Botany Commons^™

Evaluating The Roles Of Pollinators In Shaping The Floral Color Variation Of Phacelia Dubia, Katherine Riddle

All Theses

Floral color variation within a species is a common occurrence and its maintenance has been a long-standing question in evolutionary biology. Differences in flower color between populations can be shaped by pollinator-mediated selection. Pollinators can exhibit innate and learned preferences for color that may influence floral color variation. These preferences may be molded by the visual environment in which pollinators forage. Most current understanding of how pollinators shape floral color variation involves dramatic differences in dominant pollinators between populations (e.g., hawkmoth vs. bee) and most behavioral work utilized model pollinators like honeybee and bumble bee. However, less is known about …

Elevation And Population Size Effects On The Survival Of Drosera Rotundifolia, Jessica Williams

Electronic Theses and Dissertations

Carnivorous plants face significant conservation challenges due to habitat destruction, climate change, and illegal harvesting. This study explores how elevation and population size influence key-life history traits of D. rotundifolia, such as flowering phenology, prey capture efficiency, seed production, and germination rates. Higher elevations and larger populations are associated with extended flowering durations and increased prey capture. However, seed production and germination rates show complex patterns that are likely influenced by genetic diversity, resource availability, or environmental conditions. These insights inform targeted conservation strategies, emphasizing habitat preservation, enhancing prey availability, and maintaining genetic diversity. Public education and community engagement …

Broad-Spectrum Resistance To Fungal Foliar Diseases In Wheat: Recent Efforts And Achievements, Amira M.I. Mourad, Asmaa A.M. Ahmed, P. Stephen Baenziger, Andreas Börner, Ahmed Sallam

Department of Agronomy and Horticulture: Faculty Publications

Wheat (Triticum spp.) is one of the most important cereal crops in the world. Several diseases affect wheat production and can cause 20-80% yield loss annually. Out of these diseases, stripe rust, also known as yellow rust (Puccinia striiformis f. sp. tritici), stem rust (Puccinia graminis f. sp. tritici), leaf rust (Puccinia recondita), and powdery mildew (Blumeria graminis f. sp. tritici) are the most important fungal diseases that infect the foliar part of the plant. Many efforts were made to improve wheat resistance to these diseases. Due to the continuous advancement in …

Disentangling Genotype And Environment Specific Latent Features For Improved Trait Prediction Using A Compositional Autoencoder, Anirudha Powadi, Talukder Zaki Jubery, Michael C. Tross, James C. Schnable, Baskar Ganapathysubramanian

Department of Agronomy and Horticulture: Faculty Publications

In plant breeding and genetics, predictive models traditionally rely on compact representations of high-dimensional data, often using methods like Principal Component Analysis (PCA) and, more recently, Autoencoders (AE). However, these methods do not separate genotype-specific and environment-specific features, limiting their ability to accurately predict traits influenced by both genetic and environmental factors. We hypothesize that disentangling these representations into genotype-specific and environment-specific components can enhance predictive models. To test this, we developed a compositional autoencoder (CAE) that decomposes high-dimensional data into distinct genotype-specific and environment-specific latent features. Our CAE framework employed a hierarchical architecture within an autoencoder to effectively separate …

Industrial Hemp Biomass Negatively Affected By Herbicide Drift From Corn And Soybean Herbicides, Milos Zaric, Bruno Canella Vieira, Barbara Houston, Guilherme Sousa Alves, Samuel E. Wortman, Julie A. Peterson, Greg R. Kruger

Department of Agronomy and Horticulture: Faculty Publications

The establishment of industrial hemp (Cannabis sativa L.) fields near row crops has raised concerns about the potential adverse effects of herbicide drift on hemp production. This study examined hemp susceptibility to drift of herbicides registered for use in corn and/or soybeans. Herbicide solutions (2,4-D, dicamba, glufosinate, glyphosate, imazethapyr, lactofen, mesotrione) were applied separately in the wind tunnel (3.6 m s⁻¹ airspeed), simulating drift scenarios, with conventional TP95015EVS (TP) and air inclusion AI95015EVS (AI) flat fan nozzles calibrated to deliver 140 L ha⁻¹ carrier volume at 230 kPa. Mylar cards and hemp plants (20–25 cm tall) were placed …

