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Iowa State University

Soybean

Plant Sciences

Graduate Theses and Dissertations

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Modeling Yield Loss Due To Soybean Sudden Death Syndrome At Different Spatial Scales, Muhammad Mohsin Raza Jan 2019

Modeling Yield Loss Due To Soybean Sudden Death Syndrome At Different Spatial Scales, Muhammad Mohsin Raza

Graduate Theses and Dissertations

Sudden death syndrome (SDS), caused by Fusarium virguliforme (Fv), is one of the major yield-limiting diseases of soybean in the Midwest. In the U.S., annual yield losses due to SDS have ranged between 0.6 to 1.9 million metric tons during the years from 2006 to 2014, and monetary losses of up to 6.75 billion dollars have been attributed to SDS for the period of 1996 to 2016. Our understanding of the relationships between varying disease levels, pathogen density, and yield is still limited. The first objective in this study was to quantify the relationship between SDS ...


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 ...


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 ...


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 ...


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 ...


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 ...


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 ...


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 ...


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 ...


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 ...


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 ...


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 ...


Influence Of Bradyrhizobium Inoculation And Fungicide Treatment On Development And Yield Of Selected Pulse Crops; Nutritional Composition Of Pulse Legume Leaves And The Impact Of Leaf Removal On Yield, Rosemary Bulyaba Jan 2015

Influence Of Bradyrhizobium Inoculation And Fungicide Treatment On Development And Yield Of Selected Pulse Crops; Nutritional Composition Of Pulse Legume Leaves And The Impact Of Leaf Removal On Yield, Rosemary Bulyaba

Graduate Theses and Dissertations

Part 1

Declining soil fertility due to inadequate nitrogen in most soils limits farmers’ goals of increasing yield. There is environmental and agricultural benefit of reducing dependence on nitrogen fertilizer by emphasizing adaptation of favorable farming practices that minimize nitrogen fertilizer. Cowpea [Vigna unguiculata (L.) Walp.] and lablab (Lablab purpureus (L.)] are pulses with potential for grain, forage, and cover crops in the Midwest of United States, but little is known about their growth, development, and productivity potential in Iowa. We conducted a two-year field study to determine the influence of rhizobia inoculation and fungicide seed treatment of selected pulses ...


Local Vs. Systemic Modifications Of Soybean (Glycine Max) Defense Signals In Response To Soybean Aphid (Aphis Glycines Matsumura) Infestation, Khoi Nguyen Jan 2015

Local Vs. Systemic Modifications Of Soybean (Glycine Max) Defense Signals In Response To Soybean Aphid (Aphis Glycines Matsumura) Infestation, Khoi Nguyen

Graduate Theses and Dissertations

Soybean aphids, Aphis glycines, are a specialized phloem-feeding pest of soybeans. They are known to employ different mechanisms to bypass plant defenses and reduce soybean plant yields of up to 50% a year. Once attacked or sensing distress, soybeans induce the oxylipin pathway, a biosynthetic pathway that produces key plant hormones. Among these hormones is jasmonic acid (JA), which is produced from linolenic acid (18:3). Jasmonic acid can signal the production of protease inhibitors as one of the products that obstructs the attackers’ ability to digest protein. Previous studies show that levels of three key fatty acid precursors (palmitic ...


Plant Tissue Analysis To Assess Phosphorus And Potassium Nutritional Status Of Corn And Soybean In Iowa, Andrew John Stammer Jan 2015

Plant Tissue Analysis To Assess Phosphorus And Potassium Nutritional Status Of Corn And Soybean In Iowa, Andrew John Stammer

Graduate Theses and Dissertations

Interest in re-evaluating the value of tissue testing to assess P and K status in corn (Zea mays L.) and soybean (Glycine max L. Merr.) is increasing. The objective of this research was to study relationships between grain yield response to P and K and the concentration of these nutrients in plant tissue. Single-year and multi-year response trials were conducted in Iowa at 30 sites for P (32 sites-years with corn and 34 with soybean) and at 53 for K (67 sites years with corn and 52 with soybean) that encompassed 17 soil series. We sampled above-ground plant parts at ...


Phenotypic And Genetic Variation In An Apios Americana Breeding Collection; And Characterization Of The Hd-Zip Gene Family, Involved In Abiotic Stress Responses In Glycine Max, Vikas Belamkar Jan 2015

Phenotypic And Genetic Variation In An Apios Americana Breeding Collection; And Characterization Of The Hd-Zip Gene Family, Involved In Abiotic Stress Responses In Glycine Max, Vikas Belamkar

Graduate Theses and Dissertations

This dissertation has two main objectives: (1) morphological and genetic characterization of a little-studied edible legume native to North America, Apios americana; and (2) characterization of the soybean (Glycine max) homeodomain leucine zipper (HD-Zip) transcription factor family (involved in abiotic stress responses), and identification of candidate genes for dehydration and salt stress. In these projects, next generation sequencing (NGS) is evaluated as a tool for rapidly characterizing genetic variation (in Apios) and fine-scale genetic responses to abiotic stress (in soybean).

Apios, commonly called “potato bean,” is a nitrogen-fixing legume that is adapted to diverse climatic conditions of central and eastern ...


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 ...


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 ...


13c-Metabolic Flux Analysis Of Soybean Somatic Embryos For Identification Of Metabolic Control Points In Developing Seed, Quyen Xuan Truong Dec 2012

13c-Metabolic Flux Analysis Of Soybean Somatic Embryos For Identification Of Metabolic Control Points In Developing Seed, Quyen Xuan Truong

Graduate Theses and Dissertations

Of the world's major agronomic food crops soybeans rank highest in protein content (~40% Dwt) while also containing significant quantities of oil (~20% Dwt). Based on these unique characteristics soy has become a mainstay in world agriculture, providing a protein source for livestock and human nutrition (68% of global vegetable protein meal consumption in 2011) as well as a primary source of vegetable oil (28% of global vegetable oil consumption in 2011; http://www.soystats.com/2012). The value of soy is therefore found both in its oil and protein content and increasing the content of both is therefore ...


Variability In Soybean Agronomic Performance Traits In Response To 41 C Heat And High Relative Humidity Seed Stress, Ruth Ann Rolling Jan 2012

Variability In Soybean Agronomic Performance Traits In Response To 41 C Heat And High Relative Humidity Seed Stress, Ruth Ann Rolling

Graduate Theses and Dissertations

Incorporation of genetic diversity into soybean [Glycine max (L.) Merr.] cultivars can be used to increase yield and plant adaptation to stresses. Genetic variation has been found in commercial soybean cultivars, but using a seed stress to generate intra-cultivar variation has not been studied. The first objective of this study was to use seed stress in an attempt to generate variation in soybean agronomic traits of field stand, plant maturity, plant height, seed size, seed yield, seed protein content, seed oil content, seed standard germination and seed vigor. The second objective was to evaluate if changes in variation were heritable ...


Analysis Of Iron Transporters In The Soybean (Glycine Max (L.) Merr.) Genome, Dan Stribe Jan 2012

Analysis Of Iron Transporters In The Soybean (Glycine Max (L.) Merr.) Genome, Dan Stribe

Graduate Theses and Dissertations

Iron plays a significant role in numerous cellular functions. Improved uptake and efficiency of use can have strong positive effects on the health of plants, animals and humans. Major players in iron homeostasis are the Iron-Regulated Transporters (IRT). The purpose of this research is to identify putative Iron-Regulated Transporter genes in soybean, structurally characterize these genes and examine their relational phylogeny. Additionally, gene sequence data and gene expression patterns will be considered to differentiate each gene's potential role in iron homeostasis of soybean. In this study, we identified fourteen soybean gene models with significant predicted protein similarity to A ...


Agronomic And Seed Traits Of Soybean Lines With Genes For Aphid Resistance, Inheritance And Mapping Of Cowpea Mild Mottle Virus-Like Resistance In Soybean, And Fatty Ester Composition Of Low-Phytate, Low-Saturate Soybean Lines, Ryan Christopher Brace Jan 2012

Agronomic And Seed Traits Of Soybean Lines With Genes For Aphid Resistance, Inheritance And Mapping Of Cowpea Mild Mottle Virus-Like Resistance In Soybean, And Fatty Ester Composition Of Low-Phytate, Low-Saturate Soybean Lines, Ryan Christopher Brace

Graduate Theses and Dissertations

Evaluation of aphid resistant backcross (BC) lines containing the Rag1 or Rag2 alleles alone, or with the two alleles combined, indicated that the mean yields of resistant BC lines were less than the mean of the two entries of their susceptible recurrent parent in each of the three experiments. This reduction in mean yield was significant for BC lines containing Rag1 and its combination with Rag2, but not for BC lines with only Rag2. Among the BC lines in each experiment, only a small percentage were significantly different from the mean yield of their susceptible recurrent parent. Significant differences in ...


Agronomic, Seed Traits And Oleate Stability Of Soybean Lines Containing The High-Oleate Transgene Dp-305423-1 And The Molecular Characterization Of The Genomic Region Flanking The High-Oleate Transgene, Jordan Dustin Spear Jan 2012

Agronomic, Seed Traits And Oleate Stability Of Soybean Lines Containing The High-Oleate Transgene Dp-305423-1 And The Molecular Characterization Of The Genomic Region Flanking The High-Oleate Transgene, Jordan Dustin Spear

Graduate Theses and Dissertations

To improve the oxidative stability of soybean [Glycine max (L.) Merr.] oil, it is desirable to increase the percentage of the monounsaturated fatty ester oleate. By altering the endogenous FAD2-1gene in soybean, oleate concentrations of greater than 750 g kg-1 can be obtained. From a commercial perspective, it is important to understand the influence of this genetic alteration on agronomic and seed traits, as well as the stability of the increased oleate concentration across a range of environments.

Objective one of my research was to evaluate the influence of the DP-305423-1 high-oleate (HO) transgene on agronomic and seed ...


A Type Ii Metacaspase Interacts With Rps1-K-2 In Soybean And Analysis Of The Soybean Metacaspase Gene Family, James Andrew Baskett Jan 2012

A Type Ii Metacaspase Interacts With Rps1-K-2 In Soybean And Analysis Of The Soybean Metacaspase Gene Family, James Andrew Baskett

Graduate Theses and Dissertations

Soybean suffers from the root and stem rot disease caused by the oomycete pathogen, Phytophthora sojae. A series of Rps genes confer Phytophthora resistance, and have been utilized in fighting this serious disease in soybean. Earlier we reported the cloning of the coiled coil-nucleotide binding-leucine rich repeat gene, Rps1-k-2. Here we report the identification of a type II metacaspase, Gmmc11 that interacted with the coiled-coil (CC) domain of Rps1-k-2 in vivo in yeast. The interaction was verified by conducting in vitro pull down assays in unpublished work. RNA interference of Gmmc11 in cotyledons resulted in loss of Phytophthora resistance. Gmmc11 ...


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 ...