Botany Commons^™

Wildflower Pollen Quality In Roadside Habitats, With Particular Emphasis On Hedera Helix, Aoife Mcmullin, Paul Hamilton

SURE Journal: Science Undergraduate Research Experience Journal

The quality of air is of more significance today than ever before. Human population growth and pollutants emitted through fossil fuel consumption put pressures on air quality. It is widely acknowledged that atmospheric pollutants negatively impact human health; the same is also true for the health of wildlife and plants exposed to these pollutants (Brunekreef & Holgate, 2002; EEA, 2019; Schiavoni, et al., 2017). Pollen and seed formation of flowering plants have been affected when grown in areas of poor air quality (Azzazy, 2016; Sénéchal, et al., 2015). The purpose of this research was to assess pollen of …

A Machine Learning Interpretation Of The Contribution Of Foliar Fungicides To Soybean Yield In The North‐Central United States, Denis A. Shah, Thomas R. Butts, Spyridon Mourtzinis, Juan I. Rattalino Edreira, Patricio Grassini, Shawn P. Conley, Paul D. Esker

Department of Agronomy and Horticulture: Faculty Publications

Foliar fungicide usage in soybeans in the north-central United States increased steadily over the past two decades. An agronomically-interpretable machine learning framework was used to understand the importance of foliar fungicides relative to other factors associated with realized soybean yields, as reported by growers surveyed from 2014 to 2016. A database of 2738 spatially referenced fields (of which 30% had been sprayed with foliar fungicides) was fit to a random forest model explaining soybean yield. Latitude (a proxy for unmeasured agronomic factors) and sowing date were the two most important factors associated with yield. Foliar fungicides ranked 7th out of …

Global Population Divergence Of A Cosmopolian Desert Plant, Victor Ryan Alfaro

Biology ETDs

Genetic and phenotypic variation can have different patterns within a species if it has populations with contrasting histories. Populations can have discrete differences that are shaped by different evolutionary scenarios, but within each population, range, or region, traits and association with fitness can also be affected by both edaphic and landscape variation. For my dissertation, I surveyed and experimentally analyzed variation and adaptive potential in Sahara mustard (Brassica tournefortii), a desert annual that has endemic, invasive, and agricultural populations in Africa, Asia, and the Americas. Although my multi-trait analysis generated complex results, my findings can be applied to …

Implications Of Cover Crop Planting And Termination Timing On Rainfed Maize Production In Semi-Arid Cropping Systems, Alexandre T. Rosa, Cody Creech, Roger W. Elmore, Daran Rudnick, John L. Lindquist, Miguel Fudolig, Liberty E. Butts, Rodrigo Werle

Department of Agronomy and Horticulture: Faculty Publications

Despite the potential to increase soil organic matter, cycle soil nutrients, and suppress weeds, there is a concern that cover crops (CCs) soil water use negatively impacts subsequent crops in water-limited environments. Cover crop management practices such as planting and termination timing may mitigate the detrimental impacts of CCs in semi-arid cropping systems. To determine the effects of CCs under water-limited environments, we evaluated the total CC biomass produced in the fall and spring, soil water content during the subsequent maize growing season, weed density and biomass, crop residue, and soil nutrients at the maize V6 development stage, and maize …

Contributions Of Individual Cover Crop Species To Rainfed Maize Production In Semi-Arid Cropping Systems, Alexandre T. Rosa, Cody Creech, Roger W. Elmore, Daran Rudnick, John L. Lindquist, Liberty Butts, Italo K. Pinho De Faria, Rodrigo Werle

Department of Agronomy and Horticulture: Faculty Publications

Cover crop (CC) species selection can contribute to reducing soil penetration resistance (brassica species), improved soil nitrogen (N) cycling (legume species), and suppression of weeds (grass species). However, one of the main concerns about including CCs in water-limited environments is soil water use and the consequences to subsequent crops. To determine the effects of individual CC species under water-limited environments, we evaluated fall and spring CC biomass produced, and soil water and N content, penetration resistance, weed density and biomass during the maize growing season, and maize grain yield. The experiment was conducted under a winter wheat-maize-fallow rotation at two …