Designing A Decision-Support Tool For Fertilizer Recommendations In Oil Palm Smallholders, Rana Farrasati

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

Oil palm (Elaeis guineensis Jacq.), originally from West Africa, now accounts for 42% of global vegetable oil production and mainly includes key regions cultivated in tropical regions of Southeast Asia, West Africa, South America, and Central America. Despite its economic significance, the oil palm industry faces challenges of stagnant yields and large yield gaps, particularly among independent smallholders. These issues often stem from inadequate nutrient management practices and limited agronomic knowledge. Our objective was to quantify nutrient requirements for mature oil palm plantations as a basis to design a decision support tool (DST) for fertilizer recommendations. To do so, …

Bio-Based Sprayable Mulch For Weed Control In Row Crop Systems, Camila Chiaranda Rodrigues

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

Improving current crop productivity levels requires transformative advancements in management, engineering, and science. One of the main challenges is the increasing difficulty of weed management due to herbicide-resistant weeds. There is a growing need for alternative weed management methods to reduce pesticide use and improve environmental safety. An emerging technology that is being developed is spray-on films which could help address these challenges. Spray-on films are liquid solutions that after spraying on the soil will dry and form a physical barrier. The overall objective of this research was to evaluate the effectiveness of a chicken feather bio-based sprayable mulch film …

Assessing The Above- And Belowground Productivity Of Fall-Planted Cover Crop Cultivars In Nebraska's Diverse Ecoregions, Bridget Mckinley

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

Cover crops (CC) provide essential ecosystem services including soil conservation, nutrient cycling, and weed suppression, through the accumulation of aboveground (AGB) and belowground (BGB) biomass. While AGB has been widely studied, BGB contributions, particularly root development and distribution, remain less understood. This study evaluated fall-planted CC across three Nebraska ecoregions, assessing AGB productivity, BGB biomass, and correlations between ground cover, plant height, and AGB.

Thirty treatments, including grasses, legumes, brassicas, and mixtures, were evaluated over two fall growing seasons (2022–2023 and 2023–2024) at three UNL research centers in northeast, west central, and west Nebraska. AGB was highest at west site …

Twas Facilitates Gene-Scale Trait Genetic Dissection Through Gene Expression, Structural Variations, And Alternative Splicing In Soybean, Delin Li, Qi Wang, Yu Tian, Xiangguang Lyv, Hao Zhang, Huilong Hong, Huawei Gao, Yan-Fei Li, Chaosen Zhao, Jiajun Wang, Ruizhen Wang, Jinliang Yang, Bin Liu, Patrick S. Schnable, James C. Schnable, Ying-Hui Li, Li-Juan Qiu

Department of Agronomy and Horticulture: Faculty Publications

A genome-wide association study (GWAS) identifies trait-associated loci, but identifying the causal genes can be a bottleneck, due in part to slow decay of linkage disequilibrium (LD). A transcriptome-wide association study (TWAS) addresses this issue by identifying gene expression–phenotype associations or integrating gene expression quantitative trait loci with GWAS results. Here, we used self-pollinated soybean (Glycine max [L.] Merr.) as a model to evaluate the application of TWAS to the genetic dissection of traits in plant species with slow LD decay. We generated RNA sequencing data for a soybean diversity panel and identified the genetic expression regulation of 29 …

Parkway Pocket Garden Maintenance Booklet, Plaster Creek Stewards

Print Materials

Parkway pocket gardens are designed for areas between the sidewalk and street, but without a basin and curb-cut. By replacing lawn in parkways with native plants, it can soak up rainwater that falls on the gardens, provide habitat and a food source for pollinators and birds, and increase biodiversity in your neighborhood. This maintenance guide covers the Michigan native plants that may be found in a parkway pocket garden, maintenance recommendations, and weeds you may encounter.

