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2006

Agricultural Science

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Current Trends In Quarantine Entomology, Peter A. Follett, Lisa G. Neven Jan 2006

Current Trends In Quarantine Entomology, Peter A. Follett, Lisa G. Neven

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

With world trade in agricultural commodities increasing, the introduction of exotic insects into new areas where they become pests will increase. The development and application of quarantine treatments or other mitigation approaches to prevent pest introduction in traded commodities raise many research and regulatory issues. The probit 9 standard for quarantine treatment efficacy has given way to risk-based alternatives. Varietal testing may have merit for some treatments or commodities but not for others. Development of generic treatments to control broad groups of insects or insects in all commodities can expedite new trade in agricultural products. Area-wide pest management programs lower …


Rna Polymerase Ii Gene (Rpb2) Encoding The Second Largest Protein Subunit In Phaeosphaeria Nodorum And P. Avenaria, Arkadiusz Malkus, Pi-Fang Linda Chang, Sabina M. Zuzga, Kuang-Ren Chung, Jonathan Shao, Barry M. Cunfer, Edward Arseniuk, Peter P. Ueng Jan 2006

Rna Polymerase Ii Gene (Rpb2) Encoding The Second Largest Protein Subunit In Phaeosphaeria Nodorum And P. Avenaria, Arkadiusz Malkus, Pi-Fang Linda Chang, Sabina M. Zuzga, Kuang-Ren Chung, Jonathan Shao, Barry M. Cunfer, Edward Arseniuk, Peter P. Ueng

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

A 5586 bp sequence (accession no. DQ278491), which includes the RNA polymerase II gene (RPB2) encoding the second largest protein subunit (RPB2), was obtained from the wheat biotype Phaeosphaeria nodorum (PN-w) by PCR amplification. The 3841 bp full length RPB2 gene contains two exons and a 52 bp intron, and encodes a complete 1262 amino acid protein. Similar to the C-terminals of the b subunits of prokaryotes and yeast RNA polymerases, the deduced RPB2 protein contained many structural features needed for gene transcription. Based on the phylogenetic analysis with the deduced RPB2 polypeptide sequences, the PN-w was closely related to …


Comparison Of Three Alternative Ann Designs For Monthly Rainfall-Runoff Simulation, Jurgen D. Garbrecht Jan 2006

Comparison Of Three Alternative Ann Designs For Monthly Rainfall-Runoff Simulation, Jurgen D. Garbrecht

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

The performance of three artificial neural network (ANN) designs that account differently for the effects of seasonal rainfall and runoff variations were investigated for monthly rainfall-runoff simulation on an 815 km2 watershed in central Oklahoma. The ANN design that accounted explicitly for seasonal variations of rainfall and runoff performed best by all performance measures. Explicit representation of seasonal variations was achieved by use of a separate ANN for each calendar month. For the three ANN designs tested, a regression of simulated versus measured runoff displayed a slope slightly under 1 and positive intercept, pointing to a tendency of the …


Evaluating The Influence Of Storage Time, Sample-Handling Method, And Filter Paper On The Measurement Of Water-Extractable Phosphorus In Animal Manures, Kristen Baum, Gary Pierzynski, Peter Kleinman, John Kovar, Rory Maguire, Philip Moore, Tiequan Zhang Jan 2006

Evaluating The Influence Of Storage Time, Sample-Handling Method, And Filter Paper On The Measurement Of Water-Extractable Phosphorus In Animal Manures, Kristen Baum, Gary Pierzynski, Peter Kleinman, John Kovar, Rory Maguire, Philip Moore, Tiequan Zhang

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

Surface-applied manures create a potential phosphorus (P) runoff hazard, especially when unincorporated. In such cases, the concentration of water- extractable P in the manure has been correlated to soluble P concentrations in runoff. This study evaluated the influence of holding time, sample-handling procedure, and filtration method on measurement of the water-extractable P content of manures in a 3 ×3 ×2 factorial arrangement of treatments. A two-way interaction between holding time and sample-handling procedure occurred for most samples. Six samples had waterextractable P concentrations that were less than or equal to dried and dried/ground treatments. Only one sample had higher water-extractable …


Natural Abundance Of Foliar 15N As An Early Indicator Of Nitrogen Deficiency In Fertilized Cotton, S. Stamatiadis, C. Christofides, C. Tsadilas, V. Samaras, James S. Schepers Jan 2006

