Plant Sciences Commons^™

Integrated Management Strategies For Phytophthora Sojae Combining Host Resistance And Seed Treatments, A. E. Dorrance, A. E. Robertson, S. Cianzo, L. J. Giesler, C. R. Grau, M. A. Draper, A. U. Tenuta, T. R. Anderson

Department of Plant Pathology: Faculty Publications

Phytophthora sojae has re-emerged as a serious soybean pathogen in the past decade. This may be due in part to changes in resistance levels in current cultivars, adoption of P. sojae populations to deployed Rps genes, and highly favorable environments in the past decade. This multilocation study evaluated the effect of seed treatments on the incidence and severity of Phytophthora root and stem rot on soybeans with different combinations of Rps genes and levels of partial resistance. The efficacy of the seed treatments was highly variable across locations. Seed treatments (metalaxyl and mefenoxam) provided protection and increased yields across cultivars …

A High-Oleic-Acid And Low-Palmitic-Acid Soybean: Agronomic Performance And Evaluation As A Feedstock For Biodiesel, George L. Graef, Bradley J. Lavallee, Patrick Tenopir, Mustafa Tat, Bruce Schweiger, Anthony J. Kinney, Jon H. Van Gerpen, Thomas E. Clemente

Department of Agronomy and Horticulture: Faculty Publications

Phenotypic characterization of soybean event 335-13, which possesses oil with an increased oleic acid content (> 85%) and reduced palmitic acid content (< 5%), was conducted across multiple environments during 2004 and 2005. Under these conditions, the stability of the novel fatty acid profile of the oil was not influenced by environment. Importantly, the novel soybean event 335-13 was not compromised in yield in both irrigated and non-irrigated production schemes. Moreover, seed characteristics, including total oil and protein, as well as amino acid profile, were not altered as a result of the large shift in the fatty acid profile. The novel oil trait was inherited in a simple Mendelian fashion. The event 335-13 was also evaluated as a feedstock for biodiesel. Extruded oil from event 335-13 produced a biodiesel with improved cold flow and enhanced oxidative stability, two critical fuel parameters that can limit the utility of this renewable transportation fuel.

Evaluation Of Competition Between Turfgrass And Trees In The Landscape, Christopher A. Hendrickson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Population growth in regions of the Intermountain West has resulted in rapid growth of residential neighborhoods. In Utah, the landscapes associated with these expanding neighborhoods consume vast quantities of treated water. This is a concern in all states of the Intermountain West, as water becomes increasingly scarce. Traditionally used turfgrasses, trees and other plants in Intermountain West landscapes require significant amounts of supplemental water considering the intense sunlight, dry winds and sparse rainfall typical of the region. Characterizing the interactions between turfgrass and tree species in these landscapes can aid in the identification of candidate species that consume less nutritional …

First Report Of Soybean Rust Caused By Phakopsora Pachyrhizi In Nebraska, S. R. Watson, L. J. Giesler, A. D. Ziems, T. E. Brovont

Department of Plant Pathology: Faculty Publications

Soybean rust caused by Phakopsora pachyrhizi Sydow was first observed in the continental United States in Louisiana in November 2004 (2). As part of the national soybean rust monitoring effort, samples were collected on 3 October 2007 during the scouting of fields with green leaves in southeastern Nebraska. After incubation at room temperature for 24 h, uredinea and urediniospores were observed with microscopic examination. Urediniospores were obovoid, hyaline to pale brown, and measured 20 to 30 × 18 to 20 μm.

Center For Grassland Studies Newsletter, Fall 2008, Volume 14, No. 4

Center for Grassland Studies: Newsletters

Contents:
Managing Grasslands for Structural Heterogeneity by Alexander Smart, Department of Animal and Range Sciences, South Dakota State University
Yellow Nutsedge: The Scourge of Lawns and Landscapes in Nebraska by Roch Gaussoin, Department of Agronomy and Horticulture, UNL
Targeting Habitat Dollars with Computers: Maximizing the Value of Data for Conservation by Drew Tyre, School of Natural Resources, UNL, with Naikoa Aguilar-Amustechegui, University of North Carolina-Wilmington and Max Post van der Burg, SNR, UNL
2008 Nebraska Grazing Conference Best Yet!

