Download or read book Ecological and Quantitative Studies of Occurrence of Soybean Sclerotinia Stem Rot Caused by Sclerotinia Sclerotiorum in the North Central Region of the United States written by Asimina Leonidas Mila and published by . This book was released on 2002 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the early 90's, Sclerotinia stem rot of soybeans (SSR), caused by Sclerotinia sclerotiorum (Lib.) de Bary, has emerged as a serious problem in the north-central soybean production region of the United States. Understanding the epidemiology of Sclerotinia sclerotiorum and developing models that explain, and eventually may forecast, the risk of SSR occurrence in the region may help extension specialists and growers manage the disease. Regional prevalence of soybean SSR was modeled using historical data collected between 1995 and 1998 from 4 states of the North-Central Region of the United States (Illinois, Iowa, Minnesota and Ohio). Tillage practices, soil texture, and summer weather variables from the National Oceanic and Atmospheric Administration (average monthly air temperature and total precipitation during July and August) were used as input variables. Logistic regression was used to estimate the probability of stem rot prevalence in the four states. A developed model had high explanatory power (77.8%). Bayesian analysis suggested that the four-year data set used in the analysis may not be informative enough to produce reliable estimates of the effect of some explanatory variables on SSR prevalence. The variable most sensitive to extra-sample incorporated information was precipitation of August. The relationships between management practices, weather variables and soybean yield were examined using multiple linear regression to investigate whether high potential yield environments are also high SSR risk environments. Occurrence of SSR was indeed found to be strongly associated with high attainable yield. Differences in soil temperature and water potential have been observed under different combinations of tillage regimes and planting row widths, with soil surface temperature and moisture fluctuating more under the combination of no tillage and wide rows than under other combinations. Experiments were conducted to determine the effects of soil temperature and water potential fluctuations on sclerotium germination, and apothecium production of Sclerotinia sclerotiorum. Our results showed that small temperature fluctuations increased sclerotia germination and apothecium production compared to large or no temperature fluctuations. Moisture fluctuations were detrimental to sclerotium germination and apothecium production, with the constant saturation treatment yielding the highest number of germinated sclerotia and apothecia.
Download or read book Studies on the Reaction of Soybean to SCLEROTINIA SCLEROTIORUM Causal Agent of Stem Rot of Soybean written by Laura Beth Kao and published by . This book was released on 1987 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modernizing Integrated Management Practices for Sclerotinia Stem Rot of Soybean Glycine Max written by Richard Webster (Ph.D.) and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soybean production in the Upper Midwest region of the United States is consistently threatened by Sclerotinia stem rot (SSR), caused by the fungal pathogen Sclerotinia sclerotiorum. Management practices for this disease have historically been studied in depth. However, a reevaluation and modernization of these practices is greatly needed. To achieve this, many methods of control are being examined such as the assessment of integrating multiple cultural practices, the reassessment of chemical controls, the development of improved genetic resistance through both classical breeding and reverse genetics, and the integration of resistant genotypes into predictive models. From this research, the optimum cultural and chemical practices were identified for controlling SSR across the Midwest. These practices were examined for their effect on partial profits to understand their economic feasibility. Through breeding efforts, three elite soybean genotypes were identified with high levels of resistance to SSR, and more early-generation breeding lines are being progressed from additional breeding populations. Furthermore, four breeding lines were identified as having differential consistent responses to S. sclerotiorum, and these four lines were established as standardized checks. Using these four check lines, the integration of resistance into S. sclerotiorum apothecial models is being studied to improve predictive accuracy. Collectively, these research efforts will help to modernize management and control of SSR from both research and production perspectives.
