Other Plant Sciences Commons^™

Fire And Road Disturbance Impacts On Forest Plant Species And Seed Rain In Table Mountain Fire Arai, Kittitas County, Washington, Jonathan A. Betz

All Master's Theses

Forest communities are in a constant state of change. Disturbance events can alter the physical landscape and create conditions favorable to some species while negatively impacting others. Fire has been a natural, reoccurring source of disturbance in Pacific Northwest forests. Over the past centuries the fire paradigm has changed in favor of fire suppression. Forest roads permit access provide greater access but further fracture forest community’s continuity. The 2012 Table Mountain Fire and road influence have altered the plant community’s seed rain and vegetation. This study measured dispersed seeds and understory vegetation cover as functions of roads and fire intensity. …

When Viruses Infect Plants, Hernan Garcia-Ruiz

Department of Plant Pathology: Faculty Publications

Just as human beings can catch a cold, plants can also get viral infections. Understanding the mechanisms regulating the interactions between plants and viruses is the first step towards developing better management strategies and using biotechnology methods to immunise plants and engineer genetic resistance to viruses in plants. This is the focus of research by Dr Hernan Garcia-Ruiz and his team based at the University of Nebraska, USA.

Viral diseases in plants can cause important economic losses as a result of poor-quality products and lower yield. This impact can particularly seriously affect developing countries which are more likely to be …

The Genome Of Broomcorn Millet, Changsong Zou, Leiting Li, Daisuke Miki, Delin Li, Qiming Tang, Lihong Xiao, Santosh Rajput, Ping Deng, Li Peng, Wei Jia, Ru Huang, Meiling Zhang, Yidan Sun, Jiamin Hu, Xing Fu, Patrick S. Schnable, Yuxiao Chang, Feng Li, Hui Zhang, Baili Feng, Xinguang Zhu, Renyi Liu, James C. Schnable, Jian-Kang Zhu, Heng Zhang

Department of Agronomy and Horticulture: Faculty Publications

Broomcorn millet (Panicum miliaceum L.) is the most water-efficient cereal and one of the earliest domesticated plants. Here we report its high-quality, chromosome-scale genome assembly using a combination of short-read sequencing, single-molecule real-time sequencing, Hi-C, and a high-density genetic map. Phylogenetic analyses reveal two sets of homologous chromosomes that may have merged ~5.6 million years ago, both of which exhibit strong synteny with other grass species. Broomcorn millet contains 55,930 proteincoding genes and 339 microRNA genes. We find Paniceae-specific expansion in several subfamilies of the BTB (broad complex/tramtrack/bric-a-brac) subunit of ubiquitin E3 ligases, suggesting enhanced regulation of protein dynamics …

Applicability Of The Dual Isotopes Δ15n And Δ18o To Identify Nitrate In Groundwater Beneath Irrigated Cropland, R. F. Spalding, A. J. Hirsh, M. E. Exner, N. A. Little, K. L. Kloppenborg

Department of Agronomy and Horticulture: Faculty Publications

Identification of the nitrate sources that adversely impact groundwater quality is a necessary first step in the control of this major worldwide pollutant. The impact of nitrate leachate from urea-ammonium nitrate (UAN) (50% urea-N, 25% ammonium-N, 25% nitrate-N) fertilizer, whose use has increased dramatically in the last three decades largely because it can be applied through sprinkler irrigation systems to corn in all growth stages, is investigated. The dual isotopes δ¹⁵N_NO3 and δ¹⁸O_NO3 were measured in groundwater samples from 39 irrigation wells in two intensively sprinkler-irrigated, corn-growing areas of Nebraska with nitrate-contaminated (N …

Restoring Fire-Grazer Interactions To Pursue Heterogeneity In Sandhills Prairie, Jack R. Arterburn, Dirac L. Twidwell Jr, Carissa L. Wonkka, Walter H. Schacht, David A. Wedin

Department of Agronomy and Horticulture: Faculty Publications

Heterogeneity has emerged as a fundamental principle for grassland management and the importance of environmental heterogeneity for biological diversity has raised questions about the appropriateness of grassland practices that seek to promote uniform grassland structure and composition. Principles of uniformity in grassland management reflect a utilitarian target of “managing for the middle” by minimizing both overgrazing and underutilization while avoiding or preventing fire and other disturbances that consume aboveground biomass. We evaluated pioneering efforts to restore fire-grazer interactions via patch burning in an effort to increase spatial heterogeneity at the patch scale in the Nebraska Sandhills, a sandy soil, mixed-grass …

