Download or read book Identification and Characterizations of Pathogenicity Genes in Fusarium Virguliforme the Causal Agent of Soybean Sudden Death Syndrome SDS written by Kazi Tariqul Islam and published by . This book was released on 2015 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Identification and Characterization of Pathogenicity Genes in Fusarium Virguliforme the Causal Agent of Sudden Death Syndrome SDS in Soybean written by Saara Mansouri and published by . This book was released on 2012 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fusarium virguliforme is a soil-borne pathogen that causes sudden death syndrome (SDS) disease in soybean. SDS is one of the most significant diseases of soybean in the United States. Fungal infection results in root and crown rot as well as SDS typical foliar symptoms including chlorosis, necrosis and complete defoliation. The use of soybean cultivars tolerant to SDS is still the most effective way to overcome the disease. On the other hand, the fungal isolates are known to have varied levels of aggressiveness on soybean indicated by the field and greenhouse experiments. Understanding the pathogen and its defense mechanism is the first step in exploring the pathogen-plant interaction. Therefore, the primary aim of this research was to elucidate the mechanism behind F. virguliforme response to soybean defense mechanisms. We further attempted to identify chromosome length polymorphism among F. virguliforme isolates and characterize the possible relationship to their level of aggressiveness. The findings are instrumental in identifying novel pathogenicity such as the ones involved in phytotoxin production, fungicide resistance and aggressiveness.

Download or read book Investigating Management and Genetics of Soybean Sudden Death Syndrome Pathogens Fusarium Virguliforme and F Brasiliense written by Mitchell G. Roth and published by . This book was released on 2019 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: Annual soybean production in the U.S. is worth nearly $40 billion, valued for its oils and protein content. Many pathogens and pests cause significant soybean yield losses each year, but one of the top threats is sudden death syndrome (SDS). At least five fungal species cause soybean SDS globally, but only two have been found in the U.S.; Fusarium virguliforme and F. brasiliense. These soil-borne pathogens infect root tissues and cause root rot, with continued infection leading to foliar interveinal chlorosis, interveinal necrosis, leaf drop, and yield loss. The pathogens are strong saprophytes that can overwinter in soybean and corn residue, so successful management is difficult. Long-term crop rotations and seed treatments with fungicides show some efficacy, but these strategies can be costly for growers. Growers desire genetic resistance to SDS, but no soybean germplasm has shown 100% resistance to SDS to date. Therefore, the overall goals of projects presented in this dissertation were to help improve SDS management and explore the biology and genetics of F. virguliforme and F. brasiliense. To achieve these goals, I developed a risk prediction tool for integration with current SDS management strategies (Chapter 2). This study revealed that pathogen data collected from soil at-planting can be used to accurately model spatial distributions pathogens and model future SDS development and yield loss at a field level. This risk prediction study used a qPCR assay specific for F. virguliforme, but a similar qPCR assay for F. brasiliense did not exist. Therefore, I developed a qPCR assay that can distinguish F. brasiliense from close relatives (Chapter 3). This tool that can be used to generate SDS-prediction models for F. brasiliense and I predict will be valuable in diagnostic labs across the country to distinguish between these two species. To advance our understanding of the biology and genetics of these pathogens, I developed a new protoplast generation and transformation method to generate fluorescent strains of each pathogen (Chapter 4). This chapter is the first to report genetic transformation in F. brasiliense. Furthermore, I used the fluorescent strains to investigate the synergistic role of soil-borne nematodes in SDS (Chapter 5). The interactions between these fungal pathogens and nematodes in vitro show that F. virguliforme and F. brasiliense can colonize immobile nematodes, but suggest that they are not actively vectored into soybean roots by nematodes. The genetic mechanisms of SDS development are poorly understood, so I developed high quality genome sequences for F. virguliforme and F. brasiliense (Chapter 6) and investigated two recognized effector proteins; FvTox1 and FvNIS1 (Chapter 7). The genome assemblies developed here have significantly improved continuity, with improved genome assembly metrics like contig length (N50) and contig number. However, whole-genome alignments between F. virguliforme and F. brasiliense from soybean (Glycine max) or dry bean (Phaseolus vulgaris) did not reveal obvious mobile pathogenicity chromosomes that have been observed in the close relative F. oxysporum. However, these genome resources should facilitate discovery of new fungal effector proteins like FvTox1 and FvNIS1. Interestingly, my results show that FvNIS1 is able to induce a hypersensitive response in tobacco, while FvTox1 is not, suggesting a conserved mechanism between soybean and tobacco for FvNIS1 recognition. Overall, this work provides valuable tools for managing and studying SDS-causing fungi, while also revealing insights into the genetics and genomics of the SDS-causing pathogens F. virguliforme and F. brasiliense.

