Digital Commons Network^™

A Robust Agroinfiltration Method, Bryce N. Trull

Masters Theses

Stable transformation of soybean (Glycine max) is a markedly slow and laborious process. Thus, a tool that enables rapid evaluation of genetic elements in planta is critical to advance complex research and genetic engineering in soybean. To that end, a substantially robust agroinfiltration method was innovated in this work. Agroinfiltration is a technique that leverages Agrobacterium-mediated transient transformation to deliver genetic elements to the cells of whole plant tissues, usually leaves. Several factors were found to be relevant to successful soybean leaf agroinfiltration, including genotype, surfactant, developmental stage, and Agrobacterium culture medium. The research represents not only …

Evaluating The Ecological Relationships Among Beauveria Bassiana, Kudzu Bug And Kudzu, Kassie L. Hollabaugh

Masters Theses

When kudzu bug, Megacopta cribraria, was identified in the United States in 2009 as an invasive species, populations began to establish, increase, and spread throughout the southeastern region at intense rates. Kudzu bug invades urban structures, causing unpleasant scenes for homeowners, and reduces crop yield, such as soybean. Kudzu bug caused about $2.8 million in soybean yield loss and treatment in Tennessee in 2020. Although initial spread was rapid throughout the southeastern U.S., spatial modeling has shown populations of kudzu bug are declining and reducing risk of crop damage to growers. These local and regional declines in populations appear …

Relative Soybean Response To Aminocyclopyrachlor, 2,4-D, Dicamba, And Aminopyralid, Trey I. Clark

Masters Theses

This research compared the visual symptomology of four auxin herbicides applied at three rates to simulate tank contamination on non-auxin tolerant soybeans. The herbicides examined were aminocyclopyrachlor (ACP), 2,4-D, dicamba, and aminopyralid. The standard labeled rates (SLR) used to base the application rates were 0.12 kg ae ha^-1 for ACP and aminopyralid while dicamba and 2,4-D used 1.12 kg ae ha^-1. These four herbicides exhibit similar symptoms on soybeans which is problematic when diagnosing soybean response. One goal of this project was to obtain high-quality images of the four herbicide’s effect on soybeans, with the hope of …

Identifying Drought Tolerance Traits In Tennessee Soybean Genotypes: Recovery From Severe Water Deficit Stress, Samuel W. Purdom

Masters Theses

Ninety-four percent of U.S. grown soybeans are produced under rainfed conditions with intermittent droughts occurring late in the season during reproductive growth stages. Due to the temporary nature of drought, the ability of a crop to survive and recover effectively from water deficit stress is important for ensuring yield stability. In 2019 and 2020, two greenhouse experiments and two field studies were conducted to screen eleven soybean genotypes for transpiration response and recovery from water deficit stress and high vapor pressure deficit (VPD). In the first greenhouse study, soybean plants were grown in pots sealed to prevent evaporation and plants …

Defining Bee Pollinator Community Composition In Tennessee Soybean, Andrew L. Lawson

Masters Theses

Two planting dates of various soybean varieties were planted in Jackson and Knoxville, TN during 2018 and 2019 with the overall intent of surveying the diversity bee (Hymenoptera) genera in these agroecosystems and also to assess the potential for using late maturing soybean as a food resource for bees during the dearth of floral resources that often occurs during the fall. We also investigated how manipulating planting dates and soybean variety selection affected the occurrence of insect pests that occurred in the soybean.

Both active (netting) and passive (bee bowls and blue-vane traps) sampling were used to collect the bees, …

Quantitative Trait Loci Analysis Of A Ril Soybean Population To Determine Chromosomal Regions Governing Seed Protein, Oil, And Linolenic Acid Content, Ronald E. Moore

Masters Theses

180 RILs (recombinant inbred lines) segregating for protein, oil, and fatty acids were produced from a cross between TN12-4098 and TN13-4303. These lines were grown across three locations spread horizontally across Tennessee: Research Education Center at Milan (RECM), Highland Rim Research and Education Center (HRREC), and East Tennessee Research and Education Center (ETREC) in 2018 and 2019. 21 quantitative trait loci (QTLs) spanning 7 chromosomes were found using WinQTLCart2.5.

Influence Of Traditional And Dual-Use Cropping On Arthropods And Slugs In Soybean In Tennessee, Matthew L. Longmire

Masters Theses

Soybean is the number one agricultural crop in Tennessee for both number of hectares planted and economic value. Soybean, used in various products, is marketed globally. In recent years, Tennessee soybean growers have shown an increased interest in the use of cover crops with soybean. A cover crop is planted before the cash crop and can minimize some weeds, diseases, insects, and other pests. Traditionally, cover crops are terminated in the spring before cash crop planting. Traditional methods of cover cropping provide many benefits but can also produce some undesired results. Dual-use cover cropping is a newer method of cover …

Predictive Promoter Activity In Soybean Using A Novel Cell-Suspension Culture And Transient Expression Analysis In Protoplasts, Mst Shamira Sultana

Masters Theses

Transient gene expression in plant protoplasts has been widely utilized for rapid functional screening of promoters. This project describes a novel soybean cell suspension culture and protoplast system for rapid and predictive analysis of promoter activity. Since recovery of transgenic lines is low in soybean stable transformation, high-throughput studies of promoter activity have intrinsic limitations. First, I describe a novel cell suspension culture system from leaf-derived callus. Once the cell culture is established, it is easy to maintain, sterile, and produces fast-growing cells amenable for protoplast production. Second, I describe an efficient and simple protoplast preparation procedure. The results revealed …

Breeding For Improved Oil Quality In High Yielding Soybean Lines Using Molecular Markers For Selecting Fad2-1a, Fad2-1b, Fad3a And Fad3c Mutant Alleles To Produce A High Oleic, Low Linolenic (Holl) Soybean., Alison Rose Willette

Masters Theses

Soybean oil is a major commodity in the US with practical uses for both food and industrial products. A declining market for soybean oil production caused by added restrictions on oil hydrogenation practices, has fueled improvements in oil industry standards. Typical soybean oil contains 8 to 12 g kg^-1 of linolenic acid which causes unfavorable odor and rapid rancidity which has been dealt with using hydrogenation in the past. Scientists have identified fatty acid desaturase genes which when mutated, produce oil that does not require hydrogenation. Breeders use single nucleotide polymorphism (SNP) analysis to select for soybean mutations containing …

Optimizing Soybean (Glycine Max L.) Yield With Nitrogen And Sulfur Applications, Kacey A. Cannon

Masters Theses

Although soybean (Glycine max L.) yields have increased over the past decade, even greater improvement is in demand. Nontraditional practices such as applying nitrogen (N) to soybean for yield optimization, might be one way to meet this demand. Also, sulfur (S) is becoming a more important limiting nutrient in production due to higher yielding crops, lower S containing production inputs, and reduced supply from the environment. The N study involved two environments, irrigated and dryland, in Milan (35.9198° N, 88.7589° W) and Jackson (35.6145° N, 88.8139° W), TN in 2015 and 2016. Urea fertilizer treatments were 34, 67, and …

Incentive Payments For Planting Upland Bird Habitat Field Borders In Tennessee, Nathaniel Scott Bruce

Masters Theses

Crop yields along field perimeters that are adjacent to trees and other tall-herbaceous are known to have the lowest yields in a field. An alternative use of these areas that might be more profitable and sustainable is to remove the land from crop production and enroll these areas into the upland bird habitat (UBH) buffer program. However, the adoption of UBH buffers have been limited by producers, despite being eligible for receiving an incentive payment for adopting UBH buffers. Therefore, the objective of this thesis was to determine the breakeven incentive payment for corn [Zea mays L.] and soybean …

Effect Of The Mutant Danbaekkong Or Stem Termination Alleles On Soybean Seed Protein Concentration, Amino Acid Composition, And Other Seed Quality And Agronomic Traits, Mia Justina Cunicelli

Masters Theses

Soybean [Glycine max (L.) Merr.] is the world’s leading source of vegetable oil and high quality protein meal. Increasing soybean protein concentration through selection while maintaining oil concentration and yield has been a constant goal for plant breeders, as there is a negative correlation between protein and oil and protein and yield. The objective of this study was to determine if marker assisted selection (MAS) for the Danbaekkong (Dan) protein allele influences agronomic and seed quality traits. A population of 24 F_8:10 [eighth filial generation advanced to the tenth filial generation] near isogenic lines (NILs) of soybean was …

Comparison Of Roundup Ready And Conventional Soybean (Glycine Max L.) Weed Control Systems For Optimizing Yield And Economic Profitability, Brittany Lee Gaban

Masters Theses

Research was conducted in 2010, 2011 and 2012 at the East Tennessee Research and Education Center in Knoxville, TN, in order to compare differences in soybean yield among differing levels of weed control within Roundup Ready® [Glyphosate-resistant] (RR)and conventional soybean cultivars to gain a better understanding of the impact different intensities of weed control have on RR and conventional cropping systems. Results determined that after applying the weed control regimens, there was no significant difference (p

Glyphosate resistant weeds introduce new challenges and create a more costly weed control regimen, especially when using a RR based soybean cultivation operation. Therefore, …

Heritability And Genetic Gain Of Seed Protein, Oil, And Yield Among Ril Of Soybean, Benjamin T. Wiggins

Masters Theses

Soybean is a remarkable crop that is used in many aspects of our everyday lives. The seed protein is used primarily for livestock feed, though it is becoming more available as a meat substitute for human consumption. Soybean oil is used in many products such as plastics, foods, and industrial products. Seed yield is the major trait that is selected for in a breeding program. A population of 239 F₄ derived RIL from the cross of USG 5601T × U99-310255 was used to calculate heritability estimates by parent offspring regression and on an entry mean basis. This population was …

Two Studies Evaluating Input Use In Soybean And Cotton Production, Nathanael Mark Thompson

Masters Theses

Farmers are price takers for both inputs and outputs. Therefore, when the prices of inputs rise, as they have with many inputs used in agricultural production, optimal production practices may change. Two separate studies of the impacts of agricultural technology on input use in crop production were undertaken in this thesis. The first study evaluated economically optimal plant population considering seeding rate, maturity group, row spacing, and input-output prices in soybean production in the rolling uplands region of the upper Midsouthern United States. Data from field experiments at the University of Tennessee Research and Education Center at Milan, Tennessee during …