Agronomy and Crop Sciences Commons^™

Transcriptome Profiling Of Kentucky Bluegrass (Poa Pratensis L.) Accessions In Response To Salt Stress, Shaun B. Bushman, Keenan L. Amundsen, Scott E. Warnke, Joseph G. Robins, Paul G. Johnson

Department of Agronomy and Horticulture: Faculty Publications

Background: Kentucky bluegrass (Poa pratensis L.) is a prominent turfgrass in the cool-season regions, but it is sensitive to salt stress. Previously, a relatively salt tolerant Kentucky bluegrass accession was identified that maintained green color under consistent salt applications. In this study, a transcriptome study between the tolerant (PI 372742) accession and a salt susceptible (PI 368233) accession was conducted, under control and salt treatments, and in shoot and root tissues.

Results: Sample replicates grouped tightly by tissue and treatment, and fewer differentially expressed transcripts were detected in the tolerant PI 372742 samples compared to the susceptible …

Plant Functional Trait And Hyperspectral Reflectance Responses To Comp B Exposure: Efficacy Of Plants As Landmine Detectors, Paul V. Manley Ii

Theses and Dissertations

At least 110 million landmines have been planted since the 1970s in about 70 nations, many of which remain in place today. Some risk of detection may be mitigated using currently available remote sensing techniques when vegetation is present. My study focused on using plants as phytosensors to detect buried explosives. I exposed three species representing different functional types (Cyperus esculentus (sedge), Ulmus alata (tree), Vitis labrusca (vine)) to 500 mg kg^-1 of Composition B (Comp B; 60/40 mixture of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and 2,4,6-trinitrotoluene (TNT)), a commonly used explosive mixture, and measured functional traits and reflectance over …

Phenotypic Characterization Of The Peach (Prunus Spp.) Collection At The National Clonal Germplasm Repository In Davis, California, Tim Moran

EWU Masters Thesis Collection

"Germplasm repositories are an invaluable resource for the collection and preservation of important living genetic material, and provide a multitude of research opportunities for crop improvement. Advances in genomics research have created an urgent demand for phenotypic data in order to assist researchers in identifying relationships between genetic makeup and phenotypic variability. The peach, Prunus persica, is an important economic crop species that is heavily bred and cultivated. In peach, specific tree growth habits are used in breeding to select for tree architectures that may provide growers with more options for orchard design and cultural practices. The presence of extrafloral …

A Novel Transcription Factor In Arabidopsis Thaliana Abiotic Stress Response, Achira S. Weerathunga Arachchilage

LSU New Orleans Theses and Dissertations

Plants respond to environmental stress by altering their gene expression. Under stress conditions some genes are activated and some genes are repressed. Even though a lot of work has been done to understand mechanisms of gene activation under abiotic stress very little information is available on how stress responsive genes are kept repressed under normal growth conditions. Recent work has revealed that plants use transcriptional repression as common mechanism of gene repression. Transcriptional repression is achieved by recruitment co-repressor complexes to the target genes. Recent studies have revealed that the co-repressor LUH complexes with SLK1 and SLK2 to silence Arabidopsis …

Extension Agriculture And Natural Resources In The U.S. Midwest: A Review And Analysis Of Challenges And Future Opportunities, Mahdi M. Al-Kaisi, Roger Wesley Elmore, Gerald A. Miller, David Kwaw-Mensah

Department of Agronomy and Horticulture: Faculty Publications

This review addresses key changes in U.S. agricultural extension and future opportunities. Agricultural extension has been a part of the land-grant university (LGU) system for more than 100 years. The Morrill Act of 1862 established the LGU system by authorizing states access to federally controlled land and funding for public institutions offering educational opportunities focusing on agriculture and mechanical arts for farmers and the working class. Current surveys in Iowa reveal changing trends in extension: more than 90% of farmers identified private-sector crop advisers as their primary source for recommendations, whereas more than 80% of those advisors identified Iowa State …

Assessing Foliar Ascorbate Content In A Rice Diversity Panel And In Selected Mapping Population Lines With Varying Levels Of Seedling Cold Tolerance, Sonia Elizabeth Castillo Gonzalez

Student Theses and Dissertations

Rice is economically, culturally, and socially important to many people in the world. Arkansas is the main rice producer in the USA. Climate change continues to increase the incidence of abiotic stresses such as cold, heat, drought, water excess, and soil salinity. These stresses pose a particular challenge to rice cultivation. Rice has lower yields under cold stress, particularly when plants are exposed to cold at the seedling and reproductive stages. Early spring plantings and field irrigation with underground cold water expose rice seedlings to cold stress. Previous studies in Arabidopsis thaliana have shown that lines engineered to have elevated …

Soybean Yield And Nodulation Response To Crop History And Inoculation, Stephen Mason, Tomie Galusha, Zaher Kmail

Department of Agronomy and Horticulture: Faculty Publications

Soybean [Glycine max (L.) Merr.] inoculation was imposed on a long-term continuous grain sorghum [Sorghum bicolor (L.) Moench] and soybean cropping systems study with and without manure application at Mead, NE. The objective was to determine the influence of 28-yr history of continuous grain sorghum and soybean production, inoculation, and manure on soybean yield and nodulation. Average 2-yr soybean grain yield was 0.5 Mg ha^–1 greater on plots with continuous grain sorghum crop history rather than soybean history, even after this history was broken by 2-yr crop rotation with grain sorghum in the 2 yr previous to …

Soil Moisture Affects Growing-Season Wildfire Size In The Southern Great Plains, Erik S. Krueger, Tyson E. Ochsner, David M. Engle, J. D. Carlson, Dirac L. Twidwell, Samuel D. Fuhlendorf

Department of Agronomy and Horticulture: Faculty Publications

The increasing availability of soil moisture data presents an opportunity for its use in wildfire danger assessments, but research regarding the influence of soil moisture on wildfires is scarce. Our objective was to identify relationships between soil moisture and wildfire size for Oklahoma wildfires during the growing (May-October) and dormant seasons (November-April). We hypothesized that soil moisture influences wildfire size when vegetation is growing but is less important when most vegetation is dead or dormant. Soil moisture, as fraction of available water capacity (FAW), and commonly measured weather variables were determined for 38,419 wildfires from 2000–2012. Wildfires were grouped by …

Molecular Genetic Aspects Of Iron And Copper Cross-Talk In Arabidopsis Thaliana, Qingyuan Xiang

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

Iron (Fe) and copper (Cu) are essential micronutrients for plants and humans who consume plants. Their functions are tightly linked. For example, both of Fe and Cu work as cofactors in superoxide dismutase proteins to prevent reactive oxygen species damage. When Fe is removed from nutrient solution, plants uptake more Cu, but how plants sense and respond to Fe status is not fully understood. This thesis includes two projects that focus on Fe and Cu interaction, homeostasis and cross-talk in Arabidopsis thaliana.

Two Arabidopsis ecotypes, Kas-1 and Tsu-1, have difference in timing of Cu accumulation in rosettes under Fe …

Gopher Intrusion In Cropping Systems, Kenneth Romero, Paul Cardinalli

Agricultural Education and Communication

The purpose of this project was to determine if no till vs. till on gopher populations was more beneficial. Which is more efficient at controlling gophers and explain the damage they can cause and the diseases they can potentially vector. What are the different options of pest managements that have to be used when dealing with a gopher infestation in a tilled field vs. a no-tilled field.

The Effects Of Meloidogyne Incognita And Heterodera Glycines On The Yield And Quality Of Edamame In Arkansas, Juliet Fultz

Graduate Theses and Dissertations

Edamame (Glycine max), also known as vegetable soybean, was introduced to the United States from Japan in 1890 and has been growing in popularity as a nutrient-rich, low-sugar snack in recent years. In 2012, the American Vegetable Soybean and Edamame, Inc. established the first domestic commercial processing plant in Mulberry, Arkansas and contracted local growers for production. Since the crop is harvested when seed are immature, management practices are different from those for traditional soybean. Plant-parasitic nematodes, particularly Meloidogyne incognita (southern root-knot) and Heterodera glycines (soybean cyst), are common in Arkansas and are pests of concern for edamame growers. Edamame …

Improving Establishment Of Seeded Buffalograss, Luqi Li

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

Buffalograss [Buchloë dactyloides (Nutt.) Engelm.] is a warm-season grass native to the North American Great Plains. Buffalograss is drought resistant, heat resistant and cold tolerant, and thus is well-adapted to many uses in areas that require low maintenance or erosion control. Since buffalograss is slow-growing, one challenge of establishing seeded buffalograss is to maximize seedling maturation and establishment before winter. We evaluated dormant seeding buffalograss in late fall and winter, when germination is not expected until soils warm in spring. We successfully dormant seeded ‘Sundancer’, ‘Bowie’ or ‘Cody’ buffalograss at 146 kg ha^-1 from late November though …

Cotton Injury Due To Soil- Or Foliar-Applied Herbicides: An Assessment Based On The Influences Of Genetic, Agronomic, And Environmental Factors, Brandon William Schrage

Graduate Theses and Dissertations

Increasing populations of glyphosate-resistant weeds, such as Palmer amaranth, have prompted growers to pursue alternative means of weed control in cotton. In many cropping systems, this means the utilization of older chemistries and residual herbicides. The goal of this research was to evaluate and understand the agronomic and environmental factors that affect the inconsistent injury often associated with these herbicides as well as determine the impact of Palmer amaranth emergence date on seed production, biomass, and cotton yield. Experiments were conducted in three counties in Arkansas giving a distinct range of climate and soil texture. Injury, biomass, and number of …

Goss's Bacterial Wilt Development And Clavibacter Michiganensis Subsp. Nebraskensis Interactions With Spray Adjuvants, Sarah A. Schlund

