Life Sciences Commons^™

Evaluation Of Provisia Rice In Arkansas Rice Production Systems, Zachary Lancaster

Graduate Theses and Dissertations

With the continued evolution of herbicide resistance, it is becoming more difficult to achieve adequate weed control in Arkansas rice production systems. Thus, new technologies are needed to combat these troublesome weeds. A new non-GMO, herbicide-resistant rice type is under development that is resistant to quizalofop, an acetyl coenzyme A carboxylase (ACCase)-inhibiting herbicide that will allow for selective grass weed control in rice. With the commercialization of this technology by 2018, research was conducted to determine the best fit for quizalofop-resistant rice in current production systems. Experiments included evaluation of off-target movement of quizalofop, determination of plant-back risk from quizalofop …

Distinguishing Isolates Of Rotylenchulus Reniformis Endemic In Louisiana On The Basis Of Root-Associated Females And Egg Masses, Benjamin Mcinnes

LSU Master's Theses

The reniform nematode Rotylenchulus reniformis is a major pathogen of soybean and cotton in Louisiana. Previous studies have shown that populations of reniform nematode throughout the southern United States vary in reproduction and pathogenicity. Limited studies have been conducted to evaluate the reproduction and pathogenicity of populations of R. reniformis endemic in Louisiana. Studies with isolates of the nematode from eight cotton-producing parishes focused solely on reproduction of the root-associated infective and swollen female life stages with and without attached egg masses on the cotton genotypes MT2468 Ren3, M713 Ren5, and Stoneville 4946GLB2 and the soybean genotypes PI 548316, PI …

Occurrence Of Putative Endornaviruses In Non-Cultivated Plant Species And Characterization Of A Novel Endornavirus In Geranium Carolinianum, Rachel Herschlag

LSU Master's Theses

Endornaviruses are RNA viruses, which can infect plants yet cause no apparent symptoms. To date, most descriptions of endornaviruses infecting plants have been in cultivated species. A survey for endornaviruses in non-cultivated plants was initiated in 2015 and continued through 2017 in Baton Rouge, Louisiana. Two hundred and seven plant species were tested for distinctive dsRNA profiles by selective extraction and gel electrophoresis, of which seven contained endornavirus-like dsRNA. RT-PCR amplification of an endornavirus-specific sequence supported the endornavirus nature of six of the seven samples. Of the six host species, one species, Geranium carolinianum was confirmed as being infected with …

Characterization Of Aspergillus Flavus Soil And Corn Kernel Populations From Eight Mississippi River States, Jorge A. Reyes Pineda

LSU Master's Theses

Aspergillus flavus is a saprophytic ascomycete that can also actively invade the seed of crops and potentially contaminate them with harmful aflatoxins. Management of A. flavus currently relies mostly on biocontrol. However, there is still a lot to learn about its biology and ecology so the current approach can be improved. An A. flavus population survey was undertaken during the fall of 2014 across eight Mississippi River states to determine population diversity and geographic distribution of VCGs. Isolates from corn and soil were also characterized for VCG, sclerotial morphotype, mating type, cyclopiazonic acid, and aflatoxin production in order to determine …

Sweetpotato Virus C And Its Contribution To The Potyvirus Complex In Sweetpotato (Ipomoea Batatas), Favio E. Herrera Eguez

LSU Doctoral Dissertations

In Louisiana, sweetpotato (Ipomoea batatas) is infected in Louisiana by the four ubiquitous potyviruses: Sweetpotato feathery mottle virus (SPFMV), Sweetpotato virus G (SPVG), Sweetpotato virus 2 (SPV2) and the strain of SPFMV previously known as the common strain, recently renamed as Sweetpotato virus C (SPVC). These four viruses belong to the Potyviridae family, with single stranded RNA of ~11kb. In this group of plant viruses, a single polyprotein is coded entirely but later cleaved into ten mature proteins: P1, HC-pro, P3, 6K1, CI, 6K2, NIa-VPg, NIa-Pro Nib and Coat Protein (CP). In sweetpotato potyviruses, two additional open reading …

The Characterization Of Alpha-Carbonic Anhydrases Through Mutagenesis And Subcellular Localization In Arabidopsis Thaliana, Lance E. Pounds

