Agricultural Science Commons^™

Conservation And Evaluation Of Natural Enemies In Ipm Systems For Bemisia Tabaci, Steven E. Naranjo

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

Conservation biological control emphasizes the preservation and enhancement of natural enemies and is the cornerstone of all approaches to biological control. This review critically examines recent and current research efforts in conservation biological control by predators and parasitoids of Bemisia tabaci worldwide. A large number of natural enemy species have been identified from many agricultural systems. Further research has demonstrated that these natural enemies may act along with other mortality agents to inflict high levels of mortality on populations of B. tabaci. Less effort has been placed on determining the factors constraining or potentially enhancing biological control. The widespread …

Managing Crop Residue With Green Manure, Urea, And Tillage In A Rice–Wheat Rotation, Milkha S. Aulakh, T. S. Khera, John W. Doran, Kevin F. Bronson

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

Most double-crop grain farmers in South Asia remove or burn cropresidue to facilitate seedbed preparation and to avoid possible yield reductions. This results in loss of soil organic matter (SOM) and nutrients. In this study, we determined whether incorporating wheat (Triticum aestivum L.) residue, rice (Oryza sativa L.) residue, and sesbania (Sesbania aculeta L.) green manure with urea fertilizer N in a rice–wheat cropping system can improve grain yields, N use efficiency, and SOM. We incorporated wheat residue (6 Mg ha^-1, C/N = 94), rice residue (6 Mg ha^-1, C/N = 63), or …

Simplified Method For Soil Particle-Size Determination To Accompany Soil-Quality Analyses, T. A. Kettler, John W. Doran, T. L.. Gilbert

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

Soil textural analysis is a key component of any minimum data set used for assessing soil quality and sustainability of agricultural-management practices. However, conventional methods of soil textural analysis can be costly and time-consuming. The objective of this study was to develop a rapid and simple method for evaluating soil particle-size distribution, which could be employed as a tool for initial soil-quality assessment. The method uses a combination of sieving and sedimentation steps and is designed to be used in conjunction with analysis of particulate organic matter (POM), or as a stand-alone textural analysis. Soils of varied texture and organic-matter …

Polyacrylamide For Surface Irrigation To Increase Nutrient-Use Efficiency And Protectwater Quality, Rodrick D. Lentz, Robert E. Sojka, Charles W. Robbins, Dennis C. Kincaid, Dale T. Westermann

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

Furrow irrigation systems have a greater application capacity, are less costly, and use less energy than sprinkler systems but furrow irrigation produces greater runoff, erosion, and deep percolation losses. Phosphorus (P) and nitrogen (N) losses are associated with runoff sediment, and can be minimized by eliminating irrigationinduced erosion. Excessive leaching of inorganic and organic solutes commonly occurs at the inflow region of furrow irrigated fields where infiltration opportunity times are longer. In one conservation practice, a high molecular weight, anionic polyacrylamide (PAM) is applied to advancing furrow stream flows at a concentration of 10 mg L^-1. Because PAM …

Genetic Analysis Of Kafirins And Their Phenotypic Correlations With Feed Quality Traits, In Vitro Digestibility, And Seed Weight In Grain Sorghum, C. Hicks, S. R. Bean, G. L. Lookhart, Jeffrey F. Pedersen, K. D. Kofoid, M. R. Tuinstra

Department of Agronomy and Horticulture: Faculty Publications

Twenty-three entries of grain sorghum (Sorghum bicolor (L.) Moench), including eight inbred lines (five males and three females) and 15 hybrids, were evaluated to determine the proportion of γ, αII, and β-αI-kafirins and their association with contents of crude protein, fat, and starch; protein digestibility; in vitro dry matter disappearance; and seed weight. The male lines included three normal-seeded lines (TX2737, TX435, and P954063) and two large-seeded lines (Eastin1 and PL-1). Female lines consisted of three common U.S. seed parent lines (Wheatland, Redlan, and SA3042). The lines and their hybrids were grown under dryland conditions at two locations in …

High-Throughput Genotyping For A Polymorphism Linked To Soybean Cyst Nematode Resistance Gene Rhg4 By Using TaqmanTm Probes, Khalid Meksem, Eliza Ruben, David L. Hyten, Michael E. Schmidt, David A. Lightfoot

Department of Agronomy and Horticulture: Faculty Publications

An individual soybean breeder can generate over one hundred thousand new genotypes each year. The efficiency of selection in these populations could be improved if these genotypes were effectively screened with one DNA marker that identified an important gene, and if laboratory throughput was high and costs were low. Our aim was to develop a rapid genotyping procedure for resistance to the soybean cyst nematode. A high-throughput genotyping method was developed with fluorogenic probes to distinguish between two insertion polymorphisms in alleles of an AFLP marker that is located about 50 kbp from the Rhg4 gene candidate. The assay uses …

Conversion Of Aflp Bands Into High-Throughput Dna Markers, K. Meksem, E. Ruben, D. L. Hyten, K. Triwitayakorn, D. A. Lightfoot

Department of Agronomy and Horticulture: Faculty Publications

The conversion of AFLP bands into polymorphic sequence-tagged-site (STS) markers is necessary for high-throughput genotype scoring. Technical hurdles that must be overcome arise from genome complexity (particularly sequence duplication), from the low-molecular- weight nature of the AFLP bands and from the location of the polymorphism within the AFLP band. We generated six STS markers from ten AFLP bands (four AFLPs were from co-dominant pairs of bands) in soybean (Glycine max). The markers were all linked to one of two loci, rhg1 on linkage group G and Rhg4 on linkage group A2, that confer resistance to the soybean cyst nematode (Heterodera …

Planning And Design Considerations For Hybrid Poplar Timberbelts, Scott J. Josiah, Gary Kuhn

Agroforestry Notes (USDA-NAC)

The demand for wood products and wood fiber has led to the development of a production system based on fast growing trees known as Short Rotation Woody Crops (SRWCs). Traditionally, SRWCs are grown in large, intensively managed blocks, but the technology may also be used on agricultural lands in integrated applications such as timberbelts. Timberbelts are multiple row windbreaks that are planted with commercially valuable trees to produce wood products. Trees such as hybrid poplar (typically cottonwood and to a lesser extent aspen), hybrid willow, hybrid pine, paulownia, etc., are particularly suited for use in timberbelts because of their rapid …

From A Pasture To A Silvopasture System, James L. Robinson, Terry Clason

Agroforestry Notes (USDA-NAC)

There is potential to diversify a grazing operation and improve economic or environmental benefits on many acres through conversion of pasture to silvopasture. Silvopasture is the integration of trees with livestock grazing and forage operations. Research has demonstrated that, if managed properly, forage production can be maintained while producing high value timber.

De Sistemas Pastoriles A Silvopastoriles, James L. Robinson, Terry Clason

Agroforestry Notes (USDA-NAC)

Existe el potencial para diversificar la operación pastoril y mejorar los beneficios económicos y ambientales en muchas áreas a través de la conversión de pastoreo a silvopastoreo. Silvopastoreo es la integración de árboles y ganado junto con forraje. Estudios han demostrado que bajo una buena administración es posible la producción de pastos y de madera de alta calidad.

Two Large-Insert Soybean Genomic Libraries Constructed In A Binary Vector: Applications In Chromosome Walking And Genome Wide Physical Mapping, K. Meksem, K. Zobrist, E. Ruben, D. L. Hyten, T. Quanzhou, H-B. Zhang, D. A. Lightfoot

Department of Agronomy and Horticulture: Faculty Publications

Large DNA insert libraries in binary T-DNA vectors can assist in the isolation of the gene(s) under-lying a quantitative trait locus (QTL). Binary vectors facilitate the transfer of large-insert DNA fragments containing a QTL from E. coli to Agrobacterium sp. and then to plants. We constructed two soybean large-insert libraries from cv. Forrest in the pCLD04541 (V41) binary vector after partial digestion of genomic high-molecular-weight DNA with BamHI or HindIII. The libraries contain 76,800 clones with an average insert size of 125 kb, and therefore represent 9.5-fold haploid genome equivalents. Colony hybridization using a chloroplast-specific probe infers that …

Murine Monoclonal Antibodies Specific For Lipopolysaccharide Of Escherichia Coli O26 And O111, Mildred Rivera-Betancourt, James E. Keen

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

Monoclonal antibody (MAb) 12F5 reacted with 35 Escherichia coli O26 isolates and cross-reacted with 1 of 365 non-E. coli O26 isolates. MAb 15C4 reacted with 30 E. coli O111 strains and 8 Salmonella O35 strains (possessing identical O antigen) but not with 362 other bacterial strains. Lipopolysaccharide immunoblots confirmed MAb O-antigen specificity.

