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Articles 11971 - 12000 of 12511

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Pest Management Benefits Of Compost Mulch In Apple Orchards, M. W. Brown, Thomas Tworkoski Jan 2004

Pest Management Benefits Of Compost Mulch In Apple Orchards, M. W. Brown, Thomas Tworkoski

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

The effect of compost application on weed, fungal, and insect pest management in apple orchards was investigated from 1999 to 2001. Composted poultry manure was applied in June 1999 to half of two small research orchards which had previously received little or no management. The compost provided weed control for 1 year after application. There was no effect of compost on apple scab (Venturia inaequalis) infection. In a laboratory experiment, growth of the brown rot fungus (Monilinia fructicola) was significantly slower on a compost substrate than a sterilized compost substrate. The compost significantly affected arthropod abundance …

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Conservation Of Natural Enemies In Cotton: Role Of Insect Growth Regulators In Management Of Bemisia Tabaci, Steven E. Naranjo, Peter C. Ellsworth, James R. Hagler Jan 2004

Conservation Of Natural Enemies In Cotton: Role Of Insect Growth Regulators In Management Of Bemisia Tabaci, Steven E. Naranjo, Peter C. Ellsworth, James R. Hagler

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

Field studies were conducted from 1997 to 1999 to contrast the effects of two insect growth regulators (IGRs) and conventional insecticides on natural enemy conservation in cotton within the context of alternative management strategies for Bemisia tabaci (Gennadius). Compared with an untreated control, insecticide regimes based on the initial use of the IGR buprofezin or pyriproxyfen reduced densities of eight predator taxa out of 20 examined in at least one year, including common species such as Geocoris punctipes (Say), Nabis alternatus Parshley, Chrysoperla carnea s.l., and the empidid fly Drapetis nr. divergens. Patterns of predator and pest population change relative …

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Supplemental Forms Of Intellectual Property Protection For Plants, Mark D. Janis Jan 2004

Supplemental Forms Of Intellectual Property Protection For Plants, Mark D. Janis

Articles by Maurer Faculty

A new hierarchy of intellectual property protection for plant innovation is emerging. Utility patent protection is poised to become the dominant intellectual property mechanism for plants in the U.S. and perhaps elsewhere. Plant breeder's rights systems continue to garner a dedicated following, especially in developing countries, as a means for complying with international intellectual property treaty obligations. But while utility patent and plant breeder's rights regimes have come to occupy the first tier of the intellectual property hierarchy for plants, other forms of intellectual property protection remain important, albeit in a supplemental role. This article surveys supplemental intellectual property strategies …

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Effects Of Burial And Soil Condition On Postharvest Mortality Of Boll Weevils (Coleoptera: Curculionidae) In Fallen Cotton Fruit, S. M. Greenberg, A. T. Showler, T. W. Sappington, J. M. Bradford Jan 2004

Effects Of Burial And Soil Condition On Postharvest Mortality Of Boll Weevils (Coleoptera: Curculionidae) In Fallen Cotton Fruit, S. M. Greenberg, A. T. Showler, T. W. Sappington, J. M. Bradford

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

Effects of soil condition and burial on boll weevil, Anthonomus grandis grandis Boheman, mortality in fallen cotton, Gossypium hirsutum L., fruit were assessed in this study. During hot weather immediately after summer harvest operations in the Lower Rio Grande Valley of Texas, burial of infested fruit in conventionally tilled field plots permitted significantly greater survival of weevils than in no-tillage plots. Burial of infested squares protected developing weevils from heat and desiccation that cause high mortality on the soil surface during and after harvest in midsummer and late summer. A laboratory assay showed that burial of infested squares resulted in …

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Using Multi-Spectral Imagery To Evaluate Corn Grown Under Nitrogen And Drought Stressed Conditions, Shannon L. Osborne, James S. Schepers, Mike R. Schlemmer Jan 2004

Using Multi-Spectral Imagery To Evaluate Corn Grown Under Nitrogen And Drought Stressed Conditions, Shannon L. Osborne, James S. Schepers, Mike R. Schlemmer