Download or read book Insights of Chemical Cultural and Genetic Exploration for Soybean Sudden Death Syndrome Management and Fusarium Virguliforme written by Amy Marie Baetsen-Young and published by . This book was released on 2019 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soybean sudden death syndrome, caused by Fusarium virguliforme, is a key limitation in reaching soybean (Glycine max) yield potential, stemming from limited disease management through cultural practices and partial host resistance. The research within this thesis reveals the economic potential of fungicide seed treatment SDS fluopyram to alleviate yield loss, provides insights into field management of F. virguliforme and highlights transcriptomic plasticity of diverse host-fungal interactions. Previously, farm level studies have found the fungicide seed treatment of fluopyram profitable, yet the benefit across an aggregate level of soybean production at risk to SDS yield loss is unknown. To estimate economic benefits of fluopyram adoption in SDS at risk acres, in the light of U.S public research and outreach costs, an economic surplus approach was applied to calculate ex ante net benefits from 2018 to 2032. Through this framework of fluopyram adoption for alleviation of SDS associated yield losses, we estimated a net benefit of $5,829 million over 15 years, considering public seed treatment research costs from 2014 to present and future extension communication. While chemical seed treatments aid disease management of SDS, the ability of this pathogen to colonize asymptomatic hosts may increase the prevalence of F. virguliforme. Thus, the impact of cultural tactics upon F. virguliforme colonization of an asymptomatic host, and the ability of this colonization to alter subsequent SDS symptoms when rotated to soybean were explored. The exploration of tillage, and residue management across four U.S. states provided clarity to variable reports, revealing that no-tillage inconsistently enhances F. virguliforme colonization of corn and soybean roots, while corn residue did not alter pathogen colonization. Alternatively, an asymptomatic host provides a unique application to discover genetic factors facilitating soybean sudden death syndrome through investigation host-fungal interactions. Exploring this plant disease through a comparative orthologous mRNA-Seq on soybean and corn hosts under colonization of F. virguliforme uncovered transcriptional responses enabling a robust defense response in corn, and delayed immune induction within soybean permitting pathogenic colonization and susceptibility. To colonize both hosts, F. virguliforme exhibited a massive transcriptional rewiring of an infection program. Transcriptomic responses suggest, F. virguliforme is less suited for colonization of monocots by delayed colonization, and lower induction of CAZymes and effector proteins. Integration of the data generated through the mRNA-Seq experiments, including a micro-like RNA-Seq analysis of soybean host during colonization by F. virguliforme revealed an intimate communication between the plant and fungal pathogen; we posit that a micro-like RNA cross-talk potentially regulates host susceptibility. Overall, several hypotheses were generated surrounding hemibiotrophic enhancement of host senescence, and fungal ecological plasticity through transcriptomic reprogramming, which will deliver transparency upon a currently difficult and enigmatic syndrome.

Download or read book Identification of Phytotoxins Produced by Fusarium Virguliforme Associated with Foliar Symptoms of Sudden Death Syndrome and Genome wide Association Studies for Soybean Disease Resistance written by Hao-Xun Chang and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Studies of Fusarium Virguliforme Causing Sudden Death Syndrome of Soybean written by Ramiz Mahdi Salih Alabdalsaid and published by . This book was released on 2021 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fusarium virguliforme is one of the important pathogens on soybeans, and it is a soil borne pathogen. This pathogen causes sudden death syndrome on soybean (SDS). The fungus remains in the soil or on the plant residues for many years in the form of chlamydospores. When the appropriate conditions are available for the infection, the pathogen penetrates the soybean's roots and causes symptoms on the roots that appear in the form of reddish-brown, discoloration and necrosis. On the leaves the symptoms appear in the form of irregular spots shape. In the development of the infection the fall of leaves, abortion of flowers and pods occur. Due to the economic importance of the disease and the fungus that causes it. This study conducted to gain more information and understand the behavior of the pathogen. The results study of the effect of some culture media, pH and nitrogen sources on F. virguliforme growth in vitro showed that the pathogen has able to grow on all culture media that used. on culture media Czapek Dox agar (CDA) and Malt Extract Agar (MEA), the F. virguliforme was grown fast to cover plate in 8 days of incubation. Potato Sucrose Agar (PSA) and Malt Extract Agar (MEA) were the best culture media for fungal sporulation while the lowest number of spores was on Glucose yeast peptone Agar (GYPA). Also, the study showed the best pH for radial growth was 7 at 20, 25 and 30 C. But the radial growth of Fungus was slow at pH 10. The fungal sporulation at pH 6 was good comparing to fungal sporulation at pH 10 which was less. The radial growth of fungus was affected by different nitrogen sources and concentration. In general, the ammonium sulphate was not suitable for fungal radial growth and The best fungal sporulation was on media with peptone 2 g comparing with other nitrogen sources. In the second chapter, the results of histopathology of roots for two soybean varieties infected by F. virguliforme showed that the pathogen uses the same strategy to attack the roots of soybean varieties, penetration and colonization. The pathogen can grow intercellular and intracellular. During infection the pathogen causes damage to the root cells. Accumulating of materials inside root's cells because pathogen invasion. The last chapter in this study is, effect light on F. virguliforme growth. The study showed that the radial growth of the fungus was the maximum under continuous darkness comparing to fungal radial growth under light/dark cycle 12/12 LD, 16/8 LD and 18/6 LD. In addition to that colorful bands were formed when the fungus grew under under light/dark cycle. The results showed the ability of pathogen to cause Lesion on soybean stems under light/dark cycle. Also, using two inoculum 105, 106 of pathogen to test it pathogenicity on soybean roots showed no significant differences.

Download or read book Molecular Quantification and Carbon Source Utilization of Fusarium Virguliforme the Causal Agent of Soybean Sudden Death Syndrome written by Eugenia Tang and published by . This book was released on 2008 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Developing Novel Molecular Tools to Study the Fusarium Virguliforme soybean Interaction written by Saara Mansouri and published by . This book was released on 2007 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fusarium virguliforme is a soil-borne pathogen that causes Sudden Death Syndrome (SDS) in soybeans. Since the use of resistant varieties is still the most effective way to combat the disease, the need to develop new molecular tools to study the interaction between the fungus and the plant is required. To reach this goal, we have developed a protoplast based fungal transformation system for F. virguliforme. One of the applications of the transformation system was the production of a green fluorescent protein (GFP)-expressing fungal transformant. The GFP-expressing fungus can be used to study the fungal infection process including fungal penetration, colonization, and spread, especially at the early stages of disease development. Furthermore, in an attempt to increase the genetic resources available to identify and characterize fungal virulence genes involved in the F. virguliforme-soybean system, we generated random insertional mutations in F. virguliforme using Restriction Enzyme Mediated Integration (REMI).

Download or read book Effect of Infection Site and Glyphosate Application on the Foliar Symptoms Expression of Soybean Sudden Death Syndrome written by and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soybean sudden death syndrome (SDS), caused by Fusarium virguliforme, is an important root disease that can cause root rot and express foliar symptoms leading to premature defoliation and yield reduction. Earlier reports suggested that the germination of F. virguliforme macroconidia and penetration of their germination tube may differ among the sites along the root system of soybean plants. Glyphosate [N-(phosphonomethyl) glycine] is a post-emergent broad spectrum non-selective herbicide that is largely used in soybean production systems. Previous study shows that infection does not always lead to disease in this host-pathogen interaction as the fungus can reach high level of infection of colonization and remain asymptomatic. Expression of foliar symptoms is critical to the occurrence of SDS. The objectives of this study were (1) to assess effects of different root inoculation sites on foliar symptom expression and the effect of mechanical injury of seedling tap roots on foliar symptoms expression of SDS and (2) to evaluate the effect of glyphosate application on SDS foliar symptom development two greenhouse experimentsWe evaluated three different sites of infection: root tip, middle root portion and upper root. After inoculation, seedlings were transplanted to cones filled with sterile potting mixture. Rhizosphere temperature was controlled by using a water bath (20°C). Plants were evaluated three weeks after transplanting for incidence and severity of SDS. Root sites were not significant for incidence of SDS. Higher incidence was observed when root tips were wounded, probably because tissue wound increased xylem infections. A field survey was done to compare disease levels for plants grown in greenhouse to plants in the fields. Adjacent symptomatic and asymptomatic plants were collect from three fields naturally infested with F. virguliforme. Our results suggested that F. virguliforme can infect plants and remain asymptomatic at a high incidence level. To evaluat

Download or read book Genetic Mapping of Resistance to Soybean Sudden Death Syndrome and Soybean Oil Quality written by Paul Joseph Collins and published by . This book was released on 2019 with total page 123 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soybean (Glycine max) is the world's leading oilseed crop and is a critical source of protein for poultry and swine production. Soybean production is limited by many biotic factors including soybean sudden death syndrome (SDS) which is caused by a soil-borne fungal pathogen, Fusarium virguliforme. Effective management methods for soybean sudden death syndrome include long-term rotations, fluopyram seed treatment, and planting SDS resistant varieties. Host resistance to F. virguliforme is a quantitative resistance, as it is controlled by many genes, largely of small effect. To more efficiently breed SDS resistant soybean varieties, researchers have sought to identify the loci on the soybean genome responsible for SDS-resistance. Three recombinant inbred line (RIL) populations were evaluated for foliar SDS resistance at a naturally infested field site in Decatur, MI during the 2014 and 2015 growing seasons. These populations segregated for SDS resistance, as they were derived from a parent resistant to SDS and a parent susceptible to SDS. The parents and a subset of RILs from each population were genotyped with the SoySNP6K Illumina Infinium BeadChip. Linkage maps unique to each population were constructed using JoinMap ver. 2. Composite interval mapping was done using WinQTLCartographer (ver. 2.5). Six quantitative trait loci (QTL) were identified to be associated with SDS resistance. Three of the QTL associated with SDS resistance were identified across multiple years and/or populations. While biotic factors, such as SDS, work to limit soybean production, soybean quality factors, such as oil quality, can offer new production opportunities. Soybean oil is predominantly composed of five fatty acids: palmitic acid (11%), stearic acid (4%), oleic acid (25%), linoleic acid (52%), and linolenic acid (8%). While there is little variability in most commodity soybean varieties for fatty acid content, soybean breeders have been able to introduce oil quality traits into the soybean germplasm. Oil quality traits for soybean oil include high oleic acid content (>75%), low linolenic acid content (

Download or read book Resistance of Soybean Glycine Max L Merr to Fusarium Solani F Sp Glycines Causal Agent of Sudden Death Syndrome written by Austeclinio Lopes de Farias Neto and published by . This book was released on 2005 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: Sudden death syndrome (SDS) caused by the soilborne fungus Fusarium solani f. sp. glycine (FSG) is a major disease in soybean [Glycine max (L.) Merr.]. Slecetion for SDS resistance in the field is difficult because of the impact of the environment on disease development. The objective of my first study was to evaluate the effect of field inoculation methods, soil compaction, and irrigation timing on the occurrence of SDS symptons. Six treatments which included FSG infested grain of white sorghum [Sorghum bicolor (L.) Moench], popcorn (Zea mays everta) or oat (Avena sativa L.) were planted in the furrow with the soybean seed, broadcasted and incorporated into the soil prior to planting or placed below the soybean seed just prior to planting. Three experiments were also conducted to evaluate the effect of compaction and irrigation on SDS symptom occurrence. Irrigation treatments that included water application at V3, V7, R3, R4 and/or R5 growth stages were applied. In all experiments disease incidence (DI) and disease severity (DS) ratings were taken to evaluate foliar SDS symptom and a disease index (DX) was determined. The inoculation methods that produced the most severe foliar symptom included placing infested sorghum below the seed prior to planting (DX=36.1) and planting infested popcorn in the furrow with the soybean seed (DX=28.7). No significant effects of soil compaction on SDS foliar symptom development were observed. The irrigation treatments during mid to late reproductive growth stages resulted in the greatest increases in SDSfoliar symptom development. Evaluation of a great number of lines for SDS resistance in the field is time consuming and expensive. The objective of the second study was to evaluate two SDS greenhouse screening methods and determine which best correlates with field resistance of soybean genotypes. Three sets of genotypes were previously evaluated for field reaction to SDS. All three sets were evaluated with the greenhouse cone method and two sets were evaluated with the greenhouse tray method ...

Download or read book Investigation of Soybean Sudden Death Syndrome Caused by Fusarium Solani F Sp Glycines Cell free culture filtrates written by Junli Ji and published by . This book was released on 2004 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fusarium Solani f. sp. glycines (Fsg) have been reported to produce at least two phytotoxins. Cell-free Fsg-culture filtrates containing phytotoxins have been shown to induce the development of foliar sudden death syndrome (SDS) symptoms in soybean. We have investigated the changes in protein profiles of symptomatic leaves created by treatment with cell-free Fsg-culture filtrates prepared from Fsg isolates. Two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis was conducted to test the protein profiles of symptomatic and healthy leaves. An approximately 55 kDa protein was found to be degraded in leaves with SDS foliar symptom. MALDI-TOF MS was applied to determine the mass fingerprint of this protein. A protein sequence database (NCBInr 2003) search using the mass fingerprint revealed that the 55 kDa protein is the ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco, E.C. Number: 4.1.1.39) large subunit, which is involved in carbon assimilation and photorespiration. The Rubisco large subunit degradation was confirmed by western hybridation. Light was important for degradation of Rubisco large subunit by cell-free Fsg-culture filtrates. Degradation of Rubisco large subunit is accompanied by accumulation of reactive oxygen species following exposure of cell-free Fsg-culture filtrate-fed seedlings to light. Terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) assay data suggested that programmed cell death is iniated in leaves of seedlings fed with cell-free Fsg culture-filtrates. The degradation of Rubisco large subunit, accumulation of free radicals and programmed cell death also occured in leaves fed with active column fractions prepared from cell-free Fsg-culture filtrates. It is suggested that cell-free Fsg culture-filtrted cause SDS foliar symptoms in a light dependent manner and foliar symptom development is accompanied by degradation of Rubisco large subunit and accumulation of reactive oxygen species.

Download or read book Evaluation of Soybean Recombinant Inbred Lines for Yield Potential and Resistance to Sudden Death Syndrome written by James Anderson and published by . This book was released on 2012 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: Evaluation of soybean recombinant inbred lines for seed weight yield, agronomic traits, and resistance to sudden death syndrome Sudden death syndrome (SDS) caused by Fusarium virguliforme is a devastating disease in soybean (Glycine max (L.) Merr.) that causes up to 70% of yield losses depending on the developmental stage when the plant become infected. The characterization of resistance is greatly significant for disease management. Therefore, three populations were developed by crossing three resistant lines, 'Hamilton', LS90-1920 and LS97-1610 with a susceptible line to SDS, 'Spencer'. Ninety-four F5:6 recombinant inbred lines from each population (Hamilton x Spencer, LS90-1920 x Spencer, and LS97-1610 x Spencer) were evaluated for two years (2009 and 2010) at two locations (Carbondale and Valmeyer) in southern Illinois. Population statistics, genotype x environment interaction, and broad-sense heritability were used to reveal any major resistance genes. Genetic correlation coefficients of SDS resistance with important agronomic traits such as lodging, pubescence, growth habit, and plant height were also calculated. The information from this study will be helpful to breeders in developing populations for genetic analyses and enforcing selection practices.

