Download or read book Effect of Soybean Seed Treatments on Oomycete Evolution and Diversity for Improved Seedling Disease Management written by Zachary Albert Noel and published by . This book was released on 2019 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soybean (Glycine max L.) is the second most important crop in the United States. Soil conservation efforts combined with earlier planting dates has led to increased crop residue and cooler soil at planting. This exposes seeds and developing seedlings to adverse conditions for extended periods of time, which can increase disease pressure from many oomycete pathogens causing pre- or post-emergence damping-off. In North America, at least 84 oomycete species within the genera Pythium, Phytophthora, Phytopythium, and Aphanomyces are associated with soybean seedlings. The number of oomycete species makes management decisions difficult and seed applied anti-oomycete chemicals (oomicides) are the primary management tool against the majority of these species. Therefore, the overall theme of this dissertation was to determine the effect of soybean seed treatments on oomycete evolution and diversity to improve management recommendations. First, in chapter 1, I provide a review of current literature and background information on soybean seedling disease management, fungicide (including oomicide) resistance theory, Peronosporalean taxonomy and evolution, and review current methods to study oomycete diversity. Secondly, since an essential step in monitoring for oomicide resistance is in vitro testing, I provide clarification of terms and models involved in the analysis of in vitro dose-response data for improved reproducibility (chapter 2). Next, in chapter 3, the level of interspecific variation in mefenoxam and ethaboxam sensitivity was determined using a newly developed high-throughput assay for oomycetes that utilized growth curves and Z'-factor for quality control. This revealed that that interspecific variation in sensitivity to ethaboxam was greater than mefenoxam. Therefore, in chapter 4, the genetic and evolutionary mechanism of ethaboxam insensitivity was investigated. This revealed for the first time that inherent insensitivity to ethaboxam was linked to the convergent evolution of a specific substitution in the target gene, which resulted in lineage-specific insensitivity to ethaboxam. In chapter 5, the effect of location, and seed treatments containing either mefenoxam or ethaboxam and metalaxyl on the recovery of oomycetes from soybean taproot or lateral root tissue. This study demonstrated that oomycete communities were largely structured by location and that the recovery oomycetes from soybeans were dependent on the unique combination of location, tissue, and seed treatment. Finally, in chapter 6, an oomycete metabarcoding approach (amplicon sequencing) was used to study the influence of soybean seed treatment and genotype on oomycete rhizosphere diversity from a location with or without a history of seedling disease. This indicated that oomycete community diversity was driven by location and that an imbalance of oomycete taxa rather than simply the presence-absence of certain taxa might be responsible for differences in disease pressure. Additionally, there was no substantial evidence that genotype or seed treatment influenced oomycete diversity in soybean rhizosphere samples. Finally, in chapter 7, I discuss the overall conclusions and impacts of the studies presented herein. Overall, data from these studies provide essential new information for the management of oomycete communities with soybean seed treatments. Importantly, these studies advance our knowledge about the effect of soybean seed treatments on the evolution and diversity of oomycetes in a soybean agroecosystem.
