Botany Commons^™

Terror En El Orinoco: Formas Del Espanto Animal Y Vegetal En La Historia Natural De José Gumilla, Roberto E. Martinez Bachrich

Dissertations, Theses, and Capstone Projects

“Terror in the Orinoco: Forms of Animal and Plant Horror in the Natural History of José Gumilla”, analyzes the repertoire of terrifying plants and animals that the Spanish Jesuit missionary José Gumilla described in his 1745 compendium El Orinoco Ilustrado y Defendido —a work that, surprisingly, has not been read from the perspective of animal and plant studies. Based on Spanish old models of the natural history of the Indies (Fernández de Oviedo, Acosta), Gumilla reconstructs an archive of monstrous beings (alligators, piranhas, snakes, poisonous plants) that challenges old medieval religious discourses when confronted with the nascent illustrated discourses. My …

Herbaceous Production Lost To Tree Encroachment In United States Rangelands, Scott L. Morford, Brady W. Allred, Dirac L. Twidwell Jr, Matthew O. Jones, Jeremy D. Maestas, Caleb P. Roberts, David E. Naugle

Department of Agronomy and Horticulture: Faculty Publications

1. Rangelands of the United States provide ecosystem services that benefit society and rural economies. Native tree encroachment is often overlooked as a primary threat to rangelands due to the slow pace of tree cover expansion and the positive public perception of trees. Still, tree encroachment fragments these landscapes and reduces herbaceous production, thereby threatening habitat quality for grassland wildlife and the economic sustainability of animal agriculture.

2. Recent innovations in satellite remote sensing permit the tracking of tree encroachment and the corresponding impact on herbaceous production. We analysed tree cover change and herbaceous production across the western United States …

From Free-Energy Profiles To Activation Free Energies, Johannes C. Dietschreit, Dennis J. Diestler, Andreas Hulm, Christian Ochsenfeld, Rafael Gómez-Bombarelli

Department of Agronomy and Horticulture: Faculty Publications

Given a chemical reaction going from reactant (R) to the product (P) on a potential energy surface (PES) and a collective variable (CV) discriminating between R and P, we define the free-energy profile (FEP) as the logarithm of the marginal Boltzmann distribution of the CV. This FEP is not a true free energy. Nevertheless, it is common to treat the FEP as the “free-energy” analog of the minimum potential energy path and to take the activation free energy, ΔF‡ _RP, as the difference between the maximum at the transition state and the minimum at R. We show that this …

A Yield Comparison Between Small-Plot And On-Farm Foliar Fungicide Trials In Soybean And Maize, Anabelle Laurent, Emily Heaton, Peter Kyveryga, David Makowski, Laila A. Puntel, Alison E. Robertson, Laura J. Thompson, Fernando Miguez

Department of Agronomy and Horticulture: Faculty Publications

Agronomic research provides management recommendations based on small-plot trials (SPTs) and on-farm trials (OFTs) with very different characteristics. SPTs are traditionally conducted at agricultural experiment stations by research institutes or universities, while OFTs are conducted under commercial-scale conditions and managed by farmers using their own equipment. Several researchers claimed that discrepancies could occur between these two types of trials, which can make the extrapolation of results from SPTs to the farm level difficult. In our study, we conducted an extensive comparison of small-plot and on-farm trials to analyze the effect of foliar fungicide application on maize and soybean yields. We …

Snp Discovery In Proso Millet (Panicum Miliaceum L.) Using Lowpass Genome Sequencing, Rituraj Khound, Guangchao Sun, Ravi V. Mural, James C. Schnable, Dipak K. Santra

Department of Agronomy and Horticulture: Faculty Publications

Domesticated ~10,000 years ago in northern China, Proso millet (Panicum miliaceum L.) is a climate-resilient and human health-promoting cereal crop. The genome size of this self-pollinated allotetraploid is 923 Mb. Proso millet seeds are an important part of the human diet in many countries. In the USA, its use is restricted to the birdseed and pet food market. Proso millet is witnessing gradual demand in the global human health and wellness food market owing to its health-promoting properties such as low glycemic index and gluten-free. The breeding efforts for developing improved proso millet cultivars are hindered by the …

