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Approaches To Sustainable Management Of Sudden Death Syndrome Of Soybean, Joshua Winaya Budi Jan 2020

Approaches To Sustainable Management Of Sudden Death Syndrome Of Soybean, Joshua Winaya Budi

Graduate Theses and Dissertations

Sudden death syndrome (SDS) of soybean was first detected in the US in 1971 and has remained one of the most damaging soybean diseases in the US. It is caused by a soil-borne fungus, Fusarium virguliforme (Fv), that persists in the soil for multiple years. Currently, conventional management of SDS relies on partially-resistant cultivars and fluopyram seed treatment, but fluopyram seed treatment is expensive and partial resistance does not protect soybeans during severe epidemics. Extended crop rotation is an alternative strategy that has effectively suppressed SDS, but there are barriers to adoption of this strategy in the current agricultural system ...


Intercropping And Relay Cropping To Increase Productivity, Resilience, And Long-Term Sustainability Of Corn And Soybean Cropping Systems In Iowa, Swetabh Patel Jan 2020

Intercropping And Relay Cropping To Increase Productivity, Resilience, And Long-Term Sustainability Of Corn And Soybean Cropping Systems In Iowa, Swetabh Patel

Graduate Theses and Dissertations

Soil erosion and nutrient loss as a result of lack of ground cover in conventional corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] cropping systems in the U.S. Midwest warrant use of cover crops to provide improved protection to the soil. There are needs for alternate cropping systems and management practices capable of protecting our resources without sacrificing existing and future crop yield goals. Field pennycress (Thlaspi arvense L.) and winter camelina [Camelina sativa (L.) Crantz] are short season annual oilseed crops having the potential to be integrated into corn and soybean systems as cash cover crops ...


Herbicide Site Of Actions And Potential Damage To Zea Mays And Glycine Max., Justin Friedrich Jan 2020

Herbicide Site Of Actions And Potential Damage To Zea Mays And Glycine Max., Justin Friedrich

Creative Components

With the development of 2,4-D in the 1940s, farmers were able to selectively kill broadleaves in corn (Zea mays). 2,4-D was an effective and powerful tool that allowed farmers to reduce the time spent cultivating cornfields. The development of herbicides allowed farms to increase in size due to the reduction in the time spent interrow-cultivating. Monsanto’s introduction of glyphosate-resistant (Roundup Ready) soybean (Glycine max) in 1996 continued the expansion of farm size. Glyphosate-resistant crops allowed farmers to adopt a “spray and forget” weed management program that was widely adopted. The simplified weed management programs were successful until ...


What Are The Consequences Of Resistance? Exploring The Impacts Of Insecticide And Host-Plant Resistance For Insect Pest Management, Ashley Nicole Dean Jan 2019

What Are The Consequences Of Resistance? Exploring The Impacts Of Insecticide And Host-Plant Resistance For Insect Pest Management, Ashley Nicole Dean

Graduate Theses and Dissertations

Soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), has been a prominent insect pest in the northcentral region since 2000. Insecticides are the primary management tactic for this pest, but some populations of soybean aphid resistant to pyrethroid insecticides have been reported since 2015. This increases the impact of soybean aphid on soybean, Glycine max (L.) Merr (Fabales: Fabaceae), production, which is already challenged by higher input costs, declining market value, and unpredictable weather. Soybean aphid-resistant varieties are available to farmers but limited to genetic backgrounds that exclude herbicide-tolerance. This is a significant barrier to adoption since farmers rely on herbicide-tolerant ...


A Comparison Of March And April Soybean Planting Dates In South-Central Illinois, Nicholas Patrick Marley Jan 2019

A Comparison Of March And April Soybean Planting Dates In South-Central Illinois, Nicholas Patrick Marley

Creative Components

One of the biggest issues with ultra-early planting of soybean [Glycine max (L.) Merr.] is the lack of research that has been conducted. This study is designed to increase the knowledge base of soybean planting dates by looking at ultra-early (March) versus early (April) planted soybean in south-central Illinois. Field research was conducted in two fields, near Morrisonville, IL over the 2017 and 2018 growing season. In 2017, the March planted soybean required 19 days to gain 121 GDD for emergence to start. Compared to the April planting date where emergence was in 7 days with 123 GDD accumulation. In ...


The Influence Of Plant Growth Regulators On Flowering, Pod Set, Seed Size, And Seed Yield In Soybean, Matthew Wetterling Jan 2019

The Influence Of Plant Growth Regulators On Flowering, Pod Set, Seed Size, And Seed Yield In Soybean, Matthew Wetterling

Creative Components

No abstract provided.


Characterization Of Corn Stover Pelleted With Soybean Meal Or Dried Distillers Grains On Lactating Cow Performance, Eating Behavior, And Rumen Function, Brooke C. Dooley Jan 2019

Characterization Of Corn Stover Pelleted With Soybean Meal Or Dried Distillers Grains On Lactating Cow Performance, Eating Behavior, And Rumen Function, Brooke C. Dooley

Graduate Theses and Dissertations

The objective of this study was to determine the effects of alkali-treated corn stover pelleted with soybean meal (STV-SBM) or dried distillers grains (STV-DDG), on milk yield (MY), eating behavior and rumen fermentation in dairy cows. Fourty-five Holstein cows were used in replicated 5 × 5 Latin squares with 28-d periods, using a 2 × 2 + 1 augmented factorial arrangement of treatments. Diets were formulated to contain 10 or 15% corn stover-based pellets that replaced corresponding proportions of corn gluten feed pellets in the control diet. Treatments were: 1) Control (CON); 2) SBM10; 3) SBM15; 4) DDG10; and 5) DDG15. In each ...


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 ...


Drought Tolerance In Soybean: Methods For Improvement, Emily Thorp Jan 2019

Drought Tolerance In Soybean: Methods For Improvement, Emily Thorp

Creative Components

As opposed to the past, plant breeders today have access to far greater technology, and far greater obstacles to overcome. One of those challenges is the need for drought tolerance in crops such as soybeans. Soybeans are a major crop, affected by drought due to a lack of tolerance traits in cultivars grown today. Drought tolerant soybeans are important globally, because soybeans are grown in many countries around the world where yield losses from drought are frequent. Therefore, it is essential for farmers to make changes to their practices to help their crops tolerate or avoid drought, and breeding programs ...


Soybean Nitrogen Dynamics: Nitrogen Fixation, Yield, And Residue Decomposition, S Carolina Cordova Martinez Jan 2018

Soybean Nitrogen Dynamics: Nitrogen Fixation, Yield, And Residue Decomposition, S Carolina Cordova Martinez

Graduate Theses and Dissertations

Nitrogen (N) a crucial element for plant growth, often limits net primary productivity of agroecosystems. In agricultural systems it is vital to have proper management of N to secure productivity and environmental sustainability. Soybean [Glycine max (L.) Merr.] is the second most important crop in the US Corn Belt, and it can fix part of its N through biological N fixation. The overarching goal of this research was to investigate soybean N fixation dynamics in response to environmental factors, and plant tissue decomposition to understand better N cycling and improve Midwestern US N budget estimations.

A long-term incubation study was ...


Using Genomic And Gene Expression Methods To Understand The Phenotypic Response Of Soybean To Sudden Death Syndrome Caused By Fusarium Virguliforme, Alexander Stephen Luckew Jan 2018

Using Genomic And Gene Expression Methods To Understand The Phenotypic Response Of Soybean To Sudden Death Syndrome Caused By Fusarium Virguliforme, Alexander Stephen Luckew

Graduate Theses and Dissertations

Soybean sudden death syndrome (SDS) is one of the most important soybean diseases in the Midwestern United States, leading to average losses of $396 million per year from 1996 to 2015. The causal agent of SDS, soilborne fungus Fusarium virguliforme (Fv), causes root rot symptoms and releases phytotoxins taken up by the plant to produce chlorosis and necrosis in the leaves. The main management practice used to reduce the impact of SDS is planting resistant soybean cultivars. Resistance to SDS is known to be quantitative with 88 known quantitative trait loci (QTL) based on Soybase.org. Many of these QTL ...


Winter Cereal Rye And Selected Brassica Cover Crops For Forage Prior To Soybeans, Timothy James Sklenar Jan 2018

Winter Cereal Rye And Selected Brassica Cover Crops For Forage Prior To Soybeans, Timothy James Sklenar

Graduate Theses and Dissertations

Despite myriad benefits to incorporating winter cover crops into conventionally managed row crop systems farmer adoption remains low in Iowa. Commonly cited apprehensions include the costs associated with managing cover crops without any short term economic benefits and the complexities associated with management of cover crops. The management of cover crops as a forage could potentially help address both of these issues while at the same time enhancing the environmental sustainability of conventionally managed systems. The work provided in this thesis is an attempt to evaluate the potential for four selected species to be managed as dual-purpose winter cover crops ...


Functional Characterization Of A Fungal Polyamine Oxidase Fvpo1, Jordan Lillian Baumbach Jan 2018

Functional Characterization Of A Fungal Polyamine Oxidase Fvpo1, Jordan Lillian Baumbach

Graduate Theses and Dissertations

Soybean is an important source of protein and oil for both human and animal nutrition. The United States is the world’s leading soybean producing nation. In 2016, the U.S. soybean production was valued over 40.9 billion dollars. Sudden death syndrome (SDS) of soybean is ranked as one of the top ten yield limiting disease of soybean and is caused by the pathogen Fusarium virguliforme. Fusarium virguliforme is a soil borne fungal pathogen, which infects soybean roots resulting in both root sot symptoms and foliar chlorosis and necrosis. To date there is no known single gene resistance to ...


Effect Of Soybean Sudden Death Syndrome On Seed Quality And Agronomic Trait Qtls, Josh Knight Jan 2018

Effect Of Soybean Sudden Death Syndrome On Seed Quality And Agronomic Trait Qtls, Josh Knight

Graduate Theses and Dissertations

Soybean production has grown over the years and soybean has become one of the main crops in the world. Protecting and advancing soybean production has become a main goal for soybean producers and breeders. The following chapters look at the soybean-pest interaction for one of the leading soybean diseases called Fusarium virguliforme. that causes sudden death syndrome (SDS) in soybean, and potential genetic regions controlling seed quality traits. Chapter two compares Fusarium virguliforme, Fv inoculated fields vs non-inoculated fields for soybean agronomic and seed quality traits. SDS is one of the leading soybean pests in the United States. This study ...


Evaluation Of Soybean Grain Yield As Influenced By Soybean Seeding Rate And Fomesafen Herbicide, Paul Parcher Jan 2018

Evaluation Of Soybean Grain Yield As Influenced By Soybean Seeding Rate And Fomesafen Herbicide, Paul Parcher

Creative Components

Glyphosate (N-(phosphonomethyl)glycine) herbicide has been extensively used on several herbicide tolerant crops in the United States since the introduction of the first commercially available genetically modified glyphosate-tolerant soybean [Glycine max (L.) Merr.] seed in 1996. The launch of commercially available glyphosate-tolerant corn (Zea mays L.) seed in 1998 provided farmers in Iowa and other states, where corn and soybean are primarily grown, the ability to apply glyphosate to every acre of these crops annually.


Evolution Of Soybean Weed Management In The United States, Aaron Rowe Jan 2018

Evolution Of Soybean Weed Management In The United States, Aaron Rowe

Creative Components

Weeds have been an unwanted nuisance since the beginning of agriculture. The processes and technologies utilized to manage this yield limiting problem have evolved over time. Soybean [Glycine max (L.) Merr.] production in the United States has experienced all of the major agriculture revolutions. This has included horse-drawn field implements, tractor power implementation, chemical era, and the most recent era of biotechnology. There has been a continuous gain in efficiencies with the discovery and introduction of new technologies to manage weeds in soybeans. A period of rapid discovery and introduction of new and novel herbicide sites of action (SOA) with ...


Effects Of A Plant Growth Regulator Product On Soybean At R2-R3, Geoffrey Klumpp Jan 2018

Effects Of A Plant Growth Regulator Product On Soybean At R2-R3, Geoffrey Klumpp

Creative Components

The agricultural industry had a rapid increase in commodity prices from late in 2010 until the fall of 2014. With those higher prices, there was a niche market for added-value products brought to the market, many of which promised the local grower a five-bushel yield increase per acre on soybeans. I wanted to focus on a select group of these products, plant growth regulators (PGRs). I specifically worked with a commercial product that contained three phytohormones, cytokinin, a gibberellic acid, and an auxin. For this project, there were thirteen side-by-side trials for each of the following years, 2015, 2016, 2017 ...


Identification Of Spectral Disease Signatures And Resistant Qtl For Charcoal Rot Infection In Soybean, Sarah Jones Jan 2017

Identification Of Spectral Disease Signatures And Resistant Qtl For Charcoal Rot Infection In Soybean, Sarah Jones

Graduate Theses and Dissertations

Disease phenotyping is an important process for both production field scouting and disease rating in soybean [Glycine max (L.) Merr.] breeding programs because yield is affected by many pathogens including charcoal rot, Macrophomina phaseolina. Charcoal rot has limited chemical control options and affects over 500 species worldwide making crop rotation a difficult management strategy as well. Due to these management challenges, breeding for disease resistance is a valuable strategy, however traditional disease phenotyping relies on human visual ratings which are prone to human error and have scalability issues when moving to large production schemes or modern breeding programs. Furthermore, there ...


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 ...


Genetic Architecture Of Antibiosis And Antixenosis Aphid Resistance In Soybean And Elucidation Of The Molecular Effect Of Pyramiding Rag1 And Rag2 Resistance Genes, Martha Ibore Jan 2017

Genetic Architecture Of Antibiosis And Antixenosis Aphid Resistance In Soybean And Elucidation Of The Molecular Effect Of Pyramiding Rag1 And Rag2 Resistance Genes, Martha Ibore

Graduate Theses and Dissertations

Soybean aphids are a major problem to soybean growers worldwide and they cause great yield losses. In the United States, soybean aphids can cause yield losses of up to 50% especially on susceptible varieties. Yield losses attributed to feeding by soybean aphids can be reduced by cultivating resistant soybean varieties. In recent years, certain biotypes of soybean aphids that can colonize resistant soybean plants have been reported, suggesting the continued need for identification of novel sources of aphid resistance to include in plant breeding programs. While gene pyramiding, in which certain resistant soybean genotypes carry more than one aphid resistance ...


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 ...


Microscopic Characterization Of A Transposon-Induced Male-Sterile, Female-Sterile Mutant In Glycine Max L., Katherine A. Thilges Jan 2016

Microscopic Characterization Of A Transposon-Induced Male-Sterile, Female-Sterile Mutant In Glycine Max L., Katherine A. Thilges

Graduate Theses and Dissertations

A male-sterile, female-sterile mutant was identified in a transposon-tagging study in soybean (Glycine max L.). This mutant displayed abnormalities in both micro- and mega-sporogenesis, as well as gametogenesis. Vegetatively, the mutant showed no visible differences from the wild-type phenotype. Analyses of male meiotic chromosomes were done to better understand any issues that could occur to cause sterility. Wild-type and mutant anthers and ovules were cleared throughout their development, followed by confocal scanning laser microscopy to look for any abnormalities, and to determine the timing of abortion in both the male and female organs in the mutant. Additionally, scanning electron microscopy ...


Microscopic Characterization Of A Transposon-Induced Male-Sterile, Female-Sterile Mutant In Glycine Max L., Katherine A. Thilges Jan 2016

Microscopic Characterization Of A Transposon-Induced Male-Sterile, Female-Sterile Mutant In Glycine Max L., Katherine A. Thilges

Graduate Theses and Dissertations

A male-sterile, female-sterile mutant was identified in a transposon-tagging study in soybean (Glycine max L.). This mutant displayed abnormalities in both micro- and mega-sporogenesis, as well as gametogenesis. Vegetatively, the mutant showed no visible differences from the wild-type phenotype. Analyses of male meiotic chromosomes were done to better understand any issues that could occur to cause sterility. Wild-type and mutant anthers and ovules were cleared throughout their development, followed by confocal scanning laser microscopy to look for any abnormalities, and to determine the timing of abortion in both the male and female organs in the mutant. Additionally, scanning electron microscopy ...


Molecular Characterization Of Short And Long Term Iron Stress Responses In Soybean, Leorrie Ann Atencio Jan 2016

Molecular Characterization Of Short And Long Term Iron Stress Responses In Soybean, Leorrie Ann Atencio

Graduate Theses and Dissertations

Iron Deficiency Chlorosis (IDC) is a disease caused by lack of useable iron in the soil. Symptoms include stunting and interveinal chlorosis of the leaves, eventually leading to yield loss at the end of the season. IDC is particularly important in the upper Midwestern United States because soil conditions favor its development. With the use of next generation sequencing approaches, we characterized soybeans’ short and long-term response to iron stress. Our research takes advantage of two near isogenic lines that are 98% genetically identical but differ in their iron efficiency response. Clark plants are iron efficient, while Isoclark plants are ...


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 ...


Rye Cover Crop Biomass, Nutrient Composition And Crop Management Practices To Enhance Corn Yield, Swetabh Patel Jan 2016

Rye Cover Crop Biomass, Nutrient Composition And Crop Management Practices To Enhance Corn Yield, Swetabh Patel

Graduate Theses and Dissertations

Winter cereal rye (Secale cereal L.), a commonly used cover crop in corn (Zea mays L.) systems has potential to scavenge soil NO3–N through a fibrous root system. The objective of this study was to quantify root and shoot biomass, C, and N partitioning in rye cover crop at the time of termination in spring. This was a one–year study conducted at a site with a no-till corn–soybean [Glycine max (L.) Merr.] rotation, rye drilled following grain crop harvest, and three N rates applied to corn (0, 135, and 225 kg N ha–1). Rye root biomass ...


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 ...