Cattle Lack Vascular Receptors For Escherichia Coli O157:H7 Shiga Toxins, Ingrid M. Pruimboom-Brees, Tim W. Morgan, Mark R. Ackermann, Evelyn A. Dean-Nystrom, James E. Samuel, Nancy A. Cornick, Harley W. Moon

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

Escherichia coli O157:H7 causes Shiga toxin (Stx)-mediated vascular damage, resulting in hemorrhagic colitis and the hemolytic uremic syndrome in humans. These infections are often food-borne, and healthy carrier cattle are a major reservoir of E. coli O157:H7. We were interested in knowing why cattle are tolerant to infection with E. coli O157:H7. Cattle tissues were examined for the Stx receptor globotriaosylceramide (Gb₃), for receptivity to Stx binding in vitro, and for susceptibility to the enterotoxic effects of Stx in vivo. TLC was used to detect Gb3 in tissues from a newborn calf. Gb₃ was detected …

Before You Say Yes: A Planning Guide For Speakers, Charles A. Francis, Heidi Carter, Cris Carusi, James W. King

Department of Agronomy and Horticulture: Faculty Publications

We need guidelines to help us decide whether to accept invitations to speak, whether to a class on campus or a special interest group outside. As educators and workshop organizers, we could also use suggestions on how to approach potential speakers. This article describes a single-page format that can be used to guide the planning process. Essential elements include contact information, location and organization of the activity, audience, learning goals, expected content, conclusions, and evaluation. Use of this planning sheet can give organization to an often haphazard process of planning, and enhance the potential of achieving the learning goals of …

Comparison Of Three Leaf Area Index Meters In A Corn Canopy, Wally Wilhelm, K. Ruwe, Michael R. Schlemmer

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

Measurement of leaf area index (LAI) is critical to understanding many aspects of crop development, growth, and management. Avail- ability of portable meters to estimate LAI non-destructively has greatly increased our ability to determine this parameter during the cropping season. However, with several devices on the market, each with an independent set of protocols for gathering accurate estimates of LAI, it is necessary for scientists to have comparisons of these meters under field conditions before selecting one for purchase and use. The objective of our study was to compare the LAI estimates by three meters (AccuPAR, LAI-2000, and SunScan) to …

Simulating Inbred-Maize Yields With Ceres-Im, Daniel P. Rasse, Joe T. Ritchie, Wally Wilhelm, Jun Wei, Edward C. Martin

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

CERES-Maize, which was designed for simulation of hybrid maize (Zea mays L.), cannot be applied directly to seed-producing inbred maize because of specific field operations and physiological traits of inbred maize plants. We developed CERES-IM, a modified version of CERES-Maize 3.0 that accommodates these inbred-specific operations and traits, using a set of phenological measurements conducted in Nebraska (NE), and further tested this model with a set of field data from Michigan (MI). Detasseling (i.e., removal of the tassels from the female plants) was conducted prior to silking. Male rows were removed approximately 10 d following 75% silking. The thermal …

Evaluation Of Stomoxys Calcitrans (Diptera: Muscidae) Behavioral Response To Human And Related Odors In A Triple Cage Olfactometer With Insect Traps, Raul A. Alzogaray, David A. Carlson

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

A triple cage olfactometer provided with insect traps was used for evaluating behavioral responses of Stomoxys calcitrans (L.) females to human skin and breath, CO₂, and L-lactic acid analogs. After demonstrating there were no significant differences caused by cage location or time of day, 3 sets of 3 olfactometer tests were performed in a day, every 2 h beginning at 0900 hours. When a human hand was used as attractant, the attraction (expressed as percentage of trapped flies) increased as a function of the time; an inverted U-shaped relationship between attractancy and air speed was observed; and variation …

Wastewater Management Using Hybrid Poplar, Gary A. Kuhn

Agroforestry Notes (USDA-NAC)

Hybrid poplars are rapidly growing trees that are well suited to use agricultural, industrial, and community wastewater. They are being used as an alternative to expensive wastewater treatment systems, and methods which apply wastewater to annual crops or pasture. The trees serve a dual purpose as a nutrient sink for wastewater use and as a means to produce a short-rotation harvested wood product which helps offset the cost of installation and maintenance.

Planning tree wastewater use systems requires both agroforestry and engineering expertise. Omission of either in the planning process can lead to disappointing results and reduced benefits. This Agroforestry …

From Pine Forest To A Silvopasture System, Terry Clason, James L. Robinson

Agroforestry Notes (USDA-NAC)

Agroforestry systems hold the potential for land users to realize diverse income-generating possibilities from the same acreage, as well as meet environmental goals. Silvopasture systems are agroforestry systems that incorporate the production of forage and/or livestock with the growing of trees for a timber product. The silvopasture system can be developed from a pasture system with the trees incorporated into the open fields or it can be developed from a forest plantation with the forage incorporated into the plantation following a thinning to reduce tree canopy.

Waterbreaks: Managed Trees For The Floodplain, Douglas C. Wallace, Wayne A. Geyer, John P. Dwyer

Agroforestry Notes (USDA-NAC)

Historically, many of the natural woody ecosystems that were once present in floodplains across the country have been highly altered or removed. Land clearing has resulted in the loss of woody vegetation, even in areas adjacent to streams and rivers. With these alterations, came extensive flood management commitments to compensate for the loss of naturally functioning floodplains and for the protection of towns, roads, and agricultural fields. However, even with the best available flood management techniques, when rivers decide to flood - they will, often with devastating consequences. Strictly from a social and an economic standpoint, allowing the floodplain to …

De Un Bosque De Pino Hacia Un Sistema Silvopastoril, Terry Clason, James L. Robinson

Agroforestry Notes (USDA-NAC)

Los sistemas agroforestales ofrecen el potencial a los usuarios de tierras de analizar las posibilidades de generar ingresos por venta de diferentes bienes o artículos, producidos en un mismo predio de terreno, a la misma vez que se obtienen beneficios ambientales. Los sistemas silvopastoriles, son sistemas agroforestales. Éstos sitemas se componen de árboles, forrajes y ganado. Un sistema silvopastoril puede desarrollarse a partir de un predio en pastos o de un bosque al que se le incorporan forrajes. El bosque deberá ser manejado de manera que permita la entrada de luz solar para el crecimiento del forraje.

Escherichia Coli O157:H7 Causes More-Severe Systemic Disease In Suckling Piglets Than In Colostrum-Deprived Neonatal Piglets, Evelyn A. Dean-Nystrom, Joachim F. L. Pohlenz, Harley W. Moon, Alison D. O’Brien

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

Our objective was to determine if suckling neonatal piglets are susceptible to enterohemorrhagic Escherichia coli (EHEC) O157:H7 disease. Surprisingly, EHEC O157:H7 caused more-rapid and more-severe neurological disease in suckling neonates than in those fed an artificial diet. Shiga toxin-negative O157:H7 did not cause neurological disease but colonized and caused attaching-and-effacing intestinal lesions.

Effects Of Acid Adaptation Of Escherichia Coli O157:H7 On Efficacy Of Acetic Acid Spray Washes To Decontaminate Beef Carcass Tissue, Elaine Berry, Catherine N. Cutter

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

Exposure to low pH and organic acids in the bovine gastrointestinal tract may result in the induced acid resistance of E. coli O157:H7 and other pathogens that may subsequently contaminate beef carcasses. The effect of acid adaptation of E. coliO157:H7 on the ability of acetic acid spray washing to reduce populations of this organism on beef carcass tissue was examined. Stationary-phase acid resistance and the ability to induce acid tolerance were determined for a collection of E. coliO157:H7 strains by testing the survival of acid-adapted and unadapted cells in HCl-acidified tryptic soy broth (pH 2.5). ThreeE. coli …

Intsormil 2000 Annual Report, John M. Yohe, Thomas Crawford, Jr., Joan Frederick, Dorothy Stoner

INTSORMIL Impacts and Bulletins

Presently, worldwide, more than 800 million people are hungry and over I billion are desperately poor, and food demand is increasing rapidly. The majority of poor live in rural areas in developing countries and agricultural and food systems development is vital to economic growth; improving environmental quality; strengthening nutrition, health and child survival; improving the status of women; and promoting democratization. It is estimated that by 2000, the number of people living in developing countries will grow from 4.9 billion to 6.8 billion people. More than 1.3 billion people today live on less than one dollar per day. It is …

Bovine Blastocyst-Derived Trophectoderm And Endoderm Cell Cultures: Interferon Tau And Transferrin Expression As Respective In Vitro Markers, Neil C. Talbot, Thomas J. Caperna, J. Lannett Edwards, Wes Garrett, Kevin D. Wells, Alan D. Ealy

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

Continuous cultures of bovine trophectoderm (CT-1 and CT- 5) and bovine endoderm (CE-1 and CE-2) were initiated and maintained on STO feeder cells. CT-1 and CT-5 were derived from the culture of intact, 10- to 11-day in vitro-produced blastocysts. CE-1 and CE-2 were derived from the culture of immunodissected inner cell masses of 7- to 8-day in vitro-produced blastocysts. The cultures were routinely passaged by physical dissociation. Although morphologically distinct, the trophectoderm and endoderm both grew as cell sheets of polarized epithelium (dome formations) composed of approximately cuboidal cells. Both cell types, particularly the endoderm, grew on top …

Similarity And Divergence Among Viruses In The Genus Furovirus, Yukio Shirako, Nobuhiro Suzuki, Roy C. French

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

Nucleotide sequences of RNAs 1 and 2 of a Japanese strain of soil-borne wheat mosaic virus (SBWMV), the type species of the genus Furovirus, and sorghum chlorotic spot virus (SCSV) were determined from cloned cDNA. The relationship among the Japanese and US strains of SBWMV, SCSV, oat golden stripe virus (OGSV), and recently proposed Chinese wheat mosaic and European wheat mosaic viruses (CWMV and EWMV) were examined at the nucleotide and amino acid levels. Pairwise comparisons of genome-encoded proteins among the six viruses showed that the US strains of SBWMV and CWMV were the most closely related pair in RNA …

Basic Biotechnology, Jennifer Flak, Julie Albrecht

Plant and Soil Sciences eLibrary

An introduction to traditional cross-breeding and genetic engineering of plants, and to biotechnology.

Objectives - Basic Biotechnology

After completing Nutrition Basic Biotechnology, participants should be able to:

• Describe one similarity between traditional cross-breeding and genetic engineering of plants.
• Give two limitations that are encountered with traditional cross-breeding of plants.
• Explain why genetic engineering is not limited in the same way as traditional cross-breeding.
• Define biotechnology in broad terms.
• List three plant applications of biotechnology.
• List the three areas of nutritional profiles that have been improved with biotechnology.

Modules:

• Lesson home
• Objectives - Basic Biotechnology
• Historical Uses of Biotechnology
• Basic Understanding …

Effect Of Vacuum On The Performance Of The Flame Ionization Detector Used For Vacuum-Outlet Gas Chromatography, Ulrich R. Bernier, Christopher L. Bray, Richard A. Yost

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

Vacuum-outlet operation of short fused-silica open tubular columns for gas chromatography provides benefits to analysis speed by increasing the optimum velocity while minimizing the loss in resolution. Vacuum-outlet operation of a column with a gas chromatographic detector necessitates that the detector also be under vacuum. Simple modifications were made to a gas chromatograph-flame ionization detector (GC-FID) for vacuum-inlet and vacuum-outlet operation. The vacuum-inlet system was operated in the splitless mode to allow for efficient sample loading prior to operation at reduced pressures. The goal of FID operation at 100 torr or less was achieved by using oxygen in place of …

Behavioral Response Of Stomoxys Calcitrans (Diptera: Muscidae) To Conspecific Feces And Feces Extracts, David Carlson, Raul Alzogaray, Jerome Hogsette

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

The attraction response of Stomoxys calcitrans (L.) to its own feces was evaluated in a triple cage olfactometer. Both time- and concentration-response relationships were obtained for female S. calcitrans exposed to cellulose sponges impregnated with fresh fly feces or filter papers treated with chloroform: methanol extracts of fresh fly feces in 6-min tests. Attraction to feces collected on cellulose sponges decreased as the air flow increased. Feces collected on cellulose sponges and held for 28-31 d retained attractive activity. More female flies were attracted than males to feces on sponges or to polar solvent extracts of feces-contaminated cages. The activity …

Physiology And Reproduction: Plasma 17Β-Estradiol Levels And Ovarian Interstitial Cell Structure In Embryonic Japanese Quail, M. A. Abdelnabi, M. R. Bakst, J. E. Woods, M. A. Ottinger

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

Plasma concentrations of 17β-estradiol (E₂) and left ovarian histology were investigated by light and electron microscopy in female Japanese quail from Day 10 of embryonic development through Day 7, posthatch. Plasma E₂ levels remained relatively constant (102 to 140 pg/mL) in the embryo followed by a sharp decrease posthatch (47 to 70 pg/mL).

Beginning on Day 10 of incubation, cells in the medullary portion (medullary cell; MC) of the left ovaries exhibited ultrastructural evidence of steroidogenic capability. The MC had numerous lipid droplets in close proximity to the smooth endoplasmic reticulum (SER). Mitochondria were also …