Advancing Agricultural Research Using Machine Learning Algorithms, Spyridon Mourtzinis, Paul D. Esker, James E. Specht, Shawn P. Conley

Department of Agronomy and Horticulture: Faculty Publications

Rising global population and climate change realities dictate that agricultural productivity must be accelerated. Results from current traditional research approaches are difficult to extrapolate to all possible fields because they are dependent on specific soil types, weather conditions, and background management combinations that are not applicable nor translatable to all farms. A method that accurately evaluates the effectiveness of infinite cropping system interactions (involving multiple management practices) to increase maize and soybean yield across the US does not exist. Here, we utilize extensive databases and artificial intelligence algorithms and show that complex interactions, which cannot be evaluated in replicated trials, …

Final Selection Of Quality Protein Popcorn Hybrids, Leandra Parsons, Ying Ren, Abou Yobi, Ruthie Angelovici, Oscar Rodriguez, David R. Holding

Department of Agronomy and Horticulture: Faculty Publications

Quality Protein Popcorn (QPP) BC₂F₅ inbred lines were produced through an interpopulation breeding system between Quality Protein Maize dent (QPM) and elite popcorn germplasm. In 2019, five QPP F₁ hybrids were selected for further evaluation due to superior agronomics, endosperm protein quality, and popping quality traits. Though these BC₂F₅ QPP hybrids were phenotypically similar to their popcorn parents, the QPP cultivars conveyed slightly inferior popping characteristics when compared to the original popcorn germplasm. The objective of this study was twofold. First, BC₂F₅ inbred lines were crossed to their popcorn parents …

Effects Of Micro-Rates Of 2,4-D And Dicamba On Lettuce And Pumpkin In Nebraska, Xinzheng Chen

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

Off-target herbicide injury from dicamba and 2,4-D is an increasingly common problem for specialty crop growers in the Midwestern United States. Both lettuce (Lactuca sativa L.) and pumpkin (Cucurbita spp.) are common specialty crops grown in Nebraska, and their proximity to corn and soybean production makes these crops susceptible to herbicide drift injury and yield loss. The objectives of this thesis research was to quantify crop injury and yield loss in greenhouse- and field-grown lettuce and field-grown pumpkins at different growth stages after exposure to sub-lethal doses of dicamba or 2,4-D. Dose response curves were generated to determine …

Three Lc-Ms Plant Metabolomics Studies Of Hop (Humulus) Species: Wild H. Neomexicanus, Drought Stress, And Agricultural Terroir, Taylan Morcol

Dissertations, Theses, and Capstone Projects

The hop plant (Humulus L., Cannabaceae) is a dioecious, perennial, twining vine with a long history of human use. Nowadays, hop plants are generally grown for their inflorescences (“cones”), which are used in brewing for their phytochemical metabolites. Many of these metabolites are involved in plant stress response and communication. Genetics and environment are two major factors that affect plant metabolism. In three separate metabolomics studies, this project examined the effects of both genetic and environmental factors on hop phytochemistry.

In the first study, 23 hop genotypes were grown in two different locations in the Pacific Northwest region of …

Predicting Non-Native Insect Impact: Focusing On The Trees To See The Forest, Ashley N. Schulz, Angela M. Mech, Matthew P. Ayres, Jamal J.K. Gandhi, Nathan P. Havill, Daniel A. Herms, Angela M. Hoover, Ruth A. Hufbauer, Andrew M. Liebhold, Travis D. Marsico, Kenneth F. Raffa, Patrick C. Tobin, Daniel R. Uden, Kathryn A. Thomas

Department of Agronomy and Horticulture: Faculty Publications

Non-native organisms have invaded novel ecosystems for centuries, yet we have only a limited understanding of why their impacts vary widely from minor to severe. Predicting the impact of non-established or newly detected species could help focus biosecurity measures on species with the highest potential to cause widespread damage. However, predictive models require an understanding of potential drivers of impact and the appropriate level at which these drivers should be evaluated. Here, we used non-native, specialist herbivorous insects of forest ecosystems to test which factors drive impact and if there were differences based on whether they used woody angiosperms or …

Palynology And Paleoclimatology Of The Chicxulub Impact Crater In The Early Paleogene, Vann Smith

