Agricultural Science Commons^™

Identification Of Blda As A Major Regulator Of Virulence In The Sweetpotato Soil Rot Pathogen Streptomyces Ipomoeae And Characterization Of Distinct Clostridium Sweetpotato Soft Rot Isolates, Kuei-Ting Yang

LSU Doctoral Dissertations

Streptomyces ipomoeae is the causative agent of Streptomyces soil rot on sweetpotato, a disease characterized by extensive necrosis of both adventitious and storage roots. While Streptomyces potato scab pathogens produce a phytotoxin (thaxtomin A), which is induced in the presence of cellobiose and suberin, S. ipomoeae produces a less-modified, phytotoxin (thaxtomin C), whose inducer has not been identified. To investigate transcriptional regulation of thaxtomin C production, we inserted a promoter involved in thaxtomin C synthesis upstream of the gusA reporter in an S. ipomoeae strain. Reporter gene expression was significantly upregulated in the presence of size-fractionated sweetpotato extract (SPE). The …

Within-Field Yield Prediction For Sugarcane And Rice Focused On Precision Agriculture Applications, Felippe Hoffmann Silva Karp

LSU Master's Theses

Food and energy security are two main topics when it comes to the on-growing world population. Rice and sugarcane play an important role in this scenario since sugarcane can be used for energy production and rice is one of major staple cereals. In this scenario, Precision Agriculture (PA) management strategies aims to improve productivity, efficiency, profitability, and sustainability, and can help agriculture to fulfill the needs of the growing population in a sustainable way. However, yield maps are essential for PA, but its adoption is still very low. Thus, the main objective of this study was to evaluate the potential …

Ecology Of The Roseau Cane Scale (Nipponaclerda Biwakoensis, Hemiptera: Aclerdidae) In Coastal Louisiana, Leslie Alejandra Aviles Lopez

LSU Master's Theses

Common reed, Phragmites australis, is the dominant plant in the Mississippi River Delta (MRD), Louisiana. Phragmites australis stands reduce soil erosion from wave action, protect the oil infrastructure, and freshwater habitats. In the fall of 2016, widespread reed die-backs in the MRD were associated with outbreaks of an invasive scale Nipponaclerda biwakoensis (Hemiptera: Aclerdidae). Due to the recent detection of the scale, there was limited knowledge of its ecology in the adventive range, and its impacts on P. australis lineages. Therefore, the objectives of my thesis were to determine (1) the host specificity of the N. biwakoensis in important economic …

Cover Cropping In Soybean-Corn Rotation System: Economic, Agronomic, And Soil Fertility Impact, Jose Rodolfo Mite

LSU Doctoral Dissertations

Planting winter-annual cover crops prevent soil erosion, reduces water runoff, and improves soil structure and soil quality. This research was conducted from 2017 to 2019 to evaluate the nutrient turnover of different species of cover crops in soils under different row crop production systems in Northeast and Central Louisiana. In Northeast Louisiana (Site 1, 2, and 3), treatments (cover crops and no cover crop) were arranged in a strip trial with three replications. At the Ben Hur Research Station, the treatments included three planting dates (September, October, and November) with [7 kg ha^-1 of phosphorus (P) and potassium (K)] …

Soil Health On A Small-Scale Sustainable Vegetable Farm In South Louisiana, Allison Guidroz

LSU Master's Theses

One of the biggest challenges facing the world today is the need to provide nutritious food to an ever-growing population in a way that does not compromise the ecosystem services of the soil that are necessary for life. The evidence for widespread degradation of the soil has been a major contributor in the increased interest in soil health. Most of the research in soil health has focused on field crops, which has led to a gap in the research of soil health on vegetable cropping systems. This objective of this study was to analyze the health of the soil on …

Evaluation And Enhancement Of Carbon Sequestration Potential Of Existing Vegetation Along Roadsides, Vikram Kapoor, Jeffrey Hutchinson, Samer Dessouky

Data

Corresponding data set for Tran-SET Project No. 18HSTSA01. Abstract of the final report is stated below for reference:

"The objectives of this study were to evaluate the vegetative composition and carbon sequestration potential of vegetation along a major roadway in Texas. Soil and vegetation were evaluated along IH-35 within Bexar County for composition and carbon content. Three 20 m transects were placed at each site and percent vegetative cover was estimated and above ground plant biomass, and soil was collected from three 0.25 m2 subplots along each transect. Plant and soil samples were analyzed for carbon content. Two non-native grasses, …

Strategies To Overcome Antagonism Of Quizalofop-P-Ethyl When Applied In Mixture With Other Herbicides, Lucas C. Webster