Download or read book Modernizing Integrated Management Practices for Sclerotinia Stem Rot of Soybean Glycine Max written by Richard Webster (Ph.D.) and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soybean production in the Upper Midwest region of the United States is consistently threatened by Sclerotinia stem rot (SSR), caused by the fungal pathogen Sclerotinia sclerotiorum. Management practices for this disease have historically been studied in depth. However, a reevaluation and modernization of these practices is greatly needed. To achieve this, many methods of control are being examined such as the assessment of integrating multiple cultural practices, the reassessment of chemical controls, the development of improved genetic resistance through both classical breeding and reverse genetics, and the integration of resistant genotypes into predictive models. From this research, the optimum cultural and chemical practices were identified for controlling SSR across the Midwest. These practices were examined for their effect on partial profits to understand their economic feasibility. Through breeding efforts, three elite soybean genotypes were identified with high levels of resistance to SSR, and more early-generation breeding lines are being progressed from additional breeding populations. Furthermore, four breeding lines were identified as having differential consistent responses to S. sclerotiorum, and these four lines were established as standardized checks. Using these four check lines, the integration of resistance into S. sclerotiorum apothecial models is being studied to improve predictive accuracy. Collectively, these research efforts will help to modernize management and control of SSR from both research and production perspectives.
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2003 with total page 812 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Soybean Diseases of the North Central Region written by Thomas D. Wyllie and published by American Phytopathological Society. This book was released on 1988 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides timely information on the major diseases affecting soybeans in the north central soybean growing area of the United States.
Download or read book Studies on Sclerotinia Sclerotiorum Sclerotinia Stem Rot on Soybeans written by Dael Desiree Visser and published by . This book was released on 2007 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Sclerotinia Diseases of Crop Plants Biology Ecology and Disease Management written by G. S. Saharan and published by Springer Science & Business Media. This book was released on 2008-09-01 with total page 531 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fungus Sclerotinia has always been a fancy and interesting subject of research both for the mycologists and pathologists. More than 250 species of the fungus have been reported in different host plants all over the world that cause heavy economic losses. It was a challenge to discover weak links in the disease cycle to manage Sclerotinia diseases of large number of crops. For researchers and s- dents, it has been a matter of concern, how to access voluminous literature on Sclerotinia scattered in different journals, reviews, proceedings of symposia, workshops, books, abstracts etc. to get a comprehensive picture. With the pub- cation of book on ‘Sclerotinia’, it has now become quite clear that now only three species of Sclerotinia viz. , S. sclerotiorum, S. minor and S. trifoliorum are valid. The authors have made an excellent attempt to compile all the available infor- tion on various aspects of the fungus Sclerotinia. The information generated so far has been presented in different chapters. After introducing the subject various aspects viz. , the diseases, symptomatology, disease assessment, its distribution, economic importance, the pathogen, its taxonomy, nomenclature, reproduction, reproductive structures with fine details, variability, perpetuation, infection and pathogenesis, biochemical, molecular and physiological aspects of host-pathogen interaction, seed infection, disease cycle, epidemiology and forecasting, host resistance with sources of resistance, mechanism of resistance and other mana- ment strategies have been covered.
Download or read book Development and Refinement of Integrated Management Strategies for Sclerotinia Stem Rot of Soybean written by Jaime Fay Willbur and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sclerotinia stem rot (SSR), or white mold, is caused by Sclerotinia sclerotiorum and is one of the top ten yield reducing diseases of soybean worldwide. Complete commercial resistance is confounded by an incomplete understanding of resistance mechanisms and the diversity within S. sclerotiorum populations. Characterization of a diverse isolate collection facilitated the selection of a representative panel of isolates for use in ongoing germplasm resistance evaluations. These isolates were used to further identify candidate germplasm lines exhibiting durable SSR resistance for further integration into commercial soybean cultivars. Monitoring infection of resistant and susceptible lines further helped to understand S. sclerotiorum infection and potential resistance mechanisms. Chemical control is also currently incomplete and, in some cases, unnecessary as disease development requires conditions conducive for simultaneous apothecial germination, ascospore release, and soybean flowering. Multiple site-years of fungicide efficacy trials were evaluated using meta-analyses to identify effective control programs, which will assist growers in making economical management decisions. Risk assessment tools are sometimes used to more accurately predict the timing of effective fungicide applications; however, reliable tools were not available in soybean systems prior to this research. In the SSR pathosystem, dense canopies, cool temperatures, high relative humidity, and moist soil conditions have been shown to favor S. sclerotiorum infection and subsequent disease development. Additionally, studies have shown that apothecial development is sensitive to a narrow range of ultraviolet wavelengths (276-319 nm). Virtual weather data and detailed epidemiological studies have led to the development and validation of models for non-irrigated and irrigated fields which predict apothecial presence based on 30-day averages of mean air temperature, relative humidity, and maximum leaf wetness. These models will be incorporated into a mobile web-based recommendation tool. Moreover, controlled environment and in-field light studies have identified a crucial range of light (295-330 nm) which are required for apothecial development and could be targeted to further improvement of SSR management. Overall, the development of germplasm with broad-spectrum resistance, the study of resistance mechanisms, multiple site-year fungicide efficacy evaluations, and an optimized spray advisory system will provide a new, fresh approach to integrated management of SSR in soybean.
