Agricultural Science Commons^™

Effects On Commercial Broiler Chicks Of Constant Exposure To Ultraviolet Light From Insect Traps, Jerome Hogsette, Henry Wilson

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

Constant exposure of newly hatched Avian x Avian broilers to ultraviolet light from insect traps for 42 d resulted in no significant differences in mortality, weight gain, feed consumption, or feed conversion. Birds were exposed to greater intensities of ultraviolet light for longer periods than could be expected under commercial conditions. Although house flies are rarely a problem in broiler houses, our results indicate that insect traps with ultraviolet light as an attractant would not be detrimental to production of broilers. The need for additional testing of light traps for nuisance fly control in commercial broiler houses is discussed.

The Reproductive Biology And Effective Pollinators Of The Endangered Beardtongue Penstemon Penlandii (Scrophulariaceae), Vincent J. Tepedino, Sedonia D. Sipes, Terry L. Griswold

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

Penland's beardtongue, a rare endemic plant of the Colorado Plateau, displays a mixed breeding system. Plants are partially self-compatible but set more fruits when cross-pollinated than when self-pollinated. Fruit production is significantly increased by pollinators. However, in two years of study there was no indication that fruit set was being limited by inadequate pollinator visitation. Pollinator effectiveness was judged by correlating bee behavior at the flowers with analysis of the pollen carried on bee bodies. The most important pollinators were native megachilid bees, particularly in the genus Osmia. The bees that pollinate Penland's beardtongue are essential to its reproduction …

Report Of The Brassica Crops Working Group, Chris Neeser

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

The Brassicaceae family comprises about 3000 species, the majority of which are found in the Northern Hemisphere. Many common agricultural weeds, such as Brassica nigra (L.) Koch, Brassica rapa L., Cardaria draba (L.) Desv., Raphanus raphanistrum L., and Sinapis arvensis L., belong to this family. The most important crop species from this family are the oilseed Brassicas; Brassica napus L., B rapa L., and B juncea Coss., which are generally referred to as rapeseed, oilseed rape, or canola. Other widely cultivated species in this family are: B. oleracea L. (cabbage, kale, kohlrabi, Brussels sprouts, cauliflower, and broccoli), B. chinensis L. …

Report Of The Grains Working Group (Rice, Sorghum And Wheat), Donna Mitten

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

The grains working group identified three crops which have sexually compatible weedy relatives likely to be subject to gene flow in US agricultural systems (Table 1). The ease of cross pollination and the successful production of a fertile hybrid vary with each case. If the selective advantage of an introduced trait is positive, however, introgression of the new trait into an existing weed population is possible. The risk of ecological harm is then dependent upon the habitat of the weed. In the crop-weed complexes considered here, in which the habitat of the weedy relative is limited to agricultural systems, the …

Measurement Of Sorghum Stalk Strength Using The Missouri-Modified Electronic Rind Penetrometer, Jeffrey F. Pedersen, J. J. Toy

Department of Agronomy and Horticulture: Faculty Publications

Resistance to lodging is critical in sorghum [Sorghum bicolor (L.) Moench] grown for grain, yet adequate tools for plant breeders to assess this character at or before anthesis have not been developed. The objective of this study was to evaluate whether an electronic penetrometer previously shown to be an effective tool for measuring stalk strength in maize (Zea mays L.) could be usedd to differentiate among grain sorghum hybrids. Entries in three commercial grain sorghum hybrid trials were evaluated for rind penetrometer resistance (RPR) of the peduncle, the lower stalk anthesis and the lower stalk at maturity. Actual …

A Crna Probe Detects Prunus Necrotic Ringspot Virus In Three Peach Cultivars After Micrografting And In Peach Shoots Following Long-Term Culture At 4°C, K. Heuss, Q. Liu, F.A. Hammerschlag, R.W. Hammond

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

As part of a program to develop transgenic peach (Prunus persica L. Batsch) cultivars with resistance to Prunus necrotic ringspot virus (PNRSV), we are testing a system for measuring virus in peach shoot cultures. Micrografting in vitro is used for inoculation and slot-blot hybridization, with a digoxigenin (DIG)-labeled cRNA probe complementary to the 5´ open reading frame (ORF) of PNRSV RNA 3, for detection. In this study, we investigated whether infected shoots maintain virus infection over long periods of culture at 4°C and if PNRSV-infected ‘Suncrest’ shoot cultures can serve as graft bases to transmit virus equally well into …

Comparison Of Precipitation Catch Between Nine Measuring Systems, Clayton L. Hanson, Gregory L. Johnson, Albert Rango

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

A site was established by the United States Department of Agriculture-Agricultural Research Service on the Reynolds Creek Experimental Watershed in southwest Idaho in the fall of 1987 and operated through the spring of 1994, to compare precipitation catch between nine precipitation-measuring systems. This site was established as a part of the World Meteorological Organization’s program to compare current national methods of measuring solid precipitation (snow), so the primary emphasis of this study was the measurement of snowfall. Over seven seasons, four of the systems measured snowfall and total catch, which included snow, mixed snow and rain, and rain events, within …

The Concept Of Familiarity And Pest Resistant Plants, Karen Hokanson, David Heron, Subhash Gupta, Susan Koehler, Craig Roseland, Shanthu Shantharam, John Turner, James White, Michael Schechtman, Sally Mccammon, Rebecca Bech

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

Meetings such as this workshop provide an all too rare opportunity for scientists from different disciplines to share their perspectives on a topic of common interest. In this case we examine the use of pest resistant plants in managed ecosystems. USDA-APHIS has a clear interest in this subject because it is involved in regulating transgenic plants, many of which have been engineered with some sort of pest resistance, within its broad authority to protect plants under the Federal Plant Pest Act and the Plant Quarantine Act. Since 1992, when APHIS received its first request to determine non-regulated status for a …

Report Of The Cucurbit Working Group, James D. Mccreight, Jack Staub

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

Cucumber (Cucumis sativus L.) originated in India, melon (C. melo L.) and watermelon (Citrullus lanatus) in Africa, and squash, pumpkin, and gourd (Cucurbita spp.) in the Americas. Thus, cucumber, melon, and watermelon (including citron) are relatively recent introductions to the New World. Most domesticated species of Cucurbita were introduced from Mexico, Central America, and South America with the migration of native Americans centuries earlier. Wax gourd (Benincasa hispida (Thunb.) Logr.) is from Southeast Asia. Bottle gourd (Lagenaria siceraria (Molina) Stand.) is of African origin. South Asia is the probable center of …

Physical Mapping Of The Bovine, Caprine And Ovine Homologues Of The Paired Box Gene Pax8, N. L. Lòpez-Corrales, T. S. Sonstegard, T. P. L. Smith

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

The PAX8 gene, a member of the human paired box gene family, was mapped by FISH to chromosome 11 in cattle and goat and to the short arm of chromosome 3 in sheep. The cytogenetic position of PAX8 on BTA 11 and on its homologue OAR 3p lies in the region where the interleukin beta (IL1B) gene has been previously located, (BTA 11q22.1→q22.3 and OAR 3p25→q26 respectively; Lòpez-Corrales et al., 1998). The results indicated that PAX8 as well as interleukin beta and interleukin alpha (IL1B and IL1A) genes detected on the human chromosome segment HSA 2q13→q21 maintain a similar …

Analysis Of Human Skin Emanations By Gas Chromatography/Mass Spectrometry. 1. Thermal Desorption Of Attractants For The Yellow Fever Mosquito (Aedes Aegypti) From Handled Glass Beads, Ulrich R. Bernier, Matthew M. Booth, Richard A. Yost

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

Handled glass has the ability to collect and concentrate nonaqueous human skin emanations while minimizing the collection of aqueous perspiration. Compounds originating from the skin and collected on glass have previously been found to attract the Aedes aegypti species of mosquito. Therefore, glass beads were used as the medium to collect skin emanations from humans for subsequent chemical analysis. This process consisted of a 5-15-min collection of sample on glass beads, followed by loading the beads into a gas chromatograph (GC) injector insert for subsequent desorption of the collected compounds onto the GC column. After cryofocusing by liquid nitrogen at …

Midseason Stalk Breakage In Corn As Affected By Crop Rotation, Hybrid, And Nitrogen Fertilizer Rate, Wallace Wilhelm, Mark A. Liebig, Gary E. Varvel, Tracy M. Blackmer

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

In July of 1993 and 1994, southern Nebraska experienced devastating windstorms, with winds estimated to exceed 45 m s^-1. These storms resulted in severe brittle-snap of corn (Zea mays L.), with stalks breaking near the primary ear node in the basal portion of an elongating internode. In the storm path were several experiments established on a Hord silt loam (Cumulic Haplustolls) to determine the effect of selected management practices (crop rotation, hybrid selection, planting date, and N fertilization) on nitrate leaching to ground water from irrigated cropland. After the storms, the number of broken plants was determined …

Report Of The Berry Working Group (Strawberry, Raspberry/Blackberry, Blueberry), Erin Rosskopf

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

Strawberries are a relatively recently domesticated crop. The most commonly cultivated strawberry, Fragaria x ananassa, is a hybrid of the North American F. virginiana and the South American F. chiloensis (Maas 1998). These parental species are still grown in some areas and F. virginiana is the primary wild, sexually compatible relative to the cultivated strawberry. In addition to F. virginiana, F. vesca and its subspecies are also present in the United States. Fragaria x ananassa and F. virginiana readily cross. Introgression of pest resistance traits into the wild strawberry population is likely, as substantial amounts of crop-weed introgression …

Report Of The Turfgrasses Working Group, Hector Quemada

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

Over 30 species of grasses are utilized for turf (Huff 1998), while others are important in agriculture as forage crops. The commercial value of this group of plants makes them attractive for improvement through modern genetic engineering techniques (Johnson and Riordan, in press). Because of the diversity of species and the consequent differences in biology among them, broad generalizations regarding the ecological effects of pest resistance genes introduced into these crops cannot be made. Rather, questions regarding the potential for pest resistance genes must be directed toward specific cases in which the species and the particular introduced gene are known. …

Paternity Efficiency In Turkeys Differes Extensively After Hererospermic Insemination, Ann M. Donoghue, Murray R. Bakst, Paul Drummond, Shakura Haqque, Edward J. Smith, Daniel J. Donoghue

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

All commercial turkey hens in the U.S. are bred by artificial insemination (AI).  Since semen samples are pooled from 10 or more males (heterospermic inseminations), paternity of the progeny is rarely known.  Whereas it is known that sperm competition exists, the degree to which any male's sperm fertilizes ova relative to other male's remains unknown.  In this work, we determined individual male fecundity relative to that of other males in the study and attempted to establish a relationship between male fecundity and semen characteristics in turkeys.  Fingerprinting of genomic DNA from parents and offspring was used to determine parentage efficiency. …

Scales 2: Computer Program To Convert Among Developmental Stage Scales For Corn And Small Grains, Dorothy M. Harrell, Wallace Wilhelm, Gregory S. Mcmaster

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

Producers and agronomists need crop developmental scales that are easy to use, universally accepted, and accurate. Development of such a scale requires correlation of stages among scales currently in use and correlation of developmental patterns among crops. A computer program for converting among staging systems is a useful tool in developing new staging systems with wider applicability. The BBCH scale (BASF-Bayer-Ciba-Geigy-Hoechst) has been proposed as a prototype of a universal scale. We have added the BBCH scale to our scale conversion program for wheat (Triticum aestivum L.) and developed a similar conversion program for corn (Zea mays L.), …

Comparisons Of Soil Physical Characteristics In Long-Term Tillage Winter Wheat-Fallow Tillage Experiments, L. N. Mielke, Wallace Wilhelm

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

Soil physical characteristics resulting from tillage of fallow-wheat (Triticurn aestivurn L.) cropping systems were compared for two soils in western Nebraska. The soil physical environment influences the amount of water entering soil and the microenvironment that influences soil biological processes important to plant response. Effects of tillage on physical properties varied with soil type and depth of soil tillage. Generally, the 0-76 mm surface layer has the largest number of physical properties that differ as a result of tillage; however, only a few properties differed at greater depths. The Alliance silt loam (fine silty, mixed, mesic, Aridic Arguistoll) soil …

Dry-Matter Partitioning And Leaf Area Of Winter Wheat Grown In A Long-Term Fallow Tillage Comparisons In The Us Central Great Plains, Wallace Wilhelm

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

Crop management practices (tillage, residue management, fertilization, etc.) define the soil environment to which crops are exposed and through these environmental conditions control crop growth. The purpose of this paper is to report the response of winter wheat (Triticum aestivum L.) to long-term (10 years) application of fallow tillage practices (plow, sub-till, and no-till) and N fertilization in terms of above- and below-ground dry-matter partitioning. During 1978, less winter wheat root tissue was produced in the sub-till treatment compared to the average of the plow and no-till treatments. However, in 1979, all treatments produced the same amount of root …

Escherichia Coli O157:H7 Requires Intimin For Enteropathogenicity In Calves, Evelyn A. Dean-Nystrom, Brad T. Bosworth, Harley W. Moon, Alison D. O’Brien

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

Enterohemorrhagic Escherichia coli (EHEC) strains require intimin to induce attaching and effacing (A/E) lesions in newborn piglets. Infection of newborn calves with intimin-positive or intimin-negative EHEC O157: H7 demonstrated that intimin is needed for colonization, A/E lesions, and disease in cattle. These results suggest that experiments to determine if intimin-based vaccines reduce O157:H7 levels in cattle are warranted.

Is Soil Temperature Better Than Air Temperature For Predicting Winter Wheat Phenology?, Gregory S. Mcmaster, Wallace Wilhelm

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

In predicting wheat (Triticum aestivum L.) phenology, logic suggests that basing thermal unit accumulation on near-surface soil temperature should give a better representation of shoot apex thermal unit accumulation than air temperature until internode elongation raises the apex above the soil surface. A study was undertaken to determine if predictions of winter wheat phenology are improved when based on measured near-surface soil temperature rather than air temperature. Air temperature 1.5 m above the soil surface and soil temperature at crown depth (the position of the shoot apex before stem elongation) were collected for 23 site-years across the U.S. Central …

Biodegradation Of Atrazine By Agrobacterium Radiobacter J14a And Use Of This Strain In Bioremediation Of Contaminated Soil, J. K. Struthers, K. Jayachandran, T. B. Moorman

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

We examined the ability of a soil bacterium, Agrobacterium radiobacter J14a, to degrade the herbicide atrazine under a variety of cultural conditions, and we used this bacterium to increase the biodegradation of atrazine in soils from agricultural chemical distribution sites. J14a cells grown in nitrogen-free medium with citrate and sucrose as carbon sources mineralized 94% of 50 μg of [¹⁴C-U-ring]atrazine ml^-1 in 72 h with a concurrent increase in the population size from 7.9 x 10⁵ to 5.0 x 10⁷ cells ml^-1. Under these conditions cells mineralized the [ethyl-¹⁴C]atrazine …

Residual Effects Of Crop Residues On Grain Production And Selected Soil Properties, James F. Power, Paul Koerner, John W. Doran, Wallace Wilhelm

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

Returning crop residue improves water conservation and storage, nutrient availability, and crop yields. We have little knowledge, however, of the residual impacts of crop residues on soil and crop production. We hypothesized that residual impacts of crop residues vary with the amount of residues used. A 10-yr study near Lincoln, NE, evaluated the residual effects of an earlier 8-yr study of various crop residue amounts on crop growth and selected soil properties. From 1978 through 1985, crop residues were returned at 0,50, 100, and 150% of the quantity produced by the previous crop (averaging 0 to =6 Mg ha^{-1 …}

Opportunities For Growing Short-Rotation Woody Crops In Agroforestry Practices, Gary A. Kuhn, W. J. Rietveld

Agroforestry Notes (USDA-NAC)

Technologies are readily available for growing hybrid poplars and willows in block plantings as short-rotation woody crops (SRWC) for fuel and fiber. SRWC species and technologies can also be incorporated into agricultural systems as agroforestry practices. Examples are windbreaks, living snowfences, “timberbelts”, riparian buffer strips, and wastewater treatment plantings. Fast growth, convenient propagation (see AF Note - 11), and compatibility with conventional farming methods make SRWC suitable for use in agroforestry practices to provide multiple benefits such as solid wood and wood fiber products, water quality improvement, crop and soil protection, wildlife habitat, and buffers for agricultural/community interfaces.

Establishment And Cultural Guidelines For Using Hybrid Tree Species In Agroforestry Plantings, Gary A. Kuhn, W. J. Rietveld, Don E. Riemenschneider

Agroforestry Notes (USDA-NAC)

Hybrid poplars (and willows) are well-suited for agroforestry applications in many parts of the United States (See AFN-10). Their convenient propagation and fast growth allow them to establish and provide conservation benefits more quickly. This note provides general establishment and cultural guidelines to consider when using hybrid poplar cuttings for agroforestry plantings.

Differentiation Of F18ab+ From F18ac+ Escherichia Coli By Single-Strand Conformational Polymorphism Analysis Of The Major Fimbrial Subunit Gene (Feda), Brad T. Bosworth, Evelyn A. Dean-Nystrom, Thomas A. Casey, Holly L. Neibergs

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

Toxin-producing Escherichia coli expressing F18 fimbriae colonizes the small intestines of weaned pigs and causes diarrhea, edema disease, or both. The F18 family is composed of two antigenic variants, F18ab and F18ac. Because many strains do not express F18 fimbriae in vitro, identification and differentiation of these two variants are difficult. Single-strand conformational polymorphism (SSCP) analysis is a rapid method for identifying genetic mutations and polymorphisms. The F18 major fimbrial subunit genes (fedA) of 138 strains were amplified by PCR, and genetic differences were detected by SSCP analysis. The SSCP analysis of the fedA gene differentiated F18ab^{+ …}

Development Of A Blocking Enzyme-Linked Immunosorbent Assay For Detection Of Serum Antibodies To O157 Antigen Of Escherichia Coli, William Laegreid, Mark Hoffman, James Keen, Robert Elder, Jimmy Kwang

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

The O157 antigen of Escherichia coli shares structural elements with lipopolysaccharide (LPS) antigens of other bacterial species, notably Brucella abortus and Yersinia enterocolitica O9, a fact that confounds the interpretation of assays for anti-O157 antibodies. To address this problem, a blocking enzyme-linked immunosorbent assay (bELISA) was designed with E. coli O157:H7 LPS as the antigen and a monoclonal antibody specific for E. coli O157, designated 13B3, as the competing antibody. The bELISA had equivalent sensitivity to, and significantly higher specificity than, the indirect ELISA (iELISA), detecting anti-O157 antibodies in sera from cattle experimentally inoculated with O157:H7. Only 13% of sera …

Linking People, Purpose, And Place: An Ecological Approach To Agriculture, Heidi Carter, Richard Olson, Charles A. Francis

CARI Extension and Education Materials for Sustainable Agriculture

Linking Ecology and Agriculture

Whole Farm Planning

Soil Quality

Agroforestry

Grazing Systems

Weed and Insect Management

Farmer Groups

Farmland Conversion

Resources and Information Sources

Gas Chromatography/Mass Spectrometry Analysis Of The Cuticular Hydrocarbons From Parasitic Wasps Of The Genus Muscidifurax, Ulrich R. Bernier, David A. Carlson, Christopher J. Geden

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

Parasitic Hymenoptera can be difficult to identify by conventional taxonomic techniques. Examination of the cuticular hydrocarbons (CHCs) provides a basis for chemotaxonomic differentiation, which may lead to the discovery of pheromones, and can be a means of examining colonies for species cross-contamination. The parasitic wasps examined were Muscidifurax raptor, M. zaraptor, M. uniraptor, and the gregarious form of M. raptorellus. Species within the genus Muscidifurax, as well as the sex, can clearly be differentiated by examining the gas chromatograms of the CHCs. Identification of the alkanes by mass spectrometry shows uncommon dimethylalkanes and trimethylalkanes for members of the …

Elution Patterns From Capillary Gc For Methyl-Branched Alkanes, David A. Carlson, Ulrich R. Bernier, Bruce D. Sutton

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

A common and confusing problem in analyses of insect hydrocarbons is in making sense of complicated gas chromatograms and interpreting mass spectra since branched chain compounds differing by one or two carbons in backbone or chain length may elute from the column at nearly the same time. To address this confusing situation, relative gas chromatography (GC) retention times are presented for typical mono-, di-, tri-, and tetramethylalkanes comprising most of the commonly appearing series of homologous methyl-branched alkanes up to 53 carbons that are found in insect cuticular hydrocarbons. Typical insect-derived methylalkanes with backbones of 33 carbons were characterized by …

Black Flies, Simulium Spp. (Insecta: Diptera: Simuliidae), J. F. Butler, J. A. Hogsette

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

Introduction

Florida occasionally experiences outbreaks of black flies, though this is a rare occurance, and these large populations are caused by rainfall extremes. Common names for this pest include black flies and turkey gnats, as well as a number of new names applied by Floridians which are not repeatable here. Because of the hump visible behind their head when viewed in profile, black flies are also called buffalo gnats. Like eye gnats, they fly around people's heads, occasionally getting into eyes and ears as well as crawling in the hair. Because most of the specimens collected to date have been …