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2002

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Articles 61 - 79 of 79

Full-Text Articles in Agricultural Science

Oviducal Sperm Storage In Turkeys: Spatial Distribution Of Sperm Within The Uterovaginal Junction Sperm-Storage Tubules, M. R. Bakst, Bryan T. Vinyard Jan 2002

Oviducal Sperm Storage In Turkeys: Spatial Distribution Of Sperm Within The Uterovaginal Junction Sperm-Storage Tubules, M. R. Bakst, Bryan T. Vinyard

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

The spatial distribution of sperm within the sperm storage tubules (SST) found in
the uterovaginal junction (UVJ) of the turkey is not known. In this study, we inseminated sperm stained with a fluorescent dye (Hoechst 33342) to determine their distribution in SST in the ventral, dorsal, and lateral regions of the proximal, middle, and distal regions of the UVJ. There was no preferential filling in the ventral-dorsal axis of the UVJ. In contrast, preferential filling of the SST was observed in the middle section of the UVJ. Here the individual SST were clearly longer and more pleomorphic than the SST …

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Physiology And Reproduction: Embryonic Development From First Cleavage Through Seventy-Two Hours Incubation In Two Strains Of Pekin Duck (Anas Platyrhynchos), V. Dupuy, B. Nersessian, M. R. Bakst Jan 2002

Physiology And Reproduction: Embryonic Development From First Cleavage Through Seventy-Two Hours Incubation In Two Strains Of Pekin Duck (Anas Platyrhynchos), V. Dupuy, B. Nersessian, M. R. Bakst

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

Embryonic mortality is a significant problem plaguing the commercial duck industry worldwide. Yet, an objective means to stage development of the duck embryo is lacking. Such a staging procedure, which is described in this study, is essential for the critical and reproducible assessment of embryo development. The morphological features associated with duck embryo development are very similar to those of the chicken, although the duck embryo develops more slowly. The staging scheme presented here provides objective morphological criteria describing the embryonic development of the duck.

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Beet Armyworm (Lepidoptera: Noctuidae) Host Plant Preferences For Oviposition, S. M. Greenberg, T. W. Sappington, T.-X. Liu Jan 2002

Beet Armyworm (Lepidoptera: Noctuidae) Host Plant Preferences For Oviposition, S. M. Greenberg, T. W. Sappington, T.-X. Liu

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

Beet armyworm, Spodoptera exigua (Hübner), oviposition preferences were determined on five host plants: cabbage (Brassica oleracea capitata L.), cotton (Gossypium hirsutum L.), bell pepper (Capsicum annuum L.), pigweed (Amaranthus retroflexus L.), and sunflower (Helianthus annuus L.) in no-choice, two-choice, and five-choice tests. Tests were conducted in the laboratory, greenhouse, and field cages. Oviposition preferences were compared on the basis of two measurements, the proportion of eggs laid on the plants to total that were deposited, and the oviposition preference index defined as [(number of eggs laid on the plant) - (number of eggs laid on …

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Soil Electrical Conductivity Classification: A Basis For Site-Specific Management In Semiarid Cropping Systems, Cinthia K. Johnson, David A. Mortensen, Brian J. Wienhold, John F. Shanahan, John W. Doran Jan 2002

Soil Electrical Conductivity Classification: A Basis For Site-Specific Management In Semiarid Cropping Systems, Cinthia K. Johnson, David A. Mortensen, Brian J. Wienhold, John F. Shanahan, John W. Doran

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

Site specific management (SSM) has the potential to improve both economic and ecological outcomes in agriculture. Effective SSM requires strong and temporally consistent relationships between identified management zones, underlying soil physical, chemical and biological parameters defining yield potential, and crop yield. In a farm-scale (250 ha) experiment in semiarid northeastern Colorado, each of eight 31-ha fields was individually mapped for soil apparent electrical conductivity (ECa) and classified into four management zones (ranges of ECa). Soil analyses revealed a strong negative relationship between ECa zones and soil parameters associated with innate fertility (P ≤ 0.06). …