LSU Doctoral Dissertations

At the end of the Cretaceous Period, a large bolide impacted the Earth and formed the Chicxulub impact crater in the Yucatán Peninsula, Mexico. In 2016, International Ocean Discovery Program (IODP) Expedition 364 Site M0077 drilled into the buried peak ring of the crater, recovering a marine Paleocene to early Eocene post-impact section deposited on top of the impact breccia. Palynological analysis of 195 samples from the post-impact section has yielded the first pre-Holocene vegetational record from inside the Chicxulub impact crater and the first palynological record of the recovery of life following the end-Cretaceous mass extinction from inside the …

Impact Of Cover Crop Monocultures And Mixtures On Organic Carbon Contents Of Soil Aggregates, Daphne Topps, Imam Ul Khabir, Hagir Abdelmagid, Todd Jackson, Javed Iqbal, Boakai K. Robertson, Zahida Hassan Pervaiz, Muhammad Saleem

Department of Agronomy and Horticulture: Faculty Publications

Cover crops are considered an integral component of agroecosystems because of their positive impacts on biotic and abiotic indicators of soil health. At present, we know little about the impact of cover crop types and diversity on the organic carbon (OC) contents of different soil aggregate-size classes. In this study, we investigated the effect of cover plant diversity on OC contents of different soil aggregates, such as macro- (<2000–500 µm), meso- (<500–250 µm), and micro-aggregates (<250 µm). Our experiment included a total of 12 experimental treatments in triplicate; six different monoculture treatments such as chickling vetch (Vicia villosa), crimson clover (Trifolium incarnatum), hairy vetch (Vicia villosa), field peas (Pisum sativum), oilseed radish (Raphanus sativus), and mighty mustard (Brassica juncea), and their three- and six-species mixture treatments, including one unplanted control treatment. We performed this experiment usingdeep pots that contained soil collected from a corn-soybean rotation field. At vegetative maturity of cover plants (about 70 days), we took soil samples, and the soil aggregate-size classes were separated by the dry sieving. We hypothesized that cover crop type and diversity will improve OC contents of different soil aggregate-size classes. We found that cover plant species richness weakly positively increased OC contents of soil macro-aggregates (p = 0.056), whereas other aggregate-size classes did not respond to cover crop diversity gradient. Similarly, the OC contents of macroaggregates varied significantly (p = 0.013) under cover crop treatments, though neither monoculture nor mixture treatments showed significantly higher OC contents than the control treatment in this short-term experiment. Interestingly, the inclusion of hairy vetch and oilseed radish increased and decreased the OC contents of macro- and micro-aggregates, respectively. Moreover, we found a positive correlation between shoot biomass and OC contents of macroaggregates. Overall, our results suggest that species-rich rather than -poor communities may improve OC contents of soil macroaggregates, which constitute a major portion of soil systems, and are also considered as important indicators of soil functions.

Enhancing Our Understanding Of Plant Cell-To-Cell Interactions Using Single-Cell Omics, Sandra Thibivilliers, Marc Libault

Department of Agronomy and Horticulture: Faculty Publications

Plants are composed of cells that physically interact and constantly adapt to their environment. To reveal the contribution of each plant cells to the biology of the entire organism, their molecular, morphological, and physiological attributes must be quantified and analyzed in the context of the morphology of the plant organs. The emergence of single-cell/nucleus omics technologies now allows plant biologists to access different modalities of individual cells including their epigenome and transcriptome to reveal the unique molecular properties of each cell composing the plant and their dynamic regulation during cell differentiation and in response to their environment. In this manuscript, …

Tandem Duplicate Expression Patterns Are Conserved Between Maize Haplotypes Of The Α-Zein Gene Family, Preston Hurst, James C. Schnable, David R. Holding

Department of Agronomy and Horticulture: Faculty Publications

Tandem duplication gives rise to copy number variation and subsequent functional novelty among genes as well as diversity between individuals in a species. Functional novelty can result from either divergence in coding sequence or divergence in patterns of gene transcriptional regulation. Here, we investigate conservation and divergence of both gene sequence and gene regulation between the copies of the α-zein gene family in maize inbreds B73 and W22. We used RNA-seq data generated from developing, self-pollinated kernels at three developmental stages timed to coincide with early and peak zein expression. The reference genome annotations for B73 and W22 were modified …

Pollination Habitat And Flower Plating For City Beautification, Jim Speer

2021 Spring Reports (Sullivan)

The City of Sullivan identified needs to improve sustainable infrastructure and green space in Sullivan, IN through their Quality of Life plan. Students in ENVI460 were tasked with providing recommendations for their daily operations and site plans that could improve habitats and attractiveness for the community and tourists. Students provided recommendations for native habitat planting and community involvement/education. They also provided site recommendations for community garden and green space updates.

International Rice Outlook: International Rice Baseline Projections 2020-2030, A. Durand-Morat, S. Bairagi

AAES Research Reports and Research Bulletins

The coronavirus (COVID-19) pandemic and subsequent lockdowns impacted all economies worldwide and created an economic recession far graver than the Great Recession, contracting the global growth of gross domestic product (GDP) nearly by 4.0% in 2020, compared to -2.0% in 2009 (IHS Markit database). COVID-19 disrupted global and local food supply chains, and resulted in a significant increase in food prices (FAO, 2021). Both global and domestic rice prices increased, driven primarily by temporary export restrictions imposed by several leading rice exporters, such as Vietnam and Myanmar. The market uncertainty also created in panic-buying and hoarding; consequently, the rice demand …

Partnering With Archivists To Process The Manuscript Collection Present At The Marshall University Herbarium, Pamela Puppo, Lori Thompson

Biological Sciences Faculty Research

The Marshall University Herbarium (MUHW) is located on the third floor of the Science Building at Marshall University in Huntington, West Virginia, United States. It was founded in the 1930's by Dr. Frank A. Gilbert when Marshall was still Marshall College. Today, MUHW is the second largest herbarium in West Virginia with about 50,000 specimens, including 20 types. Mostly composed of vascular plants, the herbarium also contains small collections of non-vascular plants, fungi, algae, fossils, and some ethnobotanical material, mainly brought from Ecuador by one of the former curators, Dr. Dan Evans between the 1980's and 2000's. Apart from these …

Evaluating Evapotranspiration And Management Of Glyphosate-Resistant Palmer Amaranth (Amaranthus Palmeri S. Watson), Jasmine M. Mausbach

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

Palmer amaranth (PA) is the most problematic weed in agronomic cropping systems in the United States. Acetolactate synthase (ALS) inhibitor-/glyphosate-resistant (GR) PA has been confirmed in Nebraska and is widespread in several counties. Soybean resistant to isoxaflutole/glufosinate/glyphosate has been developed to provide additional herbicide sites of action for control of herbicide-resistant weeds. The objectives of this study were to evaluate herbicide programs for control of ALS inhibitor/GR PA and their effect on PA density and biomass, as well as soybean injury and yield in isoxaflutole/glufosinate/glyphosate-resistant soybean. A PRE herbicide fb glufosinate controlled PA 80%–99% 21 d after late-POST in 2018 …

Quantifying The Combined Effect Of Abiotic Factors On The Decomposition Of Organic Matter In Semiarid Grassland Soils, Elnazsadat Hosseiniaghdam

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

Grassland ecosystems play a critical role in the global carbon cycle, and their cumulative carbon dioxide (CO₂) emissions can be affected by animal grazing where litter (i.e., dead plant material) is trampled into the soil. However, the subsequent effects of trampling on litter decomposition are not well understood. Meanwhile, abiotic factors, especially temperature and soil moisture, are known to strongly affect litter decomposition. Due to the very small number of published studies that have considered litter placement, either litter on top of soil or litter mixed with soil as a factor in litter decomposition under different temperature and …

B.R. Wells Arkansas Rice Research Studies 2020, J. Hardke, X. Sha, N. Bateman

Arkansas Agricultural Experiment Station Research Series

Arkansas is the leading rice producer in the United States. The state represents 47.5% of total U.S. rice production and 48.1% of the total acres planted to rice in 2020. Rice cultural practices vary across the state and across the U.S. However, these practices are also dynamic and continue to evolve in response to changing political, environmental, and economic times. This survey was initiated in 2002 to monitor and record changes in the way Arkansas rice producers approach their livelihood. The survey was conducted by polling county extension agents in each of the counties in Arkansas that produce rice. Questions …