LSU Master's Theses

Carbonic anhydrases (CAs) are zinc metalloenzymes which catalyze the interconversion of carbon dioxide and bicarbonate. It is hypothesized that CA activity facilitates CO₂ flux in leaf mesophyll cells to maintain optimal rates of photosynthesis or to maintain a pool of inorganic carbon for other metabolic processes. There are three classes of CAs (α, β, and γ) in the model plant Arabidopsis thaliana. The βCAs and γCAs have been well studied, but the αCAs have received relatively little study. There are eight αCA genes in Arabidopsis. This study investigates which αCAs are expressed in shoots, their tissue-specific expression, their …

Incidence Of Aphelenchoides Besseyi In Rice In Louisiana And Host Status Of The Most Widely Planted Cultivars, Felipe Mendes Carvalho Godoy

LSU Master's Theses

Aphelenchoides besseyi, the causal agent of white tip disease of rice, has been considered a minor pest of rice during the past 50 years in the United States. Recently this nematode has been found in a number of quarantine samples in Louisiana and Arkansas. Objectives of this research were to determine incidence of this nematode in commercial seed sold to producers in Louisiana and to determine the host status of major cultivars currently produced in the state. During 2015-2016, a total of 216 seed samples representing 3 medium grain, 18 long grain, and 4 long grain hybrid cultivars were …

Virulence Phenotypes Of Rotylenchulus Reniformis: Evaluation Of Host Status Of Cotton And Utility Of Single Nucleotide Polymorphisms (Snps) For Identification, Churamani Khanal

LSU Doctoral Dissertations

Comparative reproduction and pathogenicity of reniform nematode (Rotylenchulus reniformis) populations derived from single-egg masses and collected form West Carroll (WC), Rapides (RAP), Morehouse (MOR), and Tensas (TEN) parishes in Louisiana were evaluated in microplot and greenhouse trials. Data from microplot trials showed significant differences among isolates of reniform nematode in both reproduction and pathogenicity on upland cotton (Gossypium hirsutum) cultivars Phytogen 499 WRF, Deltapine 1133 B2RF, and Phytogen 333 WRF. Across all cotton cultivars, MOR and RAP isolates had the greatest and the least reproduction values of 331.8 and 230.2, respectively. Reduction in plant dry weight, …

Pathogenicity And Reproduction Of Isolates Of Reniform Nematode, Rotylenchulus Reniformis, From Louisiana On Soybean And Utility Of Single Nucleotide Polymorphisms To Evaluate Genetic Variability, Herath Mudiyanselage Kularathna

LSU Doctoral Dissertations

Experiments were conducted to evaluate soybean, Glycine max (L.) Merr., responses to indigenous isolates of the reniform nematode (Rotylenchulus reniformis) in Louisiana and to understand the genetic variability of these native isolates. Microplot and greenhouse experiments were conducted to evaluate the comparative reproduction and pathogenicity of single egg-mass populations of R. reniformis isolated from West Carroll (WC), Rapides, Tensas and Morehouse (MOR) parishes of Louisiana. Data from full-season microplot trials, displayed significant differences in reproduction and pathogenicity of the nematode with the commercial soybean cultivars REV 56R63, Pioneer P54T94R, and Dyna-Gro 39RY57. Significantly low population density was observed …

Better Health Through Horticulture: Using Horticulture To Influence Behavior And Reduce Stress, Rachel Ochylski

All NMU Master's Theses

Horticultural intervention in the form of gardening workshops connect participants to nature while they nurture another living organism. Horticultural intervention provides opportunities to socialize and engage in a meaningful activity, which have been recognized as helpful in the treatment of common mental health difficulties such as depression and anxiety. There is a lack of experimental studies based on quantitative data that focus on the effects of horticulture on holistic human health. The author evaluated the effects of a horticultural intervention on two separate groups, older adults and college students. The behavioral effects of engaging in gardening activities were evaluated using …

Optimizing Monitoring Efforts Of Kit Fox (Vulpes Macrotis) In Utah, Kelsey Alina Richards

Theses and Dissertations

The kit fox (Vulpes macrotis) is a species of conservation concern in western North America. Recent methods for monitoring populations of kit fox include using lures and remote cameras in an occupancy-modeling framework and habitat modeling to predict areas of occupancy. In chapter one, we tested the optimal lure and movement procedure for scent stations to maximize visits and detection of foxes, thereby improving estimates of occupancy. Between May 2015 and October 2016, we placed remote cameras at 522 random locations throughout nine study areas in the Colorado Plateau, Great Basin Desert, and Mojave Desert. Each location was …

Impacts Of A Mixed Ungulate Community On Aspen Forests: From Landscape To Leaf, Aaron C. Rhodes

