Agriculture Commons^™

Fusarium Head Blight Resistance Genes Impact Agronomic Performance, Flavor, Milling, And Baking Traits In Soft Red Winter Wheat, Joyce Morris

Theses and Dissertations--Plant and Soil Sciences

Fusarium Head Blight (FHB) is an economically devastating disease of wheat (Triticum aestivum L.) causing low yields and poor quality. FHB, caused by Fusarium graminearum, disrupts the grain filling phase and results in bleached spikes and shriveled seeds. Deoxynivalenol (DON) is a mycotoxin produced by the fungal pathogen when it infects the plant; DON is harmful when consumed by humans and causes feed rejection in livestock. Using FHB resistant varieties and timely applications of fungicides is the optimum strategy for management of this disease. However, there has been little research focusing on the impact of FHB resistance genes …

Influence Of Industrial Hemp On Soil Health Parameters In A Kentucky Cropping System, Jack T. Eaker

Theses and Dissertations--Plant and Soil Sciences

Industrial hemp (fiber, floral, and grain: Cannabis sativa L.) legalization has prompted research into its incorporation into agronomic rotations and impacts on agroecosystem services such as nutrient dynamics. This study quantified the effects of integrating grain and fiber hemp on soil health, hypothesizing hemp would positively impact soil health due to its taproot, reported C benefits, and nutrient requirements. Conducted in Kentucky at two locations, a completely randomized block design included six crop rotation treatments, with soil cores collected at initiation (2020) and post three growing seasons (2023). Soil parameters analyzed included particulate organic matter, short-term CO2 mineralization, water-extractable organic …

Revolutionizing Grapevine Breeding Programs: A Mobile Genome Editing System For Perennial Crops, Bridget Bolt

Theses and Dissertations--Plant and Soil Sciences

Grapevine (Vitis vinifera) faces unprecedented challenges from climate change, with up to 90% of current growing regions potentially becoming unsuitable for production within decades. Traditional breeding approaches require 25-30 years for variety development, creating a time constraint incompatible with the pace of environmental change. This research establishes the approach for a novel mobile RNA-based gene editing platform that addresses longstanding bottlenecks in grapevine improvement while preserving cultivar identity and reducing breeding timelines.

This research developed a three-component system for transgene-free gene editing in grapevine. First, a mobile CRISPR/Cas9 system was established using Agrobacterium rhizogenes transformation and the cut-and-dip …

Exploring The Role Of Living Roots In Soil Organic Matter Dynamics, Sharmin Akther

Theses and Dissertations--Plant and Soil Sciences

Roots play a central role in soil organic matter (SOM) formation, yet the contributions of living roots compared with root- and shoot-derived litter remain incompletely understood across systems and management contexts. This thesis combines a global meta-analysis with a two-year field experiment to evaluate how continuous living root activity shapes soil organic carbon (SOC) dynamics. The meta-analysis synthesized 21 studies (57 observations) comparing cropping systems with enhanced living root continuity to systems with fallow periods or annual-only rotations. Perennial and continuous cropping systems increased annual C inputs and SOC stocks relative to controls, but their SOC sequestration efficiency declined because …

Plant Model Of Α-Synucleinopathy: Expression Of Α-Synuclein A53t Variant In Hairy Root Cultures Leads To Proteostatic Stress And Dysregulation Of Iron Metabolism, Jasmina Kurepa, Kristen A. Bruce, Greg A. Gerhardt, Jan A. Smalle

Neurology Faculty Publications

Synucleinopathies, typified by Parkinson’s disease (PD), entail the accumulation of α- synuclein (αSyn) aggregates in nerve cells. Various αSyn mutants, including the αSyn A53T variant linked to early-onset PD, increase the propensity for αSyn aggregate formation. In addition to disrupting protein homeostasis and inducing proteostatic stress, the aggregation of αSyn in PD is associated with an imbalance in iron metabolism, which increases the generation of reactive oxygen species and causes oxidative stress. This study explored the impact of αSyn A53T expression in transgenic hairy roots of four medicinal plants (Lobelia cardinalis, Artemisia annua, Salvia miltiorrhiza, and Polygonum multiflorum). In all …

Ecology And Management Of The Crapemyrtle Aphid (Hemiptera: Aphididae) On Crapemyrtle (Myrtales: Lythraceae) In The Southern United States, Caleb J. Wilson, Matthew A. Bertone

Entomology Faculty Publications

Crapemyrtle aphid [Sarucallis kahawaluokalani (Kirkaldy 1907)] (CMA) is an introduced pest of crapemyrtle (Lagerstroemia spp. L.), which is among the most common ornamental tree genera in the southern United States. Native to Southeast Asia, CMA has become established on 5 other continents. CMAs produce honeydew as they feed which supports sooty mold growth and can result in leaf defoliation on infested trees. CMAs tend to be most abundant in crapemyrtles planted in locations with extensive surrounding impervious surface cover. A large community of generalist natural enemies are found in close association with CMA, which suggests that CMAs may help conserve …

Feeding Systems And Fresh Lamb Color Stability, Koushik Mondal

Theses and Dissertations--Animal and Food Sciences

Consumers consider the surface color of fresh lamb as the indicator of freshness and wholesomeness, which affects their purchase decisions. The redox chemistry of myoglobin (Mb) determines the color of fresh lamb. Artificial raising on milk replacer (a pre-weaning strategy) as well as red clover supplementation are management strategies used in lamb production. This thesis focuses on the effects of artificial raising on milk replacer and red clover supplementation on the color and oxidative stability of fresh lamb.

In the first experiment, the effect of pre-weaning with milk replacer on the carcass attributes, color stability and lipid oxidation of lamb …

Chemical Control Of Turfgrass Diseases 2024, Bruce B. Clarke, Paul Vincelli, Paul Koch, Ming-Yi Chou

Agriculture and Natural Resources Publications

Turfgrasses under intensive management are often subject to outbreaks of infectious diseases. Diseases usually are most damaging when weather or cultural conditions favor the disease-causing agent but not plant growth and vigor. Cultural conditions that predispose turfgrass to diseases include close mowing, inadequate or excessive fertility, light or frequent irrigation, excessive thatch, poor drainage, and shade. Good turf management practices often greatly reduce the impact of disease by promoting healthy plants that are better able to resist infections. Even under good management, however, diseases sometimes cause excessive damage to highly managed turfgrasses. The proper use of fungicides in these instances, …

Polymorphism And Plasticity In The Termite Caste System, Austin Merchant

Theses and Dissertations--Entomology

Developmental plasticity, manifested as a caste system, is integral to the success of eusocial insects because of the way in which it decouples the various tasks that a single, solitary organism would normally be responsible for, allowing individuals to specialize towards their given roles while keeping vulnerable members of the colony, such as those responsible for reproduction, safe from harm. Termites exhibit particularly complex caste systems that can be divided into three types of castes: workers perform manual labor, such as foraging and brood care; soldiers defend the nest; and reproductives lay eggs. Each of these castes, as well as …

An Rnai-Based Approach To Ips Calligraphus Management: A Promising Strategy For Forest Protection, Mary Wallace

Theses and Dissertations--Entomology

As climate change leads to more frequent and severe extreme weather, host tree stress is increasing the occurrence of large-scale bark beetle outbreaks. One such beetle, Ips calligraphus (Germar), a native bark beetle in the southeastern United States, has traditionally been considered a secondary pest of pine trees. Management has relied on silvicultural practices that enhance forest resilience, enabling host trees to effectively use natural defenses to deter beetle infestation. However, during periods of forest stress caused by storms, droughts, human disturbance, and other factors, beetle outbreaks can cause considerable ecological and economic damage.

