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An Evaluation Of Watermelon (Citrullus Spp.) Germplasm For Additional Sources Of Resistance To The Twospotted Spider Mite (Tetranychus Urticae Koch)., Hector Cantu Jr.

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

Fourteen U.S plant introduction (PI) accessions of C. lanatus var. lanatus (4), C. lanatus var. citroides (5) C. colocynthis (5) and a known susceptible commercial cultivar ‘Sugar Baby’ were evaluated for resistance to the twospotted spider mite, Tetranychus urticae Koch, in a limited free-choice and free-choice bioassay under laboratory conditions. The limited free choice bioassay, involved nine Petri dish cages that held five randomly assigned leaves individually inoculated with two adult females and one adult male. Eggs, larva, and adults were counted over a nine day period. The free choice bioassay involved the even distribution of three mite infested …

Nitrogen Management Practices And Colored Plastic Mulch Films Affecting Spider Mites And Aphids On Winter Strawberry In A High Tunnel, Kevin Philip Durden

Graduate Theses and Dissertations

Off season high tunnel strawberry production has the potential to augment income for Arkansas fruit growers during an unproductive time of the year, however management guidelines do not exist. At the University of Arkansas Agricultural Research and Extension Center in Fayetteville, AR studies were conducted to evaluate the effects of four nitrogen (46-0-0 urea fertilizer) fertigation rates (0.75, 0.50, 0.25, 0.0 kg N/day/ha) and red or black colored plastic mulch films on densities of twospotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae), numbers of parasitized cotton aphids, and fruit yield weight. Foliar and …

Summaries Of Arkansas Cotton Research 2013, Derrick M. Oosterhuis

Arkansas Agricultural Experiment Station Research Series

No abstract provided.

Infiltration And Runoff Parameters For Tilled And No-Till Row Crops, Andrew J. Volkmer

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Infiltration and runoff are hydrologic processes that effect the amount of water available to plants, for groundwater recharge, and for stream flow. No-till planting (NT) is a management practice used to reduce soil erosion, increase water infiltration, and reduce soil water evaporation, and can have great impact on infiltration and runoff. An investigation was conducted to determine the impact of NT on infiltration and runoff when compared to tilled conditions.

Runoff and precipitation data was gathered from sites at Fillmore County, NE, Phelps County, NE, the USDA-ARS North Appalachian Experimental Watersheds (NAEW) near Coshocton, OH, and the Lennoxville Research Station …

B. R. Wells Arkansas Rice Research Studies 2013, R. J. Norman, K.A. K. Moldenhauer

Arkansas Agricultural Experiment Station Research Series

No abstract provided.

Ammonia-Oxidizing Bacteria And Archaea Under Continuous Maize: The Influence Of Tillage, N Input And Aggregation On Abundance And Community Composition, Lauren Segal

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

Nitrification involves the oxidation of ammonium (NH₄⁺) and is an important component of the overall N cycle. Nitrification occurs in two steps; first by oxidizing ammonium to nitrite, and then to nitrate. The first step is often the rate limiting step. Until recently ammonia-oxidizing bacteria (AOB) were thought to be the sole contributors to this process; however, the discovery of crenarchaeota, ammonia-oxidizing archaea (AOA), in marine environments has led to further study of their role in nitrification. Current literature supports the dominance of AOA over AOB in terrestrial ecosystems; however, little is known about what drives their …

Selection On Crop-Derived Traits And Qtl In Sunflower (Helianthus Annuus) Crop-Wild Hybrids Under Water Stress, Birkin R. Owart, Jonathan Corbi, John M. Burke, Jennifer M. Dechaine

All Faculty Scholarship for the College of the Sciences

Locally relevant conditions, such as water stress in irrigated agricultural regions, should be considered when assessing the risk of crop allele introgression into wild populations following hybridization. Although research in cultivars has suggested that domestication traits may reduce fecundity under water stress as compared to wild-like phenotypes, this has not been investigated in crop-wild hybrids. In this study, we examine phenotypic selection acting on, as well as the genetic architecture of vegetative, reproductive, and physiological characteristics in an experimental population of sunflower crop-wild hybrids grown under wild-like low water conditions. Crop-derived petiole length and head diameter were favored in low …

Management Of Root Knot Nematode (Meloidogyne Incognita ) In Indiana Soybeans, David Edgardo Perla Martinez

Open Access Theses

The aim of this project was to evaluate different strategies for management of Root Knot Nematode (RKN) on soybean and tomato in Indiana. Seed treatments were evaluated under field and greenhouse conditions, but no effect on RKN populations was observed. Soybean lines evaluated for resistance to RKN under greenhouse conditions showed that six lines may be resistant to RKN. Four different commercial mustard cover crops were evaluated for their bio-fumigant impact on RKN populations in the production of tomato. Euruca sativa, Cv. Nemat was a poor host of RKN. A positive impact on the vigor of the tomato plants followed …

Fact Or Fiction: Random Mating In Field Populations Of Western Corn Rootworm (Diabrotica Virgifera Virgifera Leconte) Emerging On Bt And Refuge Corn Plants, Steven Joel Smith

Open Access Theses

The western corn rootworm, or WCR, (Diabrotica virgifera virgifera LeConte) is the most significant pest of field corn (Zea mays) in the United States, and has recently expanded its range into Europe. Since 2004, hybrid corn containing Bt toxins targeting the corn rootworm complex have been heavily adopted and are now the primary control measure for this pest in North American corn production. ^ The evolution of resistance is an ongoing concern, and to ensure Bt products will retain their usefulness, insect resistance management (IRM) tactics using various refuge structures have been adopted. One of the key …

Agronomic And Genetic Characterization Of Aluminum Tolerance In A Recombinant Inbred Population Of Sorghum [Sorghum Bicolor (L.) Moench], Amanda Christine Easterly

Open Access Theses

Acid soils are estimated to cover up to 30% of arable soils globally and lead to significant limitations on agricultural productivity, primarily through aluminum toxicity. In sorghum [Sorghum bicolor (L.) Moench], significant genetic variation exists for tolerance to phytotoxic species of aluminum; tolerance is conferred through the exudation of citrate at the root tip, binding aluminum in the soil rhizosphere. A gene in the multidrug and toxic compound extrusion (MATE) family is the primary tolerance locus in sorghum. The purpose of this research was to evaluate a recombinant inbred line (RIL) population of sorghum segregating for SbMATE to establish …

Managing Swine Manure In Double-Crop Soybean, Donald Joseph Graper

Open Access Theses

Animal production, especially swine (Sus scrofa domesticus ) and poultry, has increased in the United States prompting the need to manage the larger volume of manure beyond land applications to supply nitrogen (N) for corn (Zea mays ) production. Applying swine manure to soybean (Glycine max ) has been shown to increase grain yield due to N supply. The goal of this research was to determine if swine manure applications to double-crop soybean following wheat can limit manure N loading to the soil by extending management options, increase soybean biomass and grain production, and increase N removal …

Functional Genomics Of Maize Endosperm Maturation And Protein Quality, Lingling Yuan

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

Maize is one of the most important cereal crops and widely cultivated throughout the world. The study on maize kernel development including protein quality improvement is essential for removing dietary protein deficiency because of the lack of essential amino acids, especially lysine and tryptophan, in maize kernel. Quality Protein Maize (QPM) is a hard kernel variant of the high-lysine mutant, opaque-2. We created opaque QPM variants to identify opaque-2 modifier genes and to investigate deletion mutagenesis combined with Illumina sequencing as a maize functional genomics tool. A K0326Y-QPM deletion mutant, line 107, was null for the 27- and 50-kD …

Spatial And Temporal Distribution Of Fungicides Applied To Creeping Bentgrass, Kurt Ronald Hockemeyer

Open Access Theses

Turf managers often rely on fungicides to limit damage caused by root diseases. Since fungicides do not move basipetally, they are effective only when fungitoxic concentrations are delivered to the rhizosphere. This research focused on the distribution of modern fungicides in verdure, thatch, sand, and roots of creeping bentgrass (Agrostis stolonifera L. var. palustris (Huds.) Farw.) maintained as a putting green. Fungicides (azoxystrobin (methyl (E)-2-[2-[6-(2-cyanophenoxy)pyrimidin-4-yloxy]phenyl]-3-methoxyacrylate), propiconazole (1,2,4-Triazole, 1-((2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl)methyl), pyraclostrobin (carbamic acid, [2-[[[1-(4-chlorophenyl)-1H-pyrazol-3-yl]oxy]methyl]phenyl]methoxy-,methyl ester), and thiophanate-methyl (dimethyl 4,4'-o-phenylenebis[3-thioallophanate]) were applied to replicate field plots in a water volume of 815 L ha-1. Plots were sampled over time (0, 3, 7, 10, …

Genome Sequence Of The Listia Angolensis Microsymbiont Microvirga Lotononidis Strain Wsm3557ᵀ, Wayne Reeve, Julie Kaye Ardley, Rui Tian, Sofie E. De Meyer, Jason Terpolilli, Vanessa Melino, Ravi P. Tiwari, Ronald J. Yates, Graham William O'Hara, John Gregory Howieson, Mohamed Ninawi, Xiaojing Zhang, David Bruce, Chris Detter, Roxanne Tapia, Cliff Han, Chia-Lin Wei, Marcel Huntemann, James Han, I-Min Chen, Konstantinos Mavromatis, Victor Markowitz, Ernest Szeto, Natalia Ivanova, Ioanna Pagani, Amrita Pati, Lynne Goodwin, Tanja Woyke, Nikos Kyrpides

Grain and Other Field Crops Research Articles

Microvirga lotononidis is a recently described species of root-nodule bacteria that is an effective nitrogen- (N2) fixing microsymbiont of the symbiotically specific African legume Listia angolensis (Welw. ex Bak.) B.-E. van Wyk & Boatwr. M. lotononidis possesses several properties that are unusual in root-nodule bacteria, including pigmentation and the ability to grow at temperatures of up to 45°C. Strain WSM3557T is an aerobic, motile, Gram-negative, non-spore-forming rod isolated from a L. angolensis root nodule collected in Chipata, Zambia in 1963. This is the first report of a complete genome sequence for the genus Microvirga. Here we describe the features …

Genome Sequence Of Rhizobium Leguminosarum Bv Trifolii Strain Wsm1689, The Microsymbiont Of The One Flowered Clover Trifolium Uniflorum, Jason Terpolilli, Tian Rui, Ronald J. Yates, John Gregory Howieson, Philip Poole, Christine Munk, Roxanne Tapia, Cliff Han, Victor Markowitz, Reddy Tatiparthi, Konstantinos Mavromatis, Natalia Ivanova, Amrita Pati, Lynne Goodwin, Tanja Woyke, Nikos Kyrpides, Wayne Reeve

Grain and Other Field Crops Research Articles

Rhizobium leguminosarum bv. trifolii is a soil-inhabiting bacterium that has the capacity to be an effective N2-fixing microsymbiont of Trifolium (clover) species. R. leguminosarum bv. trifolii strain WSM1689 is an aerobic, motile, Gram-negative, non-spore-forming rod that was isolated from a root nodule of Trifolium uniflorum collected on the edge of a valley 6 km from Eggares on the Greek Island of Naxos. Although WSM1689 is capable of highly effective N2-fixation with T. uniflorum, it is either unable to nodulate or unable to fix N2 with a wide range of both perennial and annual clovers originating from Europe, North America …

Development Of Genetic Ssr Markers In Blumeria Graminis F. Sp. Hordei And Application To Isolates From Australia, Madeline Tucker, C S. Moffat, Simon R. Ellwood, K C. Tan, Kithsiri Jayasena, Richard P. Oliver

Biosecurity Research Articles

The barley powdery mildew pathogen, Blumeria graminis f. sp. hordei (Bgh), exists in numerous haplotypes and displays significant differences in fungicide sensitivity. It causes considerable yield losses throughout the world. Microsatellite SSRs are useful tools to study the population level and biogeographic aspects of intraspecific diversity, but so far none have been defined for Bgh. Here, eight polymorphic microsatellite loci were identified and characterized. Primer pairs amplifying the loci were then applied to 111 isolates of Bgh from Australia. The number of alleles per locus ranged from 4 to 13, and Nei's genetic diversity ranged from 0·25 to 0·76. The …

Grazing Method Effects On Forage Production, Utilization, And Animal Performance On Nebraska Sandhills Meadow, Miles D. Redden

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

Mob grazing using ultrahigh stocking densities is promoted as a tool to increase the health and productivity of grasslands by increasing nutrient cycling and soil organic matter. Mob grazing can be defined as a strategy in which area available to grazing animals is restricted to achieve stocking densities of 200,000 kg/ha or greater. Objectives were to determine herbage production, utilization, and cattle weight gains among ultrahigh stocking density grazing and more conventional grazing methods on a Sandhills subirrigated meadow. Treatments included two replications of each of the following: four-pasture rotational grazing with two occupations per pasture in an 80-day grazing …

Synthesis Of The Effect Of Fire On Lesser Prairie‐Chickens, Eric Thacker, Dirac L. Twidwell Jr

Department of Agronomy and Horticulture: Faculty Publications

In this synthesis, we reviewed the scientific literature pertaining to the effects of fire on lesser prairie‐chickens and their habitat. Overall, research is generally lacking that directly assesses relationships among fire, both as a regime and a discrete event, to its effect on lesser prairie‐chicken behavior and habitat value. Yet, research has quantified the effects of fire on vegetation throughout the distribution of the lesser prairie‐chicken, which has been linked to known metrics of habitat value and broad landscape‐level habitat requirements.

To summarize the literature, lesser prairie‐chickens require broad landscapes of fire‐dependent grass‐shrub vegetation. Changes in the eco‐evolutionary fire regime …

Relationship Between 1,3-Dichloropropene And Nitrogen Fertility In Cotton In The Presence Of Root-Knot And Reniform Nematodes, Amanda Michelle Greer

Graduate Theses and Dissertations

The use of soil fumigation for nematode management in cotton (Gossypium hirsutum) has become increasingly popular in recent years in the absence of effective resistant cultivars. While soil fumigation is relatively expensive, lint yields have consistently been improved to make this practice profitable in fields with severe nematode pressure. Growers in southern Arkansas have observed changes in cotton growth patterns when severely infested fields are fumigated. The most noticeable change has been excessive (rank) growth resulting in an increased need for growth regulators, especially where the nitrogen fertilization exceeds standard recommendations. Field studies were conducted between 2007 and 2010 to …

Drivers Of Spatial And Temporal Variation In Soybean Yield And Irrigation Requirements In The Western Us Corn Belt, Patricio Grassini, Jessica A. Torrion, Kenneth Cassman, Haishun Yang, James Specht

Department of Agronomy and Horticulture: Faculty Publications

Both rainfed and irrigated soybean production are important in Nebraska (western US Corn Belt), accounting for a respective 48 and 52% of the state’s soybean production of 7 Mt on a respective 55 and 45% share of the state soybean area of 1.9 Mha. To date, no assessment of factors that may account for regional and inter-annual variation in yield and irrigation amount has been performed. To accomplish that objective, we evaluated a database containing on-farm field yields and total irrigation amount used in those fields. These data have been collected annually from ca. 1000 soybean fields in six regions …

Population Dynamics Of Triticum Mosaic Virus In Various Host Species, Melissa S. Bartels

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

It has been established that RNA viruses should be genetically diverse, due to the high error rate of their RNA-dependent RNA polymerases and the lack of proof-reading capabilities. Plant RNA viruses are not as genetically diverse as expected. Evolutionary factors, such as purifying selection and bottlenecks that favor genetic stability, might be affecting plant viral populations. Otherwise RNA virus populations, with their potential for extreme diversity, might acquire a lethal number of mutations leading to the collapse of the population.

Triticum mosaic virus (TriMV) populations maintained in a controlled greenhouse environment displayed genetic stability. The mutation frequency per nucleotide of …

Spreading The Char: The Importance Of Local Compatibility In The Diffusion Of Biochar Systems To The Smallholder Agriculture Community Context, Laura C. V. Munoz

Pomona Senior Theses

This thesis enters the context of smallholder agriculture communities in the developing world. It explores the potentials of biochar and what biochar systems could bring to the smallholder communities while simultaneously bringing environmental benefits. It then acknowledges the challenges of diffusion –the spreading of an unfamiliar innovation. It seeks to answer the question of what will make diffusion of biochar systems more successful in the smallholder context, fixating on the characteristic of compatibility as well as the role local community members can play in making a new biochar system more visible to the rest of the communities.

Stacking Of A Stearoyl-Acp Thioesterase With A Dual-Silenced Palmitoyl-Acp Thioesterase And Δ12 Fatty Acid Desaturase In Transgenic Soybean, Hyunwoo Park, George L. Graef, Yixiang Xu, Patrick Tenopir, Thomas E. Clemente

Department of Agronomy and Horticulture: Faculty Publications

Soybean (Glycine max (L.) Merr) is valued for both its protein and oil, whose seed is composed of 40% and 20% of each component, respectively. Given its high percentage of polyunsaturated fatty acids, linoleic acid and linolenic acid, soybean oil oxidative stability is relatively poor. Historically food processors have employed a partial hydrogenation process to soybean oil as a means to improve both the oxidative stability and functionality in end-use applications. However, the hydrogenation process leads to the formation of trans-fats, which are associated with negative cardiovascular health. As a means to circumvent the need for the hydrogenation process, genetic …

Fungicide Resistance In Botrytis Cinerea From Strawberry - Molecular Mechanisms And Management, Anja Grabke

All Theses

The United States is the largest producer of strawberries worldwide, generating approximately $2.4 billion worth of fruit each year. Strawberry production, however, is often threatened by pathogens. One of the most destructive fungal pathogens is Botrytis cinerea, the causal agent of gray mold disease. The control of gray mold in commercial fields is largely dependent on the application of fungicides, including the dicarboximide iprodione and the hydroxyanilide fenhexamid. Because both fungicides are prone to resistance development, a survey was conducted to determine the occurrence and prevalence of fungicide resistance. Single-spore isolates were collected from strawberry fields in Florida (for …

Efficacy Of Rice Insecticide Seed Treatments At Selected Nitrogen Rates For Control Of The Rice Water Weevil, Lissorhoptrus Oryzophilus Kuschel, Mallory Elise Everett

Graduate Theses and Dissertations

Seed-applied insecticides are the standard control method used to prevent rice water weevil (Lissorhoptrus oryzophilus Kuschel) injury to rice (Oryza sativa L.) roots, and often results in greater yields than rice that receives no seed-applied insecticide. Yield increases from seed-applied insecticides often occur even when insect pressure is low and should not cause yield loss. The research objective was to evaluate the effect of urea-nitrogen rate and seed-applied insecticide on number of rice water weevil larvae, nitrogen uptake and rice grain yield. Six trials were conducted at the Pine Tree Research Station (PTRS) and the Rice Research Extension Center (RREC) …

Milling And Functional Properties Of Co-Mingled Rice Cultivars, Nikhil N. Basutkar

Graduate Theses and Dissertations

Differences have been observed in the milling and functional properties of different rice cultivars, particularly between hybrid and pureline cultivars. Co-mingling of rice cultivars commonly occurs during harvest, storage and drying operations. Thus, there is a need to study the effect of co-mingling on the milling and functional properties of rice cultivars. Two long-grain, hybrid (H) cultivars CL XL745 and CL XL729 and two long-grain, pureline (P) cultivars CL 151 and Wells were used to prepare CL XL745/CL 151 (H/P), CL XL745/CL XL729 (H/H) and Wells/CL 151 (P/P) co-mingles, mixed in various proportions. Milled rice yield (MRY), head rice yield …

Estimating Nitrogen Credits From Poultry Litter On Silt Loam Soils In Arkansas Using The Nitrogen-Soil Test For Rice: N-Star, Chester Eugene Greub

Graduate Theses and Dissertations

Rice (Oryza sativa L.) is one of the most important global cereal crops and is grown on a substantial number of hectares in Arkansas each year. Consequently, Arkansas is the leading rice producing state in the United States accounting for almost half of domestic production. The development and release of N-STaR (Nitrogen-Soil Test for Rice) allows producers to predict site-specific N fertilizer needs for rice production in Arkansas, with N-STaR being a predictor of potentially mineralizable-N. Furthermore, poultry production is a thriving commodity in Arkansas, producing a substantial amount of poultry litter (PL) annually. Rice producers are applying PL to …

Fertilizer Nitrogen Uptake Efficiency In Soft Red Winter Wheat And The Ability Of N-Star To Detect Alkaline Hydrolyzable Nitrogen In Crop Residues, Lana Aubrey Clark

Graduate Theses and Dissertations

Soil testing methods such as the Illinois Soil Nitrogen Test (ISNT) and Direct Steam Distillation (DSD) have been developed which measure alkaline hydrolyzable-N (AH-N) as a means of estimating potentially mineralizable-N. Crop residues play an important role in N cycling. However, the ability of the ISNT and DSD methods to determine AH-N within crop residues is unknown. Therefore, the first objective of this study was to determine the ability of the ISNT and DSD to quantify potentially mineralizable-N within five different crop residues common to Arkansas. Corn (Zea mays L.), soybean (Glycine max, L.), wheat, rice (Oryza sativa, L.), and …

Primocane-Fruiting Blackberry: Optimum N-Fertilization, Jose Carlos Reynoso Campos

Graduate Theses and Dissertations

This study was conducted in 2011 at the University of Arkansas, Fayetteville to determine the optimum rate and time of nitrogen (N) application for `Prime-Ark® 45' primocane-fruiting (PF) blackberries under high tunnel conditions. There were four N treatments: Control (0), 10, 10-split, and 20 kg*ha-1 (Treatments 1, 2, 3, 4, respectively). In a randomized complete block (RCB) design, the following variables were compared: total and marketable yield, fresh weight of plant above ground, and cane diameter. Total fruit yields for Treatments 2 and 3 (2.5 and 2.5 kg, respectively) were highest and significantly different from the other treatments (p< 0.05). Marketable yield had a similar trend as total fruit yield, although not significantly different. Cane diameter and plant fresh weight were not significantly affected by fertilizer treatments. There were not significant differences in N content in leaves among treatments. Results indicated that either a single or split N application of 10 kgN*ha-1 could result in better yields.

Four …

Methane Emissions And Ammonia Volatilization From Drill-Seeded, Delayed-Flood Rice On A Silt-Loam Soil In Arkansas, Christopher Wade Rogers

Graduate Theses and Dissertations

The Environmental Protection Agency (EPA) currently uses a single methane (CH4) emissions factor of 160 kg CH4-C ha-1 for a primary rice (Oryza sativa L.) crop. The emissions factor is based on studies that do not adequately represent current management practices in Arkansas. Another concern is pre-flood fertilizer nitrogen (N) management, as the common N source, urea, is prone to loss via ammonia (NH3) volatilization. Thus, the objective of this research was to investigate trace gas emissions from rice on a silt-loam soil, including CH4 emissions as influenced by nitrogen (N) fertilization (i.e., optimal N and no N) in 2011, …