Digital Commons Network^™

Site Population Trial Data, Margaret E. Maloney, Eric B. Borth, Julia I. Chapman, Ryan W. Mcewan

Data Files

No abstract provided.

Chemical Analysis Data, Charlotte A. Shade, Kevin W. Custer, Julia I. Chapman, Ryan W. Mcewan

Data Files

Hardness, Alkalinity, Orthophosphate, Soluble reactive phosphorus, Total suspended solids, Dissolved organic carbon, Total Kjeldahl nitrogen, Nitrate:Nitrite ratio

Aquatic Fine Woody Debris, Erin C. Rowekamp, Julia I. Chapman, Ryan W. Mcewan

Data Files

No abstract provided.

Prototype Data, Margaret E. Maloney, Eric B. Borth, Julia I. Chapman, Ryan W. Mcewan

Data Files

No abstract provided.

Lonicera Maackii Leaf Feeding Tests: Initial Mass, Kevin W. Custer, Julia I. Chapman, Ryan W. Mcewan

Data Files

Lymnaea stagnalis, Hyalella Azteca, and Allocapnia spp.

Lonicera Maackii Leaf Feeding Tests: Physicochemical Data, Kevin W. Custer, Julia I. Chapman, Ryan W. Mcewan

Data Files

Lymnaea stagnalis, Hyalella Azteca, and Allocapnia spp.

Lonicera Maackii Flower Leachate Toxicity: Survival And Mass, Kevin W. Custer, Julia I. Chapman, Ryan W. Mcewan

Data Files

In-stream (in situ) and in-lab microcosm trials using Hyalella Azteca and Anthopotamus verticis

Leaf Litter Basket, Erin C. Rowekamp, Taylor M. Buskey, Julia I. Chapman, Ryan W. Mcewan

Data Files

No abstract provided.

Seedling, Erin C. Rowekamp, Eric B. Borth, Julia I. Chapman, Ryan W. Mcewan

Data Files

No abstract provided.

Aquatic Coarse Woody Debris, Erin C. Rowekamp, Julia I. Chapman, Ryan W. Mcewan

Data Files

No abstract provided.

Biofilm Ash Free Dry Mass And Chlorophyll A, Kevin W. Custer, Sean D. Mahoney, Mitchell J. Kukla, Corey Kuminecz, Joseph Murphy, Julia I. Chapman, Ryan W. Mcewan

Data Files

No abstract provided.

Managing Wicked Herbicide-Resistance: Lessons From The Field, Jill Schroeder, Michael Barrett, David R. Shaw, Amy B. Asmus, Harold Coble, David Ervin, Raymond A. Jussaume Jr., Michael D. K. Owen, Ian Burke, Cody F. Creech, A. Stanley Culpepper, William S. Curran, Darrin M. Dodds, Todd A. Gaines, Jeffrey L. Gunsolus, Bradley D. Hanson, Prashant Jha, Annie E. Klodd, Andrew R. Kniss, Ramon G. Leon, Sandra Mcdonald, Don W. Morishita, Brian J. Schutte, Christy L. Sprague, Phillip W. Stahlman, Larry E. Steckel, Mark J. Vangessel

Department of Agronomy and Horticulture: Faculty Publications

Herbicide resistance is ‘wicked’ in nature; therefore, results of the many educational efforts to encourage diversification of weed control practices in the United States have been mixed. It is clear that we do not sufficiently understand the totality of the grassroots obstacles, concerns, challenges, and specific solutions needed for varied crop production systems. Weed management issues and solutions vary with such variables as management styles, regions, cropping systems, and available or affordable technologies. Therefore, to help the weed science community better understand the needs and ideas of those directly dealing with herbicide resistance, seven half-day regional listening sessions were held …

Growth, Fitness, And Overwinter Survival Of A Shattercane (Sorghum Bicolor Ssp. Drummondii) × Grain Sorghum (Sorghum Bicolor Ssp. Bicolor) F2 Population, Jared J. Schmidt, Melinda K. Yerka, Jeffrey F. Pedersen, John L. Lindquist

