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Efficacy Of A Novel Molecular Tool In Silencing Arabidopsis Genes, Chase Purnell, Vibha Srivastava, M. Aydin Akbudak, Scott J. Nicholson

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

RNA interference (RNAi), a pathway capable of silencing genes, has until recently only been achievable in the laboratory by the use of one method, expression of inverted repeat sequences of DNA. These constructs generate a double-stranded RNA, which in turn induce post-transcriptional silencing of other genes that bear sequence homology with the transgene. This approach of targeted gene silencing is extremely useful for studying the function of genes and engineering new traits in both plants and animals. It has recently been discovered that a transgene lacking the polyadenylation signal, called a truncated transgene, is also capable of inducing RNAi in …

Determining The Virulence Of Corn Pathogen Fusarium Verticillioides Utilizing Deletion Mutants Lacking Genes Fv_00027 Or Fv_Nps6, Abigail Zieman

Honors Program Theses

Fusarium verticillioides is an important fungal pathogen of com. Many pathogens have virulent genes which are genes that increase infectivity of the pathogen. After a bioinformatics study, it was determined that genes Fv _ 00027 and Fv _ NPS6 are potential virulent genes in F. verticillioides. To determine if either gene ·contributes to the virulence of the fungus, deletion mutants of F. verticillioides were created lacking either Fv _ 00027 or Fv _ NPS6 genes. These deletion mutants were utilized in an optimized com assay to determine the effect of infectivity on com. To test these deletion mutants, com seeds …

Next Generation Dna Sequencing Technology Delivers Valuable Genetic Markers For The Genomic Orphan Legume Species, Bituminaria Bituminosa, M Pazos-Navarro, Mercedes Dabauza, Enrique Correal, Kelly Hanson, Natasha L. Teakle, Daniel Real, Matthew Nelson

Grain and Other Field Crops Research Articles

Background
Bituminaria bituminosa is a perennial legume species from the Canary Islands and Mediterranean region that has potential as a drought-tolerant pasture species and as a source of pharmaceutical compounds. Three botanical varieties have previously been identified in this species: albomarginata, bituminosa and crassiuscula. B. bituminosa can be considered a genomic 'orphan' species with very few genomic resources available. New DNA sequencing technologies provide an opportunity to develop high quality molecular markers for such orphan species.

Results
432,306 mRNA molecules were sampled from a leaf transcriptome of a single B. bituminosa plant using Roche 454 pyrosequencing, resulting in an …

The Effects Of Phosphorus Enrichment On Leaf Litter Stoichiometry In A Forested Stream, Bryant Baker

Crop, Soil and Environmental Sciences Undergraduate Honors Theses

The effects of nutrient (N and P) enrichment on leaf litter decomposition in streams have been investigated extensively, but few have explored how P addition alone affects leaf litter stoichiometry (namely the C:P ratio). This study examined how the P content, C:P ratio and decomposition of two types of leaf litter (the recalcitrant Quercus stellata and the more labile Acer saccharum) responded to P enrichment from nutrient diffusing substrata (NDS) which was either unenriched agar or agar enriched with a moderate or high level of P. Leaf litter was sealed in 0.05 mm mesh bags, which excluded invertebrates, housed with …

Rice (Oryza Sativa) Response To Low Glyphosate Rates As Influenced By Cultivar, Growth Stage, And Imazethapyr Applications, Jason R. Meier

Graduate Theses and Dissertations

Off-target movement of glyphosate onto rice is a perennial concern when rice is grown in close proximity to glyphosate-tolernat crops. If differential tolerance to sub-lethal rates of glyphosate exists among rice (Oryza sativa) cultivars, these cultivars could be utilized in breeding programs or glyphosate-drift sensitive areas. Field and greenhouse experiments were conducted in 2006 and 2007 to examine differences among rice cultivars in response to sub-lethal rates of glyphosate, and to examine imidazolinone-tolerant rice response to imazethapyr and sub-lethal rates of glyphosate applied sequentially to determine the potential for either herbicide to predispose rice to greater injury. In the field …

Determination Of Poultry Litter's Nitrogen-Fertilizer Value For Winter Wheat Production, Brett Lee Gordon

Graduate Theses and Dissertations

Nitrogen (N) availability in poultry litter (PL) applied in the fall as a nutrient source for winter wheat (Triticum aestivum L.) has not been adequately characterized. Our objective was to determine a potentially available N (PAN) coefficient based on the inorganic-N fertilizer equivalence (FEQ) of fall-applied PL to winter wheat via field and laboratory research. Wheat grown at six site-years received 0, 84 and 168 kg N ha-1 as PL applied preplant and/or at-planting. The FEQ of PL-N was based on growth and yield responses of wheat fertilized with 22 to 191 kg N ha-1 applied in late winter as …

Heritable Epigenetic Variation Among Maize Inbreds, Steve R. Eichten, Ruth A. Swanson, James C. Schnable, Amanda J. Waters, Peter J. Hermanson, Sanzhen Liu, Cheng-Ting Yeh, Yi Jia, Karla Gendler, Michael Freeling, Patrick S. Schnable, Matthew W. Vaughn, Nathan M. Springer

Department of Agronomy and Horticulture: Faculty Publications

Epigenetic variation describes heritable differences that are not attributable to changes in DNA sequence. There is the potential for pure epigenetic variation that occurs in the absence of any genetic change or for more complex situations that involve both genetic and epigenetic differences. Methylation of cytosine residues provides one mechanism for the inheritance of epigenetic information. A genome-wide profiling of DNA methylation in two different genotypes of Zea mays (ssp. mays), an organism with a complex genome of interspersed genes and repetitive elements, allowed the identification and characterization of examples of natural epigenetic variation. The distribution of DNA methylation …

Miscanthus 3 Giganteus Productivity: The Effects Of Management In Different Environments, Matt Maughan, German Bollero, D.K. Lee, Robert Darmody, Stacy Bonos, Laura Cortese, James Murphy, Roch E. Gaussoin, Matthew Sousek, David Williams, Linda Williams, Fernando Miguez, Thomas Voigt

Department of Agronomy and Horticulture: Faculty Publications

Miscanthus 9 giganteus is a C4 perennial grass that shows great potential as a high-yielding biomass crop. Scant research has been published that reports M. 9 giganteus growth and biomass yields in different environments in the United States. This study investigated the establishment success, plant growth, and dry biomass yield of M. 9 giganteus during its first three seasons at four locations (Urbana, IL; Lexington, KY; Mead, NE; Adelphia, NJ) in the United States. Three nitrogen rates (0, 60, and 120 kg ha -1) were applied at each location each year. Good survival of M. 9 giganteus during its first …

Evaluation Of Perennial Forage Legumes And Herbs In Six Mediterranean Environments, Daniel Real, Guangdi D. Li, Steve Clark, Tony Albertsen, Richard C. Hayes, Matt D. Denton, Mario F. D'Antuono, B S. Dear

Grain and Other Field Crops Research Articles

There is an absence of drought tolerant herbaceous perennial forage legume and herb options other than lucerne (Medicago sativa L.) for environments with Mediterranean-like climates common in extensive areas of Southern Australia, the Mediterranean basin, and Chile. Therefore, a collection of 174 forage perennial legume and herb entries from 103 species and 32 genera was evaluated for adaptation in a diverse range of Mediterranean climatic environments in Southern Australia. The seasonal rainfall distribution varied from moderately to highly winter dominant with long term average annual rainfall ranging from 318 to 655 mm. The entries were rated for productivity and …

Effects Of In Situ Freezing On Soil Net Nitrogen Mineralization And Net Nitrification In Fertilized Grassland Of Northern China, X. Zhang, W. Bai, Frank S. Gilliam, Q. Wang, X. Han, L. Li

Biological Sciences Faculty Research

Effects of soil freezing on nitrogen (N) mineralization have been the subject of increased attention in the ecological literature, though fewer studies have examined N mineralization responses to successive mild freezing, severe freezing and cyclic freeze–thaw events. Even less is known about relationships of responses to soil N status. This study measured soil N mineralization and nitrification in the field along an experimental N gradient in a grassland of northern China during the dormant season (October 2005–April 2006), a period in which freezing naturally occurs. Net N mineralization exhibited great temporal variability, with nitrification being the predominant N transformation process. …

Substantial Equivalence Assessment Of Transgenic Corn Plants, Martina Garda

Student Theses and Dissertations

Transgenic crops are regulated until they are judged to be as safe as non-transgenic plants. To grow them without permits, they must attain regulatory approval. . A lot of data are needed to show "substantial equivalence" and safety . This work deals with corn lines that contain cellulase genes. We hypothesize that no difference exists between Genetically Engineered (GE) and non-Genetically Engineered (non-GE) corn seeds at the morphological, protein, and DNA levels, except for the protein expressed specifically from the corresponding gene. This research will address concerns in commercializing GE crops, such as those containing a gene for either an …

Selecting Improved Lotus Nodulating Rhizobia To Expedite The Development Of New Forage Species, John Gregory Howieson, Ross Andrew Ballard, Ronald J. Yates, Nigel Charman

Grain and Other Field Crops Research Articles

Aims

In the past decades the increasing focus by Australian pasture development programs on the genus Lotus has seen the evaluation of many species previously untested in Australia. In field trials, nodulation failure was commonplace. This work was undertaken to select effective symbionts for Lotus to ensure further agronomic evaluation of the genus was not compromised. The symbiotic needs of Lotus ornithopodioides were a particular focus of the studies.

Methods

Glasshouse experiments were undertaken to evaluate symbiotic relationships between 15 Lotus spp and 23 strains of nodulating Mesorhizobium loti. This was followed by evaluation of elite rhizobial strains for …

Gata-Family Transcription Factors In Magnaporthe Oryzae, Cristian F. Quispe

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

The filamentous fungus, Magnaporthe oryzae, responsible for blast rice disease, destroys around 10-30% of the rice crop annually. Infection begins when the specialized infection structure, the appressorium, generates enormous internal turgor pressure through the accumulation of glycerol. This turgor acts on a penetration peg emerging at the base of the cell, causing it to breach the leaf surface allowing its infection.

The enzyme trehalose-6- phosphate synthase (Tps1) is a central regulator of the transition from appressorium development to infectious hyphal growth. In the first chapter we show that initiation of rice blast disease requires a regulatory mechanism involving an …

B. R. Wells Rice Research Studies 2010, R. J. Norman, K. A. K. Moldenhauer

Arkansas Agricultural Experiment Station Research Series

The 2010 Rice Research Verification Program ( RRVP) was conducted on twenty-two commercial rice fields across the state. Counties rarticirating in the program included Arkansas, Ashley, Chicot, Clark, Clay, Cross, Desha, Drew, Greene, Jackson, Jefferson, Lafayette, Lawrence, Lonoke, Mississippi, Phillips, Poinsett (2 fields), Prairie, Randolph, St. Francis, and White for a total of 1456 acres. Grain yield in the 2010 RRVP averaged 167 bu/acre ranging from 113 to 215 bu/acre. The 2010 RRVP average yield was 25 bu/acre greater than the estimated Arkansas state average of 142 bu/acre. The highest yielding field was in Clay County with a grain yield …

Herbicide-Resistant Risk Assessment: Response Of Common Nebraska Weeds To Dicamba Dose, Roberto J. Crespo

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Dicamba-resistant soybeans are being developed to provide an additional herbicide mechanism of action that can be used in soybean, and to provide a tool to help manage or mitigate the evolution of other herbicide-resistant weed populations. The objectives of this thesis were to assess the risk of common Nebraska weeds developing resistance to dicamba, quantify baseline dose-response to dicamba of high-risk weed species, and survey the variability in dicamba dose-response among populations of those species. Twenty-five weed scientists were asked to estimate the risk likelihood of ten weed species evolving resistance to dicamba following the commercialization of dicamba-resistant soybean. Palmer …

Biology, Systematics, Phylogenetic Analysis And Dna Character-Based Species Diagnosis Of The False Root-Knot Nematode Nacobbus Aberrans (Thorne, 1935) Thorne & Allen 1944 (Nemata: Pratylenchidae), Angel Ramirez-Suarez

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

The False Root-Knot nematode Nacobbus aberrans is a plant parasitic nematode that causes yield losses in several crops and plant protection agencies have established regulations to prevent infestations from spreading to new agricultural areas. The taxonomic status of the nematode has been the subject of controversy due to wide degree of variation exhibited by the species. This variability has led to the suggestion that N. aberrans is actually a species complex rather than a single species. In order to test this hypothesis, we compared twelve N. aberrans populations, which include isolates from western Nebraska, two distinct regions of Mexico and …

Sweet Sorghum As An Alternative Cellulosic Biofuel In Eastern Kentucky, Sarah A. Hazenfield

Morehead State Theses and Dissertations

A thesis presented to the faculty of the College of Science and Technology at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science by Sarah A. Hazenfield in June of 2011.

Summaries Of Arkansas Cotton Research 2010, Derrick M. Oosterhuis

Arkansas Agricultural Experiment Station Research Series

No abstract provided.

Screening Synteny Blocks In Pairwise Genome Comparisons Through Integer Programming, Haibao Tang, Eric Lyons, Brent S. Pedersen, James C. Schnable, Andrew H. Paterson, Michael Freeling

Department of Agronomy and Horticulture: Faculty Publications

Background:

It is difficult to accurately interpret chromosomal correspondences such as true orthology and paralogy due to significant divergence of genomes from a common ancestor. Analyses are particularly problematic among lineages that have repeatedly experienced whole genome duplication (WGD) events. To compare multiple “subgenomes” derived from genome duplications, we need to relax the traditional requirements of “one-to-one” syntenic matchings of genomic regions in order to reflect “one-to-many” or more generally “many-to-many” matchings. However this relaxation may result in the identification of synteny blocks that are derived from ancient shared WGDs that are not of interest. For many downstream analyses, we …

A First Insight Into Population Structure And Linkage Disequilibrium In The U.S. Peanut Minicore Collection, Vikas Belamkar, Michael Gomez Selvaraj, Jamie L. Ayers, Paxton R. Payton, Naveen Puppala, Mark D. Burow

Department of Agronomy and Horticulture: Faculty Publications

Knowledge of genetic diversity, population structure, and degree of linkage disequilibrium (LD) in target association mapping populations is of great importance and is a prerequisite for LD-based mapping. In the present study, 96 genotypes comprising 92 accessions of the US peanut minicore collection, a component line of the tetraploid variety Florunner, diploid progenitors A. duranensis (AA) and A. ipaënsis (BB), and synthetic amphidiploid accession TxAG-6 were investigated with 392 simple sequence repeat (SSR) marker bands amplified using 32 highly-polymorphic SSR primer pairs. Both distance- and model-based (Bayesian) cluster analysis revealed the presence of structured diversity. In general, the wild-species accessions …

Genes Identified By Visible Mutant Phenotypes Show Increased Bias Toward One Of Two Subgenomes Of Maize, James C. Schnable, Michael Freeling

Department of Agronomy and Horticulture: Faculty Publications

Not all genes are created equal. Despite being supported by sequence conservation and expression data, knockout homozygotes of many genes show no visible effects, at least under laboratory conditions. We have identified a set of maize (Zea mays L.) genes which have been the subject of a disproportionate share of publications recorded at MaizeGDB. We manually anchored these ‘‘classical’’ maize genes to gene models in the B73 reference genome, and identified syntenic orthologs in other grass genomes. In addition to proofing the most recent version 2 maize gene models, we show that a subset of these genes, those that …

Dose–Sensitivity, Conserved Non-Coding Sequences, And Duplicate Gene Retention Through Multiple Tetraploidies In The Grasses, James C. Schnable, Brent S. Pedersen, Sabarinath Subramaniam, Michael Freeling

Department of Agronomy and Horticulture: Faculty Publications

Whole genome duplications, or tetraploidies, are an important source of increased gene content. Following whole genome duplication, duplicate copies of many genes are lost from the genome. This loss of genes is biased both in the classes of genes deleted and the subgenome from which they are lost. Many or all classes are genes preferentially retained as duplicate copies are engaged in dose sensitive protein–protein interactions, such that deletion of any one duplicate upsets the status quo of subunit concentrations, and presumably lowers fitness as a result. Transcription factors are also preferentially retained following every whole genome duplications studied. This …