The Influence Of Water Stress And Rootstocks On Nutrient Uptake And Gas Exchange Of Young Peach Trees, Naif Alshammari

All Theses

Young peach trees are often rainfed in the southeastern U.S. and periods of dry weather can cause tree water deficit that can be detrimental to orchard productivity. There is a lack of understanding of the influence of water regimes and rootstocks on the nutritional status and gas exchange of the peach tree. Most peach growers in Southeastern United States do not irrigate their young peach trees because they do not produce fruit until the third leaf. In this region, peach growers use Guardian as a rootstock, although MP-29 is also interesting for growers with orchards that have Armillaria root rot …

The Genetic Basis For Panicle Trait Variation In Switchgrass (Panicum Virgatum), Li Zhang, Alice Macqueen, Xiaoyu Weng, Kathrine D. Behrman, Jason Bonnette, John L. Reilley, Francis M. Rouquette, Philip A. Fay, Yanqi Wu, Felix B. Fritschi, Robert B. Mitchell, David B. Lowry, Arvid R. Boe, Thomas E. Juenger

Department of Agronomy and Horticulture: Faculty Publications

Key message: We investigate the genetic basis of panicle architecture in switchgrass in two mapping populations across a latitudinal gradient, and find many stable, repeatable genetic effects and limited genetic interactions with the environment. Abstract: Grass species exhibit large diversity in panicle architecture influenced by genes, the environment, and their interaction. The genetic study of panicle architecture in perennial grasses is limited. In this study, we evaluate the genetic basis of panicle architecture including panicle length, primary branching number, and secondary branching number in an outcrossed switchgrass QTL population grown across ten field sites in the central USA through multi-environment …

Characterization And Selection Of Hop Cultivars Adapted To Nebraska, Kristina Alas

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

Hop (Humulus lupulus L.) is an ingredient in the beer brewing industry that provides beer its flavor and aroma. High demand from the brewing industry has encouraged production outside of the traditional Pacific Northwest, the primary production region. Producers in the Midwest are attempting to grow cultivars adapted to the Pacific Northwest, but environmental differences have caused low yields and changes in secondary metabolite content. To aid producers, a regional breeding program was initiated to develop cultivars adapted to the Midwest. Success of any breeding program relies on the selection of genetically superior parents to generate progeny with the …

Mycorrhizae In Maize (Zea Mays L.) Cropping Systems Respond Differently To Nitrogen Fertilization Under Increasing Crop Rotational Diversity, Morgan R. Mcpherson

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

Arbuscular mycorrhizal fungi (AMF) remain a vital obligate symbiont of nearly all plants. It is well established that the symbiosis between AMF and host plant improves plant nutrient acquisition, alleviates abiotic and biotic environmental stressors, defends against plant pathogens, and contributes to overall plant fitness and productivity through modification of the soil habitat. Modifications include increased soil aggregation and stability, carbon sequestration through provision of fungal wall precursors to soil organic matter (SOM) formation, and enhanced nutrient cycling in the mycorrhizosphere. The goal of this dissertation was to assess how AMF respond to nitrogen (N) fertilization regimes in maize cropping …

Hiding In Plain Sight: Accounting For Rate Heterogeneity In Trait Evolution Models, James Boyko

Graduate Theses and Dissertations

Within the last four decades, phylogenetic comparative methods have become the defacto method of analysis for comparative biologists. The availability of high-quality comparative datasets has been matched by an explosion of possible phylogenetic models. In large part, the efforts to increase the realism of phylogenetic comparative methods has been successful as evidenced by their widespread use. To this extensive literature, my contributions are modest. I have focused my dissertation work on two main themes. First, most phenotypic evolution is not independent of other phenotypes. Changes in a particular character may influence changes in another and modeling these characters in isolation …

Chromosome Number Evolution, Phylogeography, And The Effects Of Climate Change On Species Distributions In Polyploid Plant Systems, Courtney H. Babin

