Agriculture Commons^™

Identifying Physiological, Morphological, And Genetic Drivers Of Key Intermediary Phenotypic Traits Associated With Stalk Lodging Resistance Within Genetically Diverse Maize Germplasm And Sorghum, Norbert Bokros

Theses and Dissertations--Plant and Soil Sciences

Maize stalk lodging reduces grain yields due to the permanent breakage or deformation of stalk tissue before grain harvest. To reveal new insights into the complex problem of maize stalk lodging, this dissertation will examine three primary objectives. First, the direct, diurnal influence of turgor pressure will be shown to have only marginal effects on stalk bending strength, a key trait associated with stalk lodging resistance. Up to a dozen individual stalks, grown to physiological maturity within the same field, were tested using a DARLING testing device. In parallel, stalk turgor status as measured by leaf water potential and turgor …

The Effect Of Spring And Winter Killed Cover Crops On Soil Physical Properties And Soil Organic Carbon, Danielle Doering

Theses and Dissertations--Plant and Soil Sciences

Maintaining soil organic carbon (SOC) and healthy soil physical structure in agroecosystems is crucial to sustainable production. To assess medium term impacts of cover crops on soil health in the top 90 cm, we conducted a field experiment in central Kentucky with varying levels of winter cover: spring and winter kill cover crops, weedy and bare winter fallows. After eight years of cover crop use, some soil physical properties improved: 35% greater mean weight aggregate diameter at 0-30 cm with spring kill covers and 5.2% more C held within large aggregates for both cover crop treatments compared to winter fallow. …

Evaluating Used Farm Machinery And Assessing The Sustainability Of Tile Drainage Installation, Robert C. Ellis

Theses and Dissertations--Agricultural Economics

This dissertation comprises three essays regarding the impacts of tile drainage implementation in row crop production and the evaluation of the farm machinery markets of combine harvesters and tractors. The second chapter focuses on tile drainage in traditional row crop agricultural systems. Although tile drain systems have been used for many years, recently, their popularity has increased. This increase has led to questions about these systems' costs and environmental impacts. These concerns have left many operations and individuals questioning if the system’s benefits outweigh the costs. This dissertation presents a life cycle cost (LCC) and carbon footprint (CF) Analysis for …

Clutch Analysis And Design For The Wildcat Pulling Team Quarter Scale Tractor Drivetrain, Lauren Doyle

Lewis Honors College Thesis Collection

The University of Kentucky (UK) Wildcat Pulling Team competes in the annual ASABE International Quarter Scale Tractor Student Design Competition. In 2022 the team placed 3rd overall in the competition, missing 1st place by 23 points. The loss in points was due to the clutch subassembly having issues related to maneuverability, manufacturability, and serviceability. The goal of this project was to redesign the 2022 tractor’s drivetrain for the new 2023 competition tractor. Background research was conducted on three types of clutches: manual, electric, and centrifugal. The electric clutch and centrifugal clutch with manual override were tested to determine their viability …

Three Essays On The U.S. Beef Supply Chain: Production, Marketing, And Price Dynamics, Erdal Erol

Theses and Dissertations--Agricultural Economics

This dissertation contains three essays on select economic components of the U.S. beef industry. The first and second essays concentrate on the different economic problems in beef cattle production. The third essay evaluates the price dynamics and the impact of COVID-19 along the beef supply chain.

The first essay explores the economics of culling decisions in cow-calf operations in the U.S. with a novel application of a dynamic mathematical programming model. The results provide an optimal culling strategy under the base model and a range of optimal strategies that vary with respect to different components such as fertility probabilities, market …

Community Supported Agriculture Values: A Comparison Across Groups, Thomas B. Pierce

Theses and Dissertations--Agricultural Economics

Community Supported Agriculture (CSA) programs offer consumers the chance to share the risk with farming operations while gaining access to fresh, local foods. While research on CSA shareholder values such as share affordability or the local impact of participation has been conducted in the past decade and beyond, less attention has been paid to direct value-mapping of the shareholders themselves. This research seeks to determine consumer values around the CSA purchasing decision using the Best-Worst Scaling Approach. Based on a focus group discussion with CSA shareholders in a university wellness voucher program, we used affinity diagramming to develop a list …

Data For "Linking Previous Experiences To Behavior And Health In The Honey Bee (Apis Mellifera)"", Rebecca R. Westwick, Clare C. Rittschof, Gavin P. Brackett, Cameron E. Brown, Bethany J. Ison, Zainulabbeudin Syed, Anna M. Foose

Entomology Research Data

An organism’s ability to respond to changing conditions can be vital to its success. Indeed, plasticity is a common feature of living organisms. Much of the research in this area, though, has focused on effects caused by environmental conditions. What has received relatively less attention is how social experiences and broader features of an organism’s social environment can lead to long-lasting changes in health and behavior. This knowledge gap exists despite the well-documented existence of health and behavioral effects after social interactions in certain taxa such as humans.

