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University of Arkansas, Fayetteville

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Articles 211 - 240 of 336

Full-Text Articles in Agricultural Science

Short-Term Denitrification In The Metalimnion Of A Eutrophic Reservoir, Aki Kogo, Erin M. Grantz, Thad Scott Jan 2013

Short-Term Denitrification In The Metalimnion Of A Eutrophic Reservoir, Aki Kogo, Erin M. Grantz, Thad Scott

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

Denitrification in metalimnetic water was examined under different conditions to determine how addition of nitrate (NO3 -) and particulate carbon (PC), aeration, and concentrations of nitrate affect denitrification. In the first experiment, water samples from a metalimnion were treated with different combinations of NO3 - and PC. Changes in excess N2 -N concentration for 10 days were measured using membrane inlet mass spectrometry (MIMS). The second experiment used the same treatments as the first experiment after aeration of water. Besides excess N2 -N concentrations, O2 concentrations were measured for 16 days. The third experiment examined how different initial concentrations of …

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Arkansas Soybean Performance Tests 2012, R. D. Bond, D. G. Dombek, J. A. Still, R. M. Pryor Dec 2012

Arkansas Soybean Performance Tests 2012, R. D. Bond, D. G. Dombek, J. A. Still, R. M. Pryor

Arkansas Agricultural Experiment Station Research Series

Soybean variety and strain performance tests are conducted each year in Arkansas by the University of Arkansas System Division of Agriculture Arkansas Crop Variety Improvement Program. The tests provide information to companies developing varieties and/or marketing seed within the state, and aid the Arkansas Cooperative Extension Service in formulating variety recommendations for soybean producers.

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False Smut Of Rice: Histological Analysis Of Infection, Liem Thi Thanh Nguyen Dec 2012

False Smut Of Rice: Histological Analysis Of Infection, Liem Thi Thanh Nguyen

Graduate Theses and Dissertations

False smut of rice, caused by Ustilaginoidea virens (Cooke) Takahashi (Teleomorph: Villosiclava virens), has become a common disease in most major rice growing regions throughout the world. Considerable confusion exists regarding the infection process and the disease cycle. Therefore, a clearer understanding of pathogenesis caused by Ustilaginoidea virens is critical for future efforts to develop genetic and chemical tools to manage false smut in Arkansas and other regions of the world. The overall goal of this research was to clarify the infection process underlying false smut, with emphasis on comparing and contrasting the histological basis of root and foliar infections. …

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Meta-Analysis Of Wheat Qtl Regions Associated With Heat And Drought Stress, Marlovi Andrea Acuna Galindo Dec 2012

Meta-Analysis Of Wheat Qtl Regions Associated With Heat And Drought Stress, Marlovi Andrea Acuna Galindo

Graduate Theses and Dissertations

Heat and drought are the two most important environmental constraints to wheat production globally, are often present simultaneously and will become more severe with global climate change. This presents a unique challenge to wheat scientists who must work to develop wheat cultivars that are productive and adapted to future environmental conditions. A number of recent studies have reported quantitative trait loci (QTL) associated with heat and drought tolerance, as well as QTL for stress adaptive traits such as the availability of stem carbohydrates or crop canopy temperature. The objective of this study was to perform a meta-analysis of these QTL …

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Evaluation Of The Recombination Efficiencies Of Flp Proteins, Linh Duy Nguyen Dec 2012

Evaluation Of The Recombination Efficiencies Of Flp Proteins, Linh Duy Nguyen

Graduate Theses and Dissertations

Site-specific recombination systems are powerful tools for genetic modification. They have been used to integrate a transgene into a pre-defined locus and to remove marker genes from a transgene locus. Two of the most widely used site-specific recombination systems in plants are the Cre/lox system from the bacteriophage P1 and the FLP/FRT system from the yeast Saccharomyces cerevisiae. The Cre/lox system is well-characterized and is the first choice in application of site-specific recombination system. However, some applications such as marker-free site-specific gene integration require the use of two recombination systems. In addition, the availability of alternative recombination systems can offer …

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Long-Term Effects Of Rice Rotation, Tillage, And Fertility On Near-Surface Soil Carbon And Nitrogen Cycling, Jill Marie Motschenbacher Dec 2012

Long-Term Effects Of Rice Rotation, Tillage, And Fertility On Near-Surface Soil Carbon And Nitrogen Cycling, Jill Marie Motschenbacher

Graduate Theses and Dissertations

Rice (Oryza sativa L.)-based cropping systems are different from other row crops due to the flood-irrigation scheme used from about one month after planting to a few weeks prior to harvest. The frequent cycling between anaerobic (i.e., flooding during the growing season) and aerobic (i.e., generally, the remainder of the year) conditions can influence the rate of soil organic matter (SOM) decomposition, which can greatly influence carbon (C) and nitrogen (N) storage and sequestration in the soil over time. Therefore, a study was conducted on a silt-loam soil (fine, smectitic, thermic, Typic Albaqualf) at the Rice Research and Extension Center …

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Documentation And Control Of Acetolactate Synthase-Resistant Barnyardgrass (Echinochloa Crus-Galli) In Arkansas Rice, Michael Joshua Wilson Dec 2012

Documentation And Control Of Acetolactate Synthase-Resistant Barnyardgrass (Echinochloa Crus-Galli) In Arkansas Rice, Michael Joshua Wilson

Graduate Theses and Dissertations

Barnyardgrass, the most problematic grass weed of Arkansas rice, was found resistant to propanil in 1990, and since then, it has evolved resistance to quinclorac and clomazone. Barnyardgrass is now believed to have evolved resistance to acetolactate synthase (ALS)-inhibiting herbicides. The goal of this research was to confirm and determine the level of resistance of the putative resistant biotype to the ALS-inhibiting herbicides imazethapyr, bispyribac, and penoxsulam and to develop herbicide programs for controlling ALS-, propanil-, quinclorac-, and clomazone-resistant barnyardgrass. The lethal dose needed to kill 50% of the putative ALS-resistant plants was higher than that of the susceptible biotype …

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Breeding For Modified Seed Composition In Soybean: Selection Of Genotypes, Yield Stability, And Environmental Effects, Luciano Miguel Jaureguy Dec 2012

Breeding For Modified Seed Composition In Soybean: Selection Of Genotypes, Yield Stability, And Environmental Effects, Luciano Miguel Jaureguy

Graduate Theses and Dissertations

The development of cultivars with modified seed composition represents an excellent alternative to cope with the world's need for more nutritious food. Understanding the genetic and environmental factors controlling crop seed quality traits is of crucial importance for such an endeavor. The objectives of this study were: a) to evaluate the efficiency of phenotype and marker-assisted selection for low stachyose and low phytate soybean breeding lines, and their yield stability, b) to study the effect of management practices planting date and delayed harvest on soybean seed composition, and c) to study the potential association between soil properties and leaf chemical …

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Summaries Of Arkansas Cotton Research 2011, Derrick M. Oosterhuis Nov 2012

Summaries Of Arkansas Cotton Research 2011, Derrick M. Oosterhuis

Arkansas Agricultural Experiment Station Research Series

No abstract provided.

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Arkansas Corn And Grain Sorghum Performance Tests 2012, R. D. Bond, D. G. Dombek, J. A. Still, R. M. Pryor Nov 2012

Arkansas Corn And Grain Sorghum Performance Tests 2012, R. D. Bond, D. G. Dombek, J. A. Still, R. M. Pryor

Arkansas Agricultural Experiment Station Research Series

Corn and grain sorghum performance tests are conducted each year in Arkansas by the University of Arkansas System Division of Agriculture. The tests provide information to companies marketing seed within the state and aid the Arkansas Cooperative Extension Service in formulating recommendations for producers.

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Arkansas Wheat Cultivar Performance Tests 2011-2012, R. E. Mason, R. G. Miller, J. P. Kelley, E. A. Milus Sep 2012

Arkansas Wheat Cultivar Performance Tests 2011-2012, R. E. Mason, R. G. Miller, J. P. Kelley, E. A. Milus

Arkansas Agricultural Experiment Station Research Series

Wheat cultivar performance tests are conducted each year in Arkansas by the Arkansas Agricultural Experiment Station, Department of Crop, Soil and Environmental Sciences. The tests provide information to companies developing cultivars and/or marketing seed within the state and aid the Arkansas Cooperative Extension Service in formulating cultivar recommendations for small-grain producers.

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Effects Of Environment And Genotype On Charcoal Rot Development On Soybeans, Micah Diane Doubledee Aug 2012

Effects Of Environment And Genotype On Charcoal Rot Development On Soybeans, Micah Diane Doubledee

Graduate Theses and Dissertations

Charcoal rot of soybean, caused by the soilborne fungus Macrophomina phaseolina (Tassi) Goid, is a disease associated with high soil temperature and low soil moisture. Above-ground symptoms, which can be difficult to distinguish from drought symptoms, include low vigor, dead leaves that remain attached to the plant, early senescence and yield loss. Irrigation limits damage, but does not prevent colonization of the tissue by the pathogen. No soybean line is immune to M. phaseolina, but a few lines may have moderate resistance. The objectives of this research were to 1) determine the effects of genotype and drought on the development …

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Market Analysis Of Fresh Berries In The United States, Kristina Sobekova Aug 2012

Market Analysis Of Fresh Berries In The United States, Kristina Sobekova

Graduate Theses and Dissertations

This thesis contains a market analysis of fresh berries in United States. Specifically, it addresses strawberry, blueberry, blackberry and raspberry markets during 2008-2011. A double log model and the Almost Ideal Demand model are used to gain insight into the demand side of the market. An equilibrium displacement model is used to develop suggestions for producers and decision makers. The results demonstrate that retail demand for berry crops is elastic and that the different berries are substitutes for one another. The equilibrium displacement model is used to predict producer surplus changes to industry wide efforts aimed at both production efficiencies …

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B.R. Wells Rice Research Studies 2011, R. J. Norman, K.A. K. Moldenhauer Aug 2012

B.R. Wells Rice Research Studies 2011, R. J. Norman, K.A. K. Moldenhauer

Arkansas Agricultural Experiment Station Research Series

No abstract provided.

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Weed Science Research Summaries 2011, K. L. Smith, J. A. Bullington, R. C. Doherty, J. R. Meier May 2012

Weed Science Research Summaries 2011, K. L. Smith, J. A. Bullington, R. C. Doherty, J. R. Meier

Arkansas Agricultural Experiment Station Research Series

No abstract provided.

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Multifunctionality In U.S. Rice Production: A Logit Analysis In Farmers Participation, Juan Tur Cardona May 2012

Multifunctionality In U.S. Rice Production: A Logit Analysis In Farmers Participation, Juan Tur Cardona

Graduate Theses and Dissertations

Multifunctional agriculture is particularly fundamental to some working lands conservation policies and programs, such as the Environmental Quality Incentive Program (EQIP), Conservation Security Program (CSP) and Wildlife Habitat Incentive Program (WHIP). Farmers can also be engaged in providing recreational and agri-tourism services such as hunting, fishing, bird-watching, farm tours, petting zoos and hospitality services. Using the Agricultural Resource Management Survey (ARMS) we analyze factors associated with participation in conservation, recreation and agri-tourism activities as a function of farm structure, farm financial measures, production practices, and socio-demographic characteristics of the farm operator. To estimate the functional relationships we estimate a binary …

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Identification And Confirmation Of Ssr Markers And Qtl For Seed Calcium Content And Hardness Of Soybean, Moldir Orazaly May 2012

Identification And Confirmation Of Ssr Markers And Qtl For Seed Calcium Content And Hardness Of Soybean, Moldir Orazaly

Graduate Theses and Dissertations

The health benefits and the nutritional values of soyfood products have expanded the demand for food-grade soybean varieties. For whole soyfood products such as natto, small seeded varieties with proper texture are essential. Seed calcium content and hardness are main factors in determining the seed texture. Utilizing molecular markers associated with quantitative trait loci (QTL) for marker assisted selection (MAS) has been an efficient technique for breeders. To find molecular markers associated with a trait is an initial step. The confirmation of QTL in different environments and in different genetic backgrounds is important for MAS. The objectives of this research …

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Herbicide Resistance Mechanism(S) In Italian Ryegrass (Lolium Perenne Ssp. Multiflorum) Populations In The Southern United States, Reiofeli Algodon Salas May 2012

Herbicide Resistance Mechanism(S) In Italian Ryegrass (Lolium Perenne Ssp. Multiflorum) Populations In The Southern United States, Reiofeli Algodon Salas

Graduate Theses and Dissertations

Italian ryegrass is a principal weed problem in wheat production fields in the Southern US. Resistance to herbicides diclofop, mesosulfuron, and pinoxaden among ryegrass populations has been reported. Glyphosate-resistant Italian ryegrass populations were identified in Desha County, Arkansas. This research aimed to 1) determine resistance patterns to ACCase (diclofop and pinoxaden) and ALS (imazamox, mesosulfuron, and pyroxsulam) herbicides among Italian ryegrass populations from the southern US; 2) determine if cytochrome P450-mediated enhanced herbicide metabolism contributed to resistance; and 3) elucidate the resistance mechanism to glyphosate in four Arkansas populations (Des03, Des05, Des14, and D8). For objective 1, 30 accessions from …

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Cotton Response To High Temperature Stress During Reproductive Development, Justin B. Phillips May 2012

Cotton Response To High Temperature Stress During Reproductive Development, Justin B. Phillips

Graduate Theses and Dissertations

Temperature is a primary controller of the rate of plant growth, developmental events, and fruit maturation. Increased temperatures from global climate change are projected to cause substantial losses in crop productivity by the end of the twenty-first century. Elevated temperatures affect all stages of cotton development, but the crop seems to be particularly sensitive to adverse temperatures during reproductive development. In Arkansas, temperature stress is considered to be one of the main factors affecting cotton yield. Environmental stress during floral development is a major reason for the disparity between actual and potential yields. Field and growth chamber studies were conducted …

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Arkansas Turfgrass Report 2010, Douglas Karcher, Aaron Patton, Michael Richardson Apr 2012

Arkansas Turfgrass Report 2010, Douglas Karcher, Aaron Patton, Michael Richardson

Arkansas Agricultural Experiment Station Research Series

No abstract provided.