LSU Master's Theses

A field study was conducted in 2017 and 2018 at the LSU Agricultural Center H. Rouse Caffey Rice Research Station (RRS) near Crowley, LA. to evaluate the influence of different adjuvants in overcoming the antagonism of quizalofop when mixed with bispyribac in Louisiana rice production. The antagonism of quizalofop mixed with bispyribac plus HCOC at 14 DAIT was overcome with a neutral interaction observed at 28 DAIT for barnyardgrass control with an observed control of 91%, compared with an expected control of 97%. The addition of COC, SNS or HCOC into a mixture of quizalofop plus bispyribac provided synergistic or …

The Tripartite Interaction Between Arbuscular Mycorrhizal Fungi, Rice, And Insects, Lina Bernaola Alvarado

LSU Doctoral Dissertations

Losses caused by pests remain an important limitation to achieving high rice yields in the United States. Arbuscular mycorrhizal fungi (AM fungi) are able to modify plant physiology by increasing plant growth or inducing defense responses against insect herbivores. However, studies of the role of AM fungi in agroecological factors, including natural occurrence, plant resistance, soil dependency, and plant tolerance, with specific regards to pests that feed on rice plants have not been conducted before. A three-year study revealed natural occurring colonization by AM fungi on rice roots sampled in four rice-producing areas in the southern United States. Overall, rice-AM …

Analysis Of The Soil Health Of Pastures Over-Seeded With Winter Annuals, Kathleen M. Bridges

LSU Doctoral Dissertations

Utilizing winter annuals in livestock pastures reduces feed costs of hay, and provides additional vegetative cover that is beneficial to the soil. However, how this practice affects the soil microbial communities has not been well studied. Two sites were included in this study. Both were commercial cattle grazing operations that over-seeded a mixture of grasses, legumes, and brassicas into pastures dominated by bahiagrass (Paspalum notatum). Soil health was assessed using a suite of physical, chemical, and biological properties. Soil physical assessments included bulk density and aggregate stability. Soil chemical assessments included macronutrients, pH, soil organic matter (SOM), total …

Effect Of Increasing Levels Of Monosilicic Acid On Arsenic And Phosphorus Sorption In Soil, Flávia Bastos Agostinho

LSU Doctoral Dissertations

Arsenic (As) accumulation in rice (Oryza sativa) grains has increased human’s daily intake. Studies have shown that arsenite is taken up through known silicon (Si) transporters in rice. Moreover, the availability of As in soil is affected by chemically similar ligands that have high affinity to oxides surfaces, such as Si and phosphorus (P). Studies were conducted to: (I) investigate the role of elevated levels of Si on the concentration of different As fractions in soil and on As uptake by rice; (II) evaluate the effect of increasing monosilicic acidconcentrations on As sorption and kinetics in soil; and …

Determining Growth Characteristics And Control Programs For Nealley's Sprangletop (Leptochloa Nealleyi Vasey), Trace Buck

LSU Master's Theses

ABSTRACT

Research was conducted at the LSU AgCenter Dean Lee Research and Extension center near Alexandria, La in 2016 and 2017 to evaluate the growth characteristics and control of Nealley’s sprangletop. Nealley’s sprangletop is a relatively new weed with little research available to understand its growth habit and effective control strategies.

Nealley’s sprangletop undergoes a more drastic height increase of 212 to 742 mm, 4 to 6 WAE than Amazon sprangletop 377 to 612 mm in the same time frame. Averaged across harvest interval tiller and leaf number of Nealley’s sprangletop was approximately 50 and 40% less than Amazon sprangletop. …

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 …

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, …

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 …

Discovering Potential Protein, Carbohydrate, And Lipid Based Food Ingredients In A Co-Culture Of Microalgae, Chelsea Tyus

LSU Doctoral Dissertations

Louisiana Native Co-Culture of Microalgae (Chlorella Vulgaris L. and Cyanobacteria Leptolyngbya sp.) (CCA) was studied. CCA is a viable coculture for further investigation as a food component. This research characterized the proteins, carbohydrates, and lipids present in CCA. Algae cultivation parameters were controlled and analyzed. Treatment (Trt) 1 was CCA grown in cultures exposed to average scalar irradiance (ASI) of 1041 ± 269.18 μmol m-2 s-1 PAR and trt 2 was CCA grown in cultures exposed to ASI of 430 ± 96.03 μmol m-2 s-1 PAR. The trt (irradiance exposure) had the desired response on CCA species ratio Trt …

Genetic Diversity Of Selected Sea Oats (Uniola Paniculata L.) Lines Using Amplified Fragment Length Polymorphism (Aflp), Sarah E. Bertrand

Honors Capstones

No abstract provided.