LSU New Orleans Theses and Dissertations

Polyploidy, a term used to describe organisms with cells having more than two paired sets of chromosomes, is a significant driver of diversification among land plants. Over a century of research has advanced our understanding of polyploidization in some taxa, but polyploid organisms remain understudied. In this dissertation, I investigate chromosome number evolution, phylogeographic structure, genetic differentiation, and the effects of climate change on ploidy level distribution using polyploid plant systems. In the first chapter, I inferred a molecular phylogeny of Allium, an economically important genus that includes cultivated crops and ornamentals, to investigate evolutionary transitions in chromosome number …

Flora Of Doe Mountain Recreation Area, Johnson County, Tennessee, Benjamin Mccullough

Electronic Theses and Dissertations

A botanical inventory of Doe Mountain Recreation Area (DMRA) in northeastern Tennessee was conducted to help guide conservation-based management. A total of 484 species were found in DMRA, comprising 94 families, and 285 genera, 10 species listed in the state rare plant list, and 76 exotic species. Two species, Liatris virgata and Lycopodiella inundata, were new state records. Water in the Lycopodiella seep was an order of magnitude more acid than at other sites. An analysis of the wildland-urban interface showed that only 13% of the area was classified as uninhabited. The inventory-invasion index, introduced to quantify the relative …

Water Sourcing Strategies Of Desert Vegetation In Varying Soil Textures With Vegetation Competition: A Stable Isotope Analysis, Martha Elizabeth Gardea

Open Access Theses & Dissertations

Recent studies have suggested an ecohydrological separation of water exists in the northern Chihuahuan Desert, where vegetation types, rainfall regimes, and location in the terrain seem to determine the type of water (e.g. isotopically depleted or enriched in 18O and 2H) plants are able to source and use throughout their growing cycle. That work found evidence of creosote (Larrea tridentata) and mesquite (Prosopis glandulosa) using tightly bound soil water at both a site on an ephemeral channel and a site in higher elevated flat area because the isotopic signature of plant water at the beginning of the study did not …

The Influences Of Disperser Behavior, Host Availability, And Environmental Conditions On The Distribution Of Oak Mistletoe [Phoradendron Leucarpum (Raf.) Reveal & M. C. Johnst.] In Eastern Virginia And North Carolina, Nicholas Pearce Flanders

Biological Sciences Theses & Dissertations

Mistletoes are shrubs that typically parasitize the branches of host trees and rely on avian frugivores for seed dispersal. Because mistletoes are restricted to a narrow range of suitable recruitment sites and avian frugivores are more visible than other guilds of seed dispersers, mistletoe-frugivore systems afford opportunities for assessing the roles of dispersal limitation and local environment in determining plant distribution. These mechanisms have been proposed as determinants of the observed association of oak mistletoe [Phoradendron leucarpum (Raf.) Reveal & M. C. Johnst.] with forested wetlands in eastern Virginia and North Carolina, USA. I tested the alternative hypothesis that …

Quantification And Machine Learning Based N2o–N And Co2–C Emissions Predictions From A Decomposing Rye Cover Crop, Deepak R. Joshi, David E. Clay, Sharon A. Clay, Janet Moriles-Miller, Aaron L. M. Daigh, Graig Reicks, Shaina Westhoff

Department of Agronomy and Horticulture: Faculty Publications

Cover crops improve soil health and reduce the risk of soil erosion. However, their impact on the carbon dioxide equivalence (CO_2e) is unknown. Therefore, the objective of this 2-yr study was to quantify the effect of cover crop-induced differences in soil moisture, temperature, organic C, and microorganisms on CO_2e, and to develop machine learning algorithms that predict daily N₂O–N and CO₂–C emissions. The prediction models tested were multiple linear regression, partial least square regression, support vector machine, random forest (RF), and artificial neural network. Models’ performance was accessed using R², …

Registration Of Lcs ‘Valiant’ Hard Red Winter Wheat, P. Stephen Baenziger, S. D. Masterson, J. D. Boehm Jr., Vikas Belamkar, M. D. Barnett, Devin J. Rose, Lan Xu, Stephen N. Wegulo, T. Regassa, Amanda Easterly, Cody F Creech, Dipak K. Santra, G. R. Kruger, G. W. Hergert, R. N. Klein, J. Kolmer, J. Kolmer, M.-S. Chen, Gary L. Hein, R. L. Bowden, M. J. Guttieri, G. Bai, El-Basyoni Salah, J. Poland