Theses and Dissertations

This dissertation explores the differential effects of an ungulate community (cattle, mule deer, and American elk) on aspen (Populus tremuloides) regeneration pre- and post-fire disturbance. It's first chapter examines the differential effects of cattle, mule deer, and American elk on aspen regeneration across variable topography, climate and forest type; aspen dominant to conifer dominant subalpine forests. We found that each ungulate species, if sufficiently numerous, can cause aspen regeneration failure. Also, high elevation, southern aspect and high winter snow pack increase resilience to ungulate herbivory. Chapter two compares the efficacy of four methods of estimating ungulate impact on …

Giant Salvinia, Salvinia Molesta (Salviniaceae): Evaluation Of Sub-Optimum Temperatures On Survival Of The Giant Salvinia Weevil, Cyrtobagous Salviniae (Coleoptera: Curculionidae) And Integration Of Management Practices With Aquatic Herbicides, Lauren W. Cozad

LSU Master's Theses

Salvinia molesta is one of the world’s worst aquatic weeds and has cost Louisiana nearly $7 million worth of damage and economic impact each year. While aquatic herbicides and the biological control agent, Cyrtobagous salviniae, are the most efficacious control methods, there are limitations with each technology. Therefore, studies were conducted to evaluate insect mortality at upper and lower lethal temperatures and investigate integrated pest management (IPM) with insects and herbicides. Three Louisiana populations of C. salviniae were tested to evaluate cold tolerance and found that at 0°C, the Bayou Nicholas population was 1.3- and 1.4-times more cold tolerant …

Uncovering Tasselsheath3. A Genomic And Phenotypic Analysis Of A Maize Floral Mutant., Thompson Zhang

Masters Theses

In the modern era, maize has become the most successful crop grown in the United States. According to the USDA over 90 million acres of land are planted to corn and 96.2% of the U.S feed grain production is made up of the cereal. Part of the success of maize is due to its floral architecture, and its pollination technique in which the flower opens, exposing stamens containing pollen into the air. A unique organ called the lodicule functions as a release mechanism, forcing the flower to open. Lodicules from grasses and eudicot petals are homologous, yet there is little …

Extractable And Non-Extractable Polyphenols From Apples: Potential Anti-Inflammatory Agents, Makenzi Gennette

Masters Theses

With diet being such a huge factor in the development of diseases, emerging research has supported that apple consumption is a promising candidate for disease prevention due to the high phenolic content it possesses. These polyphenols can be found in two forms: extractable polyphenols (EP) and non-extractable polyphenols (NEP). Polyphenols have been shown to have strong anti-inflammatory and anti-oxidant properties, but up until this point, most researchers focus on EP fractions, while NEP are neglected. After the EP extraction using acetone and acetic acid (99:1) from the Apple Boost powder, three additional extraction methods were conducted on the remaining powder …

Impact Of Preemergent Herbicides, Mowing Height, And Fertilization On Centipedegrass Root Architecture And Drought Tolerance, Mike J. Adams

LSU Master's Theses

Mowing, N fertilization and the application of preemergence herbicides (PRE) are cultural practices performed on centipedegrass to improve overall turf quality. It is posited that increasing mowing height and application of fertilizers can lead to greater turfgrass rooting and increase drought survival; while the application of PRE is reported to potentially have negative impacts on rooting. At two locations in Louisiana, studies examining the effects of these practices on centipedegrass rooting and drought tolerance were conducted.

In the first 11-week study conducted, centipedegrass was treated with dithiopyr, pendimethalin, prodiamine, simazine, or indaziflam at the manufacturers’ labeled rates. During the 11-wk …

Optimization Of Overhead Irrigation In Relation To Irrigation Water Use Efficiency In The Louisiana Nursery Industry, Mark A. Wilson

LSU Master's Theses

Irrigation efficiency is an essential component of nursery production in the United States. To increase productivity of Louisiana growers, a series of studies were conducted to evaluate current nursery water practices. The objectives were to determine current irrigation practices; evaluate actual water usage; and compare nursery media for water utilization. A mailed survey determined that the majority of growers used can yard production (63%), overhead irrigation (79%), had no irrigation manager (82%) and did not collect/reuse water(61%); 50% do not test/calibrate their irrigation system. Based on this information, five nurseries using overhead irrigation were selected to determine water application and …

Characterization Of Plant-Spider Mite Interactions And Establishment Of Tools For Spider Mite Functional Genetic Studies, Nicolas Bensoussan