Department of Agronomy and Horticulture: Faculty Publications

Although sorghum [Sorghum bicolor (L.) Moench ssp. bicolor] is the fifth most important grain crop in terms of global production, no commercial hybrids carry genetically engineered (GE) traits for resistance to insect pests or herbicides due to regulatory concerns about gene flow to weedy relatives. However, non-GE herbicide resistance currently is being developed in grain sorghum and will likely transfer to related weeds. Monitoring the impact of this new nuclear technology on the evolution and invasiveness of related weeds requires a baseline understanding of the population biology of grain sorghum genes once they transfer to in situ weed …

Phenotypic Data From Inbred Parents Can Improve Genomic Prediction In Pearl Millet Hybrids, Zhikai Liang, Shashi K. Gupta, Cheng-Ting Yeh, Yang Zhang, Daniel W. Ngu, Ramesh Kumar, Hemant T. Patil, Kanulal D. Mungra, Dev Vart Yadav, Abhishek Rathore, Rakesh K. Srivastava, Rajeev Gupta, Jinliang Yang, Rajeev K. Varshney, Patrick S. Schnable, James C. Schnable

Department of Agronomy and Horticulture: Faculty Publications

Pearl millet is a non-model grain and fodder crop adapted to extremely hot and dry environments globally. In India, a great deal of public and private sectors’ investment has focused on developing pearl millet single cross hybrids based on the cytoplasmic-genetic male sterility (CMS) system, while in Africa most pearl millet production relies on open pollinated varieties. Pearl millet lines were phenotyped for both the inbred parents and hybrids stage. Many breeding efforts focus on phenotypic selection of inbred parents to generate improved parental lines and hybrids. This study evaluated two genotyping techniques and four genomic selection schemes in pearl …

Isolation And Analysis Of Microbial Communities In Soil, Rhizosphere, And Roots In Perennial Grass Experiments, Morgan R. Mcpherson, Peng Wang, Robert B. Mitchell, Daniel P. Schachtman

Department of Agronomy and Horticulture: Faculty Publications

Plant and soil microbiome studies are becoming increasingly important for understanding the roles microorganisms play in agricultural productivity. The purpose of this manuscript is to provide detail on how to rapidly sample soil, rhizosphere, and endosphere of replicated field trials and analyze changes that may occur in the microbial communities due to sample type, treatment, and plant genotype. The experiment used to demonstrate these methods consists of replicated field plots containing two, pure, warm-season grasses (Panicum virgatum and Andropogon gerardii) and a low-diversity grass mixture (A. gerardii, Sorghastrum nutans, and Bouteloua curtipendula). Briefly, plants …

Hunger In The Land Of Plenty: Local Responses To Food Insecurity In Iowa, Gabrielle E. Roesch-Mcnally, Jacqueline Ann Nester, Andrea D. Basche, Eric Christianson, Emily Zimmerman

Department of Agronomy and Horticulture: Faculty Publications

Story County (estimated population 92,406 in 2013) lies in the heart of central Iowa, a state renowned for its remarkable agricultural productivity. Iowa leads all states for production of corn, soybean, and hogs. Revenues from agricultural products in Iowa total more than $30 billion annually according the 2012 Agricultural Census (USDA-NASS 2014). This productivity stems from a favorable natural and political environment. The temperate climate, productive soils, and gentle topography are ideal for our production system of commodity agriculture facilitated by federal policies, which include subsidized crop insurance and commodity payments (Horrigan, Lawrence, and Walker 2002). Despite this productivity and …

Social–Ecological Landscape Patterns Predict Woody Encroachment From Native Tree Plantings In A Temperate Grassland, Victoria M. Donovan, Jessica L. Burnett, Christine H. Bielski, Hannah E. Birge, Rebecca Bevans, Dirac L. Twidwell Jr, Craig R. Allen

Department of Agronomy and Horticulture: Faculty Publications

Afforestation is often viewed as the purposeful planting of trees in historically non-forested grasslands, but an unintended consequence is woody encroachment, which should be considered part of the afforestation process. In North America’s temperate grassland biome, Eastern redcedar (Juniperus virginiana L.) is a native species used in tree plantings that aggressively invades in the absence of controlling processes. Cedar is a well-studied woody encroacher, but little is known about the degree to which cedar windbreaks, which are advocated for in agroforestry programs, are contributing to woody encroachment, what factors are associated with cedar spread from windbreaks, nor where encroachment …

Engineering Linear, Branched-Chain Triterpene Metabolism In Monocots, Chase Kempinski, Zuodong Jiang, Garrett Zinck, Shirley J. Sato, Zhengxiang Ge, Thomas E. Clemente, Joe Chappell

Department of Agronomy and Horticulture: Faculty Publications

Triterpenes are thirty-carbon compounds derived from the universal five-carbon prenyl precursors isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP). Normally, triterpenes are synthesized via the mevalonate (MVA) pathway operating in the cytoplasm of eukaryotes where DMAPP is condensed with two IPPs to yield farnesyl diphosphate (FPP), catalyzed by FPP synthase (FPS). Squalene synthase (SQS) condenses two molecules of FPP to generate the symmetrical product squalene, the first committed precursor to sterols and most other triterpenes. In the green algae Botryococcus braunii, two FPP molecules can also be condensed in an asymmetric manner yielding the more highly branched triterpene, botryococcene. Botryococcene …

Genomic Selection In Preliminary Yield Trials In A Winter Wheat Breeding Program, Vikas Belamkar, Mary J. Guttieri, Waseem Hussain, Diego Jarquin, Ibrahim El-Basyoni, Jesse Poland, Aaron J. Lorenz, P. Stephen Baenziger

Department of Agronomy and Horticulture: Faculty Publications

Genomic prediction (GP) is now routinely performed in crop plants to predict unobserved phenotypes. The use of predicted phenotypes to make selections is an active area of research. Here, we evaluate GP for predicting grain yield and compare genomic and phenotypic selection by tracking lines advanced. We examined four independent nurseries of F_3:6 and F_3:7 lines trialed at 6 to 10 locations each year. Yield was analyzed using mixed models that accounted for experimental design and spatial variations. Genotype-by-sequencing provided nearly 27,000 high-quality SNPs. Average genomic predictive ability, estimated for each year by randomly masking lines as missing …

Transient Heat Stress During Early Seed Development Primes Germination And Seedling Establishment In Rice, Kevin Begcy, Jaspreet Sandhu, Harkamal Walia

Department of Agronomy and Horticulture: Faculty Publications

Rice yield is highly sensitive to increased temperature. Given the trend of increasing global temperatures, this sensitivity to higher temperatures poses a challenge for achieving global food security. Early seed development in rice is highly sensitive to unfavorable environmental conditions. Heat stress (HS) during this stage decreases seed size and fertility, thus reducing yield. Here, we explore the transgenerational phenotypic consequences of HS during early seed development on seed viability, germination, and establishment. To elucidate the impact of HS on the developmental events in postzygotic rice seeds, we imposed moderate (35°C) and severe (39°C) HS treatments initiated 1 day after …

Investigating The Ecology Of A Rare Species On St. John, Usvi: Reintroducing Solanum Conocarpum In Light Of Climate Change, Cecilia Rogers

Senior Honors Projects, 2010-2019

Approximately two thirds of St. John is National Park territory. However, the land has been threatened with tourism and development, greatly impacting island biodiversity. One species that may become extinct due to this degradation is Solanum conocarpum. S. conocarpum is a rare shrub, endemic to the dry tropical forests of St. John, USVI. This plant is a species of conservation concern and is one of very few native and endemic plants on this island. Very little is known about the ecology and reproduction of S. conocarpum. Most plants are found on the southern half of the island. Recent observations …

Low- Copy Nuclear Markers In Isoëtes (Isoëtaceae) Identified With Transcriptomes, Peter W. Schafran, Gabriel Johnson, W. Carl Taylor, Elizabeth A. Zimmer, Lytton J. Musselman

Biological Sciences Faculty Publications

PREMISE OF THE STUDY: Few genetic markers provide phylogenetic information in closely related species of Isoëtes (Isoëtaceae). We describe the development of primers for several putative low- copy nuclear markers to resolve the phylogeny of Isoëtes, particularly in the southeastern United States.

METHODS AND RESULTS: We identified regions of interest in Isoëtes transcriptomes based on low- copy genes in other plants. Primers were designed for these regions and tested with 16 taxa of Isoëtes and one species of Lycopodium. Parts of the pgiC, gapC, and IBR3 gene regions show phylogenetic signal within the North American and …

The Role Of Environmental Filtering In Structuring Appalachian Tree Communities: Topographic Influences On Functional Diversity Are Mediated Through Soil Characteristics, Julia I. Chapman, Ryan W. Mcewan

Biology Faculty Publications

Identifying the drivers of community assembly has long been a central goal in ecology, and the development of functional diversity indices has provided a new way of detecting the influence of environmental gradients on biotic communities. For an old-growth Appalachian forest, we used path analysis to understand how patterns of tree functional diversity relate to topography and soil gradients and to determine whether topographic effects are mediated through soil chemistry. All of our path models supported the idea of environmental filtering: stressful areas (high elevation, low soil moisture, low soil nutrients) were occupied by communities of low functional diversity, which …

Tomato Spotted Wilt Virus Nss Protein Supports Infection And Systemic Movement Of A Potyvirus And Is A Symptom Determinant, Hernan Garcia-Ruiz, Sergio M. Gabriel Peralta, Patricia A. Harte-Maxwell

Department of Plant Pathology: Faculty Publications

Plant viruses are inducers and targets of antiviral RNA silencing. To condition susceptibility, most plant viruses encode silencing suppressor proteins that interfere with antiviral RNA silencing. The NSs protein is an RNA silencing suppressor in orthotospoviruses, such as the tomato spotted wilt virus (TSWV). The mechanism of RNA silencing suppression by NSs and its role in virus infection and movement are poorly understood. Here, we cloned and tagged TSWV NSs and expressed it from a GFP-tagged turnip mosaic virus (TuMV-GFP) carrying either a wild-type or suppressor-deficient (AS9) helper component proteinase (HC-Pro). When expressed in cis, NSs restored pathogenicity and promoted …

Intermolecular Rna Recombination Occurs At Different Frequencies In Alternate Forms Of Brome Mosaic Virus Rna Replication Compartments, Hernan Garcia-Ruiz, Arturo Diaz, Paul Ahlquist

Department of Plant Pathology: Faculty Publications

Positive-strand RNA viruses replicate their genomes in membrane-bound replication compartments. Brome mosaic virus (BMV) replicates in vesicular invaginations of the endoplasmic reticulum membrane. BMV has served as a productive model system to study processes like virus-host interactions, RNA replication and recombination. Here we present multiple lines of evidence showing that the structure of the viral RNA replication compartments plays a fundamental role and that recruitment of parental RNAs to a common replication compartment is a limiting step in intermolecular RNA recombination. We show that a previously defined requirement for an RNA recruitment element on both parental RNAs is not to …

Metagenomic Analysis Of Viruses Associated With Maize Lethal Necrosis In Kenya, Mwathi Jane Wamaitha, Deepti Nigam, Solomon Maina, Francesca Stomeo, Anne Wangai, Joyce Njoki Njuguna, Timothy A. Holton, Bramwel W. Wanjala, Mark Wamalwa, Tanui Lucas, Appolinaire Djikeng, Hernan Garcia Ruiz