Enhanced Plant Nutrient Use Efficiency With Pgpr And Amf In An Integrated Nutrient Management System, A. O. Adesemoye, H. A. Torbert, J. W. Kloepper

Department of Plant Pathology: Faculty Publications

A 3-year field study was conducted with field corn from 2005 to 2007 to test the hypothesis that microbial inoculants that increase plant growth and yield can enhance nutrient uptake, and thereby remove more nutrients—especially N, P, and K—from the field as part of an integrated nutrient management system. The field trial evaluated microbial inoculants, which include a commercially available plant growth-promoting rhizobacteria (PGPR), arbuscular mycorrhiza fungi (AMF), and their combination across 2 tillage systems (no-till and conventional till) and 2 fertilization regimes (poultry litter and ammonium nitrate). Data were collected on plant height, yield (dry mass of ears and …

Center For Grassland Studies Newsletter, Summer 2008, Volume 14, No. 4

Center for Grassland Studies: Newsletters

Contents:
Are the Sandhills Fragile? by James Stubbendieck and Susan J. Tunnell, Department of Agronomy and Horticulture, UNL

Forage Triticale (X Triticosecale Wittmack) Genotypes for the Northern Great Plains by Lekgari Lekgari and P. Stephen Baenziger, Department of Agronomy and Horticulture, UNL

Progress Being Made in Implementing the Nebraska Natural Legacy Plan

Soil and Water Conservation Conference: Farming with Grass

August 1 is Pre-registration Deadline for Nebraska Grazing Conference

We’ve Moved!

Sheep Updates 2008 - Part 2, Meredith L. Sheil, Di Evans, Brown Besier, Tim Scanlon, Andre Martinho De Almeida, Johan Greeff, Tanya Kilminster, John Milton, Chris Oldham, B. L. Mcintyre, Alison Wheatley, John Lucey, Fiona Jones, Nick Costa, Ed Riggall, J. R. L. Hall, Robin Jacob, Dave Pethick, Dave Hopkins, Graham Gardner

Sheep Updates

This session covers eleven papers from different authors: The Sheep Room 1. Analgesia for Surgical Husbandry Procedures in Sheep and Other Livestock, Dr Meredith L. Sheil, Animal Ethics Pty Ltd, Associate Sydney University Faculty of Veterinary Science The Wool Enterprise 2. Unmulsed sheep - implications for chemical use, Di Evans & Brown Besier, Department of Agriculture and Food WA 3. Are Damara and Dorper sheep better adapted than Merinos to nutritional stress? - Growth rates, Tim Scanlon1, Andre Martinho de Almeida2, Johan Greeff1, Tanya Kilminster1, John Milton3, Chris Oldham1, Department of Agriculture and Food WA1, Instituto de Investigacao Cientifica Tropical, …

Method For Efficient Post Transcriptional Gene Slencing Using Intrinsic Direct Repeat Sequences And Utilization Thereof Infunctional Genomics, Amitava Mitra, Chonglie Ma

Department of Plant Pathology: Faculty Publications

It is well documented that transgenes with inverted repeats can efficiently trigger post-transcriptional gene silencing (PTGS), presumably via a double stranded RNA induced by complementary sequences in their transcripts. We show here that transgenes with intrinsic direct repeats can also induce PTGS at a very high frequency (80-100%). A transgene with three or four repeats induced PTGS in almost 100% of the primary transformants, regardless of whether a strong (en hanced 35S promoter) or a relatively weak (chlorophyll a?b binding protein promoter) promoter was used. The PTGS induced by three or four repeats is consistently inherited in Subsequent generations, and …

An Antibiotic Complex From Lysobacter Enzymogenes Strain C3: Antimicrobial Activity And Role In Plant Disease Control, S. Li, C. C. Jochum, F. Yu, K. Zaleta-Rivera, L. Du, Steven D. Harris, Gary Y. Yuen

Department of Plant Pathology: Faculty Publications

Lysobacter enzymogenes C3 is a bacterial biological control agent that exhibits antagonism against multiple fungal pathogens. Its antifungal activity was attributed in part to lytic enzymes. In this study, a heat-stable antifungal factor (HSAF), an antibiotic complex consisting of dihydromaltophilin and structurally related macrocyclic lactams, was found to be responsible for antagonism by C3 against fungi and oomycetes in culture. HSAF in purified form exhibited inhibitory activity against a wide range of fungal and oomycetes species in vitro, inhibiting spore germination, and disrupting hyphal polarity in sensitive fungi. When applied to tall fescue leaves as a partially-purified extract, HSAF at …