Electronic Thesis and Dissertation Repository

The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), is one of the most polyphagous herbivores feeding on cell contents of over 1100 plant species including more than 150 crops. However, despite its important pest status and a growing understanding of the molecular basis of its interactions with plant hosts, knowledge of the way mites interface with the plant while feeding and the plant damage directly inflicted by mites is lacking. Likewise, while the use of the reverse genetic tools in plants facilitated our understanding of the establishment of defense mechanisms against spider mite herbivory, such tools are lacking for …

Development And Evaluation Of Environmentally-Sensitive Genetic Male Sterile Lines For Louisiana Hybrid Rice, Federico Molina Casella

LSU Doctoral Dissertations

The Louisiana rice industry generates ~ 400 million dollars each year toward our state economy. Louisiana varieties are typically bred as pure lines, but hybrid (F₁) varieties have the potential to increase grain yields 15% or more over conventional sources. A primary goal of the LSU AgCenter Hybrid Breeding program is to breed elite cross combinations (hybrid varieties) through development of environmentally sensitive male sterile and fertile pollinator lines. Extensive multi-location yield trials in Louisiana have demonstrated high grain and head rice yields for candidate hybrids, but improvements in maturity, lodging, and grain chalk are needed. To address …

Characterization Of Acaricide Resistance, Plant-Mediated Rnai Against Two-Spotted Spider Mites (Tetranychus Urticae Koch), And Assessing Off- And Non-Target Effects, Hooman Hosseinzadeh Namin

Electronic Thesis and Dissertation Repository

The two-spotted spider mite (TSSM), Tetranychus urticae (Koch), is one of the most damaging agricultural pests in the world. It feeds on over 150 crops, causing considerable yield losses in greenhouses and agricultural fields. Currently, using synthetic acaricides is the main method to control TSSM. However, it can develop resistance to acaricides with repeated exposure, and typically resistance can occur within two to four years. To understand the underlying mechanisms of spider mite adaptation to acaricides is an essential part of resistance management strategy. The resistance ratio of the pyridaben-selected strain compared with the pre-selection strain was estimated at greater …

The Effect Of Diet On Midgut And Resulting Changes In Infectiousness Of Acmnpv Baculovirus In Trichoplusia Ni, Elizabeth Chen

Electronic Thesis and Dissertation Repository

The cabbage looper, Trichoplusia ni, a global generalist lepidopteran pest, has developed resistance to many synthetic and biological insecticides, requiring effective and environmentally acceptable alternatives. One possibility is the Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV). This baculovirus is highly infectious for T. ni, with potential as a biocontrol agent, however, its effectiveness is strongly influenced by dietary context. In this study, microscopy and transcriptomics were used to examine how the efficacy of this virus was affected when T. ni larvae were raised on different diets. Larvae raised on potato host plants had lower chitinase and chitin deacetylase transcript levels …

Urban Impacts To Forest Productivity, Soil Quality, And Canopy Structure In Forest Park, Portland, Oregon, Andrew David Addessi

Dissertations and Theses

Land use practices and exposure to low impact disturbances associated with an urban environment can alter forest structure and function. Past and ongoing research in Forest Park, a large urban forest in Portland, Oregon, suggests that mature mixed Douglas-fir (Psuedotsuga meziesii)-hardwood stands in the more urban end of the park lack a shade-tolerant conifer understory composed of the late successional conifer tree species, such western hemlock (Tsuga heterophylla) and western red-cedar (Thuja plicata). 5-year plot remeasurement data that characterizes productivity and mortality patterns did not show a strong relationship to urban proximity. Plot productivity …

Identity Behind Glass: The Second Gore Place Greenhouse, Sean P. Romo

Graduate Masters Theses

This thesis examines the second greenhouse at Gore Place, a historic country estate in Waltham, Massachusetts. Gore Place was owned by and named for Christopher and Rebecca Gore, members of the 18th- and 19th-century political and economic elite in New England. The greenhouse was constructed in 1806, and excavation at the site took place in 2004, 2008, and 2012. The latter two projects were data recovery excavations, which exposed portions of the greenhouse’s foundations and interior, as well as several features in the yard surrounding the building. Historic greenhouses were prestigious structures, financially accessible only to institutions, governments, and the …

Deciphering Sulfur Amino Acid Metabolism In Developing Seeds Of Common Bean, Jaya Joshi

Electronic Thesis and Dissertation Repository

With increasing food insecurity in the populated world, the number of people affected by chronic undernourishment is also increasing. Alone, protein energy malnutrition is linked to 6 million deaths annually. Despite being a good source of protein and dietary fibre, the quality of bean protein is limited because of sub optimal levels of essential sulfur amino acids: methionine and cysteine. Levels of cysteine and methionine in developing seeds have an inverse relationship with the non-protein sulfur amino acid S-methyl-cysteine (S-methylCys) and dipeptide g-glutamyl-S-methyl-cysteine (g-Glu-S-methylCys).