Department of Agronomy and Horticulture: Faculty Publications

The in-season estimation of crop stresses which have the potential of adversely affecting crop yield and/or quality could allow producers to make in-season management decisions to correct for the particular stress. A field study was conducted to evaluate the use of multispectral imagery for estimating corn (Zea mays L.) grain yield, in-season biomass and nitrogen (N) concentration under varying N and drought stresses. The experiment was a split-plot design with three replications using a factorial arrangement of treatments. Three irrigation (whole-plot) treatments included dry land, irrigation based on 0.5, and full evapotranspiration (ET). Sub-plot treatments included five N …

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Expression Of A Putative Flavonoid 3'-Hydroxylase In Sorghum Mesocotyls Synthesizing 3-Deoxyanthocyanidin Phytoalexins, Jayanand Boddu, Catherine Svabek, Rajandeep Sekhon, Amanda Gevens, Ralph L. Nicholson, A. Daniel Jones, Jeffrey F. Pedersen, David L. Gustine, Surinder Chopra Jan 2004

Expression Of A Putative Flavonoid 3'-Hydroxylase In Sorghum Mesocotyls Synthesizing 3-Deoxyanthocyanidin Phytoalexins, Jayanand Boddu, Catherine Svabek, Rajandeep Sekhon, Amanda Gevens, Ralph L. Nicholson, A. Daniel Jones, Jeffrey F. Pedersen, David L. Gustine, Surinder Chopra

Department of Agronomy and Horticulture: Faculty Publications

In sorghum, ingress of Cochliobolus heterostrophus stimulates the synthesis of 3-deoxyanthocyanidins that act as phytoalexins. Apigeninidin and luteolinidin are two major phytoalexins induced in the first 24 h after infection. In an attempt to understand genetic regulation of the biosynthesis of sorghum phytoalexins, we isolated a differentially expressed partial cDNA. Characterization and comparison showed that this cDNA sequence corresponds to a putative flavonoid 3’-hydroxylase. Full length sequence characterization allowed us to establish that the sorghum putative f3’h cDNA encodes a peptide of 517 amino acids that has domains conserved among cytochrome P450 proteins functioning in …

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Levels And Changes Of Soil Phosphorus In Subtropical Beef Cattle Pastures, Gilbert C. Sigua, Mary J. Williams, Samuel W. Coleman Jan 2004

Levels And Changes Of Soil Phosphorus In Subtropical Beef Cattle Pastures, Gilbert C. Sigua, Mary J. Williams, Samuel W. Coleman

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

Long-term pasture management is believed to change soil chemical properties, but little is known about whether pasture management, such as fertilizer application, grazing, or haying can initiate such change in sandy and well-drained subtropical beef pastures. The objective of this study was to investigate the long term effect of pasture management (grazing+haying, GZ+HY) on soil phosphorus (P) dynamics (levels and changes) in subtropical beef cattle pastures with bahiagrass (BG, Paspalum notatum) and rhizoma peanut (RP, Arachis glabrata) with (WP) or without (WNP) P fertilization in Brooksville, FL from 1988 to 2000. Soil P dynamics in Subtropical Agricultural Research …

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Aquaporins Are Observed In The Duct Epithelia Of The Epididymal Region Of The Large White Turkey, L. Zaniboni, V. Akuffo, M. R. Bakst Jan 2004

Aquaporins Are Observed In The Duct Epithelia Of The Epididymal Region Of The Large White Turkey, L. Zaniboni, V. Akuffo, M. R. Bakst

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

The cellular and molecular mechanisms regulating the reuptake of the testicular fluid supporting sperm exiting the testes in the bird are not known. The presence of aquaporins, proteins involved in transmembrane water transport, was investigated. Observations were limited to the ductuli efferentes, collecting ducts, and ductus epididymis. Interestingly all of these ducts were positive for aquaporins-2, -3, and -9 but not aquaporin- 7. When positive, aquaporin was observed localized over the whole cell or the apical plasma membrane of the nonciliated cells and the apical plasma membrane and cilia of the ciliated cells. This study is the first to clearly …

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Plasma Clearance And Tissue Distribution Of Radiolabeled Leptin In The Chicken, John P. Mcmurtry, Christopher M. Ashwell, Donna M. Brocht, Thomas J. Caperna Jan 2004