Zadoks Growth Scale, Department Of Primary Industries And Regional Development, Western Australia

Grains and other field crops factsheets

Zadoks growth scale is a 0-99 scale of development that is recognised internationally for research, advisory work, and farm practice, particularly to time the application of chemicals and fertilisers.

Summer- And Fall-Planted Cover Crops Across Nebraska: Assessing Performance Using Aerial Imagery And Evaluating Short-Term Soil Impacts, Grace Emperatriz Pacheco Jiron

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

Cover crops are widely recognized for improving soil health and promoting sustainability in agricultural systems. Despite the increasing use of monitoring tools like aerial imagery, their application in evaluating summer-planted cover crops in the Great Plains remains limited, hindering effective management strategies. Fall-planted cover crops provide long-term environmental benefits, including enhanced soil quality and erosion control; however, understanding their short-term effects on soil properties is crucial for encouraging adoption. This study assessed summer- and fall-planted cover crops across Nebraska, integrating aerial imagery and soil health analyses.

Over two years, fifteen summer-planted monocultures and five mixtures were evaluated for establishment, biomass …

What Do Turtleheads & Cotton Have In Common?, W. John Hayden

Biology Faculty Publications

I will not be offended if, dear reader, your response to the question posed in the title is something along the lines of, “Hmmm, probably not very much!”

Dissecting The Genetic Architecture Of Sunflower Disc Diameter Using Genome-Wide Association Study, Yavuz Delen, Ravi V. Mural, Semra Palali-Delen, Gen Xu, James C. Schnable, Ismail M. Dweikat, Jinliang Yang

Department of Agronomy and Horticulture: Faculty Publications

Sunflower (Helianthus annuus L.) plays an essential role in meeting the demand for edible oil worldwide. The yield of sunflower seeds encompasses several component traits, including the disc diameter. Over three consecutive years, 2019, 2020, and 2022, we assessed phenotypic variation in disc diameter across a diverse set of sunflower accessions (N = 342) in replicated field trials. Upon aggregating the phenotypic data from multiple years, we estimated the broad sense heritability (H²) of the disc diameter trait to be 0.88. A subset of N = 274 accessions was genotyped by using the tunable genotyping-by-sequencing (tGBS) method, …

Association Mapping Of Important Agronomic Traits In Mucuna Pruriens (L.) Dc., Patrush Lepcha, Mahesh Shekhar, Leelambika Murugesan, Mahammad Jaheer, Ratan Chopra, Vikas Belamkar, Narayana Sathyanarayana

Department of Agronomy and Horticulture: Faculty Publications

Background The tropical legume Mucuna pruriens (L.) DC. can meet three agricultural needs: low-cost protein, highvalue medicines, and green manure or cover crops. But like other underutilized crops, it needs more modern breeding resources. Identifying marker-trait associations (MTAs) can facilitate marker-assisted breeding and crop improvement. Recent studies have demonstrated the feasibility of identifying MTAs using a small number of accessions (< 100). We have characterized a panel of 70 M. pruriens accessions across two consecutive years and performed association analysis for 16 phenotypic traits related to seed (seed length, seed width, seed thickness, seed yield per plant, hundred seed weight); pod (pod length, pod width, number of pods …

Investigating The Adaptive Potential Of Leaf Variegation In Two Dimorphic Hexastylis Species, Cierra N. Sullivan

All Dissertations

Variegated leaves with disjointed, patterned coloration of the leaf blade are often hypothesized to have decreased photosynthetic capacity in comparison to uniformly colored leaves. Yet, many forest understory plants in tropical, subtropical, and temperate climates possess leaf variegation. Moreover, mixed findings from previous research on the physiological impacts of leaf variegation suggest variegation is adaptative under certain environmental conditions despite decreased photosynthetic tissue area. I take an eco-physiological approach to investigate agents of selection maintaining a leaf variegation polymorphism in Hexastylis, which has both quantitative and qualitative variation in variegation. First, I conduct field surveys of morph frequencies, quantitative …