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Arkansas Cotton Variety Test 2011, Fred M. Bourland, A. B. Beach, D. P. Roberts Jr. Feb 2012

Arkansas Cotton Variety Test 2011, Fred M. Bourland, A. B. Beach, D. P. Roberts Jr.

Arkansas Agricultural Experiment Station Research Series

The primary goal of the Arkansas Cotton Variety Test is to provide unbiased data regarding the agronomic performance of cotton varieties and advanced breeding lines in the major cotton-growing areas of Arkansas. This information helps seed companies establish marketing strategies and assists producers in choosing varieties to plant.

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Enhancing Soybean Profitability Using Portfolio Theory, Osemenkhian Cynthia Onyechere Dec 2011

Enhancing Soybean Profitability Using Portfolio Theory, Osemenkhian Cynthia Onyechere

Graduate Theses and Dissertations

The purpose of this study was to estimate the effect of utilizing portfolio theory on producers' profitability in the production of soybeans in three test locations - Keiser, Marianna and Rohwer - in Arkansas. The study used empirical yield data, their variances and covariances over a nine year period (2002-2010) in selecting a portfolio of soybean varieties that maintains or increases yield while minimizing the yield risk. Furthermore, carbon emissions associated with soybean production was estimated by modeling the effect of a potential carbon tax as well as the potential benefit of carbon offset payments resulting from carbon sequestration. The …

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Arkansas Soybean Performance Tests 2011, R. D. Bond, D. G. Dombek, J. A. Still, R. M. Pryor Dec 2011

Arkansas Soybean Performance Tests 2011, R. D. Bond, D. G. Dombek, J. A. Still, R. M. Pryor

Arkansas Agricultural Experiment Station Research Series

Soybean variety and strain performance tests are conducted each year in Arkansas by the University of Arkansas System Division of Agriculture Arkansas Crop Variety Improvement Program. The tests provide information to companies developing varieties and/or marketing seed within the state, and aid the Arkansas Cooperative Extension Service in formulating variety recommendations for soybean producers.

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Rice (Oryza Sativa) Response To Low Glyphosate Rates As Influenced By Cultivar, Growth Stage, And Imazethapyr Applications, Jason R. Meier Dec 2011

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 …

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Arkansas Corn And Grain Sorghum Perfomance Tests 2011, R. D. Bond, D. G. Dombeck, J. A. Still Nov 2011

Arkansas Corn And Grain Sorghum Perfomance Tests 2011, R. D. Bond, D. G. Dombeck, J. A. Still

Arkansas Agricultural Experiment Station Research Series

Corn and grain sorghum performance tests are conducted each year in Arkansas by the University of Arkansas System Division of Agriculture. The tests provide information to companies marketing seed within the state and aid the Arkansas Cooperative Extension Service in formulating recommendations for producers.

Go to article

Weed Science Research Summaries 2010, K. L. Smith, J A. Bullington, R. C. Doherty, J. R. Meier Oct 2011

Weed Science Research Summaries 2010, K. L. Smith, J A. Bullington, R. C. Doherty, J. R. Meier

Arkansas Agricultural Experiment Station Research Series

No abstract provided.

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Arkansas Wheat Cultivar Performance Tests 2010-2011, R. E. Mason, R. G. Miller, R. D. Bond, E. A. Milus, J. P. Kelley, R. K. Bacon Oct 2011

Arkansas Wheat Cultivar Performance Tests 2010-2011, R. E. Mason, R. G. Miller, R. D. Bond, E. A. Milus, J. P. Kelley, R. K. Bacon

Arkansas Agricultural Experiment Station Research Series

Wheat cultivar performance tests are conducted each year in Arkansas by the Arkansas Agricultural Experiment Station, Department of Crop, Soil and Environmental Sciences. The tests provide information to companies developing cultivars and/or marketing seed within the state and aid the Arkansas Cooperative Extension Service in formulating cultivar recommendations for small-grain producers.

Go to article

B. R. Wells Rice Research Studies 2010, R. J. Norman, K. A. K. Moldenhauer Aug 2011

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 …

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Summaries Of Arkansas Cotton Research 2010, Derrick M. Oosterhuis May 2011

Summaries Of Arkansas Cotton Research 2010, Derrick M. Oosterhuis

Arkansas Agricultural Experiment Station Research Series

No abstract provided.

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Wayne E. Sabbe Arkansas Soil Fertility Studies 2010, Nathan A. Slaton Mar 2011

Wayne E. Sabbe Arkansas Soil Fertility Studies 2010, Nathan A. Slaton

Arkansas Agricultural Experiment Station Research Series

Rapid technological changes in crop management and production require that the research efforts be presented in an expeditious manner. The contributions of soil fertility and fertilizers are major production factors in all Arkansas crops.

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