Plasma Clearance And Tissue Distribution Of Radiolabeled Leptin In The Chicken, John P. Mcmurtry, Christopher M. Ashwell, Donna M. Brocht, Thomas J. Caperna

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

Leptin is an adipose and liver tissue-derived secreted protein in chickens that has been implicated in the regulation of food intake and whole-body energy balance. In this study, the metabolic clearance and tissue uptake of leptin were examined in the chicken (Gallus gallus). Four-week-old broiler males were infused with 125I-labeled mouse leptin. Chromatography of radiolabeled leptin in plasma produced two peaks, one at 16 kDa (free leptin) and a free iodine peak. No leptin binding protein in blood was detected. Leptin was cleared with a half-life estimate of 23 min. In order to investigate the tissue distribution …

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Influence Of Different Cotton Fruit Sizes On Boll Weevil (Coleoptera: Curculionidae) Oviposition And Survival To Adulthoods., S. M. Greenberg, T. W. Sappington, M. Sétamou, R. J. Coleman Jan 2004

Influence Of Different Cotton Fruit Sizes On Boll Weevil (Coleoptera: Curculionidae) Oviposition And Survival To Adulthoods., S. M. Greenberg, T. W. Sappington, M. Sétamou, R. J. Coleman

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

Understanding the critical host plant factors that determine oviposition behavior and survival of boll weevil, Anthonomus grandis grandis Boheman, on cotton, Gossypium hirsutum L., is important for developing successful pest management strategies. However, published information is both conflicting and limited regarding how different cotton fruit sizes affect boll weevil oviposition choices and subsequent larval survival to adulthood. Consequently, we used a standard based on fruit size diameter to evaluate boll weevil feeding and oviposition punctures, and survival to adulthood on 10 different cotton fruit sizes: squares of diameter 1.5-2.0 (pinhead), 3.0-3.5 (matchhead), 5-6, 7-8, or 9-10 mm; candle; and bolls …

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Tillage And Cropping Effects On Soil Quality Indicators In The Northern Great Plains, Mark A. Liebig, D. L. Tanaka, Brian J. Wienhold Jan 2004

Tillage And Cropping Effects On Soil Quality Indicators In The Northern Great Plains, Mark A. Liebig, D. L. Tanaka, Brian J. Wienhold

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

The extreme climate of the northern Great Plains of North America requires cropping systems to possess a resilient soil resource in order to be sustainable. This paper summarizes the interactive effects of tillage, crop sequence, and cropping intensity on soil quality indicators for two long-term cropping system experiments in the northern Great Plains. The experiments, located in central North Dakota, were established in 1984 and 1993 on a Wilton silt loam (FAO: Calcic Siltic Chernozem; USDA1: fine-silty, mixed, superactive frigid Pachic Haplustoll). Soil physical, chemical, and biological properties considered as indicators of soil quality were evaluated in spring 2001 in …

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Geographic And Voltinism Differentiation Among North American Ostrinia Nubilalis (European Corn Borer) Mitochondrial Cytochrome C Oxidase Haplotypes, Brad S. Coates, Douglas V. Sumerford, Richard L. Hellmich Jan 2004

Geographic And Voltinism Differentiation Among North American Ostrinia Nubilalis (European Corn Borer) Mitochondrial Cytochrome C Oxidase Haplotypes, Brad S. Coates, Douglas V. Sumerford, Richard L. Hellmich

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

DNA sequence of European corn borer, Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae), mitochondrial cytochrome c oxidase I (cox1) and II (cox2) genes were characterized and used for population genetic analysis. Twenty-six point mutations were identified from a 2,156 bp DNA sequence alignment. The frequency of polymorphic cox1 DdeI and HaeIII, and cox2 Sau3AI and MspI restriction sites were determined from 1,414 individuals by polymerase chain reaction restriction fragment length polymorphism. Ten haplotypes were observed. A single haplotype was present among 90% of individuals examined, and a HaeIII haplotype was not present in …

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Habitat Manipulation Of The Apple Orchard Floor To Increase Ground-Dwelling Predators And Predation Of Cydia Pomonella (L.) (Lepidoptera: Tortricidae), Clarissa R. Mathews, Dale G. Bottrell, M. W. Brown Jan 2004

Habitat Manipulation Of The Apple Orchard Floor To Increase Ground-Dwelling Predators And Predation Of Cydia Pomonella (L.) (Lepidoptera: Tortricidae), Clarissa R. Mathews, Dale G. Bottrell, M. W. Brown

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

Augmenting generalist predator populations in new apple (Malus domestica Bork) plantings could potentially aid in the establishment of balanced orchard ecosystems that are less susceptible to pest outbreaks. Habitat can be an important factor in retaining predators in a system and can affect predator efficiency. We investigated the potential of increasing a complex of generalist ground-dwelling predators and enhancing biological control in a young 'Golden Delicious' apple orchard through ground habitat manipulation. We modified the orchard floor with four comparative habitat treatments: (1) detritus-rich compost mulch layer, (2) detritus-free synthetic mulch layer, (3) herbicide-treated vegetation thatch, and (4) bare …

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Comparison Of Production, Meat Yield, And Meat Quality Traits Of Nwac103 Line Channel Catfish, Norris Line Channel Catfish, And Female Channel Catfish × Male Blue Catfish F1 Hybrids, Brian G. Bosworth, William R. Wolters, Juan L. Silva, Roberto S. Chamul, Sinyoung Park Jan 2004

Comparison Of Production, Meat Yield, And Meat Quality Traits Of Nwac103 Line Channel Catfish, Norris Line Channel Catfish, And Female Channel Catfish × Male Blue Catfish F1 Hybrids, Brian G. Bosworth, William R. Wolters, Juan L. Silva, Roberto S. Chamul, Sinyoung Park

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

NWAC103 line channel catfish Ictalurus punctatus, Norris line channel catfish, and Norris line female channel catfish × Dycus Farm line male blue catfish I. furcatus F1 hybrids were compared for production, meat yield, and meat quality traits. Juvenile fish from each genetic group were stocked at 12,000 fish/ha into three, 0.04-ha ponds per genetic group. Fish were fed once daily to satiation from June through October, and fed on days when afternoon water temperatures were above 17 °C from November through December. Fish were harvested, weighed, and counted in January, and 150 fish per genetic group (50 fish …

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Molecular Mapping And Identification Of Soybean Fatty Acid Modifier Quantitative Trait Loci, D. L. Hyten Jr., Vincent R. Pantalone, Arnold M. Saxton, Michael E. Schmidt, Carl E. Sams Jan 2004

Molecular Mapping And Identification Of Soybean Fatty Acid Modifier Quantitative Trait Loci, D. L. Hyten Jr., Vincent R. Pantalone, Arnold M. Saxton, Michael E. Schmidt, Carl E. Sams

Department of Agronomy and Horticulture: Faculty Publications

Altering FA content in soybean [Glycine max (L.) Merr.] oil for improved functionality is a research goal of many soybean breeders. Several of the genes that alter palmitic, stearic, oleic, linoleic, and linolenic acids are modifier genes with small effects, causing these FA traits to act as quantitative traits. The objective of this study was to identify modifier FA quantitative trait loci (QTL) in soybean. A recombinant inbred line population was created from two prominent ancestors of currently avail-able U.S. cultivars (Essex and Williams) and grown in five environments. One hundred simple se-quence repeat markers spaced throughout the genome …

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Implementation Of A Mitochondrial Mutator, Sally Mackenzie, Ricardo Vilela Abdelnoor Jan 2004

Implementation Of A Mitochondrial Mutator, Sally Mackenzie, Ricardo Vilela Abdelnoor

Department of Agronomy and Horticulture: Faculty Publications

Plant MSH1 polynucleotides and polypeptides are described. Also described are methods for the use and modulation of such MSH1 polynucleotides and polypeptides.

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Carbon Dioxide Dynamics During A Growing Season In Midwestern Cropping Systems, J. H. Prueger, J. L. Hatfield, T. B. Parkin, W.P. Kustas, T. C. Kaspar Jan 2004

Carbon Dioxide Dynamics During A Growing Season In Midwestern Cropping Systems, J. H. Prueger, J. L. Hatfield, T. B. Parkin, W.P. Kustas, T. C. Kaspar

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

Daily and seasonal CO2-exchange dynamics between the boundary layer and biosphere is important to understanding Net Ecosystem Exchange of terrestrial ecosystems. Spatial and temporal variations of CO2 fluxes across midwestern cropping systems have not been well documented. This study was designed to monitor and evaluate spatial and temporal dynamics of CO2 exchange across a watershed region for typical production fields of corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] in the Midwest by quantifying the above-canopy, within-canopy, and soil components of C balance for this cropping system. An energy-balance approach using eddy …

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Water Quality And The Grazing Animal, R. K. Hubbard, G. L. Newton, G. M. Hill Jan 2004

Water Quality And The Grazing Animal, R. K. Hubbard, G. L. Newton, G. M. Hill

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

Grazing animals and pasture production can affect water quality both positively and negatively. Good management practices for forage production protect the soil surface from erosion compared with conventionally produced crops. Grazing animals and pasture production can negatively affect water quality through erosion and sediment transport into surface waters, through nutrients from urine and feces dropped by the animals and fertility practices associated with production of high-quality pasture, and through pathogens from the wastes. Erosion and sediment transport is primarily associated with high-density stocking and/ or poor forage stands. The two nutrients of primary concern relating to animal production are N …

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Evaluation Of Adapted Wheat Cultivars For Tolerance To Pythium Root Rot, R. W. Higginbotham, T. C. Paulitz, K. A. Garland-Campbell, K. K. Kidwell Jan 2004

Evaluation Of Adapted Wheat Cultivars For Tolerance To Pythium Root Rot, R. W. Higginbotham, T. C. Paulitz, K. A. Garland-Campbell, K. K. Kidwell

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

Genetic resistance in wheat (Triticum aestivum) against Pythium species would be an efficient means of control of this major root fungal pathogen, but so far no source has been identified. In addition, no long-term, sustainable options for controlling Pythium root rot are available; therefore, identifying and then incorporating genetic resistance into wheat cultivars would create an ideal method of control for this disease. The objective of this study was to examine the level of tolerance to Pythium root rot among a diverse set of wheat germ plasm collected from all major wheat production regions in the United States.

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Betaine Improves Growth, But Does Not Induce Whole Body Or Hepatic Palmitate Oxidation In Swine (Sus Scrofa Domestica), Diane Wray-Cahen, Ignacio Fernández-Fígares, Erkki Virtanen, Norman C. Steele, Thomas J. Caperna Jan 2004

Betaine Improves Growth, But Does Not Induce Whole Body Or Hepatic Palmitate Oxidation In Swine (Sus Scrofa Domestica), Diane Wray-Cahen, Ignacio Fernández-Fígares, Erkki Virtanen, Norman C. Steele, Thomas J. Caperna

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

Dietary betaine may reduce carcass fat in growing pigs. We explored the effects of betaine on short-term growth and in vivo and in vitro fatty acid oxidation. Pigs were housed in metabolism crates and fed diets containing either 0% (control), 0.125% or 0.5% betaine at 80% of ad libitum energy intake. Fatty acid oxidation was measured during intravenous infusions of 1-13C-palmitate and in hepatocytes incubated in the presence or absence of betaine and carnitine. CO2 and palmitate isotopic enrichments were determined by mass spectrometry. Pigs consuming 0.125% and 0.5% betaine for at least 9 days had growth …

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Case Study: Effects Of Delaying Implant And Programmed Rate Of Gain On Performance And Carcass Characteristics Of Yearling Beef Steers, G. Scaglia, L. W. Greene, F. T. Mccollum, N. A. Cole, T. H. Montgomery Jan 2004

Case Study: Effects Of Delaying Implant And Programmed Rate Of Gain On Performance And Carcass Characteristics Of Yearling Beef Steers, G. Scaglia, L. W. Greene, F. T. Mccollum, N. A. Cole, T. H. Montgomery

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

Ninety-six steers (average BW = 335 ± 36 kg) were allotted in a completely randomized design with a 2 × 2 factorial arrangement of treatments. Factors were 1) implant on d 1 or no implant and 2) ad libitum access to feed on d 1 or programmed-fed for a target BW gain of 1.4 kg/d during the first 62 d of the feeding period. On d 63, all steers were implanted with Revalor-S® (Hoechst Roussel Vet, Overland Park, KS) and provided ad libitum access to feed until harvest. From d 63 to 116, ADG and gain efficiency (g gain/kg …