Addressing worsening I. calligraphus outbreaks will …

Indoor Pests And Human Health: Characterizing Contaminants And Improving Mitigation, Johnalyn Gordon

Theses and Dissertations--Entomology

Much of the United States population spends the majority of their time indoors and within the home. Not only are indoor arthropod pests an unsightly nuisance in our homes, but they can have serious impacts on human health, especially with chronic exposure. In addition to negative health impacts, costs associated with these medical impacts can be tremendous. For these reasons, it is critical to develop comprehensive strategies for pest reduction and mitigation of associated health impacts. The work outlined in this dissertation represent examination of the distribution of a hypothesized bed bug allergen within the indoor environment, identification of a …

Addressing The Trade-Offs Of Pest Protective Row Covers For Integrated Pest Management In Vegetable Production, Kathleen Fiske

Theses and Dissertations--Entomology

The success of many integrated pest management (IPM) strategies is limited by trade-offs with economic, cultural, and environmental factors. While some IPM strategies reduce pests, they may harm pollinators, reduce the efficiency of weed or disease management, or may increase costs relative to revenue. Pest protective row covers, in the form of fine-mesh netting (referred to as mesotunnels), are an effective alternative to pesticide use, but they are not without their challenges. While row covers exclude insect pests and the pathogens they vector, it is unknown how well non-vectored diseases can be managed underneath the row cover. The exclusion of …

Practical Challenges In Delivering Dsrna For Woody Plant Protection, Zachary Bragg

Theses and Dissertations--Entomology

Unprecedented weather events associated with climate change, coupled with extensive anthropogenic stresses, have reduced the effectiveness of traditional forest pest management approaches, which can no longer keep pace with invasive species overwhelming naïve landscapes and native pests experiencing eruptive and expansive outbreaks. Double-stranded RNA-(dsRNA) mediated gene silencing, a type of RNA interference (RNAi), has been coopted for use as a biopesticide against a multitude of agricultural and horticultural pests and could serve as a powerful tool for woody plant protection. While effective initiation of gene silencing and subsequent mortality have been demonstrated in multiple tree pests, effective and efficient methods …

Consequences Of Abiotic And Anthropogenic Stressors In The Antarctic Midge, Belgica Antarctica, Jack J. Devlin

Theses and Dissertations--Entomology

The ability to tolerate stress is key to maintaining fitness in extreme environments such as the polar regions. Subject to a myriad of extreme year-round abiotic conditions, invertebrates inhabiting the terrestrial ecosystems of Antarctica provide an excellent system to investigate adaptations to stress. Understanding the response of these species to abiotic and novel stressors is crucial in a world with rapidly occurring climate change and increasing anthropogenic activity. In this dissertation, I investigated physiological and molecular responses to naturally occurring and human-derived stresses in the midge Belgica antarctica, which is Antarctica’s only endemic insect.

In my first research chapter, I …

Evaluation Of Ten Alternative Treatments For The Management Of Harlequin Bug (Murgantia Histrionica) On Brassica Crops, Sarah Clark

Theses and Dissertations--Entomology

This thesis investigates the efficacy of exclusion netting and selected biopesticides in controlling the common brassica pest harlequin bug (Murgantia histrionica); it assesses the phytotoxic effects caused by selected essential oil products; and it evaluates whether selected treatments caused mortality in common beneficial insects. This is one of the first studies to investigate the potential pest controlling properties of commercially produced bokashi fermented composting products as well as their effect on natural enemies.

During both the first and second year of the study, none of the commercially produced essential oil products or bokashi products were effective in controlling …

Weed Management Impacts On Wild Bees In Agroecosystems, Amanda Denny

Theses and Dissertations--Entomology

In agricultural landscapes, bee communities are shaped by factors including the plant community, land management, and pesticides. These factors are critical in the late winter and early spring (LWES) when floral resources are scarce and many bee species are becoming active. In this dissertation, I characterize the flowering weed community of Central Kentucky agroecosystems in the LWES, examine the response of wild bee communities to the total cover and diversity of these flowering plants, and assess the risks of glyphosate exposure on developing ground nesting bees. I found that the flowering plant community was similar across land cover types and …

Assessing Endophyte Frequency Distributions And The Effect Of Epichloë Brachyelytri In The Chemotypic And Genotypic Diversity Of Brachyelytrum Erectum, Rachel Ann Sneed

Theses and Dissertations--Plant Pathology

Seed-transmissible epichloid fungal endophytes are best known for their roles as defensive mutualists in cool-season grasses. Historically, the discovery of fungal endophytes was driven by investigations of plant toxicity to livestock, followed by extensive study of their alkaloids and protection against insects and nematodes. Epichloae can produce four classes of alkaloids: ergot alkaloids, lolines (saturated aminopyrrolizidines), indole–diterpenes, and peramine. It is increasingly evident that these hereditary symbionts have much more diverse chemical profiles both in individual populations and between them. To this end, differences in chemotypic profiles of these symbionts may translate to different evolutionary and environmental advantages across plant …

Temporal Changes In The Genome Of Apicomplexan Parasite Sarcocystis Neurona Sn3, Jamie Norris

Theses and Dissertations--Veterinary Science

Sarcocystis neurona is an apicomplexan parasite and the main etiologic agent behind Equine Protozoal Myeloencephalitis (EPM), the most diagnosed neurologic disease in horses living in the Americas. Technical advances that arose from the human genome project between 1990 and 2003 and the corresponding “omics” revolution in research have allowed scientists novel approaches to study organisms. Herein, we sought to leverage bioinformatic advances and new sequencing platforms to provide an improved understanding of the biology of S. neurona. At the outset of this project, reference genomes from two different S. neurona strains (SN3.e1 and So SN1) were available. A new and …

Manrrs Advisors And Their Perceptions Of Their Mentor Strategies, Dallas L. Cooks

Theses and Dissertations--Community & Leadership Development

Minorities in Agriculture Natural Resources and Related Sciences, also known as MANRRS, is an organization with chapters nationwide. Their main focus is to provide professional development, academic advancement, and networking to those in agriculture and related sciences. This research focuses on the advisors of MANRRS chapters across the country and at various institutions. Advisors were asked a series of questions through a Qualtrics survey about their mentor strategies with their students. Chapter Advisors were asked demographic, Likert Scale, and questions based on their personal MANRRS experience. As a result of the data, five research questions were answered. Chapter Advisors and …

Autism In Agricultural Education: A Case Study Of An Adolescent With Autism Spectrum Disorder And Their Parent On Career And Technical Education, Grace Miller

Theses and Dissertations--Community & Leadership Development

Autism spectrum disorder (ASD) is a unique and often misunderstood diagnosis. Little is known about the experiences of adolescents with ASD. As students with ASD graduate high school, many are under- and unemployed. Career and technical education (CTE) in U.S. schools is intended to prepare all students for careers post-secondary. Agricultural education is one of the predominate career clusters within CTE. This qualitative single case study sought to create a platform for both a student and their parent to share their experiences in agricultural education and CTE. Participants were an adolescent with ASD who had taken at least one year …

Pulse-Width Modulation Spray System Performance And Development Of A Novel System To Optimize Spray Use Efficacy, Prashanta Pokharel

Theses and Dissertations--Biosystems and Agricultural Engineering

The overarching objective of this research was to enhance our understanding of pulse width modulation (PWM) based nozzle control system and develop an intelligent nozzle control system for agricultural spray applications. This dissertation focused on measuring and analyzing the transient nozzle pressure characteristics and performance under PWM control. Additionally, it explored the development of an innovative multi-degree-of-freedom (DOF) nozzle control system for precise chemical applications in specialty crop systems.

The pressure dynamics of a PWM system were studied by developing an instrumentation system capable of operating a solenoid valve and recording pressure signals. A nozzle body and two manifolds of …

Inflammation And Tumor Progression: The Differential Impact Of Saa In Breast Cancer Models, Daniel Wilhelm Olivier, Carla Eksteen, Manisha Du Plessis, Louis De Jager, Lize Engelbrecht, Nathaniel Wade Mcgregor, Preetha Shridas, Frederick C. De Beer, Willem J. S. De Villiers, Etheresia Pretorius, Anna-Mart Engelbrecht

Saha Cardiovascular Research Center Faculty Publications

Background: Previous research has shown that the Serum Amyloid A (SAA) protein family is intricately involved in inflammatory signaling and various disease pathologies. We have previously demonstrated that SAA is associated with increased colitis disease severity and the promotion of tumorigenesis. However, the specific role of SAA proteins in breast cancer pathology remains unclear. Therefore, we investigated the role of systemic SAA1 and SAA2 (SAA1/2) in a triple-negative breast cancer mouse model.

Methods: Syngeneic breast tumors were established in wild-type mice, and mice lacking the SAA1/2 (SAADKO). Subsequently, tumor volume was monitored, species survival determined, the inflammatory profiles of mice …

Cyp6g2 Is The Major P450 Epoxidase Responsible For Juvenile Hormone Biosynthesis In Drosophila Melanogaster, Qiangqiang Jia, Liu Yang, Jiamin Wen, Suning Liu, Di Wen, Wei Luo, Weihua Wang, Subba R. Palli, Li Sheng

Entomology Faculty Publications

Background Juvenile hormones (JH) play crucial role in regulating development and reproduction in insects. The most common form of JH is JH III, derived from MF through epoxidation by CYP15 enzymes. However, in the higher dipterans, such as the fruitfly, Drosophila melanogaster, a bis-epoxide form of JHB3, accounted most of the JH detected. Moreover, these higher dipterans have lost the CYP15 gene from their genomes. As a result, the identity of the P450 epoxidase in the JH biosynthesis pathway in higher dipterans remains unknown.

Results In this study, we show that Cyp6g2 serves as the major JH epoxidase responsible for …

Go West: Population Genomics Reveals Unexpected Population Fluctuations And Little Gene Flow In Western Hemisphere Populations Of The Predatory Lady Beetle, Hippodamia Convergens, Arun Sethuraman, Schyler O. Nunziata, Angela Jones, John J. Obrycki, David W. Weisrock

Entomology Faculty Publications

Hippodamia convergens—the convergent lady beetle, has been used extensively in aug- mentative biological control of aphids, thrips, and whiteflies across its native range in North America, and was introduced into South America in the 1950s. Overwintering H. convergens populations from its native western range in the United States are com- mercially collected and released across its current range in the eastern USA, with little knowledge of the effectiveness of its augmentative biological control. Here we use a novel ddRADseq-based SNP/haplotype discovery approach to estimate its range- wide population diversity, differentiation, and recent evolutionary history. Our results indicate (1) significant population …

N(Alpha)-Acetyltransferase 40-Mediated Histone Acetylation Plays An Important Role In Ecdysone Regulation Of Metamorphosis In The Red Flour Beetle, Tribolium Castaneum, Sharath Chandra Gaddelapati, Smitha George, Anilkumar Moola, Karthi Sengodan, Subba Reddy Palli

Entomology Faculty Publications

Histone acetylation, a crucial epigenetic modification, is governed by histone acetyltransferases (HATs), that regulate many biological processes. Functions of HATs in insects are not well understood. We identified 27 HATs and determined their functions using RNA interference (RNAi) in the model insect, Tribolium castaneum. Among HATs studied, N-alpha-acetyltransferase 40 (NAA40) knockdown caused a severe phenotype of arrested larval development. The steroid hormone, ecdysone induced NAA40 expression through its receptor, EcR (ecdysone receptor). Interestingly, ecdysone-induced NAA40 regulates EcR expression. NAA40 acetylates histone H4 protein, associated with the promoters of ecdysone response genes: EcR, E74, E75, and HR3, and causes an increase …

