Digital Commons Network^™

Evaluation Of Genetic Diversity And Stability Of Colocasia Cultivars Using Issr, Seukmin Hong

Electronic Theses and Dissertations

Using 44 ornamental Colocasia cultivars planted at Stephen F. Austin State University (Nacogdoches, TX), cultivar assessment, genetic diversity, stability, and relationship were examined with banding patterns produced from Inter-simple sequence repeat (ISSR) markers. Comparing banding patterns of vegetatively propagated clones of each cultivar, genetic stability was examined. Unweighted pair group method with arithmetic mean (UPGMA) and principal coordinate analysis (PCO) were performed to examine genetic relationship that can explain a need for the new classification Colocasia gigantea and recent movement of re-classifying Colocasia antiquorum. Average Shannon’s diversity index for all loci was found to quantify genetic diversity. The genetic …

Pinching And Spacing Effects On Cut Sunflower (Helianthus Annuus) Production In East Texas, Rebecca B. Burnett

Electronic Theses and Dissertations

Three experiments evaluated pinching and spacing on Helianthus annuus in East Texas to determine their effects on growth and development. Experiment 1 was designed to determine the effects of pinching nodes 1, 2, 3, or 4 on ‘Pro Cut Gold’ sunflowers. Results from experiment 1 showed non-pinched plants produced marketable stem lengths and flower sizes, while pinched plants’ stem length, stem diameter, flower diameter, and disk diameter decreased compared to the non-pinched plants. The objective for experiment 2 was to evaluate pinching and spacing treatments on ‘Pro Cut Gold’ sunflowers. All spacings for non-pinched plants in experiment 2 produced marketable …

A Comparison Of Seed- And Seedling-Focused Ecologically Based Weed Management Strategies, Bryan Brown

Electronic Theses and Dissertations

Many farmers target weeds at the seedling stage, aiming to control weeds with the minimum amount of labor necessary to avoid crop yield loss. Other farmers with a more long-term, seed-focused approach aim to prevent weeds from setting seed so that emergence will be decreased in subsequent crops. These strategies likely vary in short- and long-term effects on farm ecological and economic health. In 2014–2016, I compared these strategies in a test crop of onion. Unexpectedly, due to high yields, the more labor intensive, seed-focused strategy was the most profitable. Case-study interviews of farmers who have adopted each approach indicated …

Evaluation Of Absorbezz On Swine Reproductive Health And A Comparative Study Of Two Commercially Available Swine Show Feeds, Scott G. Sutton

Electronic Theses and Dissertations

The efficacy of a feed supplement fed to gilts and sows was tested in study I. The supplement was stated to improve reproductive soundness, conception rates, immune health, and overall well-being of livestock. Thirty gilts were split into a control group (Base diet) and a treatment group (Absorbezz® 0.32 mL on base diet). Upon completion of the trial results indicate the treatment group significantly underperformed (

Two commercially available show pig growing rations were tested in study II to find a high quality, cost efficient product. A total of 10 pigs (5 barrows, 5 gilts), at an average weight of …

Evaluation Of Different Probiotic Strains Supplemented In Commercial Broiler Rations And Their Influences On Performance, Yield, And Intestinal Microbiota., Justin M. Glasscock

Electronic Theses and Dissertations

The objective of this study was to evaluate Bacillus megaterium, Bacillus licheniformis, and Bacillus subtilis, as probiotic strains compared to Bacitracin Methylene Disalicylate (BMD) 50 as the antibiotic growth promotor, supplemented in commercial broiler rations and their influences on performance, yield, and intestinal microbiota. This trial was completed as a randomized-block design with 4,800 birds split into 96, 5’x10’ pens, and randomly assigned to one of eight treatment groups. The birds were placed at a stocking density of 1.00 ft²/bird, (50 birds/pen), and reared on used pine shaving for 55 days. Throughout the study, bird …

Identification Of Physiological And Morphological Traits Governing High Water Use Efficiency In Alfalfa, Krishna Ghimire

Electronic Theses and Dissertations

Alfalfa is an important forage crop worldwide. Being deep-rooted, N2-fixing and high yielding, alfalfa has great economic, ecological and nutritional benefits. While alfalfa is a high yielding crop, its high productivity depends on irrigation water in many areas and consumes the greatest amount of water among all the major crops. With a growing demand for water resources due to an increase in human population and industrial water use, plus frequent drought due to climate change, irrigation water has become increasingly scarce and expensive. To sustain high production of alfalfa with limited water resource, alfalfa cultivars with improved water use efficiency …

Response Of Soil Properties To 23-25 Years Of Diverse Crop Rotations And Tillage Systems In South Dakota, Usa, Abdullah H. Alhameid

Electronic Theses and Dissertations

Diverse cropping systems and no-till (NT) are beneficial in improving soil organic carbon (SOC) and other soils properties. The present study was conducted to evaluate the interactions and impacts of long-term tillage and diverse crop rotation systems on soil quality indicators that include a range of soil chemical, physical, hydrological, and microbial properties. The study was established in 1991 at Beresford, South Dakota and included three crop rotation systems [2-yr; maize (Zea mays L.)-soybean (Glycine max L.), 3-yr; maize-soybean-oat (Avena sativa L.), and 4-yr; maize-soybean-oat-wheat (Triticum aestivum L.)] managed under two tillage systems (NT and CT; conventional- tillage). Soil sampling …

Using Remote Sensing To Estimate Crop Water Use To Improve Irrigation Water Management, Arturo Reyes-Gonzalez

Electronic Theses and Dissertations

Irrigation water is scarce. Hence, accurate estimation of crop water use is necessary for proper irrigation managements and water conservation. Satellite-based remote sensing is a tool that can estimate crop water use efficiently. Several models have been developed to estimate crop water requirement or actual evapotranspiration (ETa) using remote sensing. One of them is the Mapping EvapoTranspiration at High Resolution using Internalized Calibration (METRIC) model. This model has been compared with other methods for ET estimations including weighing lysimeters, pan evaporation, Bowen Ratio Energy Balance System (BREBS), Eddy Covariance (EC), and sap flow. However, comparison of METRIC model outputs to …

Investigation Of Candidate Loci Associated With Maize Perennialism, Anjun Ma

Electronic Theses and Dissertations

Developing perennial grain crops is an effective and crucial way to prevent soil erosion caused by conventional agriculture of using annual crops while meeting the increasing need of global food demand. We hypothesized that the regrowth in Zea might be controlled by two dominant complementary genes. F1 hybrids were created by crossing Zea diploperennis Iltis, Doebley & R. Guzman with annual Zea mays L. ssp. mays inbred line B73. A Total of 134 F2 plants derived from nine F1 were planted and phenotyped. A subpopulation of 94 F2 plants were genotyped with Genotype-by- Sequencing (GBS) and called 10,431 SNPs after …

Factors Affecting Feedlots' Decisions On Cattle Marketing Options: A National Study, Charlotte Owusu-Smart

Electronic Theses and Dissertations

This thesis investigates the economic implication of changing slaughter volume patterns across the cash and contract markets in the US cattle industry. Weekly time series data that spans from November 2002 to December 2015 was used in the analysis. Empirical evidence suggests that Mandatory Price Reporting (MPR) played an important role in changing slaughter volumes across the cash and contract markets. Additionally, price of feeder cattle, cattle quality characteristics (Choice-Select spread and the percentage of animals grading choice or better) among others influence feedlots’ decision to use a particular marketing arrangement.

Enhancing Cellulase Production Of Aureobasidium Pullulans For Use In Converting Dried Distillers’ Grains With Solubles Into A Higher Protein Feed, Emily L. Baldwin

Electronic Theses and Dissertations

Main limitations of dried distillers’ grains with solubles (DDGS) as meal for monogastric animals is the presence of high fiber content, reduced fat content, and poor amino acid balance. This causes a reduced economic value of DDGS for these species due to its low inclusion rates. The goal of this theses was to create new strains of a fungus, Aureobasidium pullulans, with enhanced cellulase production and use it to optimize an enzymatic saccharification, pretreatment, and fungal conversion process to enhance the nutritional value of DDGS. Various combinations of enzymatic saccharification, physical/chemical pretreatments, and mutant strains of fungi were investigated …

Performance Of The Producer Accumulator In Corn And Soybean Commodity Markets, Chad Te Slaa

Electronic Theses and Dissertations

This research quantifies risk reduction and performance of the producer accumulator contract in corn and soybean markets. To quantify performance, we use three alternative theoretical pricing models to estimate historical producer accumulator contract specifications in corn and soybean markets. We then compare the performance of the producer accumulator to eight alternative agricultural marketing strategy portfolios that are also used in new generation grain contracts. The performance measures we compare are: average bushel price that would be received by the producer, daily portfolio risk, and the Sharpe ratio. The period we examine performance was between 2008 and 2017. We investigate performance …

Encouraging Organic Agriculture: The Effects Of Conversion Subsidies, Sarah Adams Inkoom

Electronic Theses and Dissertations

This thesis examines the importance of conversional subsidies in accounting for an increase in organic acreage in the 12 North-Central States in the United States. Monthly time series data that spans from January 2002 to December 2014 was used in the analysis. Empirical evidence suggests that increase in organic acreage is due in part to the availability of conversion subsidies. Without government assistance, most small-scale farmers are not sufficiently motivated to switch to organic production due to the high initial costs involved in transitioning. Further, increased institutional support could facilitate organic adoption and its absence is detrimental to increasing the …

Human Dimensions Of Habitat Loss In The Plains And Prairie Potholes Ecoregion, Lily A. Sweikert

Electronic Theses and Dissertations

The Plains and Prairie Potholes Ecoregion (PPPE), is located in the north-central contiguous United States and is one of the most imperiled grassland regions in the world. Most of the region is privately owned and used for the production of agricultural commodities. In addition to its direct benefits to humanity, the PPPE provides multiple ecosystem services including, soil and water quality improvements, carbon sequestration, weather amelioration, and wildlife habitat. Recent increases in expansion of row crop agriculture concerns conservation practitioners about the long-term integrity of the PPPE. Conservation practitioners are looking to improve their private landowner conservation initiatives in the …

Improvement Of Milling And Nutritional Quality Characteristics Of Oats Through Genomic Selection, Sudha Neupane Adhikari

Electronic Theses and Dissertations

Oats can lower cholesterol, reduce risks of type-2 diabetes, and help prevent heart diseases when consumed daily. Therefore, it is important to evaluate and select breeding lines with desirable milling and nutritional quality traits. Genomic selection, which uses genotyping data to predict the breeding value of an individual, is a promising method to increase genetic gain by selecting for quality traits earlier in the line development process. In this study, we collected phenotypic data for three nutritional traits (protein, β- glucan, and fat content) and five milling quality traits (percent plumps, percent thins, percent plump groat, groat percent and thousand …

A Demonstration Study Of Drainage Water Management In Eastern South Dakota, Ashik Sahani

Electronic Theses and Dissertations

Subsurface drainage is a common water management practice for improving crop production in poorly drained soils; however, the practice is associated with several environmental concerns such as nutrient losses to downstream surface waters. These environmental concerns from subsurface drainage have prompted interest in drainage water management strategies such as controlled drainage. This study assessed the agronomic and environmental impacts of drainage water management in eastern South Dakota by using two demonstration plots for controlled and conventional drainage. Drain flow, nitrate and dissolved phosphorous concentration in drain water, shallow groundwater, crop yield, residual soil nitrate, soil moisture and temperature, soil penetration …

Local And Systemic Actions Of Gnrh Relating To Estradiol And Associated Reproductive Parameters In Beef Cattle, Jerica J.J. Rich

Electronic Theses and Dissertations

In cattle, estradiol is responsible for modulating many mechanisms involved in successful reproduction. Specifically estradiol is the primary signal for the initiation of standing estrus (Allrich, 1994), and cattle expressing estrus prior to fixed time AI (FTAI) have been reported to have increased preovulatory estradiol concentrations (Perry and Perry, 2008) and increased pregnancy success compared to animals that did not exhibit estrus (Richardson et al., 2016). Gonadotropin releasing hormone, classically, stimulates estradiol production via the two-cell two-gonadotropin hypothesis (Fortune and Quirk, 1988), and GnRH administered systemically in small doses (5 μg) has been reported to elicit an LH pulse similar …