Natural Abundance Of Foliar 15N As An Early Indicator Of Nitrogen Deficiency In Fertilized Cotton, S. Stamatiadis, C. Christofides, C. Tsadilas, V. Samaras, James S. Schepers

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

Information on the contribution of various soil nitrogen (N) sources to plant N uptake is often needed for the implementation of sustainable or site-specific management practices in agriculture. Considering the limitations of traditional methods in meeting these needs, this study investigated the potential of leaf δ15N as an early indicator of nutrient deficiency in cotton. The spatial and temporal natural abundance of 15N was measured in the soil and leaves of a fertilized cotton field located near the village of Moschochori (Larissa, Greece). The isotopic signal of the leaves was interpreted in the context of the relative …


Spermatogenesis In The Turkey (Meleagris Gallopavo): Quantitative Approach In Immature And Adult Males Subjected To Various Photoperiods, Jérôme Noirault, Jean-Pierre Brillard Jan 2006

Spermatogenesis In The Turkey (Meleagris Gallopavo): Quantitative Approach In Immature And Adult Males Subjected To Various Photoperiods, Jérôme Noirault, Jean-Pierre Brillard

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

The objectives of this study were to identify and quantitate the germ cell populations of the testes in sexually mature male turkeys (Trial 1), determine the duration of meiosis based on BrdU labeling and stereological analyses (Trial 2), and examine the impact of various photoperiods on germinal and somatic cell populations in immature and adult males (Trial 3). In Trial 1, both testes within a male had similar stereological components (P > 0.05) for all parameters analyzed. In Trial 2, the duration of Type-1 spermatocytes and round spermatids in turkeys lasted 4.5 ± 0.5 and 2.0 ± 0.5 days, respectively. In …


Characterization Of Storage Proteins In Wild (Glycine Soja) And Cultivated (Glycine Max) Soybean Seeds Using Proteomic Analysis, Savithiry S. Natarajan, Chenping Xu, Hanhong Bae, Thomas J. Caperna, Wesley M. Garrett Jan 2006

Characterization Of Storage Proteins In Wild (Glycine Soja) And Cultivated (Glycine Max) Soybean Seeds Using Proteomic Analysis, Savithiry S. Natarajan, Chenping Xu, Hanhong Bae, Thomas J. Caperna, Wesley M. Garrett

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

A combined proteomic approach was applied for the separation, identification, and comparison of two major storage proteins, β-conglycinin and glycinin, in wild (Glycine soja) and cultivated (Glycine max) soybean seeds. Two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) with three different immobilized pH gradient (IPG) strips was an effective method to separate a large number of abundant and less-abundant storage proteins. Most of the subunits of β-conglycinin were well separated in the pH range 3.0-10.0, while acidic and basic glycinin polypeptides were well-separated in pH ranges 4.0-7.0 and 6.0-11.0, respectively. Although the overall distribution pattern of the protein spots …


Estrogenic Activity In The Environment: Municipal Wastewater Effluent, River, Ponds, And Wetlands, Nancy W. Shappell Jan 2006

Estrogenic Activity In The Environment: Municipal Wastewater Effluent, River, Ponds, And Wetlands, Nancy W. Shappell

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

Estrogenic activity of regional water samples was evaluated. Samples obtained from wetlands and ponds involved in various agricultural land uses, from three river sites over four seasons, and from municipal wastewater effluent held in storage lagoons were evaluated. The estrogen- responsive cell line MCF-7 BOS was used in the E-screen assay to determine 17β-estradiol equivalents (E2 Eq) of water samples extracted by solid-phase extraction. Estrogenic activity in surrounding wetlands and ponds from different land uses was not different, with 10-12 M E2 Eq (0.3 ppt). Estrogenic activity of Red River samples was within the same range as wetland–pond …


Net Global Warming Potential And Greenhouse Gas Intensity In Irrigated Cropping Systems In Northeastern Colorado, Arvin R. Mosier, Ardell D. Halvorson, Curtis A. Reule, Xuejun J. Liu Jan 2006

Net Global Warming Potential And Greenhouse Gas Intensity In Irrigated Cropping Systems In Northeastern Colorado, Arvin R. Mosier, Ardell D. Halvorson, Curtis A. Reule, Xuejun J. Liu