Department of Plant Pathology: Faculty Publications

Background: Maize lethal necrosis is caused by a synergistic co-infection of Maize chlorotic mottle virus (MCMV) and a specific member of the Potyviridae, such as Sugarcane mosaic virus (SCMV), Wheat streak mosaic virus (WSMV) or Johnson grass mosaic virus (JGMV). Typical maize lethal necrosis symptoms include severe yellowing and leaf drying from the edges. In Kenya, we detected plants showing typical and atypical symptoms. Both groups of plants often tested negative for SCMV by ELISA. Methods: We used next-generation sequencing to identify viruses associated to maize lethal necrosis in Kenya through a metagenomics analysis. Symptomatic and asymptomatic leaf samples …

Susceptibility Genes To Plant Viruses, Hernan Garcia Ruiz

Department of Plant Pathology: Faculty Publications

Plant viruses use cellular factors and resources to replicate and move. Plants respond to viral infection by several mechanisms, including innate immunity, autophagy, and gene silencing, that viruses must evade or suppress. Thus, the establishment of infection is genetically determined by the availability of host factors necessary for virus replication and movement and by the balance between plant defense and viral suppression of defense responses. Host factors may have antiviral or proviral activities. Proviral factors condition susceptibility to viruses by participating in processes essential to the virus. Here, we review current advances in the identification and characterization of host factors …

Profile Of Genetically Modified Plants Authorized In Mexico, Mayra Teresa Garcia Ruiz, Aaron N. Knapp, Hernan Garcia Ruiz

Department of Plant Pathology: Faculty Publications

Mexico is a center of origin for several economically important plants including maize, cotton, and cocoa. Maize represents more than a food crop, has been declared a biological, cultural, agricultural and economic patrimony, and is linked to the national identity of Mexicans. In this review, we describe the historic and current use of genetically modified plants in Mexico and factors that contributed to the development of the biosafety regulation. We developed a database containing all permit applications received by the government to release genetically modified plants. A temporal and geographical analysis identified the plant species that have been authorized for …

Genomic-Enabled Prediction Models Using Multi-Environment Trials To Estimate The Effect Of Genotype × Environment Interaction On Prediction Accuracy In Chickpea, Manish Roorkiwal, Diego Jarquin, Muneendra K. Singh, Pooran M. Gaur, Chellapilla Bharadwaj, Abhishek Rathore, Reka Howard, Samineni Srinivasan, Ankit Jain, Vanika Garg, Sandip Kale, Annapurna Chitikineni, Shailesh Tripathi, Elizabeth Jones, Kelly R. Robbins, José Crossa, Rajeev K. Varshney

Department of Agronomy and Horticulture: Faculty Publications

Genomic selection (GS) by selecting lines prior to field phenotyping using genotyping data has the potential to enhance the rate of genetic gains. Genotype × environment (G × E) interaction inclusion in GS models can improve prediction accuracy hence aid in selection of lines across target environments. Phenotypic data on 320 chickpea breeding lines for eight traits for three seasons at two locations were recorded. These lines were genotyped using DArTseq (1.6 K SNPs) and Genotyping-by-Sequencing (GBS; 89 K SNPs). Thirteen models were fitted including main effects of environment and lines, markers, and/or naïve and informed interactions to estimate prediction …

Gene Expression Profiling Of Iron Deficiency Chlorosis Sensitive And Tolerant Soybean Indicates Key Roles For Phenylpropanoids Under Alkalinity Stress, Brian M. Waters, Keenan Amundsen, George L. Graef

Department of Agronomy and Horticulture: Faculty Publications

Alkaline soils comprise 30% of the earth and have low plant-available iron (Fe) concentration, and can cause iron deficiency chlorosis (IDC). IDC causes soybean yield losses of $260 million annually. However, it is not known whether molecular responses to IDC are equivalent to responses to low iron supply. IDC tolerant and sensitive soybean lines provide a contrast to identify specific factors associated with IDC.We used RNA-seq to compare gene expression under combinations of normal pH (5.7) or alkaline pH (7.7, imposed by 2.5mM bicarbonate, or pH 8.2 imposed by 5mM bicarbonate) and normal (25μM) or low (1μM) iron conditions from …