Agriculture Commons^™

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 …

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 …

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 …

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 …

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 …

Manipulating Species Diversity: Environmental Impacts In Row Crop, Livestock, And Grassland Agroecosystems, Alayna A. Jacobs

Theses and Dissertations--Plant and Soil Sciences

The diversity of living species in an agroecosystem affects both natural resources and agricultural production efficiency. The rise of managed plant monocultures has allowed agricultural yields to increase over time. However, simplifying agroecosystems affects the capacity of the system to sustainably provide clean air, water, and productive soils essential for continued food and fiber production. This dissertation manipulates species diversity in row crop and forage agroecosystems prevalent in the Eastern United States and tracks the associated environmental and agricultural production consequences.

In row crop agroecosystems, increasing plant diversity with winter cover crops has been suggested as a strategy to increase …

An Improved Understanding Of Diplodia Ear Rot In Kentucky Corn, Nolan Ryan Anderson

Theses and Dissertations--Plant Pathology

Stenocarpella maydis and Stenocarpella macrospora are both causal agents of Diplodia ear rot (DER) of corn in the U.S. The current prevalence and distribution of each is unknown worldwide. Signs and symptoms of DER include white mold on and between kernels, bleached husks, and pycnidia visible in the cob pith. The term hidden Diplodia describes when no mycelia or bleached husk is present, but pycnidia are still visible inside the cob. This phenomenon is reported to be caused by late infections of Stenocarpella spp. New fungicide nozzle technology has been promoted to increase spray coverage in the lower canopy, which …

Epidemiology And Management Of Frogeye Leaf Spot Of Soybean: Damage Thresholds, Efficacy And Profitability Of Foliar Fungicides, Jhonatan Paulo Barro

Theses and Dissertations--Plant Pathology

Frogeye leaf spot (FLS), caused by Cercospora sojina, is an economically important disease of soybean in many parts of the world where soybean is grown, including the United States. A meta-analytic approach was used to summarize a data set of 66 uniform field research trials conducted to evaluate fungicide efficacy against FLS on soybean. The dataset spanned 10 years (2012 to 2021) of experiments conducted across eight states in the U.S., including Alabama, Arkansas, Illinois, Iowa, Kentucky, Louisiana, Mississippi and Tennessee. First, the relationship between FLS severity and soybean yield was investigated. A significant negative slope obtained through random …

An Evaluation Of Eragrostis Tef For Future Cultivar Development, Eric Wayne Luteyn

Theses and Dissertations--Plant and Soil Sciences

The many benefits of utilizing teff (Eragrostis tef) as small grain is well documented in journal publications. Over time the domestication of this species has become essential to the diets of the local population and the livestock living in the African highlands. Current research points to a high diversity of trait characteristics found in many teff populations and the potential utilization of these traits to increase desirable characteristics in both grain and forage varieties. With the overarching goal of adding to what is already known about teff, this study evaluates the different traits that are of interest to …

Remote Sensing For Quantifying C3 And C4 Grass Ratios In Pastures, Jordyn Alyssa Bush

Theses and Dissertations--Plant and Soil Sciences

The following studies investigate the accuracy and practicality of exploiting the color dichotomy present between C₃ and C₄ grass species to estimate their respective proportions from drone or camera captured imagery. Understanding the proportions of C₃ and C₄ grasses in pastures is vital to sound decision making for livestock production. The ability to monitor these proportions remotely will also allow for large scale monitoring as well as detection of changes in botanical composition over time and in response to weather events, management, or climate change. A free green canopy cover (GCC) analyzing software, Canopeo, was used …

Bhlh Iridoid Synthesis 3 Is A Member Of A Bhlh Gene Cluster Regulating Terpenoid Indole Alkaloid Biosynthesis In Catharanthus Roseus, Sanjay Kumar Singh, Barunava Patra, Priyanka Paul, Yongliang Liu, Sitakanta Pattanaik, Ling Yuan