A Small Viral Potassium Ion Channel With An Inherent Inward Rectification, Denise Eckert, Tobias Schulze, Julian Stahl, Oliver Rauh, James L. Van Etten, Brigitte Hertel, Indra Schroeder, Anna Moroni, Gerhard Thiel

Department of Plant Pathology: Faculty Publications

Some algal viruses have coding sequences for proteins with structural and functional characteristics of pore modules of complex K⁺ channels. Here we exploit the structural diversity among these channel orthologs to discover new basic principles of structure/function correlates in K⁺ channels. The analysis of three similar K⁺ channels with ≤ 86 amino acids (AA) shows that one channel (Kmp_v1) generates an ohmic conductance in HEK293 cells while the other two (Kmpv_SP1, Kmpv_PL1) exhibit typical features of canonical Kir channels. Like Kir channels, the rectification of the viral channels is a function …

Cryopreservation Of Paramecium Bursaria Chlorella Virus-1 During An Active Infection Cycle Of Its Host, Samantha R. Coy, Alyssa N. Alsante, James L. Van Etten, Steven W. Wilhelm

Department of Plant Pathology: Faculty Publications

Best practices in laboratory culture management often include cryopreservation of microbiota, but this can be challenging with some virus particles. By preserving viral isolates researchers can mitigate genetic drift and laboratory-induced selection, thereby maintaining genetically consistent strains between experiments. To this end, we developed a method to cryopreserve the model, green-alga infecting virus, Paramecium bursaria Chlorella virus 1 (PBCV-1). We explored cryotolerance of the infectivity of this virus particle, whereby freezing without cryoprotectants was found to maintain the highest infectivity (~2.5%). We then assessed the cryopreservation potential of PBCV-1 during an active infection cycle in its Chlorella variabilis NC64A host, …

United States Midwest Soil And Weather Conditions Influence Anaerobic Potentially Mineralizable Nitrogen, Jason D. Clark, Kristen S. Veum, Fabian G. Fernandez, James J. Camberato, Paul R. Carter, Richard B. Ferguson, David W. Franzen, Daniel E. Kaiser, Newell R. Kitchen, Carrie A. M. Laboski, Emerson D. Nafziger, Carl J. Rosen, John E. Sawyer, John F. Shanahan

Department of Agronomy and Horticulture: Faculty Publications

Nitrogen provided to crops through mineralization is an important factor in N management guidelines. Understanding of the interactive effects of soil and weather conditions on N mineralization needs to be improved. Relationships between anaerobic potentially mineralizable N (PMN_an) and soil and weather conditions were evaluated under the contrasting climates of eight US Midwestern states. Soil was sampled (0–30 cm) for PMN_an analysis before pre-plant N application (PP_0N) and at the V5 development stage from the pre-plant 0 (V5_0N) and 180 kg N ha−1 (V5_180N) rates and incubated for 7, 14, and …

Foraging Preferences Of Barnacle Geese On Endophytic Tall And Red Fescues, Tuuli-Marjaana Koski, Kari Saikkonen, Tero Klemola, Marjo Helander

Human–Wildlife Interactions

Many grasses (Poaceae) have symbiotic fungal endophytes, which affect livestock by producing unpalatable or harmful secondary compounds. Less is known about the repelling effects of fungal endophytes on avian grazers despite potential wildlife management implications. Herbivorous goose (Branta spp.) species may become a nuisance in recreational use areas via fecal littering. Planting these areas with grasses that avian grazers avoid may help mitigate this damage. In 2016, we studied the foraging preference of the barnacle geese (B. leucopsis) with endophytic (E+) or endophyte-free (E-) red fescue (Festuca rubra) and/or tall fescue (Schedonorus phoenix) in …

Evaluation Of Restoration Techniques And Management Practices Of Tule Pertaining To Eco-Cultural Use, Irene A. Vasquez

Cal Poly Humboldt theses and projects

Tule (Schoenoplectus sp.) is a native plant commonly used by California tribes and Indigenous people throughout the world (Macía & Balslev 2000). Ecological, social and regulatory threats to its use in contemporary Indigenous culture highlight major issues concerning natural resource management. My ancestral homeland, what is now Yosemite National Park, stands as a figurehead in the intersection of land management and Indigenous peoples. An important element of Traditional Ecological Management (TEM) for quality basketry materials is prescribed fire, an element western science is increasingly acknowledging for creating a more biodiverse and heterogeneous landscape. This research was conducted in Mariposa and …

The Impact Of Tree Species, Elevated Nitrogen Deposition, Stand Age, And Environmental Factors On Herbaceous Plant Communities In A Central Appalachian Hardwood Forest, Lacey J. Smith

Graduate Theses, Dissertations, and Problem Reports (ETD)

Although the herb layer represents less than 1% of the biomass of temperate forests, this layer may contain up to 90% of the plant species in the forest and can contribute up to 20% of the foliar litter, thus playing an essential role in forest biodiversity and nutrient cycling. The objectives of this study were to investigate the differences in cover, species richness, Shannon-Wiener diversity, and evenness of herb layer plants a) under tree species associated with contrasting soil nitrogen levels and b) in watersheds that vary in nitrogen deposition, stand age, and watershed aspect at the Fernow Experimental Forest …

Unraveling The Influence Of Female Flowering Characteristics And Chemical Hybridizing Agent Formulations On Hybrid Wheat (Triticum Aestivum L.) Seed Production, Hannah K. Stoll

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

The success of hybrid wheat (Triticum aestivum L.) is largely limited by inefficiencies in seed production. This research aims to address these inefficiencies by examining various Chemical Hybridizing Agent (CHA) formulations using the chemical Croisor®100 on sterility, CHA damage, and female flowering characteristics. In addition, an efficient method of phenotyping female flowering characteristics (contributing factors in hybrid production seed yield) were identified using Stepwise Regression, ANCOVA, and Pearson R-Correlations, and duration of stigma receptivity in the cytoplasmic male sterile (CMS; Triticum timopheevii Zhuk.) background was determined. At an optimally timed spray application, including a moderate rate of CHA with …

Development Of Chlorophyll-Meter-Index-Based Dynamic Models For Evaluation Of High-Yield Japonica Rice Production In Yangtze River Reaches, Ke Zhang, Xiaojun Liu, Syed Tahir Ata-Ul-Karim, Songyang Li, Brian Krienke, Songyang Li, Qiang Cao, Yan Zhu, Weixing Cao, Yongchao Tian

Department of Agronomy and Horticulture: Faculty Publications

Accurate estimation of the nitrogen (N) spatial distribution of rice (Oryza sativa L.) is imperative when it is sought to maintain regional and global carbon balances. We systematically evaluated the normalized differences of the soil and plant analysis development (SPAD) index (the normalized difference SPAD indexes, NDSIs) between the upper (the first and second leaves from the top), and lower (the third and fourth leaves from the top) leaves of Japonica rice. Four multi-location, multi-N rate (0–390 kg ha^-1) field experiments were conducted using seven Japonica rice cultivars (9915, 27123, Wuxiangjing14, Wunyunjing19, Wunyunjing24, Liangyou9, and Yongyou8). Growth …

Fire Legacies In Eastern Ponderosa Pine Forests, Caleb P. Roberts, Victoria M. Donovan, Carissa L. Wonkka, Larkin A. Powell, Craig R. Allen, David G. Angeler, David A. Wedin, Dirac L. Twidwell Jr

Department of Agronomy and Horticulture: Faculty Publications

Disturbance legacies structure communities and ecological memory, but due to increasing changes in disturbance regimes, it is becoming more difficult to characterize disturbance legacies or determine how long they persist. We sought to quantify the characteristics and persistence of material legacies (e.g., biotic residuals of disturbance) that arise from variation in fire severity in an eastern ponderosa pine forest in North America. We compared forest stand structure and understory woody plant and bird community composition and species richness across unburned, low‐, moderate‐, and high‐severity burn patches in a 27‐year‐old mixed‐severity wildfire that had received minimal post‐fire management. We identified distinct …

Spatial Variability Of Soil Properties Under Different Land Use In The Dang District Of Nepal, Dinesh Panday, Roshan Babu Ojha, Devraj Chalise, Saurav Das, Bikesh Twanabasu

Department of Agronomy and Horticulture: Faculty Publications

Increased nutrient mining, soil erosion, and limited nutrient management has led to declines in soil quality and reduced productivity in many parts of Nepal. A study was conducted in the eastern part of the Dang district of Nepal in 2015 to assess the variability of selected soil properties of three different land use types (agricultural, agroforestry, and grassland) and to map their spatial distribution. A total of 120 soil samples were collected from 0–15 cm depth and analyzed for soil fertility parameters: pH, organic matter (OM), nitrogen (N), phosphorus (P), potassium (K), boron (B), and zinc (Zn). Results revealed that …

