Digital Commons Network^™

Metabolic Engineering Of Oilseed Crops To Produce High Levels Of Novel Acetyl Glyceride Oils With Reduced Viscosity, Freezing Point And Calorific Value, Jinjie Liu, Adam Rice, Kathleen Mcglew, Vincent Shaw, Hyunwoo Park, Thomas E. Clemente, Mike Pollard, John Ohlrogge, Timothy P. Durrett

Department of Agronomy and Horticulture: Faculty Publications

Seed oils have proved recalcitrant to modification for the production of industrially useful lipids. Here, we demonstrate the successful metabolic engineering and subsequent field production of an oilseed crop with the highest accumulation of unusual oil achieved so far in transgenic plants. Previously, expression of the Euonymus alatus diacylglycerol acetyltransferase (EaDAcT) gene in wild-type Arabidopsis seeds resulted in the accumulation of 45 mol% of unusual 3-acetyl-1,2- diacyl-sn-glycerols (acetyl-TAGs) in the seed oil (Durrett et al., 2010 PNAS 107:9464). Expression of EaDAcT in dgat1 mutants compromised in their ability to synthesize regular triacylglycerols increased acetyl-TAGs to 65 mol%. Camelina and soybean …

Dissection Of Gray Leaf Spot Of Maize Through Functional Genomics, Robert Louis Hirsch

Graduate Theses and Dissertations

Gray leaf spot, caused by Cercospora zeae-maydis, is a devastating disease of maize that reduces yields and increases management costs. C. zeae-maydis penetrates maize leaves through stomata, but the biological and molecular bases of this process are poorly understood. The goal of this research was to elucidate the biological parameters of stomatal infection in C. zeae-maydis, and to identify and characterize novel genetic pathways involved in stomatal sensing and pathogenesis. Histopathological observations of a GFP-expressing strain of C. zeae-maydis during infection of maize indicated that the fungus responded to host-derived stomatal cues during the infection process. C. zeae-maydis was observed …

The Effects Of Poultry Litter Biochar And Water Source On Radish Growth And Nutrition, Julia Marie Allen

Crop, Soil and Environmental Sciences Undergraduate Honors Theses

Many row-crop fields today have declined in soil fertility due to poor management practices and overuse of pesticides. Under these conditions, plant nutrient uptake can be sub-optimal. There are several soil amendments that can be used to improve soil quality and plant growth such as traditional fertilizers and manure applications. This study focused on the addition of biochar to the soil and the use of structured water to enhance plant growth. Biochar is a nutrient rich product that is produced by pyrolysis of organic feedstocks and contains high rates of carbon. Previous studies which focused on biochar have shown an …

Studies To Characterize Heavy Metal Content And Migration From Recycled Polyethyleneterephthalate, Michael John-Ross Whitt

Master's Theses

Packaging Materials account for 31% of the world’s municipal solid waste. Agencies like the Environmental Protection Agency (EPA) and the Agency for Toxic Substances and Disease Registry (ATSDR) are pushing for the increased use of recycled thermoplastic materials. Polyethylene terephthalate (PET) is a commonly recycled thermoplastic which is used to package ready-to-eat fruits and vegetables. Most recycled polyethylene terephthalate (RPET) packaging materials contain heavy metal catalysts, the most common being antimony. The recent increased use of recycled plastic materials has been suspected as the source of increased human heavy metal exposure. In this study, cadmium, chromium, nickel, lead and antimony …

Functional Genomics And Microbiome Profiling Of The Asian Longhorned Beetle (Anoplophora Glabripennis) Reveal Insights Into The Digestive Physiology And Nutritional Ecology Of Wood Feeding Beetles, Erin D. Scully, Scott M. Geib, John E. Carlson, Ming Tien, Duane Mckenna, Kelli Hoover

Department of Agronomy and Horticulture: Faculty Publications

Background: Wood-feeding beetles harbor an ecologically rich and taxonomically diverse assemblage of gut microbes that appear to promote survival in woody tissue, which is devoid of nitrogen and essential nutrients. Nevertheless, the contributions of these apparent symbionts to digestive physiology and nutritional ecology remain uncharacterized in most beetle lineages.

Results: Through parallel transcriptome profiling of beetle- and microbial- derived mRNAs, we demonstrate that the midgut microbiome of the Asian longhorned beetle (Anoplophora glabripennis), a member of the beetle family Cerambycidae, is enriched in biosynthetic pathways for the synthesis of essential amino acids, vitamins, and sterols. Consequently, the midgut …

Carbohydrate Metabolism And The Trehalose Biosynthetic Pathway In Maize Kernels Grown In Vitro Under Sucrose Starvation Stress, Samuel W. Bledsoe

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

Drought is an increasing issue that many farmers encounter especially in hot arid climates with little rainfall. High temperatures and inadequate rainfall at certain stages in crop development can have disastrous consequences to yield. In maize, drought occurring near or during the flowering stage often causes significant kernel abortion that greatly impacts potential yield. The trehalose biosynthetic pathway has recently been found to be important in plant metabolism in response to stress in higher order plants. Trehalose is currently known throughout the plant and animal kingdoms as an osmoprotectant, high energy fuel source, structural component, and involved in pathogen response. …

Short-Term Effects Of Poultry Litter Or Woodchip Biochar Amendment In A Temperate Zone Agronomic System, Katy Elizabeth Brantley

Graduate Theses and Dissertations

Biochar, a charcoal product produced by the anaerobic thermal decomposition of biomass, can provide agronomic benefits when soil applied. However, research is lacking in temperate region soils investigating specific biochar products and their effects on agronomically important crops. A greenhouse study utilizing poultry litter biochar and a field study utilizing pine woodchip biochar were conducted to observe the effects of biochar application to Northwest Arkansas soils on corn growth and nutrient availability. A third experiment investigated poultry litter and pine woodchip biochar influences on soil water retention. In all three experiments, biochar was applied at three rates (0, 5, and …

Alkaline Hydrolyzable-Nitrogen, Seeding Date, And Clay-Fixed Ammonium As Potential Indicators Of Rice Response To Nitrogen Fertilization In Arkansas, Anthony Michael Fulford

Graduate Theses and Dissertations

Several potential indicators of rice (Oryza sativa L.) response to nitrogen (N) fertilization include the soils alkaline hydrolyzableN (AHN) concentration, seeding date, and the soils clayfixed NH₄N content. Three studies were conducted to: (1) correlate AHN, determined using Illinois Soil Nitrogen Test (ISNT) or Nitrogen Soil Test for Rice (NSTaR), to plant parameters of interest and develop a fertilizer N rate calibration curve capable of predicting the 95% relative grain yield (RGY) fertilizer N rate for rice grown on clayey soils; (2) evaluate the influence of seeding date and N fertilization on rice plant growth and grain …

The Response Of Cotton (Gossypium Hirsutum L.) To Slow Release Foliar Fertilization And The Effect Of Environment On Absorption, James Matthews Burke

Graduate Theses and Dissertations

In cotton production, nitrogen (N) is the most limiting nutrient and the demand is substantial. Foliar-N fertilization is regarded as an effective and environmentally sound method of supplying cotton with N during times of deficiency and high demand. In response to the potential benefits of the foliar-N fertilization of cotton, a myriad of foliar-N based fertilizers have been created; each with their own individual chemical technology and constitution. Experiments were performed with the objectives of examining the effects of the slow-release foliar-N fertilizer, Nitamin® (1) on the growth and development of field-grown cotton, (2) on uptