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Targeted Suppression Of Soybean Bag6‐Induced Cell Death In Yeast By Soybean Cyst Nematode Effectors, Jianying Wang, Greg Yeckel, Pramod K. Kandoth, Lakmini Wasala, Richard S. Hussey, Eric L. Davis, Thomas J. Baum, Melissa G. Mitchum Jan 2020

Targeted Suppression Of Soybean Bag6‐Induced Cell Death In Yeast By Soybean Cyst Nematode Effectors, Jianying Wang, Greg Yeckel, Pramod K. Kandoth, Lakmini Wasala, Richard S. Hussey, Eric L. Davis, Thomas J. Baum, Melissa G. Mitchum

Plant Pathology and Microbiology Publications

While numerous effectors that suppress plant immunity have been identified from bacteria, fungi, and oomycete pathogens, relatively little is known for nematode effectors. Several dozen effectors have been reported from the soybean cyst nematode (SCN). Previous studies suggest that a hypersensitive response‐like programmed cell death is triggered at nematode feeding sites in soybean during an incompatible interaction. However, virulent SCN populations overcome this incompatibility using unknown mechanisms. A soybean BAG6 (Bcl‐2 associated anthanogene 6) gene previously reported by us to be highly up‐regulated in degenerating feeding sites induced by SCN in a resistant soybean line was attenuated ...


Screening Soybean Cyst Nematode Effectors For Their Ability To Suppress Plant Immunity, Gennady Pogorelko, Jianying Wang, Parijat S. Juvale, Melissa G. Mitchum, Thomas J. Baum Jan 2020

Screening Soybean Cyst Nematode Effectors For Their Ability To Suppress Plant Immunity, Gennady Pogorelko, Jianying Wang, Parijat S. Juvale, Melissa G. Mitchum, Thomas J. Baum

Plant Pathology and Microbiology Publications

The soybean cyst nematode (SCN), Heterodera glycines , is one of the most destructive pathogens of soybeans. SCN is an obligate and sedentary parasite that transforms host plant root cells into an elaborate permanent feeding site, a syncytium. Formation and maintenance of a viable syncytium is an absolute requirement for nematode growth and reproduction. In turn, sensing pathogen attack, plants activate defence responses and may trigger programmed cell death at the sites of infection. For successful parasitism, H. glycines must suppress these host defence responses to establish and maintain viable syncytia. Similar to other pathogens, H. glycines engages in these molecular ...


Homeostasis In The Soybean Mirna396–Grf Network Is Essential For Productive Soybean Cyst Nematode Infections, Jason B. Noon, Tarek Hewezi, Thomas J. Baum Jan 2019

Homeostasis In The Soybean Mirna396–Grf Network Is Essential For Productive Soybean Cyst Nematode Infections, Jason B. Noon, Tarek Hewezi, Thomas J. Baum

Plant Pathology and Microbiology Publications

Heterodera glycines, the soybean cyst nematode, penetrates soybean roots and migrates to the vascular cylinder where it forms a feeding site called the syncytium. MiRNA396 (miR396) targets growth-regulating factor (GRF) genes, and the miR396–GRF1/3 module is a master regulator of syncytium development in model cyst nematode H. schachtii infection of Arabidopsis. Here, we investigated whether this regulatory system operates similarly in soybean roots and is likewise important for H. glycines infection. We found that a network involving nine MIR396 and 23 GRF genes is important for normal development of soybean roots and that GRF function is specified in ...


Studies On The Impact Of Cover Crops On Soybean Productivity And Root Diseases, Grazieli Da Araldi Da Silva Jan 2019

Studies On The Impact Of Cover Crops On Soybean Productivity And Root Diseases, Grazieli Da Araldi Da Silva

Graduate Theses and Dissertations

Soybean (Glycine max L.) and corn (Zea mays L.) are the two main field crops grown in the Midwest, and they are usually used in a rotation system (FAOSTAT, 2018). This cropping system contributes to the elevated nitrate levels found in the surface waters in the Midwest (David et al., 1997; Dinnes et al., 2002), along with higher risk of soil erosion (Pimentel et al., 1995) and loss of nutrients and organic matter (Burkart and James, 1999; David and Gentry, 2000). Cover crops, grown between soybean or corn harvest in the fall and planting of the subsequent crop in the ...


Sifting And Winnowing: Analysis Of Farmer Field Data For Soybean In The Us North-Central Region, Spyridon Mourtzinis, Juan I. Rattalino Edreira, Patricio Grassini, Adam C. Roth, Shaun N. Casteel, Ignacio A. Ciampitti, Hans J. Kandel, Peter M. Kyveryga, Mark A. Licht, Laura E. Lindsey, Daren S. Mueller, Emerson D. Nafziger, Seth L. Naeve, Jordan Stanley, Michael J. Staton, Shawn P. Conley May 2018

Sifting And Winnowing: Analysis Of Farmer Field Data For Soybean In The Us North-Central Region, Spyridon Mourtzinis, Juan I. Rattalino Edreira, Patricio Grassini, Adam C. Roth, Shaun N. Casteel, Ignacio A. Ciampitti, Hans J. Kandel, Peter M. Kyveryga, Mark A. Licht, Laura E. Lindsey, Daren S. Mueller, Emerson D. Nafziger, Seth L. Naeve, Jordan Stanley, Michael J. Staton, Shawn P. Conley

Agronomy Publications

Field trials are commonly used to estimate the effects of different factors on crop yields. In the present study, we followed an alternative approach to identify factors that explain field-to-field yield variation, which consisted of farmer survey data, a spatial framework, and multiple statistical procedures. This approach was used to identify management factors with strongest association with on-farm soybean yield variation in the US North Central (NC) region. Field survey data, including yield and management information, were collected over two crop growing seasons (2014 and 2015) from rainfed and irrigated soybean fields (total of 3568 field-year observations). Fields were grouped ...


Genetic Architecture Of Charcoal Rot (Macrophomina Phaseolina) Resistance In Soybean Revealed Using A Diverse Panel, Sara M. Coser, R. V. Chowda Reddy, Jiaoping Zhang, Daren S. Mueller, Alemu Mengistu, Kiersten A. Wise, Tom W. Allen, Arti Singh, Asheesh K. Singh Sep 2017

Genetic Architecture Of Charcoal Rot (Macrophomina Phaseolina) Resistance In Soybean Revealed Using A Diverse Panel, Sara M. Coser, R. V. Chowda Reddy, Jiaoping Zhang, Daren S. Mueller, Alemu Mengistu, Kiersten A. Wise, Tom W. Allen, Arti Singh, Asheesh K. Singh

Agronomy Publications

Charcoal rot (CR) disease caused by Macrophomina phaseolina is responsible for significant yield losses in soybean production. Among the methods available for controlling this disease, breeding for resistance is the most promising. Progress in breeding efforts has been slow due to the insufficient information available on the genetic mechanisms related to resistance. Genome-wide association studies (GWAS) enable unraveling the genetic architecture of resistance and identification of causal genes. The aims of this study were to identify new sources of resistance to CR in a collection of 459 diverse plant introductions from the USDA Soybean Germplasm Core Collection using field and ...


Soybean-Pythium Pathosystem: Search For Host Resistance And Interaction With Fusarium Species, Elizabeth Rose Lerch Jan 2017

Soybean-Pythium Pathosystem: Search For Host Resistance And Interaction With Fusarium Species, Elizabeth Rose Lerch

Graduate Theses and Dissertations

Seedling disease of soybean is an economically important disease that reduces crop stands and may reduce yield. Symptoms of seedling disease include pre- and post-emergence damping-off and root rot. Many species of Pythium and Fusarium cause seedling disease and are frequently recovered together from diseased soybean seedlings. Host resistance as a strategy to manage multiple pathogens has only briefly been explored in soybean and the interaction between these pathogens is unclear. To better understand the soybean-Pythium pathosystem, lab and growth chamber assays were conducted to accomplish the following objectives, 1) identify with resistance to seed and root rot caused by ...


Efficacy Of Soybean Seed Treatments In Iowa And The Effect Of Cold Stress On Damping-Off Caused By Pythium Sylvaticum, Mauricio Serrano Jan 2017

Efficacy Of Soybean Seed Treatments In Iowa And The Effect Of Cold Stress On Damping-Off Caused By Pythium Sylvaticum, Mauricio Serrano

Graduate Theses and Dissertations

Soybean (Glycine max (L.) Merr.) production is negatively affected by the occurrence of seedling diseases. In Iowa, the occurrence of seedling diseases is commonly associated with cool and wet weather soon after planting, and several Pythium spp. have been found as the predominant pathogens causing seedling disease. Increasing cost of the seed, risk of seedling diseases reducing stand in cold, wet soils, and the yield benefit sometimes provided by early planting have motivated an increase in the use of fungicide seed treatment. However, a positive effect of seed treatments on soybean plant stand and yield has not been clearly demonstrated ...


Advancing Our Understanding Of Charcoal Rot In Soybeans, Martha P. Romero Luna, Daren Mueller, Alemu Mengistu, Asheesh K. Singh, Glen L. Hartman, Kiersten A. Wise Jan 2017

Advancing Our Understanding Of Charcoal Rot In Soybeans, Martha P. Romero Luna, Daren Mueller, Alemu Mengistu, Asheesh K. Singh, Glen L. Hartman, Kiersten A. Wise

Agronomy Publications

Charcoal rot [Macrophomina phaseolina (Tassi) Goid] of soybean [Glycine max (L.) Merr.] is an important but commonly misidentified disease, and very few summary articles exist on this pathosystem. Research conducted over the past 10 yr has improved our understanding of the environment conducive to disease development, host resistance, and improved disease diagnosis and management. This article summarizes the currently available research with an emphasis on disease management.


Virus-Induced Gene Silencing And Transient Gene Expression In Soybean (Glycine Max) Using Bean Pod Mottle Virus Infectious Clones, Steven A. Whitham, Lori M. Lincoln, R. V. Chowda-Reddy, Jaime D. Dittman, Jamie A. O'Rourke, Michelle A. Graham Jun 2016

Virus-Induced Gene Silencing And Transient Gene Expression In Soybean (Glycine Max) Using Bean Pod Mottle Virus Infectious Clones, Steven A. Whitham, Lori M. Lincoln, R. V. Chowda-Reddy, Jaime D. Dittman, Jamie A. O'Rourke, Michelle A. Graham

Plant Pathology and Microbiology Publications

Virus-induced gene silencing (VIGS) is a powerful and rapid approach for determining the functions of plant genes. The basis of VIGS is that a viral genome is engineered so that it can carry fragments of plant genes, typically in the 200 to 300 base pair size range. The recombinant viruses are used to infect experimental plants, and wherever the virus invades, the target gene or genes will be silenced. VIGS is thus transient, and in the span of a few weeks, it is possible to design VIGS constructs and then generate loss-of-function phenotypes through RNA silencing of the target genes ...


The Effect Of Fungicides And Pod Removal Alone Or In Combination On Green Stem Disorder Of Soybean And Further Investigation Of Genetic Components, Xavier Phillips Jan 2016

The Effect Of Fungicides And Pod Removal Alone Or In Combination On Green Stem Disorder Of Soybean And Further Investigation Of Genetic Components, Xavier Phillips

Graduate Theses and Dissertations

Green stem disorder (GSD) of soybean (Glycine max L. Merr.) is when stems remain green and fleshy after pods reach physiological maturity and are ready to harvest. Little is known about GSD and its causes. Although GSD has not been shown to directly impact yield, the immature green stems may lead to harvest issues. Harvesting at the right time is essential to preserve the quality of the seed. During 2014 and 2015, field experiments located in central Iowa were used to investigate the effect of fungicides, pod removal, and their interaction on GSD incidence. The objective of this research was ...