Response Surface Analysis Of Genomic Prediction Accuracy Values Using Quality Control Covariates In Soybean, Diego Jarquin, Reka Howard, George L. Graef, Aaron Lorenz

Department of Agronomy and Horticulture: Faculty Publications

An important and broadly used tool for selection purposes and to increase yield and genetic gain in plant breeding programs is genomic prediction (GP). Genomic prediction is a technique where molecular marker information and phenotypic data are used to predict the phenotype (eg, yield) of individuals for which only marker data are available. Higher prediction accuracy can be achieved not only by using efficient models but also by using quality molecular marker and phenotypic data. The steps of a typical quality control (QC) of marker data include the elimination of markers with certain level of minor allele frequency (MAF) and …

Ponderosa Pine Regeneration,Wildland Fuels Management, And Habitat Conservation: Identifying Trade-Offs Following Wildfire, Victoria M. Donovan, Caleb P. Roberts, Carissa L. Wonkka, David A. Wedin, Dirac L. Twidwell

Department of Agronomy and Horticulture: Faculty Publications

Increasing wildfires in western North American conifer forests have led to debates surrounding the application of post-fire management practices. There is a lack of consensus on whether (and to what extent) post-fire management assists or hinders managers in achieving goals, particularly in under-studied regions like eastern ponderosa pine forests. This makes it difficult for forest managers to balance among competing interests. We contrast structural and community characteristics across unburned ponderosa pine forest, severely burned ponderosa pine forest, and severely burned ponderosa pine forest treated with post-fire management with respect to three management objectives: ponderosa pine regeneration, wildland fuels control, and …

Beyond Bird Feed: Proso Millet For Human Health And Environment, Saurav Das, Rituraj Khound, Meenakshi Santra, Dipak K. Santra

Department of Agronomy and Horticulture: Faculty Publications

Domesticated in 8000–10,000 BP in northern China, proso millet (Panicum miliaceum L.) is the best adaptive rotational crop for semiarid central High Plains of the USA, where average annual precipitation is 356–407 mm. Proso millet has multiple benefits when consumed as human food. Proso millet is rich in minerals, dietary fiber, polyphenols, vitamins and proteins. It is gluten-free and therefore, ideal for the gluten intolerant people. Proso millet contains high lecithin which supports the neural health system. It is rich in vitamins (niacin, B-complex vitamins, folic acid), minerals (P, Ca, Zn, Fe) and essential amino acids (methionine and cysteine). …

Developments In Agricultural Soil Quality And Health: Reflections By The Research Committee On Soil Organic Matter Management, Michelle M. Wander, Larry J. Cihacek, Mark Coyne, Rhae A. Drijber, Julie M. Grossman, Jessica L. M. Gutknecht, William R. Horwath, Sindhu Jagadamma, Daniel C. Olk, Matt Ruark, Sieglinde S. Snapp, Lisa K. Tiemann, Ray Well, Ronald F. Turco

Department of Agronomy and Horticulture: Faculty Publications

The North Central Education and Research Activity Committee (NCERA-59) was formed in 1952 to address how soil organic matter formation and management practices affect soil structure and productivity. It is in this capacity that we comment on the science supporting soil quality and associated soil health assessment for agricultural lands with the goal of hastening progress in this important field. Even though the suite of soil quality indicators being applied by U.S. soil health efforts closely mirrors the “minimum data set” we developed and recommended in the mid-1990s, we question whether the methods or means for their selection and development …

Molecular Marker Dissection Of Stem Rust Resistance In Nebraska Bread Wheat Germplasm, Amira M. I. Mourad, Ahmed Sallam, Vikas Belamkar, Stephen Wegulo, Guihua Bai, Ezzat Mahdy, Bahy Bakheit, Atif Abo El-Wafa, Yue Jin, P. Stephen Baenziger

Department of Agronomy and Horticulture: Faculty Publications

Stem rust (caused by Puccinia graminis f. sp. tritici) is a major disease of wheat. To understand the genetic basis of stem rust resistance in Nebraska winter wheat, a set of 330 genotypes representing two nurseries (DUP2015 and TRP2015) were evaluated for resistance to a Nebraska stem rust race (QFCSC) in two replications. The TRP2015 nursery was also evaluated for its resistance to an additional 13 stem rust races. The analysis of variance revealed significant variation among genotypes in both populations for stem rust resistance. Nine stem rust genes, Sr6, Sr31, Sr1RS^Amigo, Sr24, Sr36 …