Simulated Browsing Impacts On Aspen Suckers' Density, Growth, And Nutritional Responses, Koketso Tshireletso

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Heavy and repeated ungulate browsing on reproductive suckers has limited trembling aspen (Populus tremuloides Michx.) regeneration on many Western landscapes. However, little is known about the specific effects of season and intensity of browsing. My objectives were to determine the effects of season and intensity of clipping (simulated browsing) on suckers’ (1) density and growth characteristics, and (2) nutritional quality and quantity.

Three randomly selected stands were clear-felled in mid-July, 2005, and fenced. Simulated browsing treatments of 0%, 20%, 40%, and 60% removal of current year’s growth were randomly applied in early, mid-, and late summers of 2006 and …

Plant Functional Types Do Not Predict Biomass Responses To Removal And Fertilization In Alaskan Tussock Tundra, M. Syndonia Bret-Harte, Michelle C. Mack, Gregory R. Goldsmith, Daniel B. Sloan, Jennie Demarco, Gaius R. Shaver, Peter M. Ray, Zy Biesinger, F. Stuart Chapin

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

1. Plant communities in natural ecosystems are changing and species are being lost due to anthropogenic impacts including global warming and increasing nitrogen (N) deposition. We removed dominant species, combinations of species and entire functional types from Alaskan tussock tundra, in the presence and absence of fertilization, to examine the effects of non-random species loss on plant interactions and ecosystem functioning.

2. After 6 years, growth of remaining species had compensated for biomass loss due to removal in all treatments except the combined removal of moss, Betula nana and Ledum palustre (MBL), which removed the most biomass. Total vascular plant …

Center For Grassland Studies Newsletter, Spring 2008, Volume 14, No. 2

Center for Grassland Studies: Newsletters

Contents:

Restricted Feeding Can Improve Performance of Growing Steers Prior to Grazing on Burned Native Flint Hills Pasture by Chad Anglin, Dale Blasi, KC Olson, Chris Reinhardt, Marc Epp, Rodney Derstein, and Brian Barnhardt, Department of Animal Sciences and Industry, Kansas State University

UNL Study Reports on the Cost of Growing Switchgrass as Ethanol Feedstock by Brian Williams and Richard Perrin, Department of Agricultural Economics, UNL

Water Is Focus of Prairie Conference

Professional Golf Management Highlights

2008 Nike Golf Camp in Lincoln This July

Program for 2008 Nebraska Grazing Conference

The Nebraska Range Shortcourse

2008 Nebraska Beef Cattle Report Available …

Adding Value To Swine Manure Through Accurate Prediction Of Organic Nitrogen Availability, Charles S. Wortman, Charles Shapiro, Aaron Nygren

Department of Agronomy and Horticulture: Faculty Publications

Animal manure contains organic and inorganic nitrogen. The inorganic N, which is mostly ammonium-N but nitrate-N can be significant in composted manure, is typically considered to be 100% plant available if there are not significant losses, especially due to volatilization of ammonia-N. The availability of organic N, which is mostly from undigested and partially digested plant material needs to be mineralized to become plant available, is less predictable. Field research was conducted in eastern Nebraska to improve the basis for estimating organic N availability from injected or incorporated swine manure and from surface applied composted and stockpiled FM. The factors …

Uses Of The Pseudomonas Syringae Effector Protein Hopu1 Related To Itsability To Adp-Rbosylate Eukaryotc Rna Binding Protens, James R. Alfano, Zheng Qing Fu, Thomas E. Elthon

Department of Plant Pathology: Faculty Publications

The bacterial plant pathogen Pseudomonas Syringae injects effector proteins into host cells via a type III protein secre tion system to cause disease. The invention relates to the discovery that the type III effector HopU1 is a mono-ADP ribosyltransferase (ADP-RT) and suppresses plant innate immunity. The HopU1 substrates in Arabidopsis thaliana extracts were RNA-binding proteins that possess RNA recognition motifs (RRMs). A. thaliana knock-out lines defective in the glycine-rich RNA-binding protein AtGRP7, a HopU1 substrate, were more susceptible than wild type plants to P syringae. The ADP-ribosylation of AtGRP7 by HopU1 required two arginines within the RRM. The inven tion …

Virulence Diversity Of The Common Bean Rust Pathogen Within And Among Individual Bean Fields And Development Of Sampling Strategies, C. Jochua, M. I. V. Amane, J. R. Steadman, X. Xue, K. M. Eskidge

Department of Plant Pathology: Faculty Publications

There is a dearth of information on pathogen variation within an individual field. In this study, virulence diversity of Uromyces appendiculatus, cause of bean rust, within individual fields was investigated. From six bean fields in the United States, Honduras, Dominican Republic, and South Africa, 380 U. appendiculatus isolates were differentiated into 65 virulence phenotypes on bean lines containing Andean- and Middle American-derived rust resistance genes. Race variation among bean rust isolates from different geographic regions was found, and virulence phenotypes found in fields from tropical and subtropical regions were more virulent and diverse than those found in fields from …

First Report Of Annual Bluegrass Weevil, Listronotus Maculicollis, Damage In Ohio, John L. Koenig, David J. Shetlar, Joseph W. Rimelspach, Michael J. Boehm

Department of Plant Pathology: Faculty Publications

Annual bluegrass weevil [Listronotus maculicollis (Kirby) (1)] larvae, pupae, and adults were recovered and identified in a sample received by the C. Wayne Ellett Plant and Pest Diagnostic Clinic (CWEPPDC) at Ohio State University on 19 June 2007. Damage to the approaches and collars of four golf course putting greens was detected by the superintendent of Stonewater Golf Club, Highland Heights, OH (a suburb of Cleveland) during the week of 11 June 2007. The superintendent suspected damage from the larvae of the black turfgrass ataenius, Ataenius spretulus (1). Insecticide applications applied to suppress black turfgrass ataenius did not provide …

Regulation Of Apical Dominance In Aspergillus Nidulans Hyphae By Reactive Oxygen Species, Camile P. Semighini, Steven D. Harris

Department of Plant Pathology: Faculty Publications

In fungal hyphae, apical dominance refers to the suppression of secondary polarity axes in the general vicinity of a growing hyphal tip. The mechanisms underlying apical dominance remain largely undefined, although calcium signaling may play a role. Here, we describe the localized accumulation of reactive oxygen species (ROS) in the apical region of Aspergillus nidulans hyphae. Our analysis of atmA (ATM) and prpA (PARP) mutants reveals a correlation between localized production of ROS and enforcement of apical dominance. We also provide evidence that NADPH oxidase (Nox) or related flavoproteins are responsible for the generation of ROS at hyphal tips and …

In Planta Distribution Of ‘Candidatus Liberibacter Asiaticus’ As Revealed By Polymerase Chain Reaction (Pcr) And Real-Time Pcr, Satyanarayana Tatineni, Uma Shankar Sagaram, Siddarame Gowda, Cecile J. Robertson, William O. Dawson, Toru Iwanami, Nian Wang

Department of Plant Pathology: Faculty Publications

Huanglongbing (HLB) is one of the most devastating diseases of citrus worldwide, and is caused by a phloem-limited fastidious prokaryotic α- proteobacterium that is yet to be cultured. In this study, a combination of traditional polymerase chain reaction (PCR) and real-time PCR targeting the putative DNA polymerase and 16S rDNA sequence of ‘Candidatus Liberibacter asiaticus,’ respectively, were used to examine the distribution and movement of the HLB pathogen in the infected citrus tree. We found that ‘Ca. Liberibacter asiaticus’ was distributed in bark tissue, leaf midrib, roots, and different floral and fruit parts, but not in endosperm and …

Three Genes Of Citrus Tristeza Virus Are Dispensable For Infection And Movement Throughout Some Varieties Of Citrus Trees, Satyanarayana Tatineni, Cecile J. Robertson, Stephen M. Garnsey, Moshe Bar-Joseph, Siddarame Gowda, William O. Dawson

Department of Plant Pathology: Faculty Publications

Citrus tristeza virus (CTV), a member of the Closteroviridae, possesses a 19.3-kb positive-stranded RNA genome that is organized into twelve open reading frames (ORFs). The CTV genome contains two sets of conserved genes, which are characteristic of this virus group, the replication gene block (ORF 1a and 1b) and the quintuple gene block (p6, HSP70 h, p61, CPm, and CP). With the exception of the p6 gene, they are required for replication and virion assembly. CTV contains five additional genes, p33, p18, p13, p20 and p23, in the 3′ half of the genome, some of which (p33, p18 and …

Plant Succession On Gopher Mounds In Western Cascade Meadows: Consequences For Species Diversity And Heterogeneity, Chad C. Jones, Charles B. Halpern, Jessica Niederer

Botany Faculty Publications

Pocket gophers have the potential to alter the dynamics of grasslands by creating mounds that bury existing vegetation and locally reset succession. Gopher mounds may provide safe sites for less competitive species, potentially increasing both species diversity and vegetation heterogeneity (spatial variation in species composition). We compared species composition, diversity and heterogeneity among gopher mounds of different ages in three montane meadows in the Cascade Range of Oregon. Cover of graminoids and forbs increased with mound age, as did species richness. Contrary to many studies, we found no evidence that mounds provided safe sites for early successional species, despite their …

4th Lone Star Regional Native Plant Conference, David Creech, Greg Grant, James Kroll, Dawn Stover

Lone Star Regional Native Plant Conference

No abstract provided.

Terrestrial Habitat Use Of Marbled Salamanders Ambystoma Opacum: A Site Specific Approach, Frank Piccininni

Theses, Dissertations and Capstones

Habitat destruction, fragmentation and degradation have contributed heavily to the decline of amphibian populations such as Marbled Salamanders (Ambystoma opacum). Often, ambystomatid water resources are conserved without consideration for the equally important terrestrial habitat. This is partly due to a lack of information regarding the relationship between ecological succession, plant community composition, microhabitat and salamander abundance. Three sampling transects consisting of drift fence arrays, vegetation assessments and microhabitat surveys were extended 100 m into the terrestrial habitat surrounding a seasonal wetland at Beech Fork State Park in Wayne County, West Virginia. Principal components analysis was used to identify …

Center For Grassland Studies Newsletter, Winter 2008, Volume 14, No. 1

Center for Grassland Studies: Newsletters

Contents:

Organic Matter -- Should It Matter? A Golf Course Perspective by Roch Gaussoin, Department of Agronomy and Horticulture, UNL

UNL-USDA Study: Major Net Energy Gain from Switchgrass-based Ethanol

Using the Corn Stalk Grazing Calculator as a Decision Aid by Aaron Stalker, Department of Animal Science and Matt Stockton, Department of Agricultural Economics, West Central Research and Extension Center, UNL, North Platte

Avian Response to Invasive Tree Removal on Remnant Prairie Pastures in Southeast Nebraska by Elizabeth Forbus and Craig Allen, School of Natural Resources, UNL

Conserving Wildlife and A Way of Life: Conservancy Launches Grass Exchange Program

Comparison Of Plant Growth-Promotion With Pseudomonas Aeruginosa And Bacillus Subtilis In Three Vegetables, A. O. Adesemoye, M. Obini, E. O. Ugoji

Department of Plant Pathology: Faculty Publications

Our objective was to compare some plant growth-promoting rhizobacteria (PGPR) properties of Bacillus subtilis and Pseudomonas aeruginosa as representatives of their two genera. Solanum lycopersicum L. (tomato), Abelmoschus esculentus (okra), and Amaranthus sp. (African spinach) were inoculated with the bacterial cultures. At 60 days after planting, dry biomass for plants treated with B. subtilis and P. aeruginosa increased 31% for tomato, 36% and 29% for okra, and 83% and 40% for African spinach respectively over the non-bacterized control. Considering all the parameters tested, there were similarities but no significant difference at P < 0.05 between the overall performances of the two organisms.

Inoculation Strategies To Assess Biological Interactions Between Fusarium And Alternaria Species Infecting Sorghum, Deanna L. Funnell-Harris, Jeffrey F. Pedersen

Department of Plant Pathology: Faculty Publications

New cultivars of sorghum are being developed for increased food use, as livestock feed, and for the bioenergy industry by manipulation of secondary metabolic pathways through breeding. Previous work has suggested that such modifications may have an impact on cultivar response to fungal pathogens. We investigated four inoculation strategies that may be used in studies involving pathogens of sorghum. Plants of elite sorghum genotypes ‘Wheatland’ and RTx430, commonly used in breeding programs, were inoculated with isolates of Alternaria alternata, Fusarium equiseti, Fusarium proliferatum, Fusarium solani, Fusarium thapsinum, and Fusarium verticillioides recovered from field-grown sorghum. Wound inoculation of the peduncles …

An Immunofluorescence Assay To Detect Urediniospores Of Phakopsora Pachyrhizi, Fulya Baysal-Gurel, Melanie L. Lewis Ivey, Anne E. Dorrance, Douglas Luster, Reid Frederick, Jill Czarnecki, Michael J. Boehm, Sally A. Miller

Department of Plant Pathology: Faculty Publications

An indirect immunofluorescence spore assay (IFSA) was developed to detect urediniospores of Phakopsora pachyrhizi, utilizing rabbit polyclonal antisera produced in response to intact nongerminated (SBR1A) or germinated (SBR2) urediniospores of P. pachyrhizi. Both antisera were specific to Phakopsora spp. and did not react with other common soybean pathogens or healthy soybean leaf tissue in enzyme-linked immunosorbent assay (ELISA). SBR1A and SBR2 bound to P. pachyrhizi and P. meibomiae urediniospores were detected with goat anti-rabbit Alexa Fluor 488-tagged antiserum using a Leica DM IRB epifluorescent microscope with an I3 blue filter (excitation 450 to 490 nm, emission 515 nm). The …

Rapid Development Of Fungicide Resistance By Sclerotinia Homoeocarpa On Turfgrass, Young-Ki Jo, Seog Won Chang, Michael J. Boehm, Geunhwa Jung

Department of Plant Pathology: Faculty Publications

Dollar spot, caused by Sclerotinia homoeocarpa, is the most prevalent and economically important turfgrass disease in North America. Increasing levels of fungicide resistance, coupled with tightening environmental scrutiny of existing fungicides, has left fewer options for managing dollar spot. More knowledge about S. homoeocarpa populations is needed to improve dollar spot management strategies, especially with respect to minimizing the development of fungicide resistance. Population diversity of S. homoeocarpa was examined using inter-simple sequence repeat markers and vegetative compatibility assays. Two subgroups were found in S. homoeocarpa field populations on both fairway and putting green turfgrass at a research field …

Branching Of Fungal Hyphae: Regulation, Mechanisms And Comparison With Other Branching Systems, Steven D. Harris

Department of Plant Pathology: Faculty Publications

The ability of rapidly growing hyphae to generate new polarity axes that result in the formation of a branch represents one of the most important yet least understood aspects of fungal cell biology. Branching is central to the development of mycelial colonies and also appears to play a key role in fungal interactions with other organisms. This review presents a description of the two major patterns of hyphal branching, apical and lateral, and highlights the roles of internal and external factors in the induction of branch formation. In addition, potential mechanisms underlying branch site selection are outlined, and the possible …

Registration Of ‘Darrell’ Wheat, A. M. H. Ibrahim, S. D. Haley, P. S. Baenziger, Y. Jin, M. A. C. Langham, J. Rickertsen, S. Kalsbeck, R. Little, J. Ingemansen, O. K. Chung, B. W. Seabourn, G. H. Bai, Ming-Shun Chen, D. V. Mcvey

Department of Agronomy and Horticulture: Faculty Publications

‘Darrell’ (Reg. No. CV-1024, PI 644224) hard red winter wheat (Triticum aestivum L.) was developed by the South Dakota State University–Agricultural Experiment Station and released in 2006 to seed producers by the South Dakota State University–Agricultural Experiment Station and the University of Nebraska Agricultural Experiment Station. Darrell was selected from the cross 2076-W12-11/‘Karl 92’ (PI 564245)//NE89526. NE89526 is an experimental line from the University of Nebraska with the pedigree ‘Lancota’ (CI 17389) selection/’Siouxland’ (PI 483469)//TX792729. 2076-W12-11 is an unreleased experimental line that originated from a population with an unidentified pedigree. Darrell was selected as an F3:4 line in 1998 …