Crop Updates 2011 - Nutrition, Precision Agriculture & Climate And Forecasting, Deb Archdeacon, Andrew Gulliver, David Cullen, Qifu Ma, Richard Bell, Ross Brennan, Craig Scanlan, Wen Chen, Geoff Anderson, Mike Bolland, Peter Rees, Sandy Alexander, Frank D'Emden, Stephen Davies, Breanne Best, Louise Barton, Klaus Butterbach-Bahl, Ralph Kiese, Daniel Murphy, Peter Newman, Roger Mandel, Roger Lawes, Michael Robertson, Derk Bakker, Jeremy Lemon, Alison Lacey, John Paul Collins, Glen Riethmuller, Fiona H. Evans, David Stephens, Caroline Peek, Tim Scanlon

Crop Updates

This session covers sixteen papers from different authors:

Nutrition

1. Balance® used in conventional cropping practice with half of the upfront fertiliser rate can sustain crop yield and build soil biological fertility, Deb Archdeacon1, Andrew Gulliver2 and David Cullen2, 1Agronomica, Wellington Mill, WA, 2Custom Composts, Nambeelup, WA

2. Effects of potassium (K) supply on plant growth, potassium uptake and grain Yield in wheat grown in grey sand, Qifu Ma1, Richard Bell1, Ross Brennan2 and Craig Scanlan2, 1School of Environmental Science, Murdoch University, 2Department of Agriculture and Food

3. Improving fertiliser management: redefining the …

Crop Updates 2011 - Weeds, Grant Thompson, Abul Hashem, Catherine Borger, Peter Newman, Mike Ashworth, Glen Riethmuller, David Minkey, Harmohinder Dhammu, David Nicholson, Michael Walsh, Ray Harrington, Nicholas Woods

Crop Updates

This session covers twelve papers from different authors:

1. Herbicides for selective spot spraying application on winter weeds in chemical fallow, Grant Thompson, Landmark/Crop Circle Consulting, Geraldton

2. Management of emerging weeds within the Western Australian wheatbelt, Abul Hashem and Catherine Borger Department of Agriculture and Food

3. Integrated Weed Management (IWM) – it’s all about early sowing of a big crop, Peter Newman, Department of Agriculture and Food

4. Increased water rates improve the performance of trifluralin in minimum tillage systems, Catherine Borger1, Mike Ashworth2, Glen Riethmuller1, David Minkey2, Abul …

Crop Updates 2011 - Farming Systems, Janette Drew, Rob Grima, Bob French, Raj Malik, Mark Seymour, Christine Zaicou-Kunesch, Glenn Mcdonald, Brendon Nicholas, Dennis Van Gool, James Fisher, Peter Tozer, Doug Abrecht, Michael Robertson, Cameron Weeks, Michael O'Conner, Peter Newman, Mike Clarke, Andrew Blake, Gordon Macaulay, Vijay Jayasena, Syed M. Nasar-Abbas, Larisa Cato, Robert Loughman, Ken Quail

Crop Updates

This session covers twelve papers from different authors:

1. Fallowing 50% of the farm each year – does it pay? Janette Drew and Rob Grima

Department of Agriculture and Food

2. How crop sequences affect the productivity and resilience of cropping systems in two Western Australian environments, Bob French, Raj Malik, Mark Seymour, Department of Agriculture and Food

3. When is continuous wheat or barley sustainable? Christine Zaicou-Kunesch and Rob Grima Department of Agriculture and Food

4. Identifying constraints to bridging the yield gap, Glenn McDonald, Department of Agriculture and Food

5. Land constraints limiting wheat yields in …

Crop Updates 2011 - Cereals, David Bowran, Bill Crabtree, Peter Carberry, Peter Burges, Bevan Buirchell, Ben Curtis, Sarah Ellis, Brenda Shackley, Christine Zaicou, Siva Sivapalan, Penny Goldsmith, Gae Plunkett, Darshan Sharma, Mario D'Antuono, Art Diggle, Peter Mangano, Sally Peltzer, Michael Renton, Bill Macleod, Fumie Horiuchi, George Wyatt, Geoff Anderson, Richard Bell, Ross Brennan, Wen Chen, Penny Riffkin