Soybean Vein Necrosis Virus: Impacts Of Infection On Yield Loss And Seed Quality And Expansion Of Plant Host Range, Melissa Irizarry Jan 2016

Soybean Vein Necrosis Virus: Impacts Of Infection On Yield Loss And Seed Quality And Expansion Of Plant Host Range, Melissa Irizarry

Graduate Theses and Dissertations

Soybean vein necrosis virus (SVNV) rapidly became a widespread soybean (Glycine max) virus within a few years of its initial confirmation in 2008. The economic impact of soybean vein necrosis (SVN) disease remains unknown. Soybean is a crop of global importance with nearly 4 billion bushels of soybeans produced in the United States in 2014. This study was designed to pursue two main questions; is there any yield loss or change in seed quality associated with SVN and are there horticultural or cover crop species that could be serving as sources of SVNV inoculum?

In order to determine if there ...


Identification And Characterization Of Brown Stem Rot Resistance In Soybean, Chantal Elaine Mccabe Jan 2016

Identification And Characterization Of Brown Stem Rot Resistance In Soybean, Chantal Elaine Mccabe

Graduate Theses and Dissertations

Breeding for pathogen resistance is an important objective to improve and protect soybean yields. In 2010, 14.4% of total soybean yield was suppressed by diseases. Brown stem rot (BSR), caused by the fungus Phialophora gregata, reduces yield by as much as 38%. To date, three dominant BSR resistance genes have been identified: Rbs1, Rbs2, and Rbs3. The objectives of my research were 1) to determine if plant introductions contained novel BSR resistance genes, 2) to determine the correlation between P. gregata hyphae growth and foliar symptoms as well as characterize the response of the three BSR resistance genes to ...


Studies On Cover Crops And Sudden Death Syndrome Of Soybean, Renan Kobayashi-Leonel Jan 2016

Studies On Cover Crops And Sudden Death Syndrome Of Soybean, Renan Kobayashi-Leonel

Graduate Theses and Dissertations

Soybean sudden death syndrome (SDS), caused by Fusarium virguliforme, is a major soybean disease affecting soybean production in the United States. In search for more diversified cropping systems, the adoption of cover crops in the corn-soybean rotation is being encouraged. However, there is lack of information regarding the impact that cover cropping can have on SDS. On the one hand, it is possible that the improvements in soil health caused by cover crop can create an environment that is not favorable to the disease. On the other hand, F. virguliforme is able to colonize many plant species and, if a ...


Genome-Wide Association And Epistasis Studies Of Sclerotinia Sclerotiorum Resistance In Soybean, Tara Catherine Moellers Jan 2016

Genome-Wide Association And Epistasis Studies Of Sclerotinia Sclerotiorum Resistance In Soybean, Tara Catherine Moellers

Graduate Theses and Dissertations

Sclerotinia stem rot or white mold (WM) [Sclerotinia sclerotiorum (Lib.) de Bary] is an important fungal disease affecting soybean [Glycine max (L.) Merr.] and causes yield and quality losses. WM is prevalent in cool and moist environments, particularly in the soybean growing regions of Northern United States and Canada. Although sources of complete resistance have not yet been identified, several quantitative trait loci (QTL) for partial resistance have been reported but generally using bi-parental mapping populations. Genome-wide association (GWA) studies have been used to dissect complex disease resistance traits in plants and to identify the genes controlling the expression. WM ...


Aboveground Feeding By Soybean Aphid, Aphis Glycines, Affects Soybean Cyst Nematode, Heterodera Glycines, Reproduction Belowground, Michael T. Mccarville, David H. Soh, Gregory L. Tylka, Matthew E. O'Neal Jan 2014

Aboveground Feeding By Soybean Aphid, Aphis Glycines, Affects Soybean Cyst Nematode, Heterodera Glycines, Reproduction Belowground, Michael T. Mccarville, David H. Soh, Gregory L. Tylka, Matthew E. O'Neal

Entomology Publications

Heterodera glycines is a cyst nematode that causes significant lost soybean yield in the U.S. Recent studies observed the aphid Aphis glycines and H. glycines interacting via their shared host, soybean, Glycine max. A greenhouse experiment was conducted to discern the effect ofA. glycines feeding on H. glycines reproduction. An H. glycines-susceptible cultivar, Kenwood 94, and a resistant cultivar, Dekalb 27–52, were grown in H. glycines-infested soil for 30 and 60 d. Ten days after planting, plants were infested with either zero, five, or ten aphids. At 30 and 60 d, the number of H ...


Effects Of Ilevo® On Soybean Sudden Death Syndrome And Soybean Cyst Nematode, Edward R. Zaworski Jan 2014

Effects Of Ilevo® On Soybean Sudden Death Syndrome And Soybean Cyst Nematode, Edward R. Zaworski

Graduate Theses and Dissertations

Fusarium virguliforme, the causal agent of soybean sudden death syndrome (SDS), and Heterodera glycines, soybean cyst nematode (SCN), are two of the most important pathogens of soybean. Host resistance is currently the main management strategy for both pathogens, and there are few other options available for each pathogen. Seed treatments are now an option for farmers for use of pesticides in early plant development. Bayer CropScience recently registered a seed treatment, ILeVO® (fluopyram), with reported activity against both SDS and SCN. The research described in the following manuscript tested ILeVO® in different combinations with currently available seed treatment products for ...


Identification Of Candidate Genes Involved In Early Iron Deficiency Chlorosis Signaling In Soybean (Glycine Max) Roots And Leaves, Adrienne N. Moran-Lauter, Gregory Allan Peiffer, Tengfei Yin, Steven A. Whitham, Dianne Cook, Randy Shoemaker, Michelle Graham Jan 2014

Identification Of Candidate Genes Involved In Early Iron Deficiency Chlorosis Signaling In Soybean (Glycine Max) Roots And Leaves, Adrienne N. Moran-Lauter, Gregory Allan Peiffer, Tengfei Yin, Steven A. Whitham, Dianne Cook, Randy Shoemaker, Michelle Graham

Plant Pathology and Microbiology Publications

Background

Iron is an essential micronutrient for all living things, required in plants for photosynthesis, respiration and metabolism. A lack of bioavailable iron in soil leads to iron deficiency chlorosis (IDC), causing a reduction in photosynthesis and interveinal yellowing of leaves. Soybeans (Glycine max (L.) Merr.) grown in high pH soils often suffer from IDC, resulting in substantial yield losses. Iron efficient soybean cultivars maintain photosynthesis and have higher yields under IDC-promoting conditions than inefficient cultivars.

Results

To capture signaling between roots and leaves and identify genes acting early in the iron efficient cultivar Clark, we conducted a RNA-Seq study ...


Effects Of Rag1 On The Preference And Performance Of Soybean Defoliators, Robert F. Bruner, Erin W. Hodgson, Aaron J. Gassmann Dec 2013

Effects Of Rag1 On The Preference And Performance Of Soybean Defoliators, Robert F. Bruner, Erin W. Hodgson, Aaron J. Gassmann

Entomology Publications

The Rag1 gene confers antibiotic resistance to soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), and in 2010, varieties expressing Rag1 were released for commercial use in the United States. We do not know how Rag1 varieties will influence the broader community of defoliating insects that inhabit soybean fields. In 2010 and 2011, the preference and performance of pest insects that defoliate soybeans [Glycines max (L.) Merr] were tested using Rag1 and aphidsusceptible varieties. Three coleopterans and four lepidopterans were used: northern corn rootworm, Diabrotica barberi Smith & Lawrence (Coleoptera: Chrysomelidae); southern corn rootworm, Diabrotica undecimpunctata howardi Barber (Coleoptera: Chrysomelidae); bean leaf beetle, Ceratoma trifurcata ...


Investigation Of The Arabidopsis Nonhost Resistance Mechanism Against The Soybean Pathogen, Phytophthora Sojae, Rishi Sumit Jan 2013

Investigation Of The Arabidopsis Nonhost Resistance Mechanism Against The Soybean Pathogen, Phytophthora Sojae, Rishi Sumit

Graduate Theses and Dissertations

Nonhost resistance (NHR) provides immunity to all members of a plant species against all isolates of a microorganism that is pathogenic to other plant species. Three Arabidopsis thaliana PEN (penetration deficient) genes, PEN1, 2 and 3 have been shown to provide prehaustorial NHR against the barley pathogen Blumeria graminis f. sp. hordei. Arabidopsis pen1-1 mutant is penetrated by the hemibiotrophic oomycete pathogen, Phytophthora sojae that causes root and stem rot disease in soybean. The P. sojae susceptible (pss) 1 mutant is infected by both P. sojae and the hemibiotrophic fungal pathogen, Fusarium virguliforme that causes sudden death syndrome in soybean ...


Transcriptome Analyses And Virus Induced Gene Silencing Identify Genes In The Rpp4 -Mediated Asian Soybean Rust Resistance Pathway, Aguida A.M.P. Morales, Jamie A. O'Rourke, Martijn Van De Mortel, Katherine T. Scheider, Timothy J. Bancroft, Aluizio Borem, Rex T. Nelson, Daniel S. Nettleton, Thomas J. Baum, Randy C. Shoemaker, Reid D. Frederick, Ricardo V. Abdelnoor, Kerry F. Pedley, Steven A. Whitham, Michelle Graham Jan 2013

Transcriptome Analyses And Virus Induced Gene Silencing Identify Genes In The Rpp4 -Mediated Asian Soybean Rust Resistance Pathway, Aguida A.M.P. Morales, Jamie A. O'Rourke, Martijn Van De Mortel, Katherine T. Scheider, Timothy J. Bancroft, Aluizio Borem, Rex T. Nelson, Daniel S. Nettleton, Thomas J. Baum, Randy C. Shoemaker, Reid D. Frederick, Ricardo V. Abdelnoor, Kerry F. Pedley, Steven A. Whitham, Michelle Graham

Plant Pathology and Microbiology Publications

Rpp4 (Resistance to Phakopsora pachyrhizi 4) confers resistance to Phakopsora pachyrhizi Sydow, the causal agent of Asian soybean rust (ASR). By combining expression profiling and virus induced gene silencing (VIGS), we are developing a genetic framework for Rpp4-mediated resistance. We measured gene expression in mock-inoculated and P. pachyrhizi-infected leaves of resistant soybean accession PI459025B (Rpp4) and the susceptible cultivar (Williams 82) across a 12-day time course. Unexpectedly, two biphasic responses were identified. In the incompatible reaction, genes induced at 12 h after infection (hai) were not differentially expressed at 24 hai, but were induced at 72 hai. In contrast, genes ...


A Virus-Induced Gene Silencing Method To Study Soybean Cyst Nematode Parasitism In Glycine Max, Pramod K. Kandoth, Robert Heinz, Gregory Yeckel, Nathan W. Gross, Parijat S. Juvale, John H. Hill, Steven A. Whitham, Thomas J. Baum, Melissa G. Mitchum Jan 2013

A Virus-Induced Gene Silencing Method To Study Soybean Cyst Nematode Parasitism In Glycine Max, Pramod K. Kandoth, Robert Heinz, Gregory Yeckel, Nathan W. Gross, Parijat S. Juvale, John H. Hill, Steven A. Whitham, Thomas J. Baum, Melissa G. Mitchum

Plant Pathology and Microbiology Publications

Background

Bean pod mottle virus (BPMV) based virus-induced gene silencing (VIGS) vectors have been developed and used in soybean for the functional analysis of genes involved in disease resistance to foliar pathogens. However, BPMV-VIGS protocols for studying genes involved in disease resistance or symbiotic associations with root microbes have not been developed.

Findings

Here we describe a BPMV-VIGS protocol suitable for reverse genetic studies in soybean roots. We use this method for analyzing soybean genes involved in resistance to soybean cyst nematode (SCN). A detailed SCN screening pipeline is described.

Conclusions

The VIGS method described here provides a new tool ...


Fusarium Species Infecting Soybean Roots: Frequency, Aggressiveness, Yield Impact And Interaction With The Soybean Cyst Nematode, Maria Mercedes Diaz Arias Jan 2012

Fusarium Species Infecting Soybean Roots: Frequency, Aggressiveness, Yield Impact And Interaction With The Soybean Cyst Nematode, Maria Mercedes Diaz Arias

Graduate Theses and Dissertations

Fusarium root rot is a widespread and common disease in soybean. Several Fusarium species have been reported to infect soybean roots but their occurrence, aggressiveness and impact on yield have not been quantified. To gain a better understanding of the importance of root-infecting Fusarium species in soybean productivity in Iowa, a three year root survey, and greenhouse and field experiments were conducted in order to accomplish the following objectives, 1) characterize the frequency of Fusarium species associated with soybean roots from Iowa soybean fields, 2) determine aggressiveness of predominant Fusarium species towards soybean, 3) estimate the impact of Fusarium species ...


Epidemiological Studies On The Infection Process And Symptom Expression Of Soybean Sudden Death Syndrome, Carlos Cecilio Gongora-Canul Jan 2010

Epidemiological Studies On The Infection Process And Symptom Expression Of Soybean Sudden Death Syndrome, Carlos Cecilio Gongora-Canul

Graduate Theses and Dissertations

Sudden death syndrome (SDS) caused by Fusarium virguliforme (Aoki, O'Donnel, Homma & Lattanzi) is one of the most important soybean (Glycine max (L.) Merr.) diseases in the US. Management strategies currently available for this disease are not always effective, partly due to the high variability in symptom expression that occurs in field environments. To clarify the relationship between progress of root rot and foliar symptoms, soybean seedlings were inoculated at five inoculum densities and were destructively sampled over a 50 day period. Disease severity and area under disease progress curve (AUDPC) increased in response to increasing inoculum density (P < 0.01), particularly for foliar symptoms. Root rot severity evaluated 15 to 31 days after inoculation (DAI) was most highly correlated (r ...


Nozzle And Carrier Application Effects On Control Of Soybean Leaf Spot Diseases, H. Mark Hanna, Alison E. Robertson, W. Mark Carlton, Robert E. Wolf Jan 2009

Nozzle And Carrier Application Effects On Control Of Soybean Leaf Spot Diseases, H. Mark Hanna, Alison E. Robertson, W. Mark Carlton, Robert E. Wolf

Agricultural and Biosystems Engineering Publications

Increased soybean foliar disease potential has heightened grower interest in fungicide application techniques. Application field trials comparing application rate [187 vs. 112 L/ha (20 vs. 12 gal/acre)], nozzle style (twin-orifice; single-orifice) and spray quality (fine vs. medium and coarse spray quality), and application technique (with and without air-assist) along with an unsprayed check were done at two locations over two years. Fungicide deposition (coverage and droplet size) and disease severity in the bottom, middle, and top parts of the plant canopy, and soybean yield were measured.


Nozzle And Carrier Application Effects On Control Of Soybean Leaf Spot Diseases, H. Mark Hanna, Alison E. Robertson, W. Mark Carlton, Robert E. Wolf Jan 2007

Nozzle And Carrier Application Effects On Control Of Soybean Leaf Spot Diseases, H. Mark Hanna, Alison E. Robertson, W. Mark Carlton, Robert E. Wolf

Agricultural and Biosystems Engineering Conference Proceedings and Presentations

A two-site, two-year field application experiment investigated fungicide coverage in a fully-developed soybean canopy. Application treatments included “high-rate” (187 l/ha; 20 gal/acre) and “low-rate” (112 l/ha;12 gal/acre) with fine-droplet two-orifice tips, medium-droplet two-orifice tip at 187 l/ha (20 gal/acre), a coarse-droplet single-orifice “herbicide-style” tip at 168 l/ha (18 gal/ac), and an air-assisted spray treatment. Droplet coverage and size, and foliar disease severity in the lower, middle, and top parts of the plant canopy, and crop yield were measured.

Droplet size generally followed expected manufacturer specifications. Percentage area covered and drops/cm ...