One of the strategies to improve protein quality in …

A Comparison Of Soils And Their Associated Microbial Communities As Affected By Sugarcane Cultivation, Adam Francis Bigott

LSU Master's Theses

In Louisiana, sugarcane has been grown in the same soils for over 200 years. A phenomenon wherein soils with a long-term sugarcane cropping history produce decreased yields compared to adjacent land without a recent history of sugarcane cultivation has been documented in multiple sugarcane growing regions. Research in both Louisiana and internationally has shown positive plant growth responses when soils with a long-term cultivation history are sterilized or treated with selective biocides, suggesting there is a biological component to the underlying soil health issue. In this study, soil microbial ecology was compared for paired sites with short and long-term sugarcane …

A Modelling Approach: Effects Of Exuded Organic Acids And Exogenous Chelating Ligands On Bioavailability And Uptake Of Metals By Radishes (Raphanus Sativus) Grown In Hydroponics., Sergio A. Dominguez Romero

Electronic Thesis and Dissertation Repository

Metal contamination of soil can be reduced by adding chelators to improve the efficiency of metal uptake in phytoremediation, but optimal concentrations and types of chelators have not been determined. A geochemical model (Visual MINTEQ3.1) was used to estimate the effects of four chelators on the solubility of four metals in hydroponic solution. The model showed that no iron was soluble in the absence of a chelator, while the solubilities of cadmium, copper and zinc were high with or without chelators. Despite low iron uptake in all treatments, symptoms of iron-deficiency were not visible. High concentrations of exuded organic acids …

Evaluating Mine Soil Prepared By Scraper Pans For Herbaceous Plants And Pine Seedlings At An East Texas Lignite Surface Mine, Hannah Z. Angel

Electronic Theses and Dissertations

Since 1974, Luminant Mining Company, LLC (Luminant) has planted over 38.7 million trees on its reclaimed lignite surface mine operations in Texas. For decades, the use of improved reclamation techniques on Luminant’s mined lands have resulted in over 31,160 ha reclaimed to forests, wildlife habitat, and pastures with productivity levels similar to those found on unmined lands. The development of new reclamation methodologies offers opportunities to further improve productivity of planted trees at Luminant’s Martin Lake Oak Hill Mine in east Texas. The conventional haulback or ‘truck shovel’ reclamation method uses haul trucks for the selective transport and placement of …

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 …

Response Of Glyphosate Resistant Palmer Amaranth (Amaranthus Palmeri) To Protoporphyrinogen Oxidase Inhibiting Herbicides In Tennessee, Alinna Marie Umphres

Doctoral Dissertations

In many agronomic cropping systems across the United States, Palmer amaranth (Amaranthus palmeri) is the most economic and troublesome weed for producers. The introduction of glyphosate resistant (GR) crops gave producers the benefit of controlling Palmer amaranth as well as other weeds, a broad window of application, and reduced tillage practices. With the confirmation of GR Palmer amaranth, producers implemented protoporphyrinogen oxidase (PPO or Protox)-inhibiting herbicides to control these populations in crops such as soybean [Glycine max (L.) Merr.] and cotton [Gossypium hirsutum (L.)]. However the continuous use of PPO herbicides has caused a shift in …

Genomic And Physiological Approaches To Improve Drought Tolerance In Soybean, Avjinder Kaler

Graduate Theses and Dissertations

Drought stress is a major global constraint for crop production, and improving crop tolerance to drought is of critical importance. Direct selection of drought tolerance among genotypes for yield is limited because of low heritability, polygenic control, epistasis effects, and genotype by environment interactions. Crop physiology can play a major role for improving drought tolerance through the identification of traits associated with drought tolerance that can be used as indirect selection criteria in a breeding program. Carbon isotope ratio (δ13C, associated with water use efficiency), oxygen isotope ratio (δ18O, associated with transpiration), canopy temperature (CT), canopy wilting, and canopy coverage …