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Performance And Carcass Characteristics Of Feedlot Steers: Effects Of Delayed Implanting And Programmed Feeding During The Growing Period, G. Scaglia, L. W. Greene, F. T. Mccollum Iii, N. A. Cole, T. H. Montgomery Jan 2004

Performance And Carcass Characteristics Of Feedlot Steers: Effects Of Delayed Implanting And Programmed Feeding During The Growing Period, G. Scaglia, L. W. Greene, F. T. Mccollum Iii, N. A. Cole, T. H. Montgomery

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

This experiment was conducted to determine the effect of programming the rate of gain and delaying the first implant in feedlot steers on feedlot performance and carcass characteristics. Ninety-six growing steers (269 ± 16.2 kg) were assigned to 12 pens in a completely randomized design. Treatments were implant (Synovex-S®; 20 mg estradiol benzoate and 200 mg progesterone; Fort Dodge Animal Health, Overland Park, KS) on d 1 or no implant and programmed feeding to gain at a slow (0.68 kg/d) or fast (1.14 kg/d) rate during the growing period; these treatments were randomly assigned (n = 8) to …

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Somatic Mutation-Mediated Evolution Of Herbicide Resistance In The Nonindigenous Invasive Plant Hydrilla (Hydrilla Verticillata) And Franck E. Dayan, Albrecht Michel, R. S. Arias, Brian E. Scheffler, Stephen O. Duke, Michael Netherland, Franck E. Dayan Jan 2004

Somatic Mutation-Mediated Evolution Of Herbicide Resistance In The Nonindigenous Invasive Plant Hydrilla (Hydrilla Verticillata) And Franck E. Dayan, Albrecht Michel, R. S. Arias, Brian E. Scheffler, Stephen O. Duke, Michael Netherland, Franck E. Dayan

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

Hydrilla (Hydrilla verticillata L.f. Royle) was introduced to the surface water of Florida in the 1950s and is today one of the most serious aquatic weed problems in the USA. As a result of concerns associated with the applications of pesticides to aquatic systems, fluridone is the only USEPA-approved chemical that provides systemic control of hydrilla. After a decrease in fluridone’s efficacy at controlling hydrilla, 200 Florida water bodies were sampled to determine the extent of the problem and the biological basis for the reduced efficacy. Our studies revealed that hydrilla phenotypes with two- to six-fold higher fluridone resistance …

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Putting Genes Into Genetic Coefficients, P. Stephen Baenziger, Gregory S. Mcmaster, Wallace Wilhelm, Albert Weiss Jan 2004

Putting Genes Into Genetic Coefficients, P. Stephen Baenziger, Gregory S. Mcmaster, Wallace Wilhelm, Albert Weiss

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

Plant parameters are critical inputs in crop simulation models and allow a general set of algorithms to represent features of specific cultivars. A subset of plant parameters is often referred to as "genetic coefficients". However, these genetic coefficients are developed from phenotypic observations, usually have a weak genetic basis, and are at best "genotypic" coefficients because they consider the genotype from a very integrative perspective and likely include some impact of environment on the trait or characteristic described. With increased understanding of crop genomes, we believe models can be improved by incorporating genetic coefficients that accurately describe the action of …

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Structural Attributes Of Schizachyrium Scoparium In Restored Texas Blackland Prairies, Justin D. Derner, H. Wayne Polley, Hyrum B. Johnson, Charles R. Tischler Jan 2004

Structural Attributes Of Schizachyrium Scoparium In Restored Texas Blackland Prairies, Justin D. Derner, H. Wayne Polley, Hyrum B. Johnson, Charles R. Tischler

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

Structural attributes of the C4, perennial bunchgrass Schizachyrium scoparium in restored prairies may be affected by the time since restoration. One hundred plants each in 8-, 17-, and 23-year-old restored prairies and a native Texas Blackland prairie were assessed for the presence/absence and diameter of a hollow crown (i.e., dead center portion), degree of fragmentation, plant height, and tiller density.

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Determination Of Dimethylselenide And Dimethyldiselenide By Gas Chromatography–Photoionization Detection, William J. Hunter, L. David Kuykendall Jan 2004

Determination Of Dimethylselenide And Dimethyldiselenide By Gas Chromatography–Photoionization Detection, William J. Hunter, L. David Kuykendall

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

A simple method for the determination of volatile selenium compounds employing a gas chromatograph equipped with a photoionization detector is described. The method involves the direct injection of dimethylselenide (DMS) or dimethyldiselenide (DMDS) into the gas chromatograph; no derivatization of the sample was required. The photoionization detector was capable of detecting 60 pg (0.55 pmol) of DMS and 150 pg (0.80 pmol) DMDS. Sensitivity was 10–50 times greater with DMS and 4–20 times greater with DMDS when the photoionization detector was employed than when the flame ionization detector was employed.

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Detection And Characterization Of Amitraz Resistance In The Southern Cattle Tick, Boophilus Microplus (Acari: Ixodidae), Andrew Y. Li, Ronald B. Davey, Robert J. Miller, John E. George Jan 2004

Detection And Characterization Of Amitraz Resistance In The Southern Cattle Tick, Boophilus Microplus (Acari: Ixodidae), Andrew Y. Li, Ronald B. Davey, Robert J. Miller, John E. George

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

Amitraz, a formamidine acaricide, plays an important role in the control of the southern cattle tick, Boophilus microplus (Canestrini), and other tick species that infest cattle, dogs, and wild animals. Although resistance to amitraz in B. microplus was previously reported in several countries, the actual measurement of the level of amitraz resistance in ticks has been difficult to determine due to the lack of a proper bioassay technique. We conducted a survey, by using a newly reported technique that was a modification of the standard Food and Agriculture Organization larval packet test, to measure the levels of resistance to amitraz …

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Predicting Phenological Development In Winter Wheat, Qingwu Xue, Albert Weiss, P. Stephen Baenziger Jan 2004

Predicting Phenological Development In Winter Wheat, Qingwu Xue, Albert Weiss, P. Stephen Baenziger

Department of Agronomy and Horticulture: Faculty Publications

Accurate prediction of phenological development is important in the winter wheat Triticum aestivum agroecosystem. From a practical perspective, applications of pesticides and fertilizers are carried out at specific phenological stages. In crop-simulation modeling, the prediction of yield components (kernel number and kernel weight) and wheat-grain yield relies on accurate prediction of phenology. In this study, a nonlinear multiplicative model by Wang & Engel (WE) for predicting phenological development in differing winter wheat cultivars was evaluated using data from a 3 yr field experiment. In the vegetative phase (emergence to anthesis) the daily development rate (r) was simulated based on the …

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Summaries Of Arkansas Cotton Research 2002, Derrick M. Oosterhuis Oct 2003

Summaries Of Arkansas Cotton Research 2002, Derrick M. Oosterhuis

Arkansas Agricultural Experiment Station Research Series

The average yield in Arkansas in 2002 was 871 lb lint/acre from 920,000 harvested acres (960,000 planted) for a total of 1.67 million bales at a value of$336.5 million. This yield was second only to the record 877 lb lint/acre achieved in 1994. Last year's crop yield, and the five-year average, on a per acre basis are exceeded in the U.S. Cotton Belt only by California and Arizona. Cotton yields in Arkansas increased steadily during the eighties, but in the last decade yields have leveled off. Furthermore, the last five years have had extreme year-to-year variability in yields, which is …

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Integrated Weed Management Plan For The Lower Las Vegas Wash, Elizabeth Bickmore Sep 2003

Integrated Weed Management Plan For The Lower Las Vegas Wash, Elizabeth Bickmore

Publications (WR)

The Las Vegas Wash (Wash) is the primary drainage for the metropolitan Las Vegas Valley, eventually finding its way into the Colorado River watershed system. Pursuant to the recommendations of the Water Quality Citizens Advisory Committee, the Las Vegas Wash Coordination Committee (LVWCC) was formed in 1998 to develop a comprehensive plan for the long-term stabilization and management of the Wash. Consisting of representatives from 28 government agencies, businesses, environmental groups and citizens, the LVWCC formulated the Las Vegas Wash Comprehensive Adaptive Management Plan (CAMP) and designated the Southern Nevada Water Authority (SNWA) as the lead agency for the implementation …

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