Effects Of Nozzle Type And Carrier Application On The Control Of Leaf Spot Diseases Of Soybean, H. Mark Hanna, Alison E. Robertson, W. Mark Carlton, Robert E. Wolf Jan 2006

Effects Of Nozzle Type And Carrier Application On The Control Of Leaf Spot Diseases Of Soybean, H. Mark Hanna, Alison E. Robertson, W. Mark Carlton, Robert E. Wolf

Agricultural and Biosystems Engineering Conference Proceedings and Presentations

Midwestern soybean growers seek information on effective application of foliar fungicides that do not translocate throughout the plant. Field application treatments included using a two-orifice nozzle tip producing fine droplets at 187 l/ha (20 gal/ac) and 112 l/ha (12 gal/ac) and a single-orifice nozzle tip producing a coarse droplet size more typical of herbicide applications at 168 l/ha (18 gal/ac). In addition an air-assisted sprayer was used at one of the two sites of the trials. Measurements included droplet size, droplet coverage, and foliar disease severity in the top, middle, and lower parts of ...


Studies On Seed Colouring In Soybean And Tomato, Vilas A. Tonapi, P. Harinath Babu, S. Varanavasiappan, Ch Ravinder Reddy, Shrishail S. Navi, N. Seetharama Jan 2006

Studies On Seed Colouring In Soybean And Tomato, Vilas A. Tonapi, P. Harinath Babu, S. Varanavasiappan, Ch Ravinder Reddy, Shrishail S. Navi, N. Seetharama

Plant Pathology and Microbiology Publications

The effects of seed colouring using 25 dyes (i.e. 20 chemical and 5 natural dyes) on the quality of soyabean (cv. JS 335) and tomato (cv. Pusa Ruby) seeds were studied in the laboratory. Data were recorded for seed germination percentage, root and shoot length, whole seedling length, dry weight of seedling, vigour index, speed of germination and electrical conductivity. Rhodamine-B, Fast green and Malachite green for soyabean and Rhodamine-B and Fast green for tomato were the best dyes for seed colouring.


Expression Of An Arabidopsis Phosphoglycerate Mutase Homologue Is Localized To Apical Meristems, Regulated By Hormones, And Induced By Sedentary Plant-Parasitic Nematodes, Mitra Mazarei, Kristen A. Lennon, David P. Puthoff, Steven R. Rodermel, Thomas J. Baum Nov 2003

Expression Of An Arabidopsis Phosphoglycerate Mutase Homologue Is Localized To Apical Meristems, Regulated By Hormones, And Induced By Sedentary Plant-Parasitic Nematodes, Mitra Mazarei, Kristen A. Lennon, David P. Puthoff, Steven R. Rodermel, Thomas J. Baum

Plant Pathology and Microbiology Publications

We previously isolated a partial soybean cDNA clone whose transcript abundance is increased upon infection by the sedentary, endoparasitic soybean cyst nematode Heterodera glycines. We now isolated the corresponding full-length cDNA and determined that the predicted gene product was similar to the group of cofactor-dependent phosphoglycerate mutase/bisphosphoglycerate mutase enzymes (PGM/bPGM; EC 5.4.2.1/5.4.2.4). We designated the corresponding soybean gene GmPGM. PGM and bPGM are key catalysts of glycolysis that have been well characterized in animals but not plants. Using the GmPGM cDNA sequence, we identified a homologous Arabidopsis thaliana gene, which we ...


Influence Of Herbicide Application To Soybeans On Soybean Cyst Nematode Egg Hatching, Brian C. Levene, Michael D. K. Owen, Gregory L. Tylka Sep 1998

Influence Of Herbicide Application To Soybeans On Soybean Cyst Nematode Egg Hatching, Brian C. Levene, Michael D. K. Owen, Gregory L. Tylka

Plant Pathology and Microbiology Publications

The hatching of Heterodera glycines eggs in soybean root exudates collected after postemergence application of three herbicides, and the hatching potential of H. glycines eggs from females feeding on herbicide-treated plants, were measured in vitro. Hatching in all root exudate solutions (RES) was greater than in deionized water but less than in 0.003 M ZnSO[sub4] solution. Filtering RES with a 0.22-[mu]m-filter increased H. glycines hatching in RES. Application of acifluorfen, bentazon, and lactofen to foliage of soybean plants inhibited hatching of H. glycines eggs from the same plants. Hatching in RES from the different herbicide-treated ...