Kentucky Tobacco Research and Development Center Faculty Publications

Basic helix‐loop‐helix (bHLH) transcription factors (TFs) are key regulators of plant specialized metabolites, including terpenoid indole alkaloids (TIAs) in Catharanthus roseus. Two previously characterized subgroup‐IVa bHLH TFs, BIS1 (bHLH Iridoid Synthesis 1) and BIS2 regulate iridoid biosynthesis in the TIA pathway. We reanalyzed the recently updated C. roseus genome sequence and discovered that BIS1 and BIS2 are clustered on the same genomic scaffold with a previously uncharacterized bHLH gene, designated as BIS3. Only a few bHLH gene clusters have been studied to date. Comparative analysis of 49 genome sequences from different plant lineages revealed the presence of analogous …

Incorporation Of Summer Annual Mixtures Into Grazing Systems In Kentucky, Kelly Marie Mercier

Theses and Dissertations--Plant and Soil Sciences

Utilizing summer annual grass-legume forage mixtures has the potential to improve forage yield and nutritive characteristics, and/or animal performance during times when cool-season pasture growth is limited by high temperatures. Legumes can utilize atmospheric nitrogen, which can increase crude protein and forage digestibility in mixtures. As nitrogen application generally improves both the yield and nutritive characteristics of summer annual forages, but can have a negative effect on legume competitiveness, nitrogen fertilizer recommendations for legume-containing summer annual mixtures are not well established.

Two experiments were conducted to determine the feasibility of utilizing summer annual mixtures in Kentucky, USA. The first experiment …

Improving Kentucky's Winter Wheat And Double Crop Soybean Rotation, Katherine Susan Rod

Theses and Dissertations--Plant and Soil Sciences

The winter wheat double crop soybean rotation is an economically viable rotation for Kentucky farmers. Recent decreases in commodity prices has warranted the need to evaluate intensive management practices that can increase yields and profitability in this crop rotation. There were three goals of this dissertation: 1.) identify management practices that would decrease deoxynivalenol (DON) in harvested wheat grain and increase wheat heading and anthesis uniformity, 2.) evaluate double crop soybean planting timing and identify intensive management practices to increase seed yield, and 3.) determine the profitability of these management options. These studies were conducted in Princeton KY between 2016 …

Virus-Induced Changes In Nuclear Proteins And Membranes In Nicotiana Benthamiana Cells, Caleb Mathias

Theses and Dissertations--Plant Pathology

Viruses rely on host proteins to complete their life cycles. This results in alterations to normal cell physiology to processes which benefit viral processes such as replication and movement to other cells. This may involve the relocalization of host proteins away from their original subcellular targets to sites which may benefit the virus, a process that is not as well understood as it relates to the nucleus. To identify nuclear proteins that may be involved in such processes, a library of random Nicotiana benthamiana cDNAs were expressed as GFP fusions in a transgenic marker lines expressing a histone 2B:RFP nuclear …

Arthropod Resistant Tomatoes: Screening Tools, Yield And Nutritional Quality Of Interspecific Hybrids, Mohammad Hasan Salman Ali Dawood

Theses and Dissertations--Plant and Soil Sciences

Tomato (Solanum lycopersicum) is one of the most economically important vegetable crops grown around globe but is a host for numerous pests and pathogens. In the future, tomato breeders will have to focus on increasing fruit quantity and on enhancing pest resistance. Many accessions of the wild relative of tomato, S. habrochaites display high levels of resistance towards arthropods such as spider mites. The presence of the sesquiterpene hydrocarbon, 7-epi-zingiberene, found in S. habrochaites type IV trichomes has been associated with arthropod resistance. However, the presence of other compounds in its trichome secretions may also be related …

In Pursuit Of Understanding Barrel Variation: Surveying The Lignocellulose Composition And Content Changes In Quercus Alba Barrel Staves During Cooperage And Bourbon Whiskey Maturation, Jarrad Wade Gollihue

Theses and Dissertations--Plant and Soil Sciences

Bourbon whiskey is a distilled spirit which is a uniquely American with several legal requirements including 1) the major grain in the mash is corn, 2) must be aged in a new charred white oak barrel, and 3) made in the United States of America. Kentucky is the whiskey historical home, producing most of the bourbon in the United States. Interest in whiskey has developed a need to understand more about the underlying chemistry of bourbon. The charred white oak barrel used in bourbon production is of substantial interest because the barrel has been implicated in giving American whiskey its …

Cover Crops And Cover Crop Mixes: Stratification Of Biological Effects, Landon M. Gibbs

Theses and Dissertations--Plant and Soil Sciences

The potential nutrient cycling benefits from legumes (e.g. N₂-fixation) and the high biomass potential of cereal rye are well known. Further studies are warranted to evaluate bi-culture mixtures and their effects on soil nutrient stratification and microbial enzyme activity because these two properties may be differently expressed (enhanced) by legume/grass mixes. The objectives of this study were: (1) show different cover crops and cover crop mixes containing grasses and legumes differentially stratify carbon and N; (2) show the change in microbial enzyme activity in soils planted with individual cover crops relative to cover crop mixes; 3) determine the …

Forage News [2019-11], Department Of Plant And Soil Sciences, University Of Kentucky

Forage News

• Climate Change: Are Livestock a Problem
• Kentucky Alfalfa Conference
• Get the Most from Grazing Cornstalks
• The More You Know, the Smarter You Grow
• Wendell Berry Center hosts First Grazing School
• USDA Hay Markets - October 22, 2019
• Publication of the Month: Using Dry Lots to Conserve Pastures
• Kids these Days...

Forage News [2019-10], Department Of Plant And Soil Sciences, University Of Kentucky

Forage News

• Register now for the Heart of America Grazing Conference
• Western KY Grazing Conference
• Pasture Walk with Jim Gerrish
• Harvest Drought Stressed Soybeans for Hay

Forage News [2019-09], Department Of Plant And Soil Sciences, University Of Kentucky

Forage News

• Heart of America Grazing Conference
• Register now for Fall Grazing School, Sept. 10-11 in Versailles, KY
• Blue-green Algae: Dangerous to Pets and Livestock
• 12 Habits of Highly Successful Forage Producers
• Cover Crops Following Corn Silage
• Current USDA Hay Market Prices
• Alfalfa Checkoff Funds Two University of Kentucky Projects
• Watch for Fall Army Work in Pastures

Forage News [2019-08], Department Of Plant And Soil Sciences, University Of Kentucky

Forage News

• Reclaiming Rundown Farms - Western KY Summer Forage Tour
• Oats for Fall Pasture or Hay
• KFGC Central KY Field Day
• The Birth of a Rotational Grazing System
• Caldwell County Horse Farm to Host Field Day

Forage News [2019-07], Department Of Plant And Soil Sciences, University Of Kentucky

Forage News

• Register for Heart of America and Western Kentucky Grazing Conferences today!
• The Clover Dilemma
• Improve Summer Pastures with Crabgrass
• Fall Grazing School Registration Now Open
• Clip Pastures to Reduce the Risk of Ergot

Meta-Analysis Of Yield Response Of Foliar Fungicide-Treated Hybrid Corn In The United States And Ontario, Canada, Kiersten A. Wise, Damon Smith, Anna Freije, Daren S. Mueller, Yuba Kandel, Tom Allen, Carl A. Bradley, Emmanuel Byamukama, Martin Chilvers, Travis Faske, Andrew Friskop, Clayton Hollier, Tamra A. Jackson-Ziems, Heather Kelly, Bob Kemerait, Paul Price Iii, Alison Robertson, Albert Tenuta

Plant Pathology Faculty Publications

Background

Foliar fungicide applications to corn (Zea mays L.) occur at one or more application timings ranging from early vegetative growth stages to mid-reproductive stages. Previous studies indicated that fungicide applications are profitable under high disease pressure when applied during the tasseling to silking growth stages. Few comprehensive studies in corn have examined the impact of fungicide applications at an early vegetative growth stage (V6) compared to late application timings (VT) for yield response and return on fungicide investment (ROI) across multiple locations.