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Response Of Irrigated Corn To Nitrogen Fertility Level Within Two Tillage Systems, Ardell D. Halvorson, Walter Bausch, Harold Duke, Curtis Reule Jan 2002

Response Of Irrigated Corn To Nitrogen Fertility Level Within Two Tillage Systems, Ardell D. Halvorson, Walter Bausch, Harold Duke, Curtis Reule

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

Irrigated farmers generally utilize intensive tillage to manage crop residues and prepare a seedbed for com. Nitrogen fertilizer management practices have been developed for conventional-till (CT) irrigated com production. Little information is available for no-till (NT) and reduced-till (RT) irrigated com production systems. This paper compares the response of irrigated continuous com to N fertility level under CT and NT or RT production systems on a Fort Collins clay loam soil from 1999 through 2001. Grain yields increased similarly with increasing available N level [soil NO3-N (0-3 ft) plus fertilizer N added] in 1999,2000, and 2001 for both …

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Starter Fertilizer Effects On Soybean Grain Yield And Quality, S.L. Osborne, W.E Riedell, J.L. Pikul Jr Jan 2002

Starter Fertilizer Effects On Soybean Grain Yield And Quality, S.L. Osborne, W.E Riedell, J.L. Pikul Jr

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

Fertilizing soybeans (Glycine max (L.) Merrill) is not an entirely new concept; for a number of years, scientists have investigated the effect of nitrogen (N) fertilizer on yield and quality of soybeans. The objective of this research was to investigate the effect of starter fertilizer N rates and sources on soybean yield, protein, and oil content in the cool soils of the Northern Great Plains. A field experiment was established within a two-year corn (Zea mays L.) soybean rotation. Using a split-plot design with four replications. Whole plots were no-till (NT) and conventional tillage (CT) and the split …

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Impact Of Intensive Cropping Systems On Physical Properties Of Surface Soils, G.A. Peterson, D.G. Westfall, L.A. Sherrod, T. M. Shaver Jan 2002

Impact Of Intensive Cropping Systems On Physical Properties Of Surface Soils, G.A. Peterson, D.G. Westfall, L.A. Sherrod, T. M. Shaver

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

The objective of this paper is to report the cumulative effects of cropping system intensification on the near surface soil physical properties (surface one inch of soil) within the Colorado dryland agroecoystem project, which has been in existence since 1986. Intensifying cropping systems from wheat-fallow to wheat-com-fallow to continuous cropping, increased crop residue return to the soil. Returning more residue to the soil surface: (I) decreased bulk density; (2) increased effective porosity; (3) increased sorptivity; (4) increased macro soil aggregation; and (5) appeared to improve potential water capture of the overall system. Increases in surface soil aggregation and effective porosity …

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Tillage And Beef Cattle Manure Effects On Soil Nitrogen In A Dryland Rotation, R. C. Schwartz, R.L. Baumhardt, T.H. Dao Jan 2002

Tillage And Beef Cattle Manure Effects On Soil Nitrogen In A Dryland Rotation, R. C. Schwartz, R.L. Baumhardt, T.H. Dao

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

Minimum tillage practices used in dryland cropping systems that reduce soil water evaporation and erosion may also decrease efficiency of manure nutrient utilization. We initiated a study in 1997 to investigate the effects of surface-applied stockpiled and composted beef cattle (Bos taurus) manure on soil N and sorghum [Sorghum bicolor (L.) Moench] and wheat (Triticum aestivum L.) yields and N-uptake within a wheat-sorghum-fallow dryland crop rotation. Paired terraces with no-tillage (NT) and stubble-mulch tillage (ST) systems were main plots of a single rotation phase. Stockpiled manure, composted manure, or commercial fertilizer (urea + ammonium phosphate) were …

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Particulate Soil Organic Matter Carbon In Surface Soils After 12 Years In No-Till Dryland Cropping Systems, L.A. Sherrod, G. A. Peterson, D.G. Westfall, L.R. Ahuja Jan 2002

Particulate Soil Organic Matter Carbon In Surface Soils After 12 Years In No-Till Dryland Cropping Systems, L.A. Sherrod, G. A. Peterson, D.G. Westfall, L.R. Ahuja

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

Soil organic carbon (SOC) in the surface soils has increased when summer fallow is reduced or eliminated in the central Great Plains. We evaluated the effect of no-till cropping systems of WF, wheat-com-fallow (WCF), wheat-corn-millet-fallow (WCMF), opportunity cropping (OPP), and native grass species (G) on particulate organic matter (POM-C) and mineral associated C in the silt and clay fractions. Soil organic carbon (SOC) has increased with increasing cropping intensity after 12 years, of no-till management. Particulate organic matter C accounted for 38 to 52 % of the total SOC in the 0-2.5 cm and 24 to 48 % of the …

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Development Of Granular Boric Acid Sugar Baits For House Flies (Diptera: Muscidae), Jerome A. Hogsette, David A. Carlson, Alyce S. Nejame Jan 2002

Development Of Granular Boric Acid Sugar Baits For House Flies (Diptera: Muscidae), Jerome A. Hogsette, David A. Carlson, Alyce S. Nejame

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

Freeze-dried, granular sugar baits containing boric acid as the toxicant were evaluated against house flies, Musca domestica L., in two bioassays with toxicant dose ranges of 3, 5, 7, 8, and 12%, and 3, 5, 9, 17, and 33% boric acid, respectively, calculated and expressed on a dry weight basis. Flies in bioassay 1 were mixed sex and unstarved and flies in bioassay 2 were females only and starved 4 h before testing began. LC50s were 8.97 and 14.33%, and LT50s were 59.75 and 53.34 h in bioassays 1 and 2, respectively. Baits were tested at …

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Development Of Hydrotaea Aenescens (Diptera: Muscidae) In Manure Of Unweaned Dairy Calves And Lactating Cows, Jerome Hogsette, Robert Farkas, Reginald Coler Jan 2002

Development Of Hydrotaea Aenescens (Diptera: Muscidae) In Manure Of Unweaned Dairy Calves And Lactating Cows, Jerome Hogsette, Robert Farkas, Reginald Coler

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

In laboratory studies performed in the United States and Hungary, the dump fly Hydrotaea aenescens (Wiedemann) was reared successfully in manure of 1- to 8-wk-old dairy calves, and in manure from adult lactating dairy cows. Survival in manure collected from 1-wk-old calves was poor (7.2%), better in manure collected from 2- and 3-wk-old calves (53.5%), and best in manure collected from 4- to 8-wk-old calves (71.4%). Survival in cow manure was slightly lower (47.4%) than that in calf manure. Reasons for different rates of development in the United States and in Hungary, and by calf age are discussed as are …

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Thermal Death Kinetics And Heatingrate Effects For Fifth-Instar Cydia Pomonella (L.) (Lepidoptera: Tortricidae), S. Wang, J. N. Ikediala, J. Tang, J. D. Hansen Jan 2002

Thermal Death Kinetics And Heatingrate Effects For Fifth-Instar Cydia Pomonella (L.) (Lepidoptera: Tortricidae), S. Wang, J. N. Ikediala, J. Tang, J. D. Hansen

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

Thermal death kinetic parameters of fifth-instar codlingmoths (Cydia pomonella (L.)) and the effect of three heating rates (1°Cmin-1, 10°Cmin-1, and 18°Cmin-1) on larval mortality were determined by a heatingblock system. The insects were heated to four temperatures (46°C, 48°C, 50°C, and 52°C) held for predetermined periods followed by 24 h storage at 4°C before mortality evaluation. Thermal death kinetics for fifth-instar codlingmoths followed a 0.5th order of kinetic reaction. Minimum time required to achieve 100% mortality of a given population decreased with temperature in a semi-logarithmic manner. No larval survival was observed in …

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Crop Sequence, Tillage, And Nitrogen Fertilization Effects On Soil Ph In The Northern Great Plains, Mark A. Liebig, D. L. Tanaka, A.L. Black Jan 2002

Crop Sequence, Tillage, And Nitrogen Fertilization Effects On Soil Ph In The Northern Great Plains, Mark A. Liebig, D. L. Tanaka, A.L. Black

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

Decreases in soil pH in agricultural soils can affect plant nutrient availability and crop yield. For soils possessing high levels of calcareous minerals, such as those found throughout much of the Northern Great Plains, decreases in soil pH can also enhance C loss to the atmosphere due to acid decomposition of CaCO3. We evaluated changes in soil pH over a 16 yr period for a long-term cropping systems experiment established on calcareous parent material near Mandan, ND. Management variables included in the experiment were crop sequence [spring wheat-fallow (SW-F) and spring wheat-winter wheat-sunflower (SW-WW-SF)], tillage (conventional, minimum, no-till), …

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Identification Of Waxy Wheat By Near-Infrared Reflectance Spectroscopy, S. R. Delwiche, Robert A. Graybosch Jan 2002

Identification Of Waxy Wheat By Near-Infrared Reflectance Spectroscopy, S. R. Delwiche, Robert A. Graybosch

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

Newly developed low amylose wheats (Triticum aestivum L.) have unique processing characteristics and thus allow millers to blend defined levels of amylose in mixes requiring low-amylose flour. The amount of amylose synthesized during grain fill is dependent on the expression of three structural genes that encode isoforms of granule-bound starch synthase (GBSS). Lines possessing null alleles at the three waxy (wx) loci produce starch that lacks amylose. While such wheats are readily identified by iodine staining, their identification in wheat marketing and production systems would be facilitated by the use of rapid, spectral methods. The present study …

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Review And Interpretation: Nitrogen Management Strategies To Reduce Nitrate Leaching In Tile-Drained Midwestern Soils, Dana L. Dinnes, Douglas L. Karlen, Dan B. Jaynes, Thomas C. Kaspar, Jerry L. Hatfield, Thomas S. Colvin, Cynthia A. Cambardella Jan 2002

Review And Interpretation: Nitrogen Management Strategies To Reduce Nitrate Leaching In Tile-Drained Midwestern Soils, Dana L. Dinnes, Douglas L. Karlen, Dan B. Jaynes, Thomas C. Kaspar, Jerry L. Hatfield, Thomas S. Colvin, Cynthia A. Cambardella

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

Balancing the amount of N needed for optimum plant growth while minimizing the NO3 that is transported to ground and surface waters remains a major challenge for everyone attempting to understand and improve agricultural nutrient use efficiency. Our objectives for this review are to examine how changes in agricultural management practices during the past century have affected N in Midwestern soils and to identify the types of research and management practices needed to reduce the potential for nonpoint NO3 leakage into water resources. Inherent soil characteristics and management practices contributing to nonpoint NO3 loss from Midwestern soils, …

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Molecular Cloning, Functional Characterization, And Subcellular Localization Of Soybean Nodule Dihydrolipoamide Reductase, Jose F. Moran, Zhaohui Sun, Gautam Sarath, Raul Arredondo-Peter, Euan K. James, Manuel Becana, Robert V. Klucas Jan 2002

Molecular Cloning, Functional Characterization, And Subcellular Localization Of Soybean Nodule Dihydrolipoamide Reductase, Jose F. Moran, Zhaohui Sun, Gautam Sarath, Raul Arredondo-Peter, Euan K. James, Manuel Becana, Robert V. Klucas

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

Nodule ferric leghemoglobin reductase (FLbR) and leaf dihydrolipoamide reductase (DLDH) belong to the same family of pyridine nucleotide-disulfide oxidoreductases. We report here the cloning, expression, and characterization of a second protein with FLbR activity, FLbR-2, from soybean (Glycine max) nodules. The cDNA is 1,779 bp in length and codes for a precursor protein comprising a 30-residue mitochondrial transit peptide and a 470-residue mature protein of 50 kD. The derived protein has considerable homology with soybean nodule FLbR-1 (93% identity) and pea (Pisum sativum) leaf mitochondria DLDH (89% identity). The cDNA encoding the mature protein was overexpressed …

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Continuous Production Of Extracellular Antioxidants In Suspension Cells Attenuates The Oxidative Burst Detected In Plant Microbe Interactions, C. Jacyn Baker, Nichole R. O'Neil, Kenneth Deahl, John Lydon Jan 2002

Continuous Production Of Extracellular Antioxidants In Suspension Cells Attenuates The Oxidative Burst Detected In Plant Microbe Interactions, C. Jacyn Baker, Nichole R. O'Neil, Kenneth Deahl, John Lydon

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

Suspension cells of Solanacearum tuberosum and Nicotiana tabacum placed in fresh buffer rapidly produce and maintain significant pools of extracellular antioxidants. The extracellular antioxidant was detected by first adding a known amount of exogenous H2O2 to samples and then immediately measuring the remaining H2O2. The difference between the amount added and amount remaining was used to determine the antioxidant capacity of the sample. This extracellular antioxidant pool attenuates levels of hydrogen peroxide produced during plant–bacterial interactions. When tobacco cells were inoculated with an isolate Pseudomonas syringae pv. syringae that causes a hypersensitive response …

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Comparative Life Table Statistics Of Exochomus Flaviventris Reared On The Cassava Mealybug, Phenacoccus Manihoti, Fed On Four Host Plants, B. P. Le Rü, A. Mitsipa Jan 2002

Comparative Life Table Statistics Of Exochomus Flaviventris Reared On The Cassava Mealybug, Phenacoccus Manihoti, Fed On Four Host Plants, B. P. Le Rü, A. Mitsipa

All Peer-Reviewed Publications

The demographic statistics of the ladybird Exochomus flaviventris Mader (Coleoptera: Coccinellidae) were investigated under laboratory conditions on the cassava mealybug, Phenacoccus manihoti Matile-Ferrero (Homoptera: Pseudococcidae), reared on four host plants with different levels of antibiotic resistance to the mealybug: two cassava (Manihot esculenta Crantz, Euphorbiaceae) varieties, Incoza and Zanaga, Faux-Caoutchouc (FC) (hybrid of M. esculenta x M. glaziovii Muel. Arg.) and water weed (Talinum triangulare Jack, Portulacacae). Preimaginal mortality, mean oviposition time and total fecundity of female ladybirds were strongly affected by the host plant even though there was no linkage with antibiotic resistance. The net reproduction rates R o …

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Density Effects Of The Banana Weevil, Cosmopolites Sordidus (Germar), On Its Oviposition Performance And Egg And Larval Survivorship, Clifford S. Gold, Godfrey H. Kagezi, Pontiano Nemeye, Philip E. Ragama Jan 2002

Density Effects Of The Banana Weevil, Cosmopolites Sordidus (Germar), On Its Oviposition Performance And Egg And Larval Survivorship, Clifford S. Gold, Godfrey H. Kagezi, Pontiano Nemeye, Philip E. Ragama

All Peer-Reviewed Publications

The influence of banana weevil, Cosmopolites sordidus (Germar)(Coleoptera: Curculionidae), population density on oviposition rates and larval survivorship was studied in the laboratory at the Kawanda Agricultural Research Institute in Uganda. This study was undertaken to elucidate the relationship between density-dependent factors and rates of banana weevil increase in the field. Oviposition substrates (corm pieces) were offered to a range of densities of weevils maintained in buckets. Mean oviposition rates per female at densities of 10, 20 and 40 females per bucket were 29, 37 and 53%, respectively, lower than that at a density of 5 females. Nevertheless, total oviposition for …

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