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

Goss’s bacterial wilt and leaf blight of corn (Zea mays L.), causal agent Clavibacter michiganensis subsp. nebraskensis, was first confirmed in Dawson County, NE in 1969. Disease incidence decreased in the 1980’s due to various management strategies and disease developed sporadically until the early 2000’s when it re-emerged and was economically important. A Midwest, multistate survey conducted in 2011 suggested farming practices that may have contributed to the pathogen’s re-emergence. The use of agricultural pesticides was associated with Goss’s wilt. Since spray adjuvants are often used with pesticides, and physical characteristics of these adjuvants may enable infection of …

Effect Of Genotype, Environment, And Production Packages On Yield, Agronomic Characteristics, And End-Use Quality Of Winter Wheat, Madhav Bhatta

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

Grain yield and end-use quality are the most important characteristics for hard red winter wheat (Triticum aestivium L.). Improvement of grain quality characteristics of grain from a given growing season and location requires systematic understanding of the genotype chosen, the production environment, and also knowing the consequence of rate and time of individual production packages such as seed treatment, seed rate, nitrogen (N) fertilization, and foliar fungicide applications. The objectives of this study were to: identify the effects of seed rate, genotype, and N top-dressed on yield, agronomic characteristics, and end-use quality of winter wheat; and to determine …

Field Screening Of Diverse Soybean Cultivars For Flood Tolerance, Jane Achando Khatenje Mokua

Graduate Theses and Dissertations

Flooding can significantly reduce soybean growth, development, and yield. Therefore, screening and identification of flood-tolerant soybeans will enhance development of cultivars that are well suited for flood-prone areas. Sets of screening tests were conducted in Stuttgart, Arkansas using three separate but related experiments, with the purpose of establishing effective flood tolerance screening protocol that can identify tolerant and sensitive cultivars. Each experiment was completely randomized with three replications. The first experiment involved screening of 256 maturity group (IV and V) cultivars. Flooding was imposed at the fifth-node (V5) or first-bloom (R1) stage for ten days. Post-flood visual ratings and stand …

Disaggregating The Effect Of Drought And Heat Stress During Flowering On Spikelet Fertility In Rice, Lisa Straussberger

Graduate Theses and Dissertations

Due to rice’s wide geographic distribution, extending from 50°N to 35°S, rice is

forecasted to be the most vulnerable crop to warming global climates. Previous studies have

predicted lower rice yields and increasing rice yield variability due to higher frequencies of heat

stress events, and a higher variability in precipitation patterns due to global warming. As such,

understanding the effects of drought and heat stress intensity and frequency on rice yields is of

upmost importance to feeding the growing global population.

Given that drought and high-temperature stress often occur together, it is essential to

disaggregate the two individual stressors and …

Available Nitrogen And Denitrification In Soil Altered By Ground Cover And Nutrient Source In An Organic Apple Orchard, Jade Nicole Ford

Graduate Theses and Dissertations

A shift in public demand towards more organic and locally produced fruit and vegetables has been occurring across the United States in recent years. A common practice in organic fruit production is the application of organic ground covers to supply nutrients while enhancing other soil properties. A need for research exists in the southern region of the U.S. examining the effects of regionally applicable ground cover and nutrient management on nitrogen availability and the microbial community to provide information to organic farmers in the region. Two studies were conducted to determine how 12 treatment combinations of four ground covers (compost, …

Use Of Hppd-Inhibiting Herbicides For Control Of Common Weeds In Arkansas And Current Status Of Herbicide-Resistance Among Echinochloa Populations In Arkansas, Clay Starkey

Graduate Theses and Dissertations

Herbicide-resistant weeds in Arkansas cause problems for growers. Up-to-date information and new technologies can help plan mitigation strategies to slow resistant weeds. The objectives of this research were to provide a ‘snapshot’ of herbicide-resistant Echinochloa spp. in rice producing counties, determine how much resistance has spread across the state, and understand the effectiveness of 4-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicides for control of glyphosate-resistant (GR) Palmer amaranth relative to commercial standards currently labeled in soybean. To assess the prevalence of Echinochloa spp. resistance, 82 samples were collected from 23 rice producing counties in 2010. The samples were tested for resistance to commonly …

Utilization Of Weed Ecology, Tank Mixtures, And Application Technology To Improve Efficacy Of Herbicide Applications In Soybean, Christopher John Meyer

Graduate Theses and Dissertations

New herbicide-resistant soybean traits will increase the number of herbicides that can be applied in soybean and change the technology currently used to make herbicide applications in soybean. Palmer amaranth (Amaranthus palmeri) remains one of the most difficult weeds to manage in soybean and thus is the primary focus of this research. Therefore, experiments were conducted to investigate Palmer amaranth temporal emergence, control of common Arkansas weeds with new soybean herbicide programs, and the effect of application technology on dicamba-containing tank mixtures. Palmer amaranth emergence exceeded 400 plants m-2 for tillage treatments in 2013 and 2014, and tillage events typically …