Agricultural Science Commons^™

Effects Of Prescribed Fire And Herbicide Application On Cattle Grazing And Herbage Production From Yellow Bluestem Pastures, S. A. Gunter, R. L. Gillen

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Forage management practices influence the quantity and quality of forage available to grazing cattle. The objectives of this experiment were to determine the effects of prescribed fire or herbicides on the density of forbs, the production and nutritive value of the herbage, and the performance of beef steers grazing Yellow bluestem [Bothriochloa ischaemum (L.) Keng var. ischaemum (Hack.) Celarier and Harlan] pastures. The experiment was conducted in northwestern Oklahoma from 1998 through 2000, and the untreated pastures (control) were not burned or sprayed. The prescribed-fire treatment (PFT) occurred annually between March 27 and April 10. The herbicide treatment (HT) consisted …

A Comparison Of Cumulative-Germination Response Of Cheatgrass (Bromus Tectorum L.) And Five Perennial Bunchgrass Species To Simulated Field-Temperature Regimes, Stuart P. Hardegree, Corey A. Moffet, Bruce A. Roundy, Thomas A. Jones, Stephen J. Novak, Patrick E. Clark, Frederick B. Pierson, Gerald N. Flerchinger

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Cheatgrass (Bromus tectorum L.) has come to dominate millions of hectares of rangeland in the Intermountain western United States. Previous studies have hypothesized that one mechanism conferring a competitive advantage to this species is the ability to germinate rapidly at low temperatures in the fall, winter and spring and, therefore, initiate growth and establishment more rapidly than more desirable perennial bunchgrass species. In this experiment, we developed thermal-germination-response models for multiple seedlots of cheatgrass and five perennial grass species. We conducted sensitivity analysis on potential-cumulative-germination response to a 38-year simulation of field-variable conditions of seedbed temperature and moisture. Cheatgrass …

Expression And Self-Assembly Of Virus-Like Particles From Two Genotypes Of Marine Vesiviruses And Development Of An Elisa For The Detection Of Antibodies, Shasta D. Mcclenahan, Karin Bok, Stanislav V. Sosnovtsev, John D. Neill, Kathy A. Burek, Kimberlee B. Beckmen, Alvin W. Smith, Kim Y. Green, Carlos H. Romero

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Sequences encoding the major and minor capsid proteins (VP1 and VP2) from two marine vesivirus isolates (Steller sea lion viruses V810 and V1415) were engineered for expression of virus-like particles (VLPs) in the baculovirus system. The resulting VLPs were morphologically similar to native vesivirus virions. Purified VLPs were probed in immunoblots with pooled antisera specific for nine San Miguel sea lion virus (SMSV) types, and a predominant protein of approximately 60 kDa was detected. An enzyme linked immunosorbent assay (ELISA) for the detection of antibodies was developed in which the VLPs served as antigen. The VLPs were adsorbed to the …

Groundwater Nutrient Concentrations During Prairie Reconstruction On An Iowa Landscape, M.D. Tomer, K.E. Schilling, C.A. Cambardella, P. Jacobson, P. Drobney

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

One anticipated benefit of ecosystem restoration is water quality improvement. This study evaluated NO₃-N and phosphorus in subsurface waters during prairie establishment following decades of row-crop agriculture. A prairie seeding in late 2003 became established in 2006. Wells and suction cup samplers were monitored for NO₃-N and phosphorus. Nitrate-N varied with time and landscape position. Nondetectable NO₃-N concentrations became modal along ephemeral drainageways in 2006, when average concentrations in uplands first became <10mg NO₃-N L⁻¹. This decline continued and upland groundwater averaged near 2mg NO₃-N L⁻¹ after 2007. The …

Optimized Construction Of Microsatellite-Enriched Libraries, Natascha Techen, R. S. Arias, Neil C. Glynn, Zhiqiang Pan, Ikhlas A. Khan, Brian E. Scheffler

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The construction of microsatellite-enriched libraries is an indispensable tool to search for molecular markers as complete genome sequences are still not available for the majority of species of interest. Numerous protocols are available in the literature for the construction of these libraries; however, sometimes their low efficiency or lack of optimization in the protocols can restrict their efficacy. We have designed and tested various adapters and ligation methods; we also tested oligo-repeat combinations and hybridization temperatures, and created libraries with this new protocol for four organisms: Ipomoea batatas (L.) Lam, Chionanthus retusus Lindley & Paxton, Rotylenchulus reniformis Linford & Olivera …