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

The impact of management on global warming potential (GWP), crop production, and greenhouse gas intensity (GHGI) in irrigated agriculture is not well documented. A no-till (NT) cropping systems study initiated in 1999 to evaluate soil organic carbon (SOC) sequestration potential in irrigated agriculture was used in this study to make trace gas flux measurements for 3 yr to facilitate a complete greenhouse gas accounting of GWP and GHGI. Fluxes of CO2, CH4, and N2O were measured using static, vented chambers, one to three times per week, year round, from April 2002 through October 2004 …


Microarray Based Comparison Of Two Escherichia Coli O157:H7 Lineages, Scot E. Dowd, Hiroshi Ishizaki Jan 2006

Microarray Based Comparison Of Two Escherichia Coli O157:H7 Lineages, Scot E. Dowd, Hiroshi Ishizaki

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

Background: Previous research has identified the potential for the existence of two separate lineages of Escherichia coli O157:H7. Clinical isolates tended to cluster primarily within one of these two lineages. To determine if there are virulence related genes differentially expressed between the two lineages we chose to utilize microarray technology to perform an initial screening.

Results: Using a 610 gene microarray, designed against the E. coli O157 EDL 933 transcriptome, targeting primarily virulence systems, we chose 3 representative Lineage I isolates (LI groups mostly clinical isolates) and 3 representative Lineage II isolates (LII groups mostly bovine isolates). Using standard dye …


Post-Weaning Performance Of Steers From Varying Calving And Weaning Strategies In Montana, E. E. Grings, W. A. Phillips, R. E. Short, H. Mayeux, R. K. Heitschmidt Jan 2006

Post-Weaning Performance Of Steers From Varying Calving And Weaning Strategies In Montana, E. E. Grings, W. A. Phillips, R. E. Short, H. Mayeux, R. K. Heitschmidt

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

The impact of varied calving and weaning times on post-weaning production of steer calves was evaluated in a 3- yr study. Steers (approximately 12 steers per calving-weaning treatment per year) born in late winter or early spring were weaned at 190 or 240 d of age, and steers born in late spring were weaned at 140 or 190 d of age after grazing with their dams on native range. Steers were pen-fed a growing diet until approximately 375 kg BW. They were then moved to an individual feeding facility and fed a higher-energy diet. Steers were allotted to harvest dates …


Traps And Trapping Techniques For Adult Mosquito Control, Daniel L. Kline Jan 2006

Traps And Trapping Techniques For Adult Mosquito Control, Daniel L. Kline

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

An overview is presented of the recent advancements in research activities conducted to evaluate mosquito traps. insecticide-impregnated targets baited with combinations of attractants, and strategies for using mass trapping techniques for adult mosquito population management. Technologies that use semiochemicals (attractants). traps and targets. and mass trapping are relatively new for management of adult mosquito populations. To date. emphasis has been placed primarily on developing barriers of attractant-baited and insecticide-impregnated targets. The most successful continuous use of this type of technology has been at Stevens' Landing. Collier County. Florida, Recently. commercially available traps have been evaluated for their ability to reduce …


Suppression Of House Flies (Diptera: Muscidae) In Florida Poultry Houses By Sustained Releases Of Muscidifurax Raptorellus And Spalangia Cameroni (Hymenoptera: Pteromalidae), Christopher Geden, Jerome Hogsette Jan 2006

Suppression Of House Flies (Diptera: Muscidae) In Florida Poultry Houses By Sustained Releases Of Muscidifurax Raptorellus And Spalangia Cameroni (Hymenoptera: Pteromalidae), Christopher Geden, Jerome Hogsette

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

Weekly releases of Muscidifurax raptorellus Kogan and Legner and Spalangia cameroni Perkins were made for 12 wk after house cleanouts in Florida pullet houses in either spring/summer (May-August) or fall (September-December). Releases were made by weekly placement of 62,500 and 85,000 pupae parasitized by M. raptorellus and S. cameroni, respectively, which produced an average of 79,049 and 32,841 adult female parasitoids per week. House fly (Musca domestica L.) pupal mortality, as measured by sentinel pupae, was about twice as high in the release house (40.2%) as in the two control houses (21.5 and 21.8%) in the summer release. …


Prevention Of Mosquitoes (Diptera: Culicidae) And House Flies (Diptera: Muscidae) From Entering Simulated Aircraft With Commercial Air Curtain Units, David A. Carlson, Jerome Hogsette, Daniel Kline, Chris D. Geden, Robert Vandermeer Jan 2006

Prevention Of Mosquitoes (Diptera: Culicidae) And House Flies (Diptera: Muscidae) From Entering Simulated Aircraft With Commercial Air Curtain Units, David A. Carlson, Jerome Hogsette, Daniel Kline, Chris D. Geden, Robert Vandermeer

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

Commercially available air curtain units were used to create air barriers to prevent mosquitoes and house flies from entering a simulated aircraft doorway together with passengers. Two assemblies of simulated passenger bridge and aircraft were constructed, and airflow measurements were recorded to confirm airflow characteristics for several combinations of commercial units. Three mosquito species were selected for different host-seeking characteristics, and house flies were selected to represent a large, strong-flying insect. Batches of 20 or 200 insects of four species were released into the passenger bridge just before 25 persons passed through the assembly, then insects that entered the aircraft …


Genetic And Hybridization Evidence Confirms That A Geographic Population Of Gonatocerus Morrilli (Hymenoptera: Mymaridae) From California Is A New Species: Egg Parasitoids Of The Glassy-Winged Sharpshooter Homalodisca Coagulata (Homoptera: Cicadellidae), Jesse H. De León, Walker A. Jones, Mamoudou Sétamou, David J. W. Morgan Jan 2006

Genetic And Hybridization Evidence Confirms That A Geographic Population Of Gonatocerus Morrilli (Hymenoptera: Mymaridae) From California Is A New Species: Egg Parasitoids Of The Glassy-Winged Sharpshooter Homalodisca Coagulata (Homoptera: Cicadellidae), Jesse H. De León, Walker A. Jones, Mamoudou Sétamou, David J. W. Morgan

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

We investigated the differentiation and reproductive isolation among different geographic populations of Gonatocerus morrilli, egg parasitoids of the glassy-winged sharpshooter (Homalodisca coagulata), to confirm previous observations that there may exist a cryptic species complex or a new species. Two mitochondrial genes [cytochrome oxidase subunits I (COI) and II (COII)] and the internal transcribed spacer region 2 (ITS2) of several individuals per population were sequenced. G. morrilli populations from Texas (TX), Florida (FL), California (CA), and an outgroup (G. ashmeadi) were analyzed. For comparison, a population from Argentina (G. annulicornis) morphologically similar to G. …


Effects Of Substrate And Temperature On Growth Of Aspergillus Flavus In Peanuts From Georgia, Premila Achar, Andres Sachez Jan 2006

Effects Of Substrate And Temperature On Growth Of Aspergillus Flavus In Peanuts From Georgia, Premila Achar, Andres Sachez

Faculty and Research Publications

We investigated the effects of different substrates (potato dextrose agar [PDA], nutrient agar [NA], and corn meal agar [CMA]) and temperatures on growth and aflatoxin production in Aspergillus flavus. Contaminated peanuts from retailers at different locations in Georgia were used throughout the experiment and 200 seeds were selected from each sample. PDA, NA, and CMA served as the substrate to express the mold from the contaminated seeds. Seeds were plated equidistantly on each of the media and incubated at 10° C, 27° C, 30° C, and 37° C, respectively. Seeds incubated on moist filter paper served as control. Neither growth …


Biotinylation Of K8 And K12 Co-Occurs With Acetylation And Mono-Methylation In Human Histone H4, Yap Ching Chew, Ashraf S. Raza, Gautam Sarath, Janos Zempleni Jan 2006

Biotinylation Of K8 And K12 Co-Occurs With Acetylation And Mono-Methylation In Human Histone H4, Yap Ching Chew, Ashraf S. Raza, Gautam Sarath, Janos Zempleni

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

Histones H1, H2A, H2B, H3, and H4 are proteins that are critical for folding of DNA into chromatin. Posttranslational acetylation, methylation, and biotinylation of histones participate in gene silencing, mitotic condensation of chromatin, and the cellular response to DNA damage. Various modifications of histones are known to interact ("cross-talk") in chromatin-remodeling events; interactions may be synergistic or antagonistic. Here, we sought to identify biotinylation sites in human histone H4 by using mass spectrometry (MS/MS), and we sought to determine whether biotinylation co-exists with acetylation and methylation in the same H4 molecule. Nuclear histones from human lymphoid (Jurkat) cells were digested …