Department of Agronomy and Horticulture: Faculty Publications

Historically cultivars developed jointly by the University of Nebraska-Lincoln and USDA-ARS wheat (Triticum aestivum L.) improvement project tend to be late and better adapted to the northern Great Plains. LCS ‘Valiant’ (Reg. no. CV-1196, PI 693223; tested as NE10478-1) was released based on the merits of its earliness, agronomic performance, relevant disease resistances, and end-use quality characteristics and its adaptation to the central Great Plains. As such, the line was licensed to Limagrain Cereal Seeds for their ability to market outside of Nebraska. LCS Valiant hard red winter wheat was released in March 2020 by the developing institutions and …

Association Analyses Of Host Genetics, Root-Colonizing Microbes, And Plant Phenotypes Under Different Nitrogen Conditions In Maize, Michael A. Meier, Gen Xu, Martha G. Lopez-Guerrero, Guangyong Li, Christine Smith, Brandi Sigmon, Joshua R. Herr, James R. Alfano, Yufeng Ge, James C. Schnable, Jinliang Yang

Department of Agronomy and Horticulture: Faculty Publications

The root-associated microbiome (rhizobiome) affects plant health, stress tolerance, and nutrient use efficiency. However, it remains unclear to what extent the composition of the rhizobiome is governed by intraspecific variation in host plant genetics in the field and the degree to which host plant selection can reshape the composition of the rhizobiome. Here, we quantify the rhizosphere microbial communities associated with a replicated diversity panel of 230 maize (Zea mays L.) genotypes grown in agronomically relevant conditions under high N (+N) and low N (-N) treatments. We analyze the maize rhizobiome in terms of 150 abundant and consistently reproducible …

Replacing Fallow With Field Pea In Wheat Production Systems Across Western Nebraska, Samuel T. Koeshall, Amanda Easterly, Rodrigo Werle, Strahinja Stepanovic, Cody F. Creech

Department of Agronomy and Horticulture: Faculty Publications

Integration of field pea (Pisum sativum L.) (FP) into dryland cropping systems has increased due to ecological and economic benefits, paired with a growing market for pea-derived products. Challenges exist in the High Plains that limit the integration of crop rotations to replace fallow periods with FP in wheat (Triticum aestivum L.)- based systems. This experiment compares chemical summer fallow to FP in a fallow– wheat rotation at two locations in western Nebraska. Soil water content, soil fertility, N mineralization, FP yield, and subsequent hard red winter wheat (HWW) yields were recorded. Subsequent HWW yields were not different …

Non-Destructive Classification And Quality Evaluation Of Proso Millet Cultivars Using Nir Hyperspectral Imaging With Machine Learning, Laruen E. Doyle, Julia R. Loeb, Nader Ekramirad, Dipak K. Santra, Akinbode A. Adedeji

Department of Agronomy and Horticulture: Faculty Publications

Millet is a small-seeded cereal crop with big potential and remarkable characteristics such as high drought resistance, short growing time, low water footprint, and the ability to grow in acidic soil. There is a need to develop nondestructive methods for differentiation and evaluation of the quality attributes of different of proso millet cultivars grown in the U.S. Current methods of cultivar classification are either subjective or destructive, time consuming, not allowing for the whole population to be tested, and requiring trained operators and special equipment. In this study, the feasibility of using near-infrared (NIR) hyperspectral imaging (900-1700 nm) to predict …

Prediction Of Cultivation Areas For The Commercial And An Early Flowering Wild Accession Of Salvia Hispanica L. In The United States, Mohammad Hassani, Thomas Piechota, Hagop S. Atamian

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Salvia hispanica L., commonly known as chia, is a plant-based alternative to seafood and is rich in heart-healthy omega-3 fatty acid, protein, fiber, and antioxidants. In the Northern Hemisphere, chia flowering is triggered by the fall equinox (12-h light and dark, early October) and the seeds mature after approximately three months. Chia is sensitive to frost and end of season moisture which limits its cultivation to small areas in regions with temperate climate. The U.S. chia import has increased considerably over the years; however, chia is not widely cultivated in the United States. This study used the historical U.S. temperature …