Comprehensive Structural, Thermal And Toxicological Characterization Of 1-Ethyl-3-Methylimidazolium Alkylbenzenesulfonate Ionic Liquids, Hiranmayee Kandala

Electronic Theses and Dissertations

Synthesis and characterization of 1-ethyl-3- methylimidazolium alkylbenzenesulfonate ionic liquids for extraction of lignin from prairie cord grass have been studied. The ionic liquids (ILs) 1-ethyl-3- methylimidazolium benzenesulfonate (EBS), 1-ethyl-3- methylimidazolium toluenesulfonate (ETS) and 1-ethyl-3- methylimidazolium xylenesulfonate (EXS) have been synthesized in this research. An extensive structural, physical, thermal and toxicological characterization has been performed to understand the behavior of these ionic liquids. The reaction yield for the synthesis of EBS, ETS, and EXS ionic liquids was determined to be 91.2 ± 1.5 %, 96.1 ± 0.7 %, 99.0 ± 0.5 % respectively. Spectral analysis using NMR and FTIR confirms the …

Heterogeneous Nitrogen Losses: Cost-Effectiveness Analysis Of Changes In Management Across South Dakota, Archibold Quaye

Electronic Theses and Dissertations

The loss of nitrogen fertilizer into the atmosphere and waterways is of increasing concern for citizens and policy makers. This is particularly relevant for hypoxia in rivers, lakes, and oceans, but also relevant for policy makers in reducing the increasing concentration of greenhouse gases (GHG) in the atmosphere. GHGs trap heat in the atmosphere and include: carbon dioxide, methane, nitrous oxide and fluorinated gases. Overall, the estimated contribution from the agricultural sector to GHG emissions was 9% in 2013 (EPA, 2013). Further, the addition of nitrogen to the soil through the use of synthetic fertilizers is a main contributor to …

Interactive Effects Of Cover Crops, Invertebrate Communities And Soil Health In Corn Production Systems, Claire Lacanne

Electronic Theses and Dissertations

The adoption of regenerative farming practices is gaining traction, but the costs and benefits are not often considered on a systems level. Encouraging biodiversity and soil health is the goal of many agricultural practices used in regenerative farming; regenerative systems employ practices which abide by the two main principles of increasing biodiversity and decreasing disturbance, with the goal of encouraging ecosystem functioning to minimize inputs and maximize the productivity of a farm. I examined the management of corn (Zea mays) fields across four states in the Upper Midwest region of the United States. Regenerative systems in this study …

Cultivating Ecological Literacy And Rethinking Our Connections To Nature, Sean Fretwell

Electronic Theses and Dissertations

In this dissertation I explore the complex, often contested, relationships between humankind and nature. I consider the changing state of these relationships as they are influenced by factors rooted in science, technology, and economics. I also examine these relationships as they relate to human activities with agriculture. Considering the present state of environmental crisis and the abundance of evidence indicating the deleterious activities of humankind as primary causes for the many global calamities, I argue for revising industrially-driven ideologies; particularly those driven by the economic paradigm of capitalism and self-interest. Additionally, I submit that a return to kinship with nature …

Effects Of Fertilizer And Shade Management On Nitrogen Mineralization, Nitrifying Microbial Abundance And Nitrogen-Fixing Capacity Of Erythrina Poeppigiana In Coffee (Coffea Arabica) Agroforestry Systems In Costa Rica, Stuart E. Barker Iii

Electronic Theses and Dissertations

Worldwide chemical fertilizer use has increased by four times during the last 50 years. Conventional agricultural systems have a high nitrifying nature, resulting in a loss of nearly 70% of overall nitrogen (N) fertilizer inputs, an estimated economic loss of $81 billion. Over application of fertilizer is rampant in tropical developing nations in Central America, where coffee is major crop. Agroforestry offers ecologically sustainable land management strategies that promote the provision of ecosystem services such as, protection of biodiversity, climate change mitigation, and water and soil regulation. When legume trees are incorporated as the shade tree in coffee production, direct …