Slow Ligand Binding Kinetics Dominate Ferrous Hexacoordinate Hemoglobin Reactivities And Reveal Differences Between Plants And Other Species, Benoit J. Smagghe, Gautam Sarath, Emily Ross, Jean-Louis Hilbert, Mark S. Hargrove Jan 2006

Slow Ligand Binding Kinetics Dominate Ferrous Hexacoordinate Hemoglobin Reactivities And Reveal Differences Between Plants And Other Species, Benoit J. Smagghe, Gautam Sarath, Emily Ross, Jean-Louis Hilbert, Mark S. Hargrove

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

Hexacoordinate hemoglobins are found in many living organisms ranging from prokaryotes to plants and animals. They are named “hexacoordinate” because of reversible coordination of the heme iron by a histidine side chain located in the heme pocket. This endogenous coordination competes with exogenous ligand binding and causes multiphasic relaxation time courses following rapid mixing or flash photolysis experiments. Previous rapid mixing studies have assumed a steady-state relationship between hexacoordination and exogenous ligand binding that does not correlate with observed time courses for binding. Here, we demonstrate that this assumption is not valid for some hexacoordinate hemoglobins, and that multiphasic time …


Nutrient Uptake Of Maize Affected By Nitrogen And Potassium Fertility In A Humid Subtropical Environment, H. Arnold Bruns, M. Wayne Ebelhar Jan 2006

Nutrient Uptake Of Maize Affected By Nitrogen And Potassium Fertility In A Humid Subtropical Environment, H. Arnold Bruns, M. Wayne Ebelhar

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

Nitrogen (N) and potassium (K) fertility management of maize (Zea mays L.) in the humid subtropical Mississippi Delta may differ from a temperate climate because of its use in rotation with cotton (Gossypium hirsutum L.), soil temperatures rarely falling to 0 °C, and heavy winter rains that facilitate nutrient losses. An experiment to determine the [N] (concentration = [ ]), phosphorus [P], [K], calcium [Ca], magnesium [Mg], iron [Fe], manganese [Mn], zinc [Zn], and copper [Cu] and their total contents plant-1 of maize grown in rotation with cotton, using N fertility levels of (134, 179, 224, 269, …


Evaluation Of The Single Kernel Characterization System (Skcs) For Measurement Of Sorghum Grain Attributes, S. R. Bean, O. K. Chung, M. R. Tuinstra, Jeffrey F. Pedersen, J. Erpelding Jan 2006

Evaluation Of The Single Kernel Characterization System (Skcs) For Measurement Of Sorghum Grain Attributes, S. R. Bean, O. K. Chung, M. R. Tuinstra, Jeffrey F. Pedersen, J. Erpelding

Department of Agronomy and Horticulture: Faculty Publications

The single kernel characterization system (SKCS) has been widely used in the wheat industry, and SKCS parameters have been linked to end-use quality in wheat. The SKCS has promise as a tool for evaluating sorghum grain quality. However, the SKCS was designed to analyze wheat, which has a different kernel structure from sorghum. To gain a better understanding of the meaning of SKCS predictions for grain sorghum, individual sorghum grains were measured for length, width, thickness (diameter), and weight by laboratory methods and by the SKCS. SKCS predictions for kernel weight and thickness were highly correlated to laboratory measurements. However, …


Chemical Composition And Response To Dilute-Acid Pretreatment And Enzymatic Saccharification Of Alfalfa, Reed Canarygrass, And Switchgrass, Bruce S. Dien, Hans-Joachim G. Jung, Kenneth P. Vogel, Michael D. Casler, Joann F. S. Lamb, Loren Iten, Robert C. Mitchell, Gautum Sarath Jan 2006

Chemical Composition And Response To Dilute-Acid Pretreatment And Enzymatic Saccharification Of Alfalfa, Reed Canarygrass, And Switchgrass, Bruce S. Dien, Hans-Joachim G. Jung, Kenneth P. Vogel, Michael D. Casler, Joann F. S. Lamb, Loren Iten, Robert C. Mitchell, Gautum Sarath

Department of Agronomy and Horticulture: Faculty Publications

Alfalfa stems, reed canarygrass, and switchgrass; perennial herbaceous species that have potential as biomass energy crops in temperate regions; were evaluated for their bioconversion potential as energy crops. Each forage species was harvested at two or three maturity stages and analyzed for carbohydrates, lignin, protein, lipid, organic acids, and mineral composition. The biomass samples were also evaluated for sugar yields following pretreatment with dilute sulfuric followed by enzymatic saccharification using a commercial cellulase preparation. Total carbohydrate content of the plants varied from 518 to 655 g kg-1 dry matter (DM) and cellulose concentration from 209 to 322 g kg …


Mutations In Arabidopsis Yellow Stripe-Like1 And Yellow Stripe-Like3 Reveal Their Roles In Metal Ion Homeostasis And Loading Of Metal Ions In Seeds, Brian M. Waters, Heng-Hsuan Chu, Raymond J. Didonato, Louis A. Roberts, Robynn B. Eisley, Brett Lahner, David E. Salt, Elsbeth L. Walker Jan 2006

Mutations In Arabidopsis Yellow Stripe-Like1 And Yellow Stripe-Like3 Reveal Their Roles In Metal Ion Homeostasis And Loading Of Metal Ions In Seeds, Brian M. Waters, Heng-Hsuan Chu, Raymond J. Didonato, Louis A. Roberts, Robynn B. Eisley, Brett Lahner, David E. Salt, Elsbeth L. Walker

Department of Agronomy and Horticulture: Faculty Publications

Here, we describe two members of the Arabidopsis (Arabidopsis thaliana) Yellow Stripe-Like (YSL) family, AtYSL1 and AtYSL3. The YSL1 and YSL3 proteins are members of the oligopeptide transporter family and are predicted to be integral membrane proteins. YSL1 and YSL3 are similar to the maize (Zea mays) YS1 phytosiderophore transporter (ZmYS1) and the AtYSL2 iron (Fe)-nicotianamine transporter, and are predicted to transport metal-nicotianamine complexes into cells. YSL1 and YSL3 mRNAs are expressed in both root and shoot tissues, and both are regulated in response to the Fe status of the plant. β-Glucuronidase reporter expression, driven by …


Application Of Machine Learning In Snp Discovery, Lakshmi K. Matukumalli, John J. Grefenstette, David L. Hyten, Ik-Young Choi, Perry B. Cregan, Curtis P. Van Tassell Jan 2006

Application Of Machine Learning In Snp Discovery, Lakshmi K. Matukumalli, John J. Grefenstette, David L. Hyten, Ik-Young Choi, Perry B. Cregan, Curtis P. Van Tassell

Department of Agronomy and Horticulture: Faculty Publications

Background: Single nucleotide polymorphisms (SNP) constitute more than 90% of the genetic variation, and hence can account for most trait differences among individuals in a given species. Polymorphism detection software PolyBayes and PolyPhred give high false positive SNP predictions even with stringent parameter values. We developed a machine learning (ML) method to augment PolyBayes to improve its prediction accuracy. ML methods have also been successfully applied to other bioinformatics problems in predicting genes, promoters, transcription factor binding sites and protein structures. Results: The ML program C4.5 was applied to a set of features in order to build a SNP classifier …


Snp-Phage – High Throughput Snp Discovery Pipeline, Lakshmi K. Matukumalli, John J. Grefenstette, David L. Hyten, Ik-Young Choi, Perry B. Cregan, Curt P. Van Tassell Jan 2006

Snp-Phage – High Throughput Snp Discovery Pipeline, Lakshmi K. Matukumalli, John J. Grefenstette, David L. Hyten, Ik-Young Choi, Perry B. Cregan, Curt P. Van Tassell

Department of Agronomy and Horticulture: Faculty Publications

Background: Single nucleotide polymorphisms (SNPs) as defined here are single base sequence changes or short insertion/deletions between or within individuals of a given species. As a result of their abundance and the availability of high throughput analysis technologies SNP markers have begun to replace other traditional markers such as restriction fragment length polymorphisms (RFLPs), amplified fragment length polymorphisms (AFLPs) and simple sequence repeats (SSRs or microsatellite) markers for fine mapping and association studies in several species. For SNP discovery from chromatogram data, several bioinformatics programs have to be combined to generate an analysis pipeline. Results have to be stored in …