Crop Updates

This session covers eleven papers from different authors:

OPENING, NEW CROP VARIETIES & DECISION SUPPORT

Opening

1. Overview of the 2010 season, David Bowran, Director, Practice and Systems Innovation, Department of Agriculture and Food,

2. My experience in a drought as a farmer and consultant, Bill Crabtree, Morawa, Western Australia

3. Meeting the productivity and sustainability challenges to Australian agriculture until 2030, Peter Carberry, CSIRO Sustainable Agriculture Flagship

New Crop Varieties

4. National Variety Trials (NTV) wheat variety performance – captivity vs broadacre, Peter Burgess, Kalyx Agriculture

5. WALAN2289 – a new lupin variety to replace …

Crop Updates 2011 - Pests And Diseases, Jeff Russell, Paul Umina, Svetlana Micic, Laura Fagan, Mark Seynour, Tony Dore, Pam Burgess, John Majewski, Manisha Shankar, Rob Loughman

Crop Updates

This session covers four papers from different authors:

1. Grains biosecurity – everyone’s business, Jeff Russell, Department of Agriculture and Food

2. Control of insect and mite pests in grains – insecticide resistance and integrated pest management (IPM), Paul Umina¹, Svetlana Micic² and Laura Fagan³, ¹CESAR and The University of Melbourne, ²Department of Agriculture and Food, ³University of Western Australia

3. Effect of cropping rotations on pest mites of broadacre agriculture, Svetlana Micic, Mark Seymour, Tony Dore and Pam Burgess, Department of Agriculture and Food

4. Common bunt resistance in …

Modeling Gross Primary Production Of Irrigated And Rain-Fed Maize Using Modis Imagery And Co2 Flux Tower Data, Joshua L. Kalfas, Xiangming Xiao, Diana X. Vanegas, Shashi B. Verma, Andrew E. Suyker

School of Natural Resources: Faculty Publications

Abstract

Information on gross primary production (GPP) of maize croplands is needed for assessing and monitoring maize crop conditions and the carbon cycle. A number of studies have used the eddy covariance technique to measure net ecosystem exchange (NEE) of CO₂ between maize cropland fields and the atmosphere and partitioned NEE data to estimate seasonal dynamics and interannual variation of GPP in maize fields having various crop rotation systems and different water management practices. How to scale up in situ observations from flux tower sites to regional and global scales is a challenging task. In this study, the Vegetation …

Switchgrass, Kenneth P. Vogel, Gautam Sarath, Aaron J. Saathoff, Robert B. Mitchell

Department of Agronomy and Horticulture: Faculty Publications

17.1 Introduction

Switchgrass (Panicum virgatum L.) is a warm-season perennial grass that is native to North America that is being developed into a biomass energy crop. It has been used in pastures and for conservation purposes in the Great Plains and the Midwest, USA, for over 70 years.1 The research supporting its use as a pasture and conservation species was largely conducted by US Department of Agriculture (USDA) research programs, most notably the Agricultural Research Service (ARS) project located at the University of Nebraska-Lincoln and USDA Plant Materials Centers that are located throughout the United States. In this report, …

Identification Of A Second Asian Soybean Rust Resistance Gene In Hyuuga Soybean, Mandy D. Kendrick, Donna K. Harris, Bo-Keun Ha, D. L. Hyten, P. B. Cregan, Reid D. Frederick, H. Roger Boerma, Kerry F. Pedley

Department of Agronomy and Horticulture: Faculty Publications

Asian soybean rust (ASR) is an economically significant disease caused by the fungus Phakopsora pachyrhizi. The soybean genes Rpp3 and Rpp?(Hyuuga) confer resistance to specific isolates of the pathogen. Both genes map to chromosome 6 (Gm06) (linkage group [LG] C2). We recently identified 12 additional soybean accessions that harbor ASR resistance mapping to Gm06, within 5 centimorgans of Rpp3 and Rpp?(Hyuuga). To further characterize genotypes with resistance on Gm06, we used a set of eight P. pachyrhizi isolates collected from geographically diverse areas to inoculate plants and evaluate them for differential phenotypic responses. …