Agronomy and Crop Sciences Commons^™

Genomic Selection Of Forage Agronomic Traits In Winter Wheat, Frank Maulana, Ki-Seung Kim, Joshua D. Anderson, Mark E. Sorrells, Twain J. Butler, Shuyu Liu, P. Stephen Baenziger, Patrick Byrne, Xue-Feng Ma

Department of Agronomy and Horticulture: Faculty Publications

Genomic selection (GS) can improve genetic gain of complex traits in plant breeding. Phenotyping agronomic traits of winter wheat (Triticum aestivum L.) for dualpurpose use is expensive and time-consuming. In this study, we compared the prediction accuracies of four GS models (RR-BLUP, GBLUP, GAUSS, and BL) for forage yield (FY), plant height (PH) and heading date (HD) of the hard winter wheat diversity panel (n = 298) using random and stratified sampling methods. In addition, we determined the appropriate training population (TP) size and marker density for GS of the traits. Moderate to high prediction accuracies ranging from 0.66 …

Reducing Mowing Requirements In Home Lawn And Golf Course Turfgrass, Mark A. Keck

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

Turfgrass systems are routinely managed by frequent mowing to increase aesthetics and function. Mowing is resource intensive with a high labor and energy demand. Reducing the number of mowings events in a growing season will decrease the labor and energy but may reduce quality as well. Previous work has looked at reducing mowing by changing the frequency and by using a plant growth regulator (PGR). Limited information is available about how to reduce mowing while maintaining acceptable quality. We looked at two different management practices to reduce mowing and maintain quality. The first study evaluated seven different mowing frequencies at …

Evaluating The Impact Of Grafting On Local Tomato Production In Nebraska, Raihanah Hassim

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

Vegetable grafting has been known to improve plant production under both biotic and abiotic stresses. With an increase in interest among local growers towards grafting production, it is important to provide enough vegetable grafting information. Therefore, the objective of this study is to assess the impact of grafting, rootstock cultivar, and local conditions and management on the yield and quality of tomato across the diverse growing and environmental conditions, specifically in Nebraska. Three open-field and one limited growing condition study were conducted between 2018 and 2019 across Nebraska. In the open-field trial, two determinant fresh market tomatoes, ‘Nebraska Wedding’ and …

Assessment Of Grain Safety In Developing Nations, Jose R. Mendoza

Department of Food Science and Technology: Dissertations, Theses, and Student Research

Grains are the most widely consumed foods worldwide, with maize (Zea mays) being frequently consumed in developing countries where it feeds approximately 900 million people under the poverty line of 2 USD per day. While grain handling practices are acceptable in most developed nations, many developing nations still face challenges such as inadequate field management, drying, and storage. Faulty grain handling along with unavoidably humid climates result in recurrent fungal growth and spoilage, which compromises both the end-quality and safety of the harvest. This becomes particularly problematic where there is little awareness about health risks associated with poor …

Optimization Of In-Vessel Food Waste Composting: Enzyme Activity And Microbial Dynamics, Ayawovi Selom Ametepe

Graduate Theses and Dissertations

A series of greenhouse-based, rotary-drum bioreactor experiments was designed to study microbial dynamics and enzyme activity during optimization of food waste composting. This work aims to optimize food waste composting by defining the best food waste-to-bulking agent proportion controlling conditions and by evaluating the food waste composting process when inoculated by a bacterial inoculant product compared to uninoculated compost. Three experiments were run in total. The two first experiments were conducted for 48 days with sampling at each step of composting, while the third experiment last 50 days and included one extra sampling date. In the first experiment, 50:50, 65:35 …

Influence Of Burning And Grazing Management Practices On Subirrigated Sandhill Meadow Hay Production, Tara M. Harms

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

Subirrigated meadows are a valuable forage resource to Sandhills ranching operations being used for hay production, grazing, or a combination of both. Practices that sustain meadow productivity should be encouraged to ensure a consistent feed supply for cattle. The potential influence of prescribed burning or pre-freeze and post-freeze grazing on forage production and quality are not well understood on these meadows. In grasslands, including meadows, excess dead plant material can accumulate, causing a potential reduction in forage yield and quality. Results of our three-year field study suggest that burning meadows in the spring is a suitable management option to remove …

Fungicide Resistance: Surveillance, Risk Assessment And Evolution In Two Soil-Borne Pathogens, Nikita Gambhir

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

Fungicide-resistant pathogens are an increasing threat to fungicide efficacy and plant health. The goal of this dissertation was to advance the foundational knowledge required to prevent and detect fungicide resistance development in the seedling disease pathogen, Rhizoctonia zeae and the white-mold pathogen, Sclerotinia sclerotiorum. Corn and soybean fields in 12 states (Iowa, Illinois, Indiana, Kansas, Kentucky, Michigan, Minnesota, Missouri, North Dakota, Nebraska, South Dakota, and Wisconsin) were surveyed for R. zeae. In vitro fungicide sensitivity was determined for 91 isolates to fludioxonil, sedaxane, and/or prothioconazole. Rhizoctonia zeae was sensitive to all fungicides (EC₅₀ < 3 µg/ml) except azoxystrobin (EC₅₀ > 100 µg/ml). In …

Can Soil Phosphorus Sorption Saturation Estimate Future Potential Legacy Phosphorus Sources?, A. N. Sharpley, K. R. Brye, J. M. Burke, L G. Berry, M. B. Daniels, P. Webb

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Various soil extraction methods are used to indicate plant available P in soil but do not account for soil specific sorption of subsequent applications of P. Thus, estimates of soil phosphorus sorption saturation (PSS; estimated from Mehlich-3 extractable P, Al, and Fe) have been used in conjunction with Mehlich-3 extractable soil phosphorus (M3P) to overcome these limitations. As less is known about the effect of land management on PSS than M3P under field conditions, the effect of field management on PSS was investigated for three pastures over 5 yr (2014-2018). Swine slurry was applied to two fields (Field 1 received …

Corn And Soybean Response To Wastewater-Recycled Phosphorus Fertilizers, Shane Ylagan

Crop, Soil and Environmental Sciences Undergraduate Honors Theses

The ability to recycle phosphorus (P) from wastewaters could provide a sustainable, continuous source of P that might also help protect surface water quality from P enrichment. The mineral struvite (MgNH4PO4·6H2O) is an understudied material that can be created from Pcontaining wastewater and has been shown to have agricultural fertilizer value. The objective of this study was to evaluate the effects of electrochemically precipitated struvite (ECST), chemically precipitated struvite (Crystal Green; CG), diammonium phosphate (DAP), monoammonium phosphate (MAP), rock phosphate (RP), and triple super phosphate (TSP) on corn (Zea mays) and soybean (Glycine max) response in a 79-day greenhouse pot …

Characterization Of Genetic Sources Associated With Restorability And Seed Dimension In Arkansas Restorer Rice Lines, Ozgur Azapoglu

Graduate Theses and Dissertations

Hybrid rice (Oryza sativa L.) breeding offers a significant opportunity to enhance rice production, and the cultivation of a male sterile line is the most important factor in the success of cross-breeding. One of the key elements of hybrid rice production is to develop a restorer line that is assigned as the male parent. The restorer lines provide viable pollen for fertilization of the male sterile plant due to the presence of a restorer gene (Rf) in their genomes. Any superior restorer line applied to hybrid rice production must contain genes/quantitative trait loci (QTL) associated with the desirable agronomic traits …

Impacts Of Postharvest Temperature Exposure Profiles On Rice Physicochemical Properties, Seth Graham-Acquaah

Graduate Theses and Dissertations

Heated-air drying followed by tempering (HAT) is effective for increasing rough-rice drying rates without compromising head rice yield (HRY). However, heat exposure could affect rice end-use properties. Hypothesizing that the total amount of heat exposure incurred by rice during heated-air drying determines the trend and magnitude of changes in end-use properties, this dissertation sought to 1) characterize the effects of drying and tempering regimen on changes in end-use properties, 2) derive an index to quantify and compare the amount of heat exposure that rice kernels incur during active drying and, 3) relate values of this index to changes in rice …

Soil Health, Phosphorus And Carbon Dynamics In Response To A One-Time Compost Application And Cover Crops In Organic Dryland Winter Wheat, Idowu Ademola Atoloye

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Organic dryland winter wheat (Triticum aestivum) growers in the U.S. are faced with high interannual variability in yields. This is related to the low annual precipitation and low soil fertility on the cultivated soils. Improving soil health is the key to increasing and maintaining crop yields. In this study, we compared the effects of different rates (0, 12.5, 25 and 50 Mg DW ha^-1 compost and 2 Mg ha manure^-1) of large quantities of steer manure compost and the inclusion of cover crops versus fallow on soil health and on carbon and phosphorus dynamics in …

Application Of X-Ray Imaging And Glass Transition Principles In Understanding Rice Kernel Fissure Formation, Zephania R. Odek

Graduate Theses and Dissertations

Rice kernels with internal fractures of the endosperm, fissures, tend to break during milling, leading to head rice yield (HRY) reductions. Minimizing kernel fissuring is thus an important goal of the rice industry. To minimize fissuring during the drying process, a better understanding of the fissuring process and the kinetics thereof is required. The goal of this research was to use X-ray imaging and glass transition principles to better understand rough rice kernel fissuring. First, because the instance when the fissuring process is initiated and completed during the drying process is not well known, an X-ray imaging setup that allows …

Improving Breeding Program Efficiency And Genetic Gain Through The Implementation Of Genomic Selection In Diverse Wheat Germplasm, Dylan Larkin

Graduate Theses and Dissertations

Genomic selection (GS) is an important tool for increasing genetic gain for economically important traits in breeding programs. Genomic selection uses molecular markers across the entire genome in order to predict the performance of breeding lines for a trait of interest prior to phenotyping. A training population (TP) of elite germplasm, representative of the University of Arkansas wheat breeding program, was developed in order to predict important agronomic and Fusarium head blight (FHB) resistance traits within the University of Arkansas wheat breeding program through cross-validation and forward prediction.

A genome-wide association study (GWAS) was performed on the TP to identify …

Resistance To Herbicides Conferred By Amaranthus Palmeri Protoporphyrinogen Ix Oxidase Mutations, Pamela Carvalho De Lima

Graduate Theses and Dissertations

Palmer amaranth (Amaranthus palmeri S. Wats.) is one of the most problematic agronomic weeds to control in fields across Arkansas. Thus far, this species has evolved resistance to several herbicides, including protoporphyrinogen IX oxidase (PPO) inhibitors. The majority of PPO-resistant Palmer amaranth populations harbor a target-site mutation (substitution or deletion of amino acids). The objective of this thesis was to identify the level of fomesafen resistance conferred by PPO2 mutations from Palmer amaranth. The experiments conducted aimed to (1) characterize the level of resistance conferred by the transgene Palmer amaranth ppo2 carrying ΔG210 mutation into the wild type rice (Oryza …

Rice Chilling Aeration: Assessment Of Impacts On Grain Quality, Process Modeling And Validation, Soraya Shafiekhani

Graduate Theses and Dissertations

The goal of this study is to demonstrate the effectiveness of applying chilling temperatures during on-farm, in-bin drying and storage to maintain rice quality. Specific objectives include to demonstrate the effectiveness of chilling aeration to preserve rice quality characteristics, determine the drying kinetics of rice under low temperature environments, and develop models to predict heat and mass transfer in rice kernel during drying at low temperature environment. To date, there is limited research describing storability or drying behavior of rice in chilled environments. However, it is understood that chilling of high-moisture, > 21% wet basis rough rice could reduce the time …

Molecular Genetic Analysis Of Drought Resistance And Productivity Traits Of Rice Genotypes, Yheni Dwiningsih

Graduate Theses and Dissertations

Rice (Oryza sativa L.) is the staple food for a majority of the world’s population, and uses 30% of the global fresh water during its life cycle. Drought at the reproductive stage is the most important abiotic stress factor limiting grain yield. The United States is the third largest exporter of rice, and Arkansas is the top rice-producing state. The Arkansas rice-growing region in the Lower Mississippi belt is among the 10 areas with the highest risk of water scarcity. Adapted U.S. rice cultivars were screened for drought resistant (DR) traits to find sources for breeding U.S. rice cultivars for …

Association Mapping For Soybean (Glycine Max L. Merr.) Protein And Oil Content, Joseph Najjar

Graduate Theses and Dissertations

Soybean [Glycine Max (L.) Merrill] is an important economic crop because of its high content of seed protein and oil. Seed oil and protein content are quantitative inherited traits. The genetics of seed protein and oil levels have been extensively studied, with 367 QTL reported for protein and 475 QTL reported for oil to date. Validation of such QTLs, and identification of easily-automatable molecular markers around these QTL will aid the progression of breeding for such traits. The focus of this research was to discover novel and verify previously reported QTL related to protein and/or oil content via Genome-Wide Association …

Comparison Of A T-Trellis And A Rotating Cross-Arm Trellis For Arkansas Blackberry Production, Erika Henderson

Graduate Theses and Dissertations

As blackberry production in the southeastern United States expands, the need for updated cultural practices, like alternative trellis systems that enhance blackberry fruit yield, fruit quality, and economic viability for fresh-market growers are needed. There are challenges to producing high-quality blackberry fruit with high yields in the Southeast due to intense heat, high rainfall, humidity, and heavy pest pressure. Southeastern growers are interested in the rotating cross-arm (RCA) trellis due to its potential to increase yield and fruit quality, however there is minimal research of its use in blackberry production in the Southeast. In 2019 and 2020, a trial was …

Milk Intake Improves Outcomes For Young Lambs With Continuous Exposure To Gastrointestinal Parasites In Pasture‐Based System, Robyn A. Dynes, Ray A. Moss, R. W. Mcanulty, Alec D. Mackay

IGC Proceedings (1977-2023)

No abstract provided.