Impacts Of Genetic Bottlenecks On Soybean Genome Diversity, D. L. Hyten, Qijian Song, Youlin Zhu, Ik-Young Choi, Randall L. Nelson, Jose M. Costa, James E. Specht, Randy C. Shoemaker, Perry B. Cregan Jan 2006

Impacts Of Genetic Bottlenecks On Soybean Genome Diversity, D. L. Hyten, Qijian Song, Youlin Zhu, Ik-Young Choi, Randall L. Nelson, Jose M. Costa, James E. Specht, Randy C. Shoemaker, Perry B. Cregan

Department of Agronomy and Horticulture: Faculty Publications

Soybean has undergone several genetic bottlenecks. These include domestication in Asia to produce numerous Asian landraces, introduction of relatively few landraces to North America, and then selective breeding over the past 75 years. It is presumed that these three human-mediated events have reduced genetic diversity. We sequenced 111 fragments from 102 genes in four soybean populations representing the populations before and after genetic bottlenecks. We show that soybean has lost many rare sequence variants and has undergone numerous allele frequency changes throughout its history. Although soybean genetic diversity has been eroded by human selection after domestication, it is notable that …


Soybean Cultivars Resulted From More Recombination Events Than Unselected Lines In The Same Population, T. R. Stefaniak, D. L. Hyten Jr., V. R. Pantalone, A. Klarer, T. W. Pfeiffer Jan 2006

Soybean Cultivars Resulted From More Recombination Events Than Unselected Lines In The Same Population, T. R. Stefaniak, D. L. Hyten Jr., V. R. Pantalone, A. Klarer, T. W. Pfeiffer

Department of Agronomy and Horticulture: Faculty Publications

The selection of superior adapted cultivars has contributed to the doubling of soybean [Glycine max (L.) Merr.] yields in the USA since 1930. Genetic variation was required for this selection to be effective. The objective of this study was to evaluate the importance of homologous chromosome meiotic recombination in the creation of soybean cultivars. A set of 10 adapted high-yielding cultivars selected from the cross ‘Williams’ × ‘Essex’ was com-pared with a set of 156 random recombinant inbred lines (RILs) from the same population. Crossover events were identified using 143 simple sequence repeat (SSR) markers span-ning all 20 soybean …


Ethylene Could Influence Ferric Reductase, Iron Transporter, And H+-Atpase Gene Expression By Affecting Fer (Or Fer-Like) Gene Activity, Carlos Lucera, Brian M. Waters, Francisco Javier Romera, María José García, María Morales, Esteban Alcántara, Rafael Pérez-Vicente Jan 2006

Ethylene Could Influence Ferric Reductase, Iron Transporter, And H+-Atpase Gene Expression By Affecting Fer (Or Fer-Like) Gene Activity, Carlos Lucera, Brian M. Waters, Francisco Javier Romera, María José García, María Morales, Esteban Alcántara, Rafael Pérez-Vicente

Department of Agronomy and Horticulture: Faculty Publications

In previous works, it has been shown, by using ethylene inhibitors and precursors, that ethylene could participate in the regulation of the enhanced ferric reductase activity of Fe-deficient Strategy I plants. However, it was not known whether ethylene regulates the ferric reductase gene expression or other aspects related to this activity. This paper is a study of the effects of ethylene inhibitors and precursors on the expression of the genes encoding the ferric reductases and iron transporters of Arabidopsis thaliana (FRO2 and IRT1) and Lycopersicon esculentum (= Solanum lycopersicum) (FRO1 and IRT1) plants. The effects …


Science-Based Organic Farming 2006: Toward Local And Secure Food Systems, Charles A. Francis, Katja Koehler-Cole, Twyla Hansen, Peter Skelton Jan 2006

Science-Based Organic Farming 2006: Toward Local And Secure Food Systems, Charles A. Francis, Katja Koehler-Cole, Twyla Hansen, Peter Skelton

Publications from the Center for Applied Rural Innovation (CARI)

Organic farming includes growing food and fiber—animals, agronomic crops, horticultural fruits and vegetables, related products—as one dynamic and rapidly evolving component of our complex U.S. food system. Even as more farmers are moving toward organic certification and participation in an environmentally sound and economically lucrative market, questions arise about the long-term social impacts and sustainability of a set of practices that has gone from a movement to an industry. Consolidations in the organic trade have brought multinational corporations to the table, as they have observed a grassroots activity that has grown by 20% per year for the past two decades, …