Social insects such as honey bees provide an excellent opportunity to better …

Linking Previous Experiences To Behavior And Health In The Honey Bee (Apis Mellifera), Rebecca R. Westwick

Theses and Dissertations--Entomology

An organism’s ability to respond to changing conditions can be vital to its success. Indeed, plasticity is a common feature of living organisms. Much of the research in this area, though, has focused on effects caused by environmental conditions. What has received relatively less attention is how social experiences and broader features of an organism’s social environment can lead to long-lasting changes in health and behavior. This knowledge gap exists despite the well-documented existence of health and behavioral effects after social interactions in certain taxa such as humans.

Social insects such as honey bees provide an excellent opportunity to better …

Epigenetic Regulation Of Insect Development, Yaoyu Jiao

Theses and Dissertations--Entomology

Insects undergo a series of distinct life stages such as egg, larva and pupa to develop into mature adults capable of reproduction throughout their life cycle. In the larval stage, insects experience the fastest growth with voracious feeding and multiple cuticle shedding resulting in hundreds-of-fold increasing of size. During metamorphosis, insects stop increasing body size but go through dramatic tissue transformation, developing wings and other adult features. The characteristic mode of insect development, especially the metamorphosis, makes insects the most successful group of animals on the earth. However, the epigenetic mechanisms behind insect development remain elusive. Studying the epigenetic regulation …

Foraging Behavior In The Eastern Subterranean Termite, Reticulitermes Flavipes (Kollar) (Isoptera: Rhinotermitidae), Anugerah Fajar

Theses and Dissertations--Entomology

Foraging is essential for survival, but it can be unpredictably dangerous due to organismal interactions like competition and predation to various environmental factors. Animals have come up with strategies to safeguard foraging. Social insects, with their elaborate division of labor, have developed sophisticated systems of foraging task allocation that allow them to capitalize resources beyond their competitors. In this thesis, I delve into the subjects of foraging behavior, allocation strategies, and the genetic basis of foraging in the eastern subterranean termite, Reticulitermes flavipes, the most widely distributed termite species in North America and one of the most economically important …

Understanding The Effects Of Age, Environmental Conditions, And Placement On Cockroach Gel Bait Performance, Isabelle Lucero

Theses and Dissertations--Entomology

Cockroach baits are one of the most effective tools used for German cockroach (Blattella germanica L.) control. This is due in part to the number of cockroach baits on the market with various matrix compositions and active ingredients, aiding in the control of resistant (physiologically and behaviorally) cockroach populations through bait rotation. However, it remains unclear how cockroach gel baits perform over time and under different environmental conditions. Therefore, we aged six cockroach gel baits for varying times (24 hours, one month, three months, six months) and at three relative humidities (15%, 40%, and 80%), and tested their performance …

Mechanisms Of Rnai In Insects, Jin Mo Koo

Theses and Dissertations--Entomology

RNA interference (RNAi) mechanism is found in many eukaryotes and animal cells, with its endogenous functions as defense against transposable elements and viruses, as well as post transcriptional regulation of gene expression. Since its first discovery, RNAi has contributed enormously as a reverse genetic tool for functional genomic studies. In application, RNAi is used in therapeutics, as well as agricultural crop and livestock protection. Yet, for the wider application of RNAi, improvement of its potency and delivery technologies is needed. Deeper mechanistic understanding of every step of RNAi, from cellular uptake of RNAi trigger molecule to targeted mRNA degradation is …

Costs And Benefits Of Integrating Poultry Into Cover Crop - Vegetable Rotations, Viktor Halmos

Theses and Dissertations--Entomology

Integrated livestock systems were once common leading up to the 20th century where livestock generated manure that was then used to fertilizer crop production in a closed- or semi-closed system. However, with the industrialization of agriculture in the mid to late 20th century, specialization drove simplified systems that segregated livestock from cropping systems. This segregation led to nutrient surpluses occurring in livestock operations, and nutrient demands in cropping systems creating a plethora of environmental issues. With the increased awareness of environmental issues, a renewed interest in integration has driven producers and researchers to experiment with integration again. For research, the …

Computed Tomography Image Analysis: Modeling Skeletal Injuries In Thoroughbred Racehorses, Grace Louise Camp

Theses and Dissertations--Veterinary Science

Musculoskeletal injuries account for the majority of career-ending health concerns in Thoroughbred racehorses. A small but very serious subset of these can be life-threatening and usually involve fractures of the bones in the lower limb that occur during high-speed exercise or racing competitions. Understanding the etiopathogenesis of lower forelimb bone fractures leading to catastrophic musculoskeletal injuries (CMI) is the highest safety and welfare priority in horse racing. This thesis conducted two studies utilizing computed tomography (CT) images of Thoroughbred lower limbs. The first examined bone lesion annotations in 134 horses (268 forelimbs) across 105 anatomical sites to assess the concordance …

Economics Of Maple Syrup Production In Kentucky, Bobby Thapa

Theses and Dissertations--Forestry and Natural Resources

Maple syrup production is traditionally associated with New England regions in the United States, but there is growing interest in expanding it to other regions with suitable environmental conditions, including Kentucky. This study presents an in-depth analysis of the potential production and economic impacts of maple syrup in Kentucky using a multi-method approach. First, the study applies a stochastic production model to assess the effects of climatic and tree variables on maple syrup yield. The results reveal that several variables, including the number of maple trees, taps, temperatures, tapping season length, and time, significantly affect maple syrup yield. Second, input-output …

Surveillance For Ticks And Tick-Borne Pathogens In Kentucky, Anna Rosalee Pasternak

Theses and Dissertations--Entomology

Tick-borne diseases are an emerging threat to human and animal health. In Kentucky, tick-borne disease surveillance has identified rising incidences of spotted fever rickettsiosis, ehrlichiosis, and Lyme disease. Since these diseases occur through the bites of infected ticks, effective prevention efforts are reliant upon knowing where the risk of exposure to tick bites exists. Historical data on tick distribution in Kentucky is variable, with very little reported on a statewide scale, leaving vector control workers, public health personnel, physicians, veterinarians, and others to rely on outdated, intermittent, or out-of-state information. In my dissertation, I surveyed ticks and select tick-borne pathogens …

Landscape Influences And Preventive Management For Drosophila Suzukii In Small Fruit Crops, Ryan William Kuesel

Theses and Dissertations--Entomology

Small fruit production has been greatly challenged by the repeated invasion of non-native arthropod pests, impacting economic feasibility, and increasing the need for insecticides. Spotted wing drosophila (Drosophila suzukii (Matsumura)) is the most recent invasive pest of small fruits. It causes damage by ovipositing beneath the skin of ripening fruits. Its wide-spread distribution and development of resistance to insecticides has resulted in the need for improved alternative management strategies for small fruit growers.

My surveys of D. suzukii at thirteen blackberry (Rubus fruticosus L.) and raspberry (Rubus idaeus L.) fields found that while D. suzukii was present …

Ecological Risk Assessment Of Transgenic Conditional Lethality Systems For Genetic Biocontrol Strategies, Fernan Rodrigo Perez-Galvez

Theses and Dissertations--Entomology

Genetic strategies of insect pest control are receiving increased interest due to recent advances in genetic engineering. By introducing alleles that make males functionally sterile, genetically modified (GM) insects can be used in area-wide pest management programs similar to the Sterile Insect Technique (SIT). Genetic control strategies carry several potential benefits, including improved efficacy and specificity, lower operation costs, and reduced dependence on chemical insecticides, but their use is still controversial despite extensive technical documentation indicating their innocuity to humans and the environment. This hesitation is likely due to the novel nature of the approach.

While the first field applications …

Personality Traits Of Dairy Calves And Their Relationship With Feeding Behavior, Activity, And Performance, Emily A. Michalski

Theses and Dissertations--Animal and Food Sciences

Detection of individual differences in personality traits of animals may prove beneficial for producers to help tailor management for individuals and to make selection decisions. Therefore, the objectives of this thesis were to

1) review and evaluate literature on relationships between individual cattle personality traits and feeding behavior, activity, and performance; and

2) evaluate and develop tests suitable for characterizing crossbred dairy-beef calves’ personalities and associations with behavioral patterns and performance.

The existing literature indicates that growth, intake, activity, and milk production measures from precision technologies have associations with cattle personality traits and behaviors identifiable through standardized tests. This indicates …

Effects Of Fungicide Programs And Lower Leaf Removal On Wrapper Leaf Production In Connecticut Broadleaf Cigar Wrapper Tobacco, Caleb Haygan Perkins

Theses and Dissertations--Plant and Soil Sciences

In recent years, there has been increased demand for natural leaf cigar wrappers. Kentucky and Tennessee have been of recent interest as a new area for Connecticut Broadleaf production. Initial production experiences have shown that late-season frogeye leaf spot caused by the pathogen Cercospora nicotianae Ellis & Everh. may result in ‘green spot’ in cured leaf and cause a significant problem for producers of Connecticut Broadleaf cigar wrapper tobacco. Field trials were established in 2021 at Princeton, KY and 2022 in Mayfield, KY and Springfield, TN to evaluate effects of fungicide programs and lower leaf removal on wrapper production and …

Species-Specific Microsymbiont Discrimination Mediated By A Medicago Receptor Kinase, Xiaocheng Yu

Theses and Dissertations--Plant and Soil Sciences

Legumes form a mutualistic partnership with nitrogen-fixing bacteria to meet their nitrogen requirements. This collaboration leads to the development of root nodules, offering an ideal environment for the bacteria to convert atmospheric nitrogen into ammonia. A salient aspect of this symbiotic relationship is host range specificity, such that nodulation capacity and nitrogen fixation efficiency differ significantly between different host-bacterial combinations. Understanding the genetic basis of this specificity could pave the way for strategies to overcome the host range barrier. Sinorhizobium meliloti and Sinorhizobium medicae are two closely related species that display differential symbiotic behaviors with legume plants of the Medicago …

Increasing Efficiency Of Finishing Beef Production: Strategies To Optimize Starch Digestion, Improve Flake Quality, And Reduce Methane Emissions, Ronald J. Trotta

Theses and Dissertations--Animal and Food Sciences

To continue to meet the demands of increasing food production and environmental sustainability, new strategies are needed to enhance the efficiency of finishing cattle production. A review of the literature identified several nutritional and physiological constraints that limit the ability for cattle to digest starch and absorb glucose from the small intestine. Comparative sequencing analyses revealed a missing region of the sucrase-isomaltase protein which could affect the capacity for starch digestion in cattle. Post-flaking sampling and handling recommendations were generated based on a series of experiments to improve estimates of starch availability and flaking consistency for commercial feedlots and laboratories. …

Plant Cell Wall Composition And In Vitro Fermentation Characteristics Of Cool-Season Forage Grasses From Two Growing Seasons In Central Kentucky, Sophia Danielle Newhuis

Theses and Dissertations--Animal and Food Sciences

Grass cell walls are rich in cellulose, hemicellulosic arabinoxylan (AX) polysaccharides, and lignin. AX structural differences such as degree and pattern of branching and the ester-linked phenolic acid content could affect plants’ digestibility when used as forage for livestock. However, there is little information about how these structural elements change over the growing season in the vegetative tissue of cool-season perennial grasses. Enhanced information about the cell wall composition and carbohydrate structure of forage material will provide a foundation for expanding our knowledge of how forage cell wall carbohydrate structures are utilized by ruminants. The objectives of this study were …

Improving Baking Quality Of Soft Red Winter Wheat In Kentucky Through Breeding And Sulfur-Nitrogen Fertility Management, Maria Paula Castellari

Theses and Dissertations--Plant and Soil Sciences

Soft Red Winter (SRW) wheat is an important crop grown on about 400,000 acres in Kentucky as a pivotal cash crop in the 3-crops-in-2-years rotation of corn, wheat, and soybean. The humid environment of Kentucky generates a high yielding wheat crop, with low protein concentration and weak gluten strength. This wheat is mainly sold to millers and used by the industry for cakes, pastries, cookies, and crackers. Conversely, there is a rapidly growing interest in identifying other value-added markets for this wheat different to commodity commercialization, such as artisan-baked goods and craft-distilled beverages. Evaluating the quality characteristics of wheat grown …

Comparison Of Botanical Composition Methods And Change Over Time In Kentucky Pastures, Echo Elizabeth Gotsick

Theses and Dissertations--Plant and Soil Sciences

Botanical composition of pastures has been measured with numerous methods over the last century, but there have been limited direct comparisons between methods. The objective of this study was to compare botanical composition methods, to determine the most accurate and efficient method, and to access pasture composition change over time. Six farms with two pastures each were monitored across the state of Kentucky. Sampling occurred fall 2020 through fall 2022, three times a year using the following methods: step point, visual estimation, occupancy grid, and point quadrat (used as a reference method). The occupancy grid showed the highest similarity to …

Evaluation Of Chemical Control Options, Environmental Factors, And Management Practices Associated With Angular Leaf Spot (Pseudomonas Syringae Pv. Tabaci), Andrea Brooke Webb

Theses and Dissertations--Plant and Soil Sciences

Pseudomonas syringae pv. tabaci tox^- is the causal agent of angular leaf spot in dark tobacco. Since 2015, angular leaf spot has become the most significant foliar disease in dark tobacco production in Kentucky and Tennessee. Dark tobacco producers utilize one main tool, streptomycin sulfate, for the management of this bacterial disease. Resistance to streptomycin sulfate in P. syringae pv. tabaci isolates from dark tobacco fields in western Kentucky was first observed in 2015.

Field spray trials were developed to evaluate the efficacy of alternative active ingredients compared to the grower’s standard, streptomycin sulfate. Two separate field trials were …

Management And Characterization Of Root-Knot Nematode (Meloidogyne Spp.) In Kentucky High Tunnels, Victoria Bajek

Theses and Dissertations--Plant and Soil Sciences

Kentucky is one of the most active adopters of high tunnels in the United States. Across the state, high tunnel growers have reaped the benefits of greater marketable yields, season extension, and protection from harsh weather. However, the high tunnel environment has increased soil temperatures and intensive crop production which has the potential to encourage root-knot nematode (RKN; Meloidogyne spp.) infestations. The extent and distribution of RKN in Kentucky were previously unknown. Two on-farm trials in infested high tunnels were conducted to determine whether grafting with RKN-resistant tomato rootstock is a viable management strategy. A statewide soil census to determine …

Assessing The Global Drivers Of Sustained Economic Development: The Role Of Trade Openness, Financial Development, And Fdi, Riza Radmehr, Ernest Baba Ali, Samira Shayanmehr, Sayed Saghaian, Elham Darbandi, Ebenezer Agbozo, Samuel Asumadu Sarkodie

Agricultural Economics Faculty Publications

Achieving economic development is one of the most important economic goals of every country. Identifying the determinants of economic growth, is a useful tool for adopting appropriate economic policies. This study, therefore, empirically examines the impact of trade openness, foreign direct investment, and financial development on economic growth, across 62 countries over the period 1995–2016. These countries are divided into two groups: low-income and high-income countries. We employ the pooled mean group (PMG), mean group (MG), and dynamic fixed effect (DFE) estimation techniques on the cross-country panel data. The findings show a positive long run association between trade openness, foreign …

A Hedonic Analysis Of Factors Impacting The Value Of Planters On The Used Machinery Market, John Allison Jr., Tyler B. Mark, Kenneth H. Burdine, Jordan M. Shockley

Agricultural Economics Faculty Publications

A hedonic model was employed to examine factors that influence the resale price of row crop planters on the used machinery market. Planter sale data from 2016 to 2018 were utilized to conduct the analysis. Results suggested that the primary factors impacting planter resale prices were make, age, condition, planter configuration, row number, and row spacing. As a function of age (depreciation), planter values were generally determined to decrease at a decreasing rate. Finally, it was determined that there was a significant interaction between the variables make and age, suggesting that different planter makes depreciate differently.

Functional Antagonism Of Wri1 And Tcp20 Modulates Gh3.3 Expression To Maintain Auxin Homeostasis In Roots, Que Kong, Pui Man Low, Audrey R. Q. Lim, Yuzhou Yang, Ling Yuan, Wei Ma

Kentucky Tobacco Research and Development Center Faculty Publications

Auxin is a well-studied phytohormone, vital for diverse plant developmental processes. The GH3 genes are one of the major auxin responsive genes, whose expression changes lead to modulation of plant development and auxin homeostasis. However, the transcriptional regulation of these GH3 genes remains largely unknown. WRI1 is an essential transcriptional regulator governing plant fatty acid biosynthesis. Recently, we identified that the expression of GH3.3 is increased in the roots of wri1-1 mutant. Nevertheless, in this study we found that AtWRI1 did not activate or repress the promoter of GH3.3 (proGH3.3) despite of its binding to proGH3.3. Cross-family …