The Mechanoreceptor Piezo Is Required For Spermatogenesis In Bombyx Mori, Zhongjie Zhang, Xiaojing Liu, Bo Hu, Kai Chen, Ye Yu, Chenxin Sun, Dalin Zhu, Hua Bai, Subba Reddy Palli, Anjiang Tan

Entomology Faculty Publications

Background The animal sperm shows high diversity in morphology, components, and motility. In the lepidopteran model insect, the silkworm Bombyx mori, two types of sperm, including nucleate fertile eupyrene sperm and anucleate unfertile apyrene sperm, are generated. Apyrene sperm assists fertilization by facilitating the migration of eupyrene spermatozoa from the bursa copulatrix to the spermatheca. During spermatogenesis, eupyrene sperm bundles extrude the cytoplasm by peristaltic squeezing, while the nuclei of the apyrene sperm bundles are discarded with the same process, forming matured sperm.

Results In this study, we describe that a mechanoreceptor BmPiezo, the sole Piezo ortholog in B. mori, …

Interactions Between Multiple Stressors, Nanomaterials And A Pathogen, In Caenorhabditis Elegans, Jarad Cochran

Theses and Dissertations--Plant and Soil Sciences

Metal and metal oxide nanoparticles (NP), which have received interest for use in agriculture, show in vitro and in vivo toxicity at relatively low concentrations. Silver nanoparticles (Ag NP) and zinc oxide nanoparticles (ZnO NP) cause adverse effects in model soil organisms under environmentally relevant conditions. In most toxicity assessments of nanomaterials, model organisms are exposed to a single stressor. Though single stressor experiments are essential to understanding the fate and effects of released NP, in nature, organisms are affected by multiple stressors, including pathogens, which might exacerbate or mitigate negative effects of NP exposure. There is limited research on …

Measuring Modern And Historic Maize Root Phenotypes And Their Impact On Soil Organic Carbon, Travis A. Banet

Theses and Dissertations--Plant and Soil Sciences

Supporting a growing human population under the duress of a changing global climate is arguably the greatest challenge faced by today’s world. Over the last century, agricultural development has primarily focused on improving grain yields to increase production of food, fuel, and fiber. However, recent work has emphasized that agroecosystem management can potentially help mitigate the climate crisis by storing atmospheric carbon in the soil as soil organic carbon (SOC). Furthermore, a growing body of research has focused on the critical role that roots play in building SOC. Maize crops occupy a substantial portion of the world’s cropland. As yields …

Evaluation Of Winter Cereal Cover Crops Across Nitrogen Management Strategies In No-Till Corn Production, Robert Nalley

Theses and Dissertations--Plant and Soil Sciences

Rye (Secale cereale L.) is the most popular winter cereal cover crop utilized before corn, but wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) may provide a comparable value due to their similar fibrous root systems. Despite the benefits associated with winter cereal cover crops, drawbacks are possible for the subsequent corn crop. A field study was conducted with three site-years in Kentucky to measure the impact of the three winter cereals across nitrogen (N) management strategies. Wheat produced the most biomass compared with barley or rye cover crops. Wheat and rye needed approximately 100 more …

From Code To Crops: Harnessing Bioinformatics And Artificial Intelligence (Ai) In Agricultural Omics, Lakshay Anand

Theses and Dissertations--Plant and Soil Sciences

Global agricultural faces numerous challenges, such as climate change, resource limitations, novel pests and diseases, increasing costs, and the ever-increasing human population. To tackle these challenges, we need innovative strategies that combine new technologies and data analytics approaches to enhance agricultural output, promote sustainable methods, and optimize resource allocation. The key to this innovation lies in understanding the complex molecular web within plants that governs their growth, defense, and adaptability mechanisms. By mastering this molecular network, we can cultivate crops that are more resilient, sustainable, and suitable for different climatic terrains. Moreover, studying the symbiotic relationship between plants and microorganisms …