Download or read book Effect of Fungicide Seed Treatments on Fusarium Virguliforme and Development of Sudden Death Syndrome in Soybean written by Japheth D. Weems and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Sudden death syndrome (SDS) is a soilborne disease responsible for causing significant yield reductions across soybean-producing states. Recent research indicates that infection of the soybean radicle early in the season by Fusarium virguliforme (Fv), the SDS pathogen, is critical for disease development. This suggests fungicide seed treatments could be effective in limiting early infection possibly resulting in disease control. Field, greenhouse, and laboratory studies were conducted to evaluate eight fungicides in multiple seed treatment combinations for effects on Fv infection and SDS development. Seed treatments were applied to cultivars that were moderately resistant and moderately susceptible to SDS. Field studies were conducted at two locations: in 2008, the Valmeyer, IL location was naturally infested with Fv, and in 2008 and 2009 the Urbana, IL location had a natural Fv infestation and soil was augmented with sterilized grain sorghum colonized by Fv. Similarly, the greenhouse study was inoculated with sterilized, Fv infested grain sorghum to evaluate the same seed treatments on moderately resistant and moderately susceptible cultivars. The rolled-paper towel laboratory assay tested the individual fungicides in the growth chamber using a Fv macroconidial suspension to inoculate treated seed and assess effects on seed germination, plant length, lesion size, and disease severity. Fv DNA concentrations in soybean roots were measured using quantitative polymerase chain reaction (qPCR) in early vegetative stage roots. Soybean roots from the field were collected at three timings for digital scanning and analysis with root analysis software to measure root disease symptoms. Roots were scanned and analyzed at the completion of the greenhouse trial. SDS foliar symptoms were rated several times throughout plant growth and the area under disease progress curve (AUDPC) was calculated. Harvest data were collected for the field study. In the field, seed treatments had no effect on Fv DNA concentrations in roots. Seed treatments had very little effect on roots analyzed from the field. Most seed treatments did significantly decrease SDS foliar symptoms at the Valmeyer field study compared to the control, but no differences in foliar symptoms were observed for the Urbana field studies. Yield was unaffected by seed treatments. In the greenhouse, Fv DNA concentrations were reduced by a treatment combining mefenoxam + thiophanate-methyl + azoxystrobin + B. pumilus + prothioconazole + fludioxonil compared to the non-treated control; however, the reduction in Fv DNA did not improve root growth or decrease SDS foliar symptoms compared to the non-treated control. The Fv DNA concentrations in roots did not significantly correlate to SDS foliar symptoms in the field; however, a significant positive correlation was found in the greenhouse between Fv DNA and SDS foliar symptoms. Several seed treatments decreased lesion length and disease severity compared to the non-treated inoculated control in the rolled-towel laboratory assay, but the biological seed treatment, B. pumilus, significantly decreased seed germination and plant length while increasing lesion length and SDS severity compared to the non-treated inoculated control. In conclusion, none of the seed treatments evaluated proved to have consistent effects on Fv or SDS.

Download or read book Molecular Diagnostics Epidemiology and Population Genetics of the Soybean Sudden Death Syndrome Pathogen Fusarium Virguliforme written by Jie Wang and published by . This book was released on 2016 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Assessment of Sudden Death Syndrome by Utilizing Unmanned Aerial Vehicles and Multispectral Imagery written by Lindsey McKinzie and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fusarium virguliforme is a soil-borne pathogen that is the causal agent of sudden death syndrome (SDS). This disease is one of the top contributors to major yield losses in soybean across the United States. Characteristic symptoms of the disease include interveinal chlorosis and/or necrosis of trifoliate leaves and defoliation. In some cases, the foliar symptoms may not be present, but yield loss still occurs. This disease is evaluated using an incidence rating, the percent of plants in the plot that are expressing symptoms, and a severity rating, using a one to nine scale based on varying levels of chlorosis, necrosis, and defoliation. Using remote sensing provides an alternate approach to identify and evaluate plant diseases. It provides a non-destructive method to assess the severity of foliar symptoms and their distribution across production fields. SDS was chosen as the disease to use for this system due to the unique disease symptomology and yield loss. In 2019 and 2020, SDS trials were established in a production field location that has a history of SDS in Valmeyer, IL. This seed treatment study had different chemicals with varying levels of efficacy against SDS. Disease ratings were collected at the first sign of symptoms, and aerial imagery was collected on the same day. There were multiple dates across both years when this data was collected. ArcGIS was used to analyze the multispectral imagery and do a plot by plot analysis for each of the plots. A regression analysis was performed to test the relationship between the foliar disease ratings and the plot data collected from the multispectral imagery. Multiple vegetation indices were tested, and the results showed that overall, in 2019, GNDVI had the strongest relationship with foliar ratings. In 2020, NDRE had the strongest overall relationship with foliar ratings. The relationship between NDVI and the ratings was the most consistent at the last rating of the season.

Download or read book Studies on Soybean Sudden Death Syndrome and Its Causal Organism Fusarium Solani F Sp Glycines written by Yi-Hsiou Huang and published by . This book was released on 1998 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: