistance.
Download or read book Identification of Quantitative Trait Loci (QTL) for Gray Leaf Spot Resistance, Maturity, and Grain Yield in a Semi-tropical Recombinant Inbred Population of Maize written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Identification of QTL can aide in future breeding objectives by allowing breeders either to improve a line through targeted introgressions or assist in forward breeding strategies. Such analyses may be particularly helpful in integrating exotic germplasm into a breeding program. The percentage of tropical maize germplasm grown in U.S. farmers' fields is almost nonexistent. Tropical germplasm in maize (Zea mays L.) is a valuable resource to decrease the dependence upon a limited genetic base currently used to produce commercial hybrids, extend selection limits for grain yield, and to provide an insurance function against emerging biotic and abiotic stresses. Results of research presented in this dissertation support these recommendations. Experiments were conducted to evaluate 143 S4:5 recombinant inbred lines (RILs) resulting from a cross between NC300, an all-tropical, temperate adapted line, and B104, a stiff stalk line. The 143 RILs were topcrossed to the Lancaster tester FR615xFR697 and randomly subdivided into two sets. The two sets were evaluated for resistance to GLS disease and yielding ability in three and eight North Carolina environments, respectively. Spatial trends were examined in the GLS trials. Significant (P d".01) trend effects were fitted in five of the six set-by-environment combinations, which led to improved analyses within and across environments for both sets. Ninety-three and eighty-two percent of the RILs in topcrosses (RILT) were significantly (P = 0.05) more resistant to GLS when compared to the mean of the commercial checks for set 1 and 2, respectively. Twenty-one RILs from both sets did not differ significantly (P = 0.05) for grain yield when compared to the mean of the commercial checks. RIL 2070 yielded significantly (P = 0.05) higher when compared to one commercial check, HC33. TR7322. RIL 1991 was rated the most resistant entry in set 1 and also did not differ from the mean of the commercial checks for grain yield. The RILs we.
Author : Jacqueline Marie Benson
Publisher :
ISBN 13 :
Total Pages : 254 pages
Book Rating : 4.:/5 (913 download)
Download or read book Resistance to Gray Leaf Spot of Maize written by Jacqueline Marie Benson and published by . This book was released on 2013 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gray leaf spot (GLS) is a foliar disease of maize caused by Cercospora zeae-maydis and Cercospora zeina and quantitative resistance to GLS is important for maize production. A nested association mapping (NAM) maize population, consisting of 25 populations of 150 recombinant inbred lines, was used to identify quantitative trait loci (QTL) for GLS resistance. Trials were conducted in Blacksburg, VA, in a field with high natural incidence of GLS. A multivariate mixed model was used in ASReml3 to give the best linear unbiased predictions of disease severity ratings. QTL were selected using a general linear model selection procedure in SAS 9.2. Sixteen QTL, distributed across the maize genome, were identified using a likelihood of odds (LOD) selection threshold>4. Seven of these 16 QTL displayed allelic series with significantly higher and lower effects than the common parent allele. Near-isogenic lines (NILs) extracted from heterogeneous inbred families were developed to confirm and further finemap select QTL, targeting the loci with the greatest LOD scores from the model selection QTL analysis. Phenotypic characterization of the NILs confirmed that the loci in bins 1.04, 2.09 and 4.05 likely contribute significantly to disease resistance, with bins 1.04 and 2.09 conferring reductions in disease of 12% and 23%, respectively. In contrast, the susceptible allele in bin 4.05, which was associated with the distance between major veins, conferred an increase of 8.4%. This disease-related venation trait was confirmed using the 4.05 NILs. Genome-wide association studies revealed candidate genes related to the production of carotenoids, anthocyanins and antioxidant compounds that may play a role in cercosporin detoxification. Expression analysis of 1.05 NILs treated with cercosporin implicated a flavin-monooxygenase gene in cercosporin detoxification. Furthermore, significant associations between NAM parental allelic effects and parental phenotypes at the microscopic level for the 1.02 and 1.06 loci implicated callose plug and phenolic accumulation, respectively, in host defense. Elucidating the genetics of quantitative disease resistance loci provides breeders with valuable information that may enhance their ability to use molecular markers as a means to rapidly introgress loci that provide quantitative disease resistance.
Author : Michael Joe Clements
Publisher :
ISBN 13 :
Total Pages : 82 pages
Book Rating : 4.:/5 (441 download)
Download or read book Quantitative Trait Loci Associated with Resistance to Gray Leaf Spot of Corn written by Michael Joe Clements and published by . This book was released on 1999 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Anke Lehmensiek
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (668 download)
Download or read book Molecular Markers for Quantitative Trait Loci (QTLs) in Maize Gray Leaf Spot (GLS) Resistance written by Anke Lehmensiek and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Jesse Abner Poland
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (613 download)
Download or read book The Genetic Architecture of Quantitative Disease Resistance in Maize written by Jesse Abner Poland and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Several large scale quantitative genetic studies were conducted to better understand the genetic basis for quantitative disease resistance (QDR) in plants. The focus of these studies was the economically important disease of maize (Zea mays L. ssp. mays), northern leaf blight (NLB, caused by Setosphaeria turcica L. anamorph Exserohilum turcicum). The maize nested association mapping (NAM) population, a reference design population consisting of 4,630 recombinant inbred lines, was evaluated over three environments for quantitative resistance to NLB, giving highly heritable resistance phenotypes. Over 200 resistance alleles at 30 different quantitative trait loci (QTL) for disease resistance were identified. Genome-wide nested association mapping for NLB resistance identified genes at six of the QTL that have been associated with disease resistance including three receptor-like kinases, two ethylene response factors, and one Mlo-like gene. Further insight on QDR, with a focus on multiple disease resistance (MDR), was gained by jointly analyzing independent data on NAM for resistance to southern leaf blight (SLB), gray leaf spot (GLS) and NLB. To examine the possibility of MDR genes, the estimated allele effects from each founder inbred were compared at loci were QTL for two or more diseases co-localized. At seven loci, positively correlated allele effects provided evidence for MDR genes. Analysis of the NAM population suggested that resistance to the three diseases studied here is largely due to the accumulation of disease-specific genes and, to a limited extent, pleiotropic genes that condition MDR. A final study was conducted to determine the effect of variability in visual disease rating on mapping disease QTL by assessing the effects of scorer variability and rating scales on mapping QTL for NLB in a single recombinant inbred line population from NAM. Stepwise general linear model selection (GLM) and inclusive composite interval mapping (ICIM) were used for QTL mapping. For both GLM and ICIM the same QTL were largely found across scorers, though some QTL were only identified by some scorers. Strikingly, the magnitudes of estimated allele effects from different scorers at identified QRL were drastically different, sometime by as much as three fold. The studies conducted here advance the understanding of QDR in plants and lay groundwork for identifying the genes responsible for resistance to NLB in maize. A greater understanding of QDR will assist in the development of durable resistant crop cultivars, improving food security and safety.
Author : Junyun Yang
Publisher :
ISBN 13 :
Total Pages : 310 pages
Book Rating : 4.E/5 ( download)
Download or read book Phenotypic and Genotypic Investigation of Multiple Disease Resistance in Maize written by Junyun Yang and published by . This book was released on 2007 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Xiaowu Lu
Publisher :
ISBN 13 :
Total Pages : 292 pages
Book Rating : 4.:/5 (526 download)
Download or read book Identification and Mapping of Quantitative Trait Loci Conferring Disease and Insect Resistances in Maize written by Xiaowu Lu and published by . This book was released on 1999 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Combined Population Analyses for Mapping Loci Conditioning Resistance to Southern Corn Leaf Blight written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Southern leaf blight (SLB) is a fungal disease that attacks the leaves of maize plants, forming tan elliptical lesions. The causal agent is Cochliobolus heterostrophus, a necrotrophic ascomycete, which is endemic to hot, humid maize-growing regions. Most maize hybrids have at least a moderate level of quantitative resistance to SLB, which is the primary method of control for the disease. Quantitative resistance is conditioned by small effects of many genes; thus, to make most efficient use of the genetic variation present for SLB resistance, the number of genes involved, the effects they have singly and in combinations, and their potential interactions with the environment must be elucidated. Because the maize-SLB pathosystem is an excellent model for host-necrotroph genetics, the identification of genes underlying the disease response will not only accelerate breeding progress for SLB resistance, but also for necrotrophic resistance in other crop species. Several attempts have been made to map quantitative trait loci (QTL) responsible for conditioning resistance to SLB in biparental segregating populations; however, the precision of the positional estimates of the resultant loci does not allow for identification of genes underlying the response. In addition, the limited germplasm studied only offers the potential of examining two alleles per locus. Many more alleles exist in breeding germplasm, and for this reason, usefulness of results are limited. The objective of the two studies presented here is to address these limitations by combining data across distinct populations. The first study jointly analyzed data from four independently derived B73 x Mo17 populations to validate the existence of and fine map an SLB resistance QTL in bin 3.04, the most significant QTL detected in a study of the IBM population (a set of advanced intercross lines derived from a B73 x Mo17 cross). The four populations used consisted of the IBM population, a set of recombinant inbred line.
Author : Jose M. Alonso
Publisher : Humana
ISBN 13 : 9781493949137
Total Pages : 0 pages
Book Rating : 4.9/5 (491 download)
Download or read book Plant Functional Genomics written by Jose M. Alonso and published by Humana. This book was released on 2016-10-05 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This second edition volume discusses the revolutionary development of faster and less expensive DNA sequencing technologies from the past 10 years and focuses on general technologies that can be utilized by a wide array of plant biologists to address specific questions in their favorite model systems. This book is organized into five parts. Part I examines the tools and methods required for identifying epigenetic and conformational changes at the whole-genome level. Part II presents approaches used to determine key aspects of a gene’s function, such as techniques used to identify and characterize gene regulatory networks. This is followed by a discussion of tools used to analyze the levels of mRNA, mRNA translation rates and metabolites. Part III features a compilation of forward and reverse genetic approaches that include recent implementation of high-throughput sequencing in classical methodologies such as QTL mapping. The final two parts explore strategies to facilitate and accelerate the generation and testing of functional DNA elements and basic computational tools used to facilitate the use of systems biology approached by a broad spectrum of plant researchers. Written in the highly successful Methods of Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols and key tips on troubleshooting and avoiding known pitfalls. Practical and timely, Plant Functional Genomics: Methods and Protocols, Second Edition highlights the latest developments in DNA sequencing technologies that are likely to continue shaping the future of functional genomics.
Author : Jeff L. Bennetzen
Publisher : Springer Science & Business Media
ISBN 13 : 0387794182
Total Pages : 593 pages
Book Rating : 4.3/5 (877 download)
Download or read book Handbook of Maize: Its Biology written by Jeff L. Bennetzen and published by Springer Science & Business Media. This book was released on 2008-12-25 with total page 593 pages. Available in PDF, EPUB and Kindle. Book excerpt: Handbook of Maize: Its Biology centers on the past, present and future of maize as a model for plant science research and crop improvement. The book includes brief, focused chapters from the foremost maize experts and features a succinct collection of informative images representing the maize germplasm collection.
Author : Michael Richard Kerns
Publisher :
ISBN 13 :
Total Pages : 168 pages
Book Rating : 4.:/5 (419 download)
Download or read book Identification of Quantitative Trait Loci Im Maize written by Michael Richard Kerns and published by . This book was released on 1998 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Godfrey Rox Asea
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (698 download)
Download or read book Genetic Characterization of Partial Resistance and Comparative Strategies for Improvement of Host-resistance to Multiple Foliar Pathogens of Maize written by Godfrey Rox Asea and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Foliar diseases are important biotic constraints limiting maize production globally. Northern corn leaf blight (NCLB) incited by Exserohilum turcicum, gray leaf spot (GLS) incited by Cercospora zeae-maydis and maize streak incited by maize streak virus (MSV), are among the most destructive. Most of the maize foliar diseases are managed by means of quantitative partial resistance. Quantitative trait loci (QTL) conditioning partial-resistance to these pathogens have been identified. Validation of candidate QTL conferring partial resistance would present marker-assisted selection as a potentially viable strategy to improve host resistance. We were interested in determining the usefulness of molecular markers linked to consensus QTL controlling partial-resistance systems for improving the overall resistance level. We examined QTL for NCLB in chromosomal bins 3.06, 5.04 and 8.06; GLS QTL in bins 2.09 and 4.08; and a consensus MSV QTL in bin 1.04 as potential targets for selection in improving host resistance. We also examined the effectiveness of different selection strategies for the purpose of pyramiding resistance loci to these diseases. Field evaluations and subsequent selections were conducted independently for each disease in a population of 410 F2:3 lines derived from hybridization between inbred line CML202 with known resistance to NCLB and MSV, and VP31 a breeding line with known resistance to GLS. Maize streak evaluations were conducted in Zimbabwe, GLS tests were performed in Ohio, and NCLB evaluations were conducted in Uganda and Ohio. Genetic gains were calculated for simultaneous improvement of partial resistance following phenotype-based, marker-based, combined phenotype- and marker-based selection (MAS index), and random selection. Narrow-sense heritability estimates were 0.22, 0.25 and 0.39 for MSV, NCLB and GLS, respectively. Analysis of gene action using orthogonal contrasts showed mostly dominant gene action for NCLB, GLS and MSV. For NCLB, resistance due to presence of alleles from QTL in bins 3.06 and 5.04 was detected across two seasons. The chromosomal region in bin 4.08 for GLS resistance was significant (0.0001
Author : Thomas Lane Gocken
Publisher :
ISBN 13 :
Total Pages : 290 pages
Book Rating : 4.:/5 (29 download)
Download or read book Identification of Quantitative Trait Loci (QTL) in Maize on the Basis of F3 and Testcross Progeny Performance written by Thomas Lane Gocken and published by . This book was released on 1993 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : John Charles Zwonitzer
Publisher :
ISBN 13 :
Total Pages : 177 pages
Book Rating : 4.:/5 (281 download)
Download or read book Genetic Analysis of Southern Leaf Blight, Gray Leaf Spot, and Northern Leaf Blight Resistance Using Near-isogenic Lines and Mapping Populations in Maize written by John Charles Zwonitzer and published by . This book was released on 2008 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt: Keywords: southern leaf blight, gray leaf spot, northern leaf blight, quantitative disease resistance, multiple disease resistance, disease resistance quantitative trail loci, near-isogenic lines, maize, recombinant inbred lines.
Download or read book Enhancing Genetic Gain in Maize with Tropical Germplasm, QTL Mapping, and Spatial Methodologies written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Advance-cycle breeding is restricting the germplasm base for U.S. maize (Zea Mays L.). Many breeding programs devote efforts to adapt diverse germplasm to U.S. growing conditions, but few are participating in continual enhancement. Incorporating tropical germplasm into U.S. breeding pools could broaden the maize germplasm base, while concomitantly providing favorable alleles for yield and disease resistance. Knowing the genomic regions, or quantitative trait loci (QTL), for disease resistance can enhance gain by permitting selection on marker genotypes in the absence of disease expression. In addition, accounting for spatial variability can improve the precision of experiments and aid breeders in line advancement decisions and QTL mapping. Recombinant inbred (RI) lines were derived from a cross between NC300, a temperate-adapted, all-tropical line, and B104, a Stiff-Stalk-synthetic line. The RI lines were topcrossed to the tester FR615. FR697 (a C103 sister line cross). Resistance QTL for Southern Rust (rust) (Puccinia polysora) were mapped in the topcrosses, while Gray Leaf Spot (GLS) (Cercospora zeae-maydis) QTL were mapped in both the RI lines and topcross populations. A major resistance gene for rust was identified on the short-arm of chromosome 10, while ten GLS QTL mapped to chromosomes 1, 2, 3, 4, 8, and 10. Similar markers on chromosome 1 and 8 flanked three GLS and flowering time QTL pairs, and the resistance alleles were associated with increased flowering time. No flowering time regions co-localized with rust-resistance loci. The major rust-resistance gene and three GLS QTL corresponded to regions mapped in prior populations. The tropical parental allele, NC300, increased resistance at three of these four loci. Extensively haplotyping germplasm at these four consensus regions could aid in forward breeding strategies to efficiently integrate resistance packages into U.S. maize breeding populations. Spatial analyses, such as trend and trend analysis with cor.