Download or read book Evaluation of Prediction Models for Sclerotinia Stem Rot Sclerotinia Sclerotiorum of Soybean Glycine Max in Quebec written by Césarée Morier-Gxoyiya and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "In Québec's soybean (Glycine max (L.) Merr.) farms, Sclerotinia stem rot (SSR), a disease caused by the fungal pathogen Sclerotinia sclerotiorum (Lib.) de Bary, is commonly controlled by chemical fungicides sprayed during the crop's flowering growth stages. However, fungicide use efficiency varies largely based on the risk of disease outbreak, which is strongly influenced by agro-environmental conditions. Unnecessary or improperly timed fungicide applications are costly not only economically, but also environmentally. Prediction models can guide disease management decisions by informing of the necessity and timing of fungicide applications. In this project, S. sclerotiorum sclerotia were placed in commercial and research fields across soybean-producing regions of Québec. The goal was to assess the relationship between environmental and agronomic conditions and carpogenic germination of S. sclerotiorum. The predictive ability of Sclerotinia-related logistic regression models was evaluated under Québec's climatic conditions using data collected over three growing seasons. Based on the nature of the models selected, the predictive performance was assessed for two disease indicators: disease severity and apothecia presence. Upon validation and improvement, the models with the highest accuracy and predictive ability could be implemented in an integrated decision-support system for soybean producers in Québec"--
Download or read book Field Scale Spatial Distribution and Genotypic Diversity of Sclerotinia Sclerotiorum in Soybeans written by Tyler Mcfeaters and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: White mold (WM) in soybeans, caused by Sclerotinia sclerotium (S.s.), is the second most devastating disease of soybeans in the world. The disease causes an average of 2.5% yield loss in soybean production annually in Pennsylvania (PA), which equates to approximately $6,000,000. However, many growers still do not scout for white mold or have not been able to manage it well. My thesis aims to increase our understanding of the biology of S.s. at the field-scale, which will improve sampling strategies, crop loss estimations, and field experimental designs. Studying the genotypic diversity of S.s. populations at a field scale will help to improve management strategies like fungicide applications. The first objective of my thesis was to determine the spatial distribution of WM disease incidence and of S.s. sclerotia in the soil. My second objective was to determine if there was evidence of clonality in field-scale populations of S.s. Third, we determined if the state-scale Pennsylvania population of S.s. was clonal and compared that population to New York and Minas Gerais, Brazilian populations. Fourth, we validated the Sporecaster mobile application for use by soybean growers to forecast WM risk in the Northeast United States. Eight fields were selected for soil sampling of thirty-five quadrats. S.s. sclerotia were manually removed and isolated in the lab. DNA was extracted for 286 isolates and genotyped by fragment analysis. Microsatellite regions of the DNA were amplified at 10 loci and PCR products were analyzed by capillary electrophoresis. The same fields were also scouted to quantify the disease incidence in each quadrat. Lastly, soybean fields in PA and New York were monitored and scouted to conduct a validation of the Sporecaster mobile application for forecasting white mold risk. Across both years, the maximum number of sclerotia in a field was 3.3 sclerotia/kg soil and the maximum disease incidence for a field was 14% due to warmer and drier weather conditions at most locations. The spatial distribution of the pathogen at a field-scale was randomly distributed and only one field showed aggregation. Genotypic results indicated 83 multilocus genotypes were present across PA. Despite a high genotypic diversity, populations at a field scale were clonal and showed little evidence of outcrossing. The Sporecaster mobile application had a two-year average accuracy of 57-74% at predicting white mold disease incidence. Our increased knowledge of the pathogen and the use of the Sporecaster app will help to improve management recommendations and guide future research of white mold management tactics.
