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Epidemiological Studies Of Soybean Vein Necrosis Virus And Potential Resistance Mechanisms To Its Vector Neohydatothrips Variabilis (Beach), Jing Zhou Dec 2018

Epidemiological Studies Of Soybean Vein Necrosis Virus And Potential Resistance Mechanisms To Its Vector Neohydatothrips Variabilis (Beach), Jing Zhou

Theses and Dissertations

Soybean (Glycine max (L.) Merrill) is one the most important crops in global agriculture with annual production of over 260 million metric tons. As the dependence of a growing global population to soybean has increased, so does the importance of soybean diseases and pests. Over 200 pathogens attack soybean; among them, viruses pose a major threat to the soybean industries accounting for approximately 10% of the annual yield reduction caused by diseases in the past two decades. Soybean vein necrosis virus (SVNV) is a relatively newly discovered virus causing the homonymous disease. The widespread occurrence of the disease in major ...


Physiological Characterization Of The Soynam Parental Lines Under Field Conditions, Akshita Mishra Dec 2018

Physiological Characterization Of The Soynam Parental Lines Under Field Conditions, Akshita Mishra

Theses and Dissertations

The narrow genetic pool of soybean (Glycine max L. Merr.) in North America can limit its future yield gains. Among the worldwide germplasm collection of 45,000 unique landraces, only 80 contribute 99% to the collective parentage of North American soybean cultivars. Among these 80 landraces, just 17 contribute to 86% of the collective parentage of the modern cultivars. The Soybean Nested Association Mapping population (SoyNAM) was therefore developed with the objective of diversifying the soybean gene pool. Forty diverse soybean genotypes from maturity groups (MG) 1 through 5 were crossed with a common MG 3 parent to develop 40 ...


Evaluation Of Soybean Maturity Group And Planting Date In A Soybean-Rice Rotation On Overall Crop Productivity, Carrie Ortel Dec 2018

Evaluation Of Soybean Maturity Group And Planting Date In A Soybean-Rice Rotation On Overall Crop Productivity, Carrie Ortel

Theses and Dissertations

Little is known about the effects of soybean (Glycine max L.) management techniques on soil-nitrogen (N) credit development and its impact on the subsequent rice (Oryza sativa L.) crop’s success. This study was conducted to determine how soybean maturity group (MG) and planting date effect overall soybean productivity and its influence on the following rice crop. Various soybean planting dates (optimum and late) and MGs (3.5, 4.7, 5.4, and 5.6) were grown and followed in rotation with a rice crop. Six rates of pre-flood fertilizer-N (0, 44, 89, 134, 179, 224 kg N ha-1) were ...


Linkage Mapping For Soybean (Glycine Max) Flood Tolerance, Wade Stiles Hummer Dec 2018

Linkage Mapping For Soybean (Glycine Max) Flood Tolerance, Wade Stiles Hummer

Theses and Dissertations

Flood tolerance in soybean (Glycine max) is not a well-characterized trait, yet flooding damage is second only to drought stress in terms of yield reduction. The objectives of this study were to determine genetic variation for flooding tolerance in two populations of soybean recombinant inbred lines (RILs) and to identify and confirm flood tolerant QTL. Population A (WHA) consisted of 111 RILs derived from the cross 5002T by 91210-350 and Population B (WHB) consisted of 79 RILs from the cross RA-452 by Osage. Experiments were conducted at the Rice Research and Extension Center (RREC) near Stuttgart, AR in 2015 and ...


Soybean Response To Dicamba: Associated Injury Criteria And Development Of A Model To Predict Yield Loss, Matthew Ryan Foster Oct 2018

Soybean Response To Dicamba: Associated Injury Criteria And Development Of A Model To Predict Yield Loss, Matthew Ryan Foster

LSU Doctoral Dissertations

In research conducted using indeterminate soybean [Glycine max (L.) Merr.], fourteen injury criteria observed following dicamba at 0.6 to 280 g ae ha-1 (1/1000 to ½ of 560 g ha-1 use rate) were rated using a scale of 0= no injury, 1= slight, 2= slight to moderate, 3= moderate, 4= moderate to severe, and 5= severe. Greatest crop injury 15 d after treatment (DAT) was observed following dicamba applied at 0.6 to 4.4 g ha-1 at V3/V4 for upper canopy pale leaf margins (3.8 to 4.2) and at R1/R2 ...


Genetic And Phytopathological Studies On Charcoal Rot Resistance In Soybean [Glycine Max (L) Merr.], Marcos Paulo Da Silva May 2018

Genetic And Phytopathological Studies On Charcoal Rot Resistance In Soybean [Glycine Max (L) Merr.], Marcos Paulo Da Silva

Theses and Dissertations

Charcoal rot of soybean (Glycine max (L.), caused by Macrophomina phaseolina is a disease of economic significance in the United States. The identification and quantification of the resistance is difficult, and very little is known about the genetics and markers linked to the charcoal rot (CR) resistance genes. Current assay methods can be time consuming, and data may vary between tests. The objectives of this study were to 1) create a robust seed plate assay (SPA) for CR resistance by comparing results with cut-stem and CFUI assays; 2) correlate and compare field data disease assessments with SPA; 3) identify QTLs ...


Evaluation Of Dicamba Off-Target Movement And Subsequent Effects On Soybean Offspring, Gordon Travis Jones May 2018

Evaluation Of Dicamba Off-Target Movement And Subsequent Effects On Soybean Offspring, Gordon Travis Jones

Theses and Dissertations

Commercial launch of cotton with resistance to dicamba, glyphosate, and glufosinate occurred in 2015 and launch of soybean with resistance to dicamba and glyphosate occurred in early 2016. It is likely that non-dicamba-resistant soybean will be planted in close proximity to dicamba-resistant soybean and cotton. Therefore, experiments were conducted to examine the distance dicamba moves during an application using commercial application equipment, as well as the effect the drift events have upon soybean offspring. Additional experiments were designed to investigate the effect glyphosate addition to dicamba has upon soybean growth and yield as well as possible effects on offspring. Lastly ...


Dicamba Effects On Soybean (Glycine Max) Growth, Yield, And Offspring, Mark Spencer Mccown May 2018

Dicamba Effects On Soybean (Glycine Max) Growth, Yield, And Offspring, Mark Spencer Mccown

Theses and Dissertations

Introduction of a new dicamba-resistant (Xtend) trait in soybean and cotton will increase dicamba herbicide use. Consequently, concern for injury to sensitive crops from off-target movement and tank contamination will likely increase. For soybean, foliar symptoms associated with dicamba damage do not necessarily reflect yield losses; hence, experiments were conducted to determine the effects of dicamba on soybean growth, yield, and offspring. Low rates of dicamba [1/64X (8.75 g ae ha-1) and 1/256X (2.18 g ae ha-1) of a normal 1X field rate (560 g ae ha-1)] were applied at two vegetative growth stages (V4, V6 ...


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 ...


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 ...


Ecophysiological Analysis Of Yield Determination In Soybean Of Different Relative Maturities, Maria Morrogh Bernard Jan 2018

Ecophysiological Analysis Of Yield Determination In Soybean Of Different Relative Maturities, Maria Morrogh Bernard

Theses and Dissertations--Plant and Soil Sciences

Soybean yield differences are a combination of the genotype, environmental conditions, and management practices. Understanding how these factors interact through the analysis of the components involved in yield determination, provides a way to increase potential and actual yields in Kentucky.

Two irrigated experiments were conducted to quantify differences in the mechanisms of yield determination across soybean maturity groups (MG) 2 to 5 (Chapter 1), and to quantify management options (seeding rate and choice of MG cultivar) that increase yield potential of double crop soybean systems (Chapter 2).

Results showed that cultivars used different physiological strategies to achieve high yields, but ...


Regulation Of Local Auxin Metabolism During Soybean Nodule Development, Suresh Damodaran Jan 2018

Regulation Of Local Auxin Metabolism During Soybean Nodule Development, Suresh Damodaran

Electronic Theses and Dissertations

Legume-rhizobia symbiosis leads to the development of secondary root organs called nodules. Rhizobia bacteria housed inside nodules assimilate atmospheric nitrogen and convert them into plant usable forms thereby reducing the need for fertilizer application in crop legumes like soybean. Nodule development is a coordinated process orchestrated by multiple plant hormones. In soybean, the auxin responsive gene expression was detected in nodule primordia and in the periphery of mature nodules, primarily in nodule vasculature. Auxin hypersensitivity reduces nodule formation in soybean and also polar auxin transport inhibition at the site of nodule development is not crucial for determinate nodule formation. Therefore ...


Insecticidal Seed And In-Furrow Treatment Recommendations For Soybean And Sunflower, Brady Hauswedell Jan 2018

Insecticidal Seed And In-Furrow Treatment Recommendations For Soybean And Sunflower, Brady Hauswedell

Electronic Theses and Dissertations

Throughout the 2016 and 2017 growing season, field research experiments were replicated across South Dakota. Many times seed treatments are used prophylactic, which is neither good for the producers or the environment. Producers will be able to reduce production costs, if they only use a seed treatment when necessary. The purpose of the first experiment was to determine the effects of seed treatments in combination with planting date and seeding rate on soybean yield. To determine the effects, two years of field data from four eastern South Dakota locations were compared. Within each year and location we compared two planting ...