Download or read book Oomycete Community Diversity and Pathogenicity Associated with Soybean in Ohio written by Krystel A. Navarro-Acevedo and published by . This book was released on 2019 with total page 187 pages. Available in PDF, EPUB and Kindle. Book excerpt: The oomycetes, Phytophthora (Ph.), Phytopythium (Pp.), and Pythium (Py.) cause detrimental effects to soybean yields when susceptible cultivars are planted, and conducive conditions occur. Soils with high clay content found in many soybean production areas of Ohio paired with heavy rainfall, allows for water retention for longer periods of time. This enables the germination of oospores and mobility of zoospores towards soybean roots. Subsequently, infections occur and early symptoms include pre-and post- emergence damping-off of soybean seed and seedlings. In addition, mid-season infections lead to root rots but one species, Phytophthora sojae causes stem rot which results in plant death. Within the genus Phytophthora, only Ph. sojae and Ph. sansomeana have been recovered from soybean seedlings and reported as pathogens. In contrast, a vast diversity of Pythium species have been recovered from soybean seedlings across major soybean producing states in the U.S. and Canada. Pythium sylvaticum, Py. irregulare, Py. ultimum var. ultimum, Py. ultimum var. sporangiiferum and Py. heterothallicum are among the most frequently recovered species. More importantly, more than one species has been recovered from symptomatic seedlings or roots, suggesting that these occur as species complexes. To better manage this root pathogen complex, an integrated disease management approach is recommended. This includes a combination of fungicide seed treatments paired with host resistance. Fungicide efficacy is variable among species and host resistance has shown to be the best means of management in regions with high levels of inoculum and conducive environments. The distribution and species diversity of Phytophthora, Phytopythium and Pythium among soybean and corn producing states have been documented in several previous surveys that used different isolation techniques. These surveys suggested that soil edaphic factors may play a role in species distribution and diversity. However, how community composition and species diversity change when soil edaphic factors remain constant was unexplored. Thus, the first objective of this study was to test the effects of temperature and agronomic practices on the community composition and species diversity of Phytophthora, Phytopythium and Pythium. A soil baiting technique was used to identify the pathogen complex in soils from five fields with different A soil baiting technique was used to identify the pathogen complex in soils from five fields with different rotation schemes and tillage practices but with similar soil edaphic factors. Soils were incubated at 15 and 25oC and seed of the susceptible cultivar Sloan was used as bait. Symptomatic seedlings were collected for direct isolation of pathogens onto oomycete selective media. Additionally, rhizosphere soil was collected for metabarcoding approach in which DNA was extracted, followed by amplification with oomycete primers of the ITS1 region and sequencing. Regardless of temperature or agronomic practice, Py. sylvaticum, and Py. ultimum were isolated through the baiting procedure and these along with Py. acrogynum, Py. attrantheridium, and Py. heterothallicum were detected with amplicon sequencing at all temperatures and all fields and were considered as the core species associated with soybean. More importantly, there were distinct communities between fields with different agronomic practices. Pythium arrhenomanes and Py. inflatum, were found in greater abundance in soil from the field under continuous corn while Ph. sojae was higher in soils from fields planted to a soybean corn rotation. There were also differences in community composition due to temperature, six Pythium species were abundant at 15oC while another six were favored by 25oC. These findings demonstrated that the diversity of Phytophthora, Phytopythium, and Pythium, associated with soybean roots can be influenced by temperature and potentially production practices which may explain in part the differences in species composition among the many surveys that have taken place as well as the importance previous production practices may be having on the community composition within a field. The second objective was to evaluate if soybean genotype could impact the abundance of Phytophthora, Phytopythium, and Pythium. Here, three cultivars (Kottman, Lorain, and Sloan) with different levels and types of resistance towards these three genera were planted across eleven environments with high disease pressure in Ohio over a two-year period. At soybean growth stage V1-V3, seedlings from each environment were collected for direct isolation, and rhizosphere soil used for a metabarcoding approach. In addition, data for early plant population and yield was collected from each environment to determine the performance of the cultivars under natural field conditions. Based on both a metabarcoding approach and direct isolation, the environment played a significant role on the Phytophthora, Phytopythium, and Pythium communities and these were also influenced by different soybean growth stages. In addition, cultivar significantly affected the abundance of Phytophthora species in the rhizosphere of soybean seedlings. Here the greater number of Ph. sojae reads were recovered from rhizosphere soil and symptomatic seedlings of the moderately susceptible cultivar Sloan compared to Kottman with race-specific resistance towards Ph. sojae. Two species, Py. periilum and Pythium sp. CAL, not reported previously in Ohio, were detected in the soybean rhizosphere using a metabarcoding approach. Pythium periilum was only detected in the rhizosphere while the undescribed Pythium sp. CAL. was only recovered from seedlings retrieved from one environment although it was detected in 9 environments. When tested against different soybean cultivars this species was highly pathogenic and optimal growth was approximately 25oC. In culture, oospores and sporangia were observed however, zoospores were not produced. This species was highly abundant across soybean fields in Ohio and further studies should be conducted to classify this species among the Pythium clades. Furthermore, Py. periilum was not isolated from seedlings suggesting that temperature during isolation or type of media should be modified to recover this species from the field. The seresults provide evidence that disease, when observed in the field, is often caused by more than one pathogen. In addition, the effect of cultivar was observed for Ph. sojae providing further evidence that host resistance is still an effective management strategy in environments conducive for disease development. These results will also allow for the development of targeted disease management approaches for fields in which conducive conditions for disease development are often encountered. Finally, species of Phytophthora, Phytopythium, and Pythium should be continuously monitored since populations can change and novel species can emerge that can be detrimental to soybean production.
Download or read book Diversity of Oomycetes Associated with Soybean Seedling Diseases written by Jorge Alejandro Rojas-Flechas and published by . This book was released on 2016 with total page 265 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Global Perspectives on the Health of Seeds and Plant Propagation Material written by Maria Lodovica Gullino and published by Springer. This book was released on 2014-10-16 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume continues the series of books on “Plant Pathology in the 21st Century”, and contains the papers given at the 10th International Congress of Plant Pathology (ICPP 2013) held in Beijing, August 25-30, 2013 concerning seed health. Many pathogens are transmitted throughout infected seeds and propagation material .The fact that propagation material production is very much concentrated in few establishments, favors the quick spread of new diseases throughout seed commercialization. This phenomenon is very much accelerated in a globalized system. The book covers case studies of contamination, aspects of detection and diagnosis as well as disease management strategies, with special emphasis towards seed treatments with unconventional products. This book will be useful for all plant pathologists as well as students in advanced courses.
Download or read book Oomycete Genetics and Genomics written by Kurt Lamour and published by John Wiley & Sons. This book was released on 2009-06-17 with total page 602 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book brings together the knowledge from and tools for genetic and genomic research into oomycetes to help solve the problems this pathogen poses to crops and animals. Armed with the information presented here, researchers can use oomycete data to solve practical problems and gain insight into future areas of interest. Key Features: Offers an up-to-date coverage of research into oomycetes – which has advanced with biochemical and molecular analyses in recent years Helps researchers use oomycete data to solve practical problems, like damage to crop and animal resources Includes a section on interactions with animal hosts Offers perspective on future areas of research Assembles an international author base
Download or read book Modern Crop Protection Compounds written by Peter Jeschke and published by John Wiley & Sons. This book was released on 2019-05-06 with total page 1772 pages. Available in PDF, EPUB and Kindle. Book excerpt: The leading reference on this topic has just gotten better. Building on the success of the previous two editions, all the chapters have been updated to reflect the latest developments in the field, and new chapters have been added on picolinic acids, oxathiapiprolin, flupyradifurone, and other topics. This third edition presents the most important active ingredients of modern agrochemicals, with one volume each for herbicides, fungicides, and insecticides. The international team of first-class authors from such renowned crop science companies as Bayer, Syngenta, Dow AgroSciences, DuPont (now Corteva Agriscience), and BASF, address all crucial aspects from the general chemistry and the mode of action to industrial-scale synthesis, as well as from the development of products and formulations to their application in the field. A comprehensive and invaluable source of timely information for all of those working in modern biology, including genetics, biochemistry and chemistry, and for those in modern crop protection science, whether governmental authorities, researchers in agrochemical companies, scientists at universities, conservationists, or managers in organizations and companies involved in improvements to agricultural production.
Download or read book Fungicide Resistance in Plant Pathogens written by Hideo Ishii and published by Springer. This book was released on 2015-08-31 with total page 481 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume offers a comprehensive coverage of the general principles and recent advances in fungicide resistance. It describes the development, mechanisms, monitoring, and management of resistance and covers the most important group of fungicides that have caused resistance on various crops. An historical review of fungicide resistance over the past 40 years sets the scene for up-to-date basic information on mode of action, as well as the genetics, mechanisms, and evolution of resistance. Monitoring for resistance, including the latest developments in molecular diagnostics, moves readers into the practical aspects of resistance management, which is dealt with through a series of case studies outlining fungicide-use strategies on several key crops. The chapters reflect the experience of authors internationally recognised for their significant contributions to fungicide resistance research. The majority of crop diseases are caused by fungal pathogens, and disease control relies heavily on chemically synthesized fungicides. However, modern fungicides often encounter the problem of resistance development in target pathogens. Thus pathogen resistance to fungicides is an important factor that causes loss of yield and quality of crops. It often threatens biosecurity through the decrease of fungicide efficacy in the fields. To manage fungicide resistance successfully will require the promotion of integrated disease management, involving not just chemical fungicides, but also host plant resistance, agronomic factors, and reliable biological control agents where these are available. Well referenced throughout, the book offers a comprehensive account of resistance, which will be useful as a source of material for lecturers and for both industrial and academic scientists involved in fungicide resistance research. It is also a valuable sourcebook for students.
Download or read book Compendium of Soybean Diseases and Pests written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Potato Crop written by Hugo Campos and published by Springer Nature. This book was released on 2019-12-03 with total page 524 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is open access under a CC BY 4.0 license. This book provides a fresh, updated and science-based perspective on the current status and prospects of the diverse array of topics related to the potato, and was written by distinguished scientists with hands-on global experience in research aspects related to potato. The potato is the third most important global food crop in terms of consumption. Being the only vegetatively propagated species among the world’s main five staple crops creates both issues and opportunities for the potato: on the one hand, this constrains the speed of its geographic expansion and its options for international commercialization and distribution when compared with commodity crops such as maize, wheat or rice. On the other, it provides an effective insulation against speculation and unforeseen spikes in commodity prices, since the potato does not represent a good traded on global markets. These two factors highlight the underappreciated and underrated role of the potato as a dependable nutrition security crop, one that can mitigate turmoil in world food supply and demand and political instability in some developing countries. Increasingly, the global role of the potato has expanded from a profitable crop in developing countries to a crop providing income and nutrition security in developing ones. This book will appeal to academics and students of crop sciences, but also policy makers and other stakeholders involved in the potato and its contribution to humankind’s food security.
Download or read book Rhizosphere Engineering written by Ramesh Chandra Dubey and published by Academic Press. This book was released on 2022-02-15 with total page 566 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rhizosphere Engineering is a guide to applying environmentally sound agronomic practices to improve crop yield while also protecting soil resources. Focusing on the potential and positive impacts of appropriate practices, the book includes the use of beneficial microbes, nanotechnology and metagenomics. Developing and applying techniques that not only enhance yield, but also restore the quality of soil and water using beneficial microbes such as Bacillus, Pseudomonas, vesicular-arbuscular mycorrhiza (VAM) fungi and others are covered, along with new information on utilizing nanotechnology, quorum sensing and other technologies to further advance the science. Designed to fill the gap between research and application, this book is written for advanced students, researchers and those seeking real-world insights for improving agricultural production. Explores the potential benefits of optimized rhizosphere Includes metagenomics and their emerging importance Presents insights into the use of biosurfactants
Download or read book Scientific Review of the Impact of Climate Change on Plant Pests written by IPPC Secretariat and published by . This book was released on 2021-08-30 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study warns that climate change may increase the risk of pests being introduced to new areas. It recommends conducting pest risk analyses and strengthening international cooperation as preventive measures to protect plant health.
Download or read book The Soybean written by Guriqbal Singh and published by CABI. This book was released on 2010 with total page 506 pages. Available in PDF, EPUB and Kindle. Book excerpt: The soybean is a crop of global importance and is one of most frequently cultivated crops worldwide. It is rich in oil and protein, used for human and animal consumption as well as for industrial purposes. Soybean plants also play an important role in crop diversification and benefit the growth of other crops, adding nitrogen to the soil during crop rotation. With contributions from eminent researchers from around the world, The Soybean provides a concise coverage of all aspects of this important crop, including genetics and physiology, varietal improvement, production and protection technology, utilization and nutritional value.
Download or read book Seed Endophytes written by Satish Kumar Verma and published by Springer. This book was released on 2019-04-05 with total page 507 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on the importance and roles of seed microbiomes in sustainable agriculture by exploring the diversity of microbes vectored on and within seeds of both cultivated and non-cultivated plants. It provides essential insights into how seeds can be adapted to enhance microbiome vectoring, how damaged seed microbiomes can be assembled again and how seed microbiomes can be conserved. Plant seeds carry not only embryos and nutrients to fuel early seedling growth, but also microbes that modulate development, soil nutrient acquisition, and defense against pathogens and other stressors. Many of these microbes (bacteria and fungi) become endophytic, entering into the tissues of plants, and typically exist within plants without inducing negative effects. Although they have been reported in all plants examined to date, the extent to which plants rely on seed vectored microbiomes to enhance seedling competitiveness and survival is largely unappreciated. How microbes function to increase the fitness of seedlings is also little understood. The book is a unique and important resource for researchers and students in microbial ecology and biotechnology. Further, it appeals to applied academic and industrial agriculturists interested in increasing crop health and yield.
Download or read book The plant microbiome and its importance for plant and human health written by Martin Grube and published by Frontiers E-books. This book was released on 2015-01-22 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of plant-microbe associations by new techniques has significantly improved our understanding of the structure and specificity of the plant microbiome. Yet, microbiome function and the importance of the plant’s microbiome in the context of human and plant health are largely unexplored. Comparable with our human microbiome, millions of microbes inhabit plants, forming complex ecological communities that influence plant growth and health through its collective metabolic activities and host interactions. Viewing the microbiota from an ecological perspective can provide insight into how to promote plant health and stress tolerance of their hosts or how to adapt to a changing climate by targeting this microbial community. Moreover, the plant microbiome has a substantial impact on human health by influencing our gut microbiome by eating raw plants such as lettuce and herbs but also by influencing the microbiome of our environment through airflow. This research topic comprising reviews, original and opinion articles highlights the current knowledge regarding plant microbiomes, their specificity, diversity and function as well as all aspects studying the management of plant microbiomes to enhance plant growth, health quality and stress tolerance.
Download or read book Fusarium Wilt of Banana written by Randy C. Ploetz and published by American Phytopathological Society. This book was released on 1990 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fusarium wilt of banana: some history and current status of the disease; Importante of fusarium wilt in different banana-growing regions; Taxonomy of fungi in the genus fusarium with emphasis on fusarium oxysporum; Genetic exchange within sexual and asexual populations of the genus fusarium; Molecular genetics of plant pathogenic fusarium oxysporum; Using karyotype variability to investigate the origins and relatednes of isolates of fusarium oxysporum f. sp. cubense; Population biology of fusarium oxysporum f. sp. cubense; Biological control of diseases caused by fusarium oxysporum; Influence of mineral nutrition on fusarium wilt: a proposed mechanism involving cell water relations; Host responses to the pathogen; Banana breeding and fusarium wilt; Breeding bananas and plantains for resistance to fusariu m wilt: the track record; Somaclonal resistance in cavendish banana to fusarium wilt; Baseline tissue and cell culture studies for use in banana improvement schemes.
Download or read book Forest Pathology and Plant Health written by Matteo Garbelotto and published by MDPI. This book was released on 2018-04-13 with total page 243 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue "Forest Pathology and Plant Health" that was published in Forests
Download or read book Biological Control of Plant Diseases written by E.C. Tjamos and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt: The papers contained in this book were presented at a NATO Advanced Research Workshop (ARW) held at Cape Sounion, Athens, Greece, 19-24 May, 1991. The twenty-eight more comprehensive papers represent the key subjects of the ARW covered by invited speakers. The thirty-four short papers pre sented in a research format are contributions of those invited to participate in the ARW. There was a total of 70 participants from 21 countries. The objectives of the ARW were as follows: to review current knowledge of biological control of plant diseases and plant parasitic nematodes, with emphasis on mechanisms at the molecular, cellular, organismal, and ecosystem level; to examine and expand on current concepts and synthesize new concepts; to identify and prioritize limitations in the use of biological control for plant diseases and nematodes and the scientific research needed to overcome these limitations; and to develop strategies for biological control through management of resident agents or introduction of natural or modified agents.