Download or read book Epidemiological Studies on Sclerotinia Stem Rot Caused by Sclerotinia Sclerotiorum Lib de Bary on Canola written by Issa Suleiman Qandah and published by . This book was released on 2008 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Compendium of Potato Diseases written by W. J. Hooker and published by International Potato Center. This book was released on 1981 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: Disease in the absence of infectious pathogens. Genetic abnormalities. Adverse environment. Nutrient imbalance. Disease in the presence of infectious pathogens. Fungi. Viruses. Mycoplasmas. Insect toxins. Nematodes. Aphids. Seed potato certification.
Download or read book Diseases Pests and Disorders of Potatoes written by Stuart J. Wale and published by Elsevier. This book was released on 2008 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: Covering the most important pathogens of potatoes, this handbook provides clear, concise descriptions of the symptoms and cycles of diseases. It also provides detail on the distribution, economic importance, and advice on the control. Illustrated with over 250 color photographs of affected crops, pest profiles and detailed characteristics of common prey to potato crops, this book is the ultimate aid to the rapid identification and control of disease for this important crop. * Coverage includes identifcation, disease cycle, economic importance, and control * Problem-oriented organization * Over 250 color illustrations; full color * Field guide practicality
Download or read book The Molecular Basis of Plant Genetic Diversity written by Mahmut Caliskan and published by BoD – Books on Demand. This book was released on 2012-03-30 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Molecular Basis of Plant Genetic Diversity presents chapters revealing the magnitude of genetic variations existing in plant populations. Natural populations contain a considerable genetic variability which provides a genomic flexibility that can be used as a raw material for adaptation to changing environmental conditions. The analysis of genetic diversity provides information about allelic variation at a given locus. The increasing availability of PCR-based molecular markers allows the detailed analyses and evaluation of genetic diversity in plants and also, the detection of genes influencing economically important traits. The purpose of the book is to provide a glimpse into the dynamic process of genetic variation by presenting the thoughts of scientists who are engaged in the generation of new ideas and techniques employed for the assessment of genetic diversity, often from very different perspectives. The book should prove useful to students, researchers, and experts in the area of conservation biology, genetic diversity, and molecular biology.
Download or read book Plant Programmed Cell Death written by Arunika N. Gunawardena and published by Springer. This book was released on 2015-10-08 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: Programmed cell death (PCD) is a genetically encoded, active process which results in the death of individual cells, tissues, or whole organs. PCD plays an essential role in plant development and defense, and occurs throughout a plant’s lifecycle from the death of the embryonic suspensor to leaf and floral organ senescence. In plant biology, PCD is a relatively new research area, however, as its fundamental importance is further recognized, publications in the area are beginning to increase significantly. The field currently has few foundational reference books and there is a critical need for books that summarizes recent findings in this important area. This book contains chapters written by several of the world’s leading researchers in PCD. This book will be invaluable for PhD or graduate students, or for scientists and researchers entering the field. Established researchers will also find this timely work useful as an up-to-date overview of this fascinating research area.
Download or read book Rhizoctonia Species Taxonomy Molecular Biology Ecology Pathology and Disease Control written by B. Sneh and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 561 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rhizoctonia Species: Taxonomy, Molecular Biology, Ecology, Pathology and Control, written by the world's most reputable experts in their respective fields of Rhizoctonia research, summarizes years of research in the various aspects of the ubiquitous complex group of soil-borne fungi belonging to the anamorph genus Rhizoctonia. Species of Rhizoctonia worldwide cause economically important diseases on most of the world's important plants such as cereals, potato, cotton, sugarbeet, vegetables, ornamentals and trees in nurseries. The subject reviews covered in the book include classic as well as modern approaches to Rhizoctonia research in: Taxonomy and Evolution, Genetics and Pathogenicity, Plant-Rhizoctonia Interactions, Ecology, Population and Disease Dynamics, Disease Occurrence and Management in Various Crops, Cultural Control, Biological Control, Germplasm for Resistance, Chemical and Integrated Control Strategies. It aims to be the standard reference source book on Rhizoctonia for the next decade or more, just as Parmeter et al. (1970) has been in the past. It will be an important publication for Rhizoctonia investigators, plant pathologists, students, extension specialists, crop producers and companies dealing with plant disease control.