Objective

Compare yield response of fungicide application timing across multiple fungicide classes and calculate the probability …

Forage News [2019-06], Department Of Plant And Soil Sciences, University Of Kentucky

Forage News

• Managing Pastures this Summer
• 2019 Western Kentucky Summer Forage Tour: Resuscitating a Rundown Farm
• The Wonder Grass: The Story of Tall Fescue in the United States now available
• UK Weed Sceicne to Host a Pair of Field Days at UKREC in Princeton
• Grass Decline? Check Your Cutting Height
• We're Producing and Feeding Less Hay

Forage News [2019-05], Department Of Plant And Soil Sciences, University Of Kentucky

Forage News

• Register for 2019 Kentucky Fencing School in Russellville on May 30th
• Things in the Hay Production Book We Missed
• Insure High Quality Forage: Make Baleage
• Optimizing Production from Perennial Cool-Season Hayfields
• UK Equine Farm and Facilities Expo - May 30
• Purdue Extension Hosts Educational Events This Summer - June 21 and 22
• Tariffs, Water Reshuffled the Hay Export Deck

Forage News [2019-04], Department Of Plant And Soil Sciences, University Of Kentucky

Forage News

• Register today for the Kentucky Grazing School
• Fencing School spaces still open in Burkesville and Russellville
• More Stuff Not in the Book
• Simplifying Grain Drill Calibration
• New Mandatory Paraquat Training Requirements for Applicators
• Grass-Fed and -Finished Beef Production & Marketing: an OAK Field Day - May 2, 2019

Nitrogen Fertilizer Suppresses Mineralization Of Soil Organic Matter In Maize Agroecosystems, Navreet K. Mahal, William R. Osterholz, Fernando E. Miguez, Hanna J. Poffenbarger, John E. Sawyer, Daniel C. Olk, Sotirios V. Archontoulis, Michael J. Castellano

Plant and Soil Sciences Faculty Publications

The possibility that N fertilizer increases soil organic matter (SOM) mineralization and, as a result, reduces SOM stocks has led to a great debate about the long-term sustainability of maize-based agroecosystems as well as the best method to estimate fertilizer N use efficiency (FNUE). Much of this debate is because synthetic N fertilizer can positively or negatively affect SOM mineralization via several direct and indirect pathways. Here, we test a series of hypotheses to determine the direction, magnitude, and mechanism of N fertilizer effect on SOM mineralization and discuss the implications for methods to estimate FNUE. We measured the effect …

Forage News [2019-03], Department Of Plant And Soil Sciences, University Of Kentucky

Forage News

• Novel Tall Fecue Workshop - March 20
• Round Bale Binding Materials Evaluated
• Impact of Tedding on Alfalfa Silage
• Spring Grazing School April 23-24
• Spring Fencing School: 3 Dates, 3 Locations

Survey And Adjourn, Kentucky Alfalfa And Stored Forages Conference

Kentucky Alfalfa and Stored Forage Conference

No abstract provided.

How Good Is Our Kentucky Haylage? A Summary Of 2017-18 Farm Results, Jimmy C. Henning, Jeff Lehmkuhler, Levi Berg, April Wilhoit, Corinne Belton, Tommy R. Yankey

Kentucky Alfalfa and Stored Forage Conference

The ability to harvest moist forage as hay gives Kentucky producers many advantages, including timely harvest, higher forage quality, and less weathering loss over hay systems. The baleage system allows producers to utilize commonly available forage equipment (mowers, rakes, balers) rather than requiring choppers and silo structures or bags. Making high quality baleage requires timely access to bale wrappers.