Greater Aperture Counteracts Effects Of Reduced Stomatal Density On Water Use Efficiency: A Case Study On Sugarcane And Meta-Analysis, Daniel Lunn, Baskaran Kannan, Amandine Germon, Alistair Leverett, Thomas E. Clemente, Fredy Altpeter, Andrew D.B. Leakey

Department of Agronomy and Horticulture: Faculty Publications

Stomata regulate CO₂ and water vapor exchange between leaves and the atmosphere. Stomata are a target for engineering to improve crop intrinsic water use efficiency (iWUE). One example is by expressing genes that lower stomatal density (SD) and reduce stomatal conductance (g_sw). However, the quantitative relationship between reduced SD, g_sw, and the mechanisms underlying it is poorly understood. We addressed this knowledge gap using low-SD sugarcane (Saccharum spp. hybrid) as a case study alongside a meta-analysis of data from 10 species. Transgenic expression of EPIDERMAL PATTERNING FACTOR 2 from Sorghum bicolor (SbEPF2) in sugarcane …

Revisiting Fr13a For Submergence Tolerance: Beyond The Sub1a Gene, Waseem Hussain, Mahender Anumalla, Abdelbagi M. Ismail, Harkamal Walia, Vistas Kumar Singh, Ajay Kohli, Sankalp Bhosale, Hans Bhardwaj

Department of Agronomy and Horticulture: Faculty Publications

Rice landrace FR13A is the original donor of the SUB1A gene. FR13A harbors hidden genetic variation that surpasses the submergence tolerance level of SUB1A. Here, we provide an overview of the unique features of FR13A associated with exceptional recovery ability that have been overlooked since the significant discovery of the SUB1 locus. We present a detailed overview of how to underpin the new genes associated with the recovery ability seen in FR13A. Finally, we propose a unique approach to develop rice cultivars that surpass submergence tolerance beyond the SUB1 locus from FR13A.

The Role Of Exogenous Gibberellic Acid (Ga3) Application In Breaking Seed Dormancy In Clematis Hirsutissima​, Ashley Grace Ogle

2024 Symposium

Seed germination in plants is controlled by several mechanisms, including the presence of phytohormones like gibberellins, as well as environmental conditions, such as temperature, light, and moisture. Germination of dormant seeds can be promoted by the exogenous application of Gibberellic Acid (GA3). GA3 acts as a natural endogenous regulator of dormancy. Clematis hirsutissima, commonly known as Sugarbowls, in the plant family Ranunculaceae, is an important perennial species that contributes to biodiversity in western prairie ecosystems by providing habitat for pollinators and wildlife; and it is also a species that shows characteristic embryo dormancy. This native to Washington, has been used …

New Insights On Hybridization In Potamogeton Floridanus (The Florida Pondweed), Kaitlyn R. Sampson

Graduate Theses and Dissertations (2019 - present)

Freshwater ecosystems are some of the most important and highest threatened habitats in the world, and aquatic plants play an important, but often-overlooked, role in maintaining them. Potamogeton is a diverse and ecologically important aquatic plant genus well known for taxonomic difficulty and rampant hybridization. lbis study aimed to 1) test the hypothesis that Potamogeton jloridanus (Florida pondweed) is a hybrid between P. oakesianus and P. pulcher, and 2) to investigate correlations in ecological conditions for the focal species. This study revealed the discovery of a new population of P. jloridanus in Big Coldwater Creek in Santa Rosa Co., FL, …

Climate And Shared Evolutionary History Drive Trait Variation Among Species Of Neotropical Understory Monocots, Eleinis Ávila-Lovera, Oscar M. Vargas, Jennifer L. Funk, Kathleen M. Kay, Gregory R. Goldsmith

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Environmental variation commonly drives functional trait diversity within species, among species, and across communities. Climate and shared evolutionary history can both influence trait–environment relationships. We studied variation in plant functional traits among closely related Costus species occurring across environmental gradients, the extent to which this variation occurs within single species, and how that variation may be influenced by shared evolutionary history. We measured leaf, aboveground stem, rhizome, and fine root traits of 17 species of Costus in eight sites in Costa Rica and Panama, which varied in elevation, temperature, and precipitation. We then assessed the relationships among traits and environmental …

Tissue‑ And Time‑Dependent Metabolite Profiles During Early Grain Development Under Normal And High Night‑Time Temperature Conditions, Nathan Abshire, Andrew L. Hauck, Harkamal Walia, Toshihiro Obata

Department of Agronomy and Horticulture: Faculty Publications

Background Wheat grain development in the first few days after pollination determines the number of endosperm cells that influence grain yield potential and is susceptible to various environmental conditions, including high night temperatures (HNTs). Flag leaves and seed-associated bracts (glumes, awn, palea, and lemma) provide nutrients to the developing seed. However, the specific metabolic roles of these tissues are uncertain, especially their dynamics at different developmental stages and the time in a day. Tissue- and time-dependent metabolite profiling may hint at the metabolic roles of tissues and the mechanisms of how HNTs affect daytime metabolic status in early grain development. …

Adopting Yield-Improving Practices To Meet Maize Demand In Sub-Saharan Africa Without Cropland Expansion, Fernando Aramburu-Merlos, Fatima A. M. Tenorio, Nester Mashingaidze, Alex Sananka, Stephen Aston, Jonathan J. Ojeda, Patricio Grassini

Department of Agronomy and Horticulture: Faculty Publications

Maize demand in Sub-Saharan Africa is expected to increase 2.3 times during the next 30 years driven by demographic and dietary changes. Over the past two decades, the area croppedwithmaize has expanded by 17million hectares in the region, with limited yield increase. Following this trend could potentially result in further maize cropland expansion and the need for imports to satisfy domestic demand. Here, we use data collected from 14,773 smallholder fields in the region to identify agronomic practices that can improve farm yield gains. We find that agronomic practices related to cultivar selection, and nutrient, pest, and crop management can …

Evaluating The Yield Of Surviving Plants From Early-Season Hail Damage In Corn: A Field Survey, I. P. Lisboa, Christopher A. Proctor, R W. Elmore, A. J. Mcmechan, N. D. Mueller, J. Wilson, G. Zobeck, Aaron Nygren, A. Bastidas, Osler Ortez

Department of Agronomy and Horticulture: Faculty Publications

Economic losses due to hailstorms acrossUS corn fields occur every year.Hailstorms result in leaf defoliation, decreasing photosynthetic area and impairing carbon assimilation and crop yield for all corn (Zea mays L.) development stages. However, more attention is often given to stand reductions rather than damage to stems or leaf defoliation. During the 2014 growing season, a natural hail event affected many areas of eastern Nebraska. Twelve affected corn fields were surveyed and included in this study. An injury score scale (1–5) was developed based on various injury and severity levels before the V6 (6-leaf corn growth stage) (six-collared leaves). …

Natural Variation In Lonely Guy-Like 1 Regulates Rice Grain Weight Under Warmer Night Conditions, Jaspreet Sandhu, Larissa Irvin, Anil Kumar Chandaran, Shohei Oguro, Puneet Paul, Balpreet Dhatt, Waseem Hussain, Shannon S. Cunningham, Cherryl O. Quinones, Argelia Lorence, Maria Arlene Adviento-Borbe, Paul E. Staswick, Gota Morota, Harkamal Walia

Department of Agronomy and Horticulture: Faculty Publications

Global nighttime temperatures are rising at twice the rate of daytime temperatures and pose a challenge for rice (Oryza sativa) production. High nighttime temperature (HNT) stress affects rice yield by reducing grain weight, size, and fertility. Although the genes associated with these yield parameters have been identified and characterized under normal temperatures, the genetic basis of grain weight regulation under HNT stress remains less explored. We examined the natural variation for rice single grain weight (SGW) under HNT stress imposed during grain development. A genome-wide association analysis identified several loci associated with grain weight under HNT stress. A …

Identifying Grassland Cores In The Southeast: Relating Spatial Covariance To Avian Communities And Vegetation Structure, Lauren L. Berry

Graduate Theses and Dissertations

Globally, grasslands are declining in range, which is leading to a decline in grassland-dependent taxa. These declines can be attributed to a variety of issues, a major one being the encroachment of woody species into historic grasslands. There is a new framework for strategizing grassland management, referred to as “Defend the Core,” which calls for proactive management of intact grasslands, meaning conserving remaining grasslands by preventing woody encroachment in the first place. To successfully defend the core, it is imperative that we develop rapid methods to identify intact grassland cores for management priority. One method that can be used for …

On-Farm Nitrogen And Irrigation Management Strategies To Protect Groundwater Quality In The Bazile Groundwater Management Area, Arshdeep Singh

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

Increasing groundwater nitrate (NO₃-N) contamination has raised significant environmental and health concerns in the irrigated sandy soils of Nebraska. Four studies were conducted to evaluate the impact the impact of 1) static (NE Yield Goal) vs. dynamic nitrogen (N) recommendations tools (Maize-N, Canopy Reflectance Sensing, Granular, and Adapt-N), 2) three N (optimum, suboptimum, and low) and irrigation rates (farmer’s full irrigation (FIT), 80% FIT, and 60% FIT), 3) conventional N sources vs. enhanced efficiency fertilizers (EEFs), and 4) multiple N splits (2, 3, 4, and 5-N splits) on agronomic (maize yield), environmental (NO3-N leaching), and economic returns (return …

Establishment Of Wildflower Islands To Enhance Roadside Health, Ecological Value, And Aesthetics, Jackson Ebbers

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

Roadsides provide an abundant opportunity to increase connectivity of fragmented landscapes with diminishing floral resources for pollinating insects. The ecological value of these sites is often overlooked as quality habitat for pollinators, particularly monarch butterflies, which have been experiencing severe declines due to loss of habitat and loss of milkweeds that provide food for their larvae. Land managers across the nation are realizing the potential of roadsides to provide high quality floral resources for the benefit of insects and other wildlife. Current wildflower seed mixes used by state transportation departments are often low diversity and may only be implemented following …

Using Annual Forages To Replace Declining Cool-Season Grass Pasture Availability, Jonathon Matthew Jenkins

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

As land area in grain crop production increases in the US Midwest, perennial pasture availability decreases but the demand increases. Matching the seasonal growth patterns of C₃ and C₄ plant species to grow forages that are complementary allows producers to fill production gaps in otherwise monoculture systems and possibly increase overall productivity. One way to fill the forage production gap of C₃ grass dominated pastures is by producing a warm-season, annual forage in a separate field. However, with continual reductions in land availability, this may not be an option. Using two studies, our objectives were to improve …

Cross-Pollination: Building A Co-Taught Course To Examine Art And Sex Through The Lens Of Botany, Christopher T. Martine, Diamanda A. Zizis, Anna K. Kell

Faculty Journal Articles

Driven by overlapping interests in plants, art, and diversity in sex expression, Anna Kell (Department of Art and Art History) and Chris Martine (Department of Biology) developed a course that integrates the perspectives of a visual artist and a botanist. Art & Sex Through the Lens of Botany seeks to impart the importance of making connections across disciplines and the value of visual literacy across academic lines. The course introduces foundational concepts in each field and encourages students to integrate and explore these different systems of knowledge and their intersections. In addition to developing fluencies related to both general botany …