Effects Of Cultivars And Nitrogen Management On Wheat Grain Yield And Protein, Deepak Ghimire, Saurav Das, Nathan D. Mueller, Cody F. Creech, Dipak Santra, P Stephen Baenziger, Amanda C. Easterly, Brian Maust, Bijesh Maharjan

Department of Agronomy and Horticulture: Faculty Publications

Low grain protein in hard red winter (HRW) wheat (Triticum aestivum L.) is a serious challenge for rainfed wheat growers, particularly in years with elevated grain yield. Proper nitrogen (N) management with adequate N rate and application timing is critical for optimizing grain yield and protein content. This 2-yr experiment evaluated the effects of different N rates and application timings (fall, spring, and split) on grain yield and protein of two HRW wheat cultivars. Field studies were conducted at four different sites across Nebraska under rainfed conditions in 2018/2019 (Year 1) and 2019/2020 (Year 2). A split plot randomized complete …

Management Of Glyphosate-Resistant Palmer Amaranth (Amaranthus Palmeri S. Watson) In Dicamba/Glyphosate-Resistant Soybean, Shawn Thomas Mcdonald

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

While not a historically problematic weed in Nebraska, Palmer amaranth has become increasingly problematic in many agronomic cropping systems. Throughout the state, several cohorts of Palmer amaranth have been found resistant to several different sites of action. Of major concern is a population found resistant to glyphosate the most common post-emergence herbicide in Nebraska. As chemical control methods are the most common forms of weed control throughout the state methods alternatives or enhancements are highly desired. Two field experiments were conducted in 2018 and 2019 at a grower’s field near Carleton, Nebraska with the objectives to evaluate the effects of …

An Assessment Of The Factors Influencing The Prediction Accuracy Of Genomic Prediction Models Across Multiple Environments, Sarah Widener, George Graef, Alexander E. Lipka, Diego Jarquin

Department of Agronomy and Horticulture: Faculty Publications

The effects of climate change create formidable challenges for breeders striving to produce sufficient food quantities in rapidly changing environments. It is therefore critical to investigate the ability of multi-environment genomic prediction (GP) models to predict genomic estimated breeding values (GEBVs) in extreme environments. Exploration of the impact of training set composition on the accuracy of such GEBVs is also essential. Accordingly, we examined the influence of the number of training environments and the use of environmental covariates (ECs) in GS models on four subsets of n = 500 lines of the soybean nested association mapping (SoyNAM) panel grown in …

Generalist Bird Exhibits Site-Dependent Resource Selection, Samantha M. Cady, Craig A. Davis, Samuel D. Fuhlendorf, Rheinhardt Scholtz, Daniel R. Uden, Dirac Twidwell

Department of Agronomy and Horticulture: Faculty Publications

Quantifying resource selection (an organism's disproportionate use of available resources) is essential to infer habitat requirements of a species, develop management recommendations, predict species responses to changing conditions, and improve our understanding of the processes that underlie ecological patterns. Because study sites, even within the same region, can differ in both the amount and the arrangement of cover types, our objective was to determine whether proximal sites can yield markedly different resource selection results for a generalist bird, northern bobwhite (Colinus virginianus). We used 5 years of telemetry locations and newly developed land cover data at two, geographically distinct but …

Effects Of Wetland Management And Associated Abiotic Factors On Rare Plant Communities Of Spring-Fed Arid Wetlands, Antonio Cantu De Leija

LSU Master's Theses

Spring-fed arid wetlands support high biological productivity and are hotspots for endemism and distribution of rare plants, making them areas of high conservation value. These systems are driven by complex interactions among groundwater discharge and the geomorphic and climatic features of the setting, which provide gradients of edaphic conditions, particularly soil moisture and salinity that influence the presence and abundance of rare plant communities. However, spring-fed arid wetlands are at particular risk of increases in salinity and drier hydrological regimes due to anthropogenic activities. Such alterations to abiotic conditions may jeopardize the distribution and abundance of rare plants by exceeding …

Data From A Public–Industry Partnership For Enhancing Corn Nitrogen Research, C J. Ransom, J D. Clark, G M. Bean, C J. Bandura, M Shafer, N R. Kitchen, J J. Camberato, P R. Carter, R B. Ferguson, F G. Fernandez, D W. Franzen, C.A.M. Laboski, D B. Myers, E D. Nafziger, J E. Sawyer, J F. Shanahan

Department of Agronomy and Horticulture: Faculty Publications

Improving corn (Zea mays L.) N management is pertinent to economic and environmental objectives. However, there are limited comprehensive data sources to develop and test N fertilizer decision aid tools across a wide geographic range of soil and weather scenarios. Therefore, a public-industry partnership was formed to conduct standardized corn N rate response field studies throughout the U.S. Midwest. This research was conducted using a standardized protocol at 49 site-years across eight states over the 2014 to 2016 growing seasons with many soil, plant, and weather related measurements. This note provides the data (found in supplemental files), outlines the data, …

Structural Insights Into The Functional Divergence Of Whib-Like Proteins In Mycobacterium Tuberculosis, Tao Wan, Magdalena Horova, Daisy Guiza Beltran, Shanren Li, Huey-Xian Wong, Li-Mei Zhang

Department of Agronomy and Horticulture: Faculty Publications

WhiB7 represents a distinct subclass of transcription factors in the WhiB-Like (Wbl) family, a unique group of iron-sulfur (4Fe-4S] cluster-containing proteins exclusive to the phylum of Actinobacteria. In Mycobacterium tuberculosis (Mtb), WhiB7 interacts with domain 4 of the primary sigma factor (σ_^A4) in the RNA polymerase holoenzyme and activates genes involved in multiple drug resistance and redox homeostasis. Here, we report crystal structures of the WhiB7:σ^A₄ complex alone and bound to its target promoter DNA at 1.55-Å and 2.6-Å resolution, respectively. These structures show how WhiB7 regulates gene expression by interacting with both …

Zygomorphic Flowers May Reduce Extinction Rates By Allowing Angiosperms To Occur In Low Abundances, Maria Belen Alvestegui

Theses

The high species richness that angiosperm show has been extensively correlated with key floral innovations. Key floral traits contribute to species boundaries and the origin of new species. However, how these relate to extinction remains largely untested. Among the multiple theories that attribute diversification to floral innovations, the reduced extinction model predicts that floral specialization allows the persistence of small populations and avoids their loss. Bilateral symmetry (zygomorphy) is a trait that has evolved recurrently in angiosperms. It is a form of floral specialization that restricts pollination to fewer visitors and precisely places pollen to ensure more effective transmission of …

An Updated Infra-Familial Classification Of Sapindaceae Based On Targeted Enrichment Data, Sven Buerki

Biology Faculty Publications and Presentations

Premise: The economically important, cosmopolitan soapberry family (Sapindaceae) comprises ca. 1900 species in 144 genera. Since the seminal work of Radlkofer, several authors have attempted to overcome challenges presented by the family’s complex infra-familial classification. With the advent of molecular systematics, revisions of the various proposed groupings have provided significant momentum, but we still lack a formal classification system rooted in an evolutionary framework.

Methods: Nuclear DNA sequence data were generated for 123 genera (86%) of Sapindaceae using target sequence capture with the Angiosperms353 universal probe set. HybPiper was used to produce aligned DNA matrices. Phylogenetic inferences were obtained using …

Arkansas Corn And Grain Sorghum Research Studies 2020, Victor Ford, Jason Kelley, Nathan Mckinney Ii

Arkansas Agricultural Experiment Station Research Series

The 2021 edition of the Arkansas Corn and Grain Sorghum Research Studies Series includes research results on topics pertaining to corn and grain sorghum production, including weed, disease, and insect management; economics; sustainability; irrigation; post-harvest drying; soil fertility; mycotoxins; cover crop management; feral hog control; and research verification program results. Our objective is to capture and broadly distribute the results of research projects funded by the Arkansas Corn and Grain Sorghum Board. The intended audience includes producers and their advisors, current investigators, and future researchers. The Series serves as a citable archive of research results. Reports in this publication are …