Genetic Improvement In Winter Wheat Yields In The Great Plains Of North America, 1959–2008, Robert A. Graybosch, C. James Peterson

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Data from USDA-coordinated winter wheat (Triticum aestivum L.) regional performance nurseries collected over the time period 1959 to 2008 were used to estimate genetic gain (loss) in grain yield, grain volume weight, days to heading, and plant height in winter wheats adapted to the Great Plains of North America. In both the Southern Regional (SRPN) and Northern Regional Performance Nurseries (NRPN), linear regression revealed significant positive relationships between relative grain yields of advanced breeding lines and calendar year of the nursery trial. The estimated genetic gain in grain yield potential since 1959 was approximately 1.1% (of the control cultivar …

Novel Carboxamides As Potential Mosquito Repellents, Alan R. Katritzky, Zuoquan Wang, Svetoslav Slavov, Dimitar A. Dobchev, C. Dennis Hall, Maia Tsikolia, Ulrich R. Bernier, Natasha M. Elejalde, Gary G. Clark, Kenneth J. Linthicum

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

A model was developed using 167 carboxamide derivatives, from the United States Department of Agriculture archival database, that were tested as arthropod repellents over the past 60 yr. An artificial neural network employing CODESSA PRO descriptors was used to construct a quantitative structure-activity relationship model for prediction of novel mosquito repellents. By correlating the structure of these carboxamides with complete protection time, a measure of repellency based on duration, 34 carboxamides were predicted as candidate mosquito repellents. There were four additional compounds selected on the basis of their structural similarity to those predicted. The compounds were synthesized either by reaction …

Structure-Activity Relationships Of 33 Carboxamides As Toxicants Against Female Aedes Aegypti (Diptera: Culicidae), Julia Pridgeon, James J. Becnel, Ulrich R. Bernier, Gary G. Clark, Kenneth J. Linthicum

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Aedes aegypti L. is the primary vector of dengue and yellow fever viruses, and use of aerosolized insecticides is one of the primary ways to control this medically important mosquito. However, few new insecticides have been developed for mosquito control in recent years. As a part of our effort to search for new insecticides to control mosquitoes, toxicities of 33 carboxamides were evaluated against female A. aegypti by topical application. This group included nine different categories of compounds, namely benzamides, phenyl-propenamides, propanamides, butanamides, butenamides, pentanamides, pentenamides, hexanamides, and hexenamides, that exhibited varying levels of toxicity against this mosquito species. The …

Potential For Stable Flies And House Flies (Diptera: Muscidae) To Transmit Rift Valley Fever Virus1, Michael J. Turell, David J. Dohm, Christopher J. Geden, Jerome A. Hogsette, Kenneth Linthicum

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Rift Valley fever (RVF), a disease of ruminants and humans, has been responsible for large outbreaks in Africa that have resulted in hundreds of thousands of human infections and major economic disruption due to loss of livestock and to trade restrictions. As indicated by the rapid spread of West Nile viral activity across North America since its discovery in 1999 and the rapid and widespread movement of chikungunya virus from Africa throughout the Indian Ocean Islands to Asia and Europe, an introduced exotic arbovirus can be rapidly and widely established across wide geographical regions. Although RVF virus (RVFV) is normally …

Efficacy Of Commercial Mosquito Traps In Capturing Phlebotomine Sand Flies (Diptera: Psychodidae) In Egypt, D. F. Hoel, D. L. Kline, Jerome Hogsette, Ulrich R. Bernier, S. S. El-Hossary, H. A. Hanafi, N. Watany, E. Y. Fawaz, B. D. Furman, P. J. Obenauer, D. E. Szumlas

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Four types of commercial mosquito control traps, the Mosquito Magnet Pro (MMP), the Sentinel 360 (S360), the BG-Sentinel (BGS), and the Mega-Catch Ultra (MCU), were compared with a standard Centers for Disease Control and Prevention (CDC) light trap for efficacy in collecting phlebotomine sand flies (Diptera: Psychodidae) in a small farming village in the Nile River Valley 10 km north of Aswan, Egypt. Each trap was baited with either carbon dioxide (CO₂) from combustion of butane gas (MMP), dry ice (CDC and BGS traps), light (MCU and S360), or dry ice and light (CDC). Traps were rotated through …

A Quantitative Phosphorus Loss Assessment Tool For Agricultural Fields, Michael J. White, Daniel E. Storm, Philip R. Busteed, Michael D. Smolen, Hailin Zhang, Garey A. Fox

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

In the United States, government sponsored conservation programs are under increasing pressure to quantify the environmental benefits of practices they subsidize. To meet this objective, conservation planners need tools to accurately predict phosphorus (P) loss from agricultural lands. Existing P export coefficient based tools are easy to use, but do not adequately account for local conditions. Hydrologic and water quality models are more accurate, but are prohibitively complex for conservation planners to use. Pasture Phosphorus Management (PPM) was developed as a user-friendly P and sediment loss prediction tool based on the Soil and Water Assessment Tool (SWAT), a popular comprehensive …

Monitoring And Analyzing Process Streams Towards Understanding Ionic Liquid Pretreatment Of Switchgrass (Panicum Virgatum L.), Rohit Arora, Chithra Manisseri, Chenlin Li, Markus D. Ong, Henrik Vibe Scheller, Kenneth P. Vogel, Blake A. Simmons, Seema Singh

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Fundamental understanding of biomass pretreatment and its influence on saccharification kinetics, total sugar yield, and inhibitor formation is essential to develop efficient next-generation biofuel strategies, capable of displacing fossil fuels at a commercial level. In this study, we investigated the effect of residence time and temperature during ionic liquid (IL) pretreatment of switchgrass using 1-ethyl-3-methyl imidazolium acetate. The primary metrics of pretreatment performance are biomass delignification, xylan and glucan depolymerization, porosity, surface area, cellulase kinetics, and sugar yields. Compositional analysis and quantification of process streams of saccharides and lignin demonstrate that delignification increases as a function of pretreatment temperature and …

Comparison Of Broiler Litter And Commercial Fertilizer At Equivalent N Rates On Soil Properties, Ardeshir Adeli, Haile Tewolde, Karamat Sistani, Dennis Rowe

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

A 3-year study was conducted to determine the effects of broiler litter relative to inorganic fertilizer on soil nutrient content and quality in an upland Loring silt loam soil. Treatments included annual broiler litter rates of 0, 2.2, 4.5, 5.6, 6.7, 10.1, and 13.4 Mg ha⁻¹ y⁻¹ and commercial fertilizer rates of 34, 68, 90, 112, 134, and 168 kg nitrogen (N) ha⁻¹ y⁻¹. Broiler litter application linearly increased soil total carbon (C), microbial biomass C, extractable soil phosphorus (P), potassium (K), soil cation exchange capacity (CEC), and the stability of soil aggregate. At the …

Overseeding Unimproved Warm-Season Pasture With Cool- And Warm-Season Legumes To Enhance Forage Productivity, P. W. Bartholomew, R. D. Williams

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Overseeding forage legumes into existing warm-season pasture may help to reduce cool-season forage deficit on small and resource-limited small farms in the southern Great Plains of the United States. Unimproved warm-season grass pastures were overseeded with Korean lespedeza (Lespedeza stipulacea Maxim) were not overseeded with summer legume. These same plots were subsequently overseeded with hairy vetch (Vicia villosa Roth), crownvetch (Coronilla varia L.), black medic (Medicago lupulina L.) or ladino white clover (Trifolium repens L.) or, not overseeded with cool-season legume. Including lespedeza in a forage mixture increased total forage yield by an average of …

Rna Interference As A Method For Target-Site Screening In The Western Corn Rootworm, Diabrotica Virgifera Virgifera, Analiza P. Alves, Marce D. Lorenzen, Richard W. Beeman, John E. Foster, Blair D. Siegfried

Department of Entomology: Faculty Publications

To test the efficacy of RNA interference (RNAi) as a method for target-site screening in Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae) larvae, genes were identified and tested for which clear RNAi phenotypes had been identified in the Coleopteran model, Tribolium castaneum. Here the cloning of the D. v. vergifera orthologs of laccase 2 (DvvLac2) and chitin synthase 2 (DvvCHS2) is reported. Injection of DvvLac2-specific doublestranded RNA resulted in prevention of post-molt cuticular tanning, while injection of DvvCHS2- specific dsRNA reduced chitin levels in midguts. Silencing of both DvvLac2 and DvvCHS2 was confirmed by RT-PCR and quantitative RT-PCR. As in T. …

Selecting Strawberry Cultivars For Winter Greenhouse Production, Ellen T. Paparozzi, Stacy A. Adams, George E. Meyer, M. Elizabeth Conley, Vicki L. Schlegel, Erin E. Blankenship, Paul E. Read

Department of Agronomy and Horticulture: Faculty Publications

Costs of transportation and food safety concerns have spawned an increase in public support of locally grown vegetables and fruit. With this in mind, a two-phase investigation was planned with the goal of combining low start up costs for sustainable greenhouse production with selection of strawberry cultivars that would provide the greatest number and largest size of berries. Additionally, berries from each cultivar will be analyzed for their beneficial nutraceutical properties to determine if there is a difference among cultivars.

Fine Mapping The Soybean Aphid Resistance Gene Rag1 In Soybean, Ki-Seung Kim, Stephanie Bellendir, Karen A. Hudson, Curtis B. Hill, Glen L. Hartman, D. L. Hyten, Matthew E. Hudson, Brian W. Diers

Department of Agronomy and Horticulture: Faculty Publications

The soybean aphid (Aphis glycines Matsumura) is an important soybean [Glycine max (L.) Merr.] pest in North America. The dominant aphid resistance gene Rag1 was previously mapped from the cultivar ‘Dowling’ to a 12 cM marker interval on soybean chromosome 7 (formerly linkage group M). The development of additional genetic markers mapping closer to Rag1 was needed to accurately position the gene to improve the effectiveness of markerassisted selection (MAS) and to eventually clone it. The objectives of this study were to identify single nucleotide polymorphisms (SNPs) near Rag1 and to position these SNPs relative to Rag1. …

A High Density Integrated Genetic Linkage Map Of Soybean And The Development Of A 1536 Universal Soy Linkage Panel For Quantitative Trait Locus Mapping, D. L. Hyten, Ik-Young Choi, Qijian Song, James E. Specht, Thomas E. Carter Jr., Randy C. Shoemaker, Eun-Young Hwang, Lakshmi K. Matukumalli, P. B. Cregan

Department of Agronomy and Horticulture: Faculty Publications

Single nucleotide polymorphisms (SNPs) are the marker of choice for many researchers due to their abundance and the high-throughput methods available for their multiplex analysis. Only recently have SNP markers been available to researchers in soybean [Glycine max (L.) Merr.] with the release of the third version of the consensus genetic linkage map that added 1141 SNP markers to the map. Our objectives were to add 2500 additional SNP markers to the soybean integrated map and select a set of 1536 SNPs to create a universal linkage panel for high-throughput soybean quantitative trait locus (QTL) mapping. The GoldenGate assay …

Inoculation With Arbuscular Mycorrhizal Fungi Or Crop Rotation With Mycorrhizal Plants Improves The Growth Of Maize In Limed Acid Sulfate Soil, Hasao Higo, Katsunori Isobe, Dong-Jin Kang, Kazuhiro Ujie, Rhae A. Drijber, Ryuichi Ishii

Department of Agronomy and Horticulture: Faculty Publications

Arbuscular mycorrhizal fungi (AMF) improve the uptake of immobile mineral nutrients such as phosphate, thereby improving plant growth. In acid sulfate soil (ASS), AMF spore density is generally low which impacts root colonization and phosphate uptake. Thus, inoculation may help increase AMF colonization of crops grown in ASS. AMF spore density decreases after cultivation of a non-host crop or bare fallow. In addition, preceding crops affect the growth and yield of subsequent crops. The production of AMF inocula requires AMF-compatible plants. The objective of the present study is to elucidate the effect of preceding crops on the persistence of inoculated …

Elevated Co2 Effects On Semi-Arid Grassland Plants In Relation To Water Availability And Competition, Feike A. Dijkstra, Dana Blumenthal, Jack A. Morgan, Daniel R. Lecain, Ronald F. Follett

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

1. It has been suggested that much of the elevated CO₂ effect on plant productivity and N cycling in semi-arid grasslands is related to a CO₂-induced increase in soil moisture, but the relative importance of moisture-mediated and direct effects of CO₂ remain unclear.

2. We grew five grassland species common to the semi-arid grasslands of northern Colorado, USA, as monocultures and as mixtures of all five species in pots. We examined the effects of atmospheric CO₂ concentration (ambient vs. 780 p.p.m.) and soil moisture (15 vs. 20% m⁄m) on plant biomass and plant N uptake. …