Plant Sciences Commons^™

The Influence Of Water Stress And Rootstocks On Nutrient Uptake And Gas Exchange Of Young Peach Trees, Naif Alshammari

All Theses

Young peach trees are often rainfed in the southeastern U.S. and periods of dry weather can cause tree water deficit that can be detrimental to orchard productivity. There is a lack of understanding of the influence of water regimes and rootstocks on the nutritional status and gas exchange of the peach tree. Most peach growers in Southeastern United States do not irrigate their young peach trees because they do not produce fruit until the third leaf. In this region, peach growers use Guardian as a rootstock, although MP-29 is also interesting for growers with orchards that have Armillaria root rot …

Identifying Temporal Sensitivity Of Poinsettia Flowering To High Temperatures, Paul Millar

All Theses

High temperatures can cause delayed flowering in poinsettia (Euphorbia pulcherrima Willd. ex Klotzsch), a phenomenon known in the industry as heat delay. The poinsettia wholesale market is concentrated to a relatively brief period from early-November through early-December putting growers at risk to heat delay. This problem is compounded by the unusual weather patterns created by climate change. The objective of this thesis was to identify periods in which poinsettia flowering is sensitive to high temperatures. First, the weeks within the growing season when the plants were sensitive to high temperatures were identified (Chpt. 2). Then within those sensitive weeks, …

Characterization Of Colletotrichum Nymphaeae Isolates, Causal Pathogen Of Apple Bitter Rot, With Reduced Sensitivity To Fluazinam And Tebuconazole, Rulyu Meng

All Theses

Apple bitter rot is caused by Colletotrichum nymphaeae and other Colletotrichum species and management relies primarily on synthetic pesticides. Very few fungicides are effective against the disease and resistance has further limited their usefulness. A recent study indicated a relatively low range of EC₅₀ values (the concentration required to inhibit 50% of mycelial growth in vitro) of C. nymphaeae isolates from Brazilian apples to fluazinam and tebuconazole, two fungicides that are not routinely used for bitter rot control. Isolates on opposite sides of the range were designated either sensitive (lowest EC₅₀ values) and reduced sensitive (highest EC_{50 …}

Intestinal Microbiota Analysis Of Broiler Chickens Under Necrotic Enteritis Challenge And Tributyrin Supplementation, Taylor Nicole Mckinney

Graduate Theses and Dissertations

Poultry is a staple protein source for most of the planet. Until recently, antibiotic growth promoters (AGPs) were used to prevent illnesses in commercial chicken production. Currently, this is not possible due to regulations and consumer concern, but without such a preventative, diseases like necrotic enteritis (NE) have reemerged, posing a threat to bird health, and ultimately, our food source. Necrotic enteritis is a severe gastrointestinal disease caused by the gram-positive pathogen, Clostridium perfringens. Clinical features of this disease are diarrhea, intestinal lesions, and death, with a high transmission rate. In a subclinical form, growth performance is diminished and is …

Investigating Hops Production In Arkansas To Support Specialty Crop Growth, James Oliver Mcclellan

Graduate Theses and Dissertations

The hop plant (Humulus lupulus L.) is a perennial, climbing species within the Cannabaceae family that produces cones used for brewing. Hops are grown worldwide. In the United States most hops production occurs in the Pacific Northwest, but growth in the craft beer industry is driving efforts for hops production in other U.S. regions. Recommendations on hops cultivar suitability, fertility, and management are needed for the U.S. mid-south region. Objectives of this research on Arkansas-grown hops were to 1) assess the impact of cultivar and fertility rate on plant and cone attributes of six cultivars of Arkansas-grown hops and 2) …

Evaluating Flavor And Aroma Attributes Of Arkansas-Grown Horticultural Crops, Jordan Chenier

Graduate Theses and Dissertations

Arkansas has a climate and geography that allows for the production of unique horticultural crops, including hops (Humulus lupulus L.), blackberries (Rubus subgenus Rubus), and muscadine grapes (Vitis rotundifolia). These crops not only have potential for growers in Arkansas but have unique flavor and aroma attributes that impact marketability. Volatile compounds present in many different agricultural plants are the primary source of biologically-derived aromas and flavors. Therefore, the volatile and other quality attributes of hops, blackberries, and muscadine grapes were evaluated at the University of Arkansas (UA System) Division of Agriculture. The quality, volatile, and sensory attributes of four hops …

Management Of Garlic Mustard (Alliaria Petiolata), Sahara Mustard (Brassica Tournefortii), And Elongated Mustard (Brassica Elongata) In Utah, Natalie Layne Fronk

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The invasive mustard species Sahara mustard (Brassica tournefortii), garlic mustard (Alliaria petiolata) and elongated mustard (Brassica elongata) negatively impact a variety of ecological systems across the state of Utah. The distribution of these species in Utah is relatively limited at the current time. If prompt action is taken, it may be possible to contain and manage these species before irreparable ecological and agricultural damage occurs. For this reason, all three mustards are listed by the State of Utah as weeds of high priority for management.

This project tested multiple strategies to determine effective species-specific …

Dairy Breed, Grass-Birdsfoot Trefoil Mixture, And Pasture Nutrition Effects On Intake, Feed Efficiency, And Grazing Adaptation, Michael Greenland

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Dairy cattle have lower dry matter intake (DMI) on pastures thus leading to less weight gain and milk production than feedlot cows. This study was conducted to determine whether different dairy breeds are better adapted to lower or higher quality pastures as measured in DMI and feed efficiency. The eight treatments consisted of Jersey, Holstein, Holstein-Jersey crossbreds, and 3-breed crossbreds (Montbéliarde-Swedish Red-Holstein) heifers on grass monocultures and grass-BFT mixtures. We observed greater DMI on grass-BFT mixtures. Among breeds, Holstein had the greatest DMI, then the two crossbreds, and Jersey had the least. Feed efficiency was most favorable for Jersey, less …

Soil Genesis Across A Climo-Lithosequence Of Western Haleakalā, Maui, Ryan C. Hodges

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The soils of western Haleakalā are incredibly diverse due to two primary reasons: 1) they receive varying levels of rainfall based on location relative to Haleakalā, and 2) volcanic vents upwind of the area indicate that volcanic ash has blanketed much of western Haleakalā in the past. Ash can weather to form short-range-order materials, which contribute to the classification of andic soil properties. Due to their structure, short-range-order materials impart soil behavior that creates benefits and challenges in land management. Therefore, an understanding of how these soils formed and differ, and where andic soils occur is crucial.

The objectives of …

Development Of Late-Heading Orchardgrass Germplasm, Megan Marie Getz

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Dactylis glomerata L., orchardgrass, is commonly grown with perennial forages such as alfalfa (Medicago sativa L.). However, commercial orchardgrass cultivars currently grown in the Intermountain West generally flower earlier than alfalfa. This results in a reduction in grass nutritional value if harvested to maximize the alfalfa yield, because the two species mature at different rates. Thus, there is a need to better understand the genetic basis of flowering time in orchardgrass and develop late-flowering populations. The objectives of this research were to evaluate the ability to identify and use molecular markers to identify and select late-heading orchardgrass; and to …

The Effect Of Water Management And Ratoon Rice Cropping On Methane Emissions And Harvest Yield In Arkansas, Marguerita Leavitt

Graduate Theses and Dissertations

Sustainable intensification of rice farming is crucial to meeting human food needs while reducing environmental impacts. Rice produces 8% of all anthropogenic CH4, which is a potent greenhouse gas. CH4 emissions can potentially be reduced by cultivation practices that minimize the number of days the fields are saturated, such as dry-seeding instead of water-seeding and irrigation using the alternate wetting and drying (AWD) technique instead of delayed, continuous flooding (DF). Ratoon cropping, wherein a second crop of rice is grown from the harvested stubble of the first crop, can be used to produce additional yield with minimal labor, but may …

Water Sourcing Strategies Of Desert Vegetation In Varying Soil Textures With Vegetation Competition: A Stable Isotope Analysis, Martha Elizabeth Gardea

Open Access Theses & Dissertations

Recent studies have suggested an ecohydrological separation of water exists in the northern Chihuahuan Desert, where vegetation types, rainfall regimes, and location in the terrain seem to determine the type of water (e.g. isotopically depleted or enriched in 18O and 2H) plants are able to source and use throughout their growing cycle. That work found evidence of creosote (Larrea tridentata) and mesquite (Prosopis glandulosa) using tightly bound soil water at both a site on an ephemeral channel and a site in higher elevated flat area because the isotopic signature of plant water at the beginning of the study did not …

Mycorrhizae In Maize (Zea Mays L.) Cropping Systems Respond Differently To Nitrogen Fertilization Under Increasing Crop Rotational Diversity, Morgan Mcpherson

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Arbuscular mycorrhizal fungi (AMF) remain a vital obligate symbiont of nearly all plants. It is well established that the symbiosis between AMF and host plant improves plant nutrient acquisition, alleviates abiotic and biotic environmental stressors, defends against plant pathogens, and contributes to overall plant fitness and productivity through modification of the soil habitat. Modifications include increased soil aggregation and stability, carbon sequestration through provision of fungal wall precursors to soil organic matter (SOM) formation, and enhanced nutrient cycling in the mycorrhizosphere. The goal of this dissertation was to assess how AMF respond to nitrogen (N) fertilization regimes in maize cropping …

Environmental Weed Risk Assessment Protocol For Growing Non-Indigenous Plants In The Western Australian Rangelands, Geoff A. Moore Mr, Christine Munday Ms, Papori Barua Dr

Bulletins 4000 -

This bulletin is a post-border environmental weed risk assessment (WRA) protocol which is based on the Environmental WRA Protocol developed for the Future Farm Industries Co-operative Research Centre (FFI CRC), but with some changes to reflect the different environment and objectives.

The WRA protocol was developed specifically as a post-border assessment of non-indigenous species that may have agricultural value in the WA rangelands and the risk that they may become environmental weeds. Weeds can occur in many land-use systems including agriculture, horticulture and forestry; however, the focus of this protocol is on the risk that non-indigenous agricultural plants may become …

Comparison Of Plant Richness And Density In Crp-42 Fields Between 2018 And 2022, Liz Wilgenbusch, Ai Wen Ph.D.

Summer Undergraduate Research Program (SURP) Symposium

Recently, the number of pollinators have decreased dramatically throughout the United States. Pollinators play an important role in food production with around ⅓ of the world’s food crops being dependent on pollinators. Providing a high-forage habitat for pollinators is a proposed solution to combat their decline. In the upper Midwest United States, the Conservation Reserve Program (CRP) helps protect pollinator habitats by providing farmers with annual payments to retire their old farmland. The purpose of this study was to compare plant density and richness in CRP fields between year 3 and year 7 post planting to find trends in the …

Landscape Tree Irrigation Calculator, Shital Poudyal

All Current Publications

Trees, undoubtedly, are the most valuable plant in a landscape and must be prioritized for irrigation in drought conditions. Grass easily recovers from a period of long drought; hence, it must be placed last on the priority list for irrigation. Many resources are available online that explain ways to irrigate landscape trees. However, growers and homeowners in Utah are still confused about quantifying and applying the appropriate amount of water a landscape tree needs. This Excel spreadsheet is an irrigation calculator designed to determine the amount of water a landscape tree needs in Utah’s hot and dry summer months. Find …

Quantification And Machine Learning Based N2o–N And Co2–C Emissions Predictions From A Decomposing Rye Cover Crop, Deepak R. Joshi, David E. Clay, Sharon A. Clay, Janet Moriles-Miller, Aaron L. M. Daigh, Graig Reicks, Shaina Westhoff

Department of Agronomy and Horticulture: Faculty Publications

Cover crops improve soil health and reduce the risk of soil erosion. However, their impact on the carbon dioxide equivalence (CO_2e) is unknown. Therefore, the objective of this 2-yr study was to quantify the effect of cover crop-induced differences in soil moisture, temperature, organic C, and microorganisms on CO_2e, and to develop machine learning algorithms that predict daily N₂O–N and CO₂–C emissions. The prediction models tested were multiple linear regression, partial least square regression, support vector machine, random forest (RF), and artificial neural network. Models’ performance was accessed using R², …

Registration Of Lcs ‘Valiant’ Hard Red Winter Wheat, P. Stephen Baenziger, S. D. Masterson, J. D. Boehm Jr., Vikas Belamkar, M. D. Barnett, Devin J. Rose, Lan Xu, Stephen N. Wegulo, T. Regassa, Amanda Easterly, Cody F Creech, Dipak K. Santra, G. R. Kruger, G. W. Hergert, R. N. Klein, J. Kolmer, J. Kolmer, M.-S. Chen, Gary L. Hein, R. L. Bowden, M. J. Guttieri, G. Bai, El-Basyoni Salah, J. Poland

Department of Agronomy and Horticulture: Faculty Publications

Historically cultivars developed jointly by the University of Nebraska-Lincoln and USDA-ARS wheat (Triticum aestivum L.) improvement project tend to be late and better adapted to the northern Great Plains. LCS ‘Valiant’ (Reg. no. CV-1196, PI 693223; tested as NE10478-1) was released based on the merits of its earliness, agronomic performance, relevant disease resistances, and end-use quality characteristics and its adaptation to the central Great Plains. As such, the line was licensed to Limagrain Cereal Seeds for their ability to market outside of Nebraska. LCS Valiant hard red winter wheat was released in March 2020 by the developing institutions and …

How Much Water Do Landscape Trees Require In Utah? An Irrigation Calculator, Shital Poudyal

All Current Publications

Trees, undoubtedly, are the most valuable plant in a landscape and must be prioritized for irrigation in drought conditions. Grass easily recovers from a period of long drought; hence, it must be placed last on the priority list for irrigation. Many resources are available online that explain ways to irrigate landscape trees. However, growers and homeowners in Utah are still confused about quantifying and applying the appropriate amount of water a landscape tree needs. This fact sheet includes a simple calculator designed to determine the amount of water a landscape tree needs in Utah’s hot and dry summer months.

Limited Effects Of Precipitation Manipulation On Soil Respiration And Inorganic N Concentrations Across Soil Drainage Classes In Northern Minnesota Aspen Forests, Anna B. Stockstad, Robert A. Slesak, Alan J. Toczydlowski, Charles R. Blinn, Randall K. Kolka, Stephen D. Sebestyen

Aspen Bibliography

It is critical to gain insight into the responses of forest soils to the changing climate. We simulated future climate conditions with growing season throughfall reduction (by 50%) and winter snow removal using a paired-plot design across a soil drainage class gradient at three upland, Populus-dominated forests in northern Minnesota, USA. In situ bulk soil respiration and concentrations of extractable soil N were measured during the summers of 2020–2021. Soil respiration and N concentrations were not affected by throughfall reduction and snow removal, which was largely attributed to the limited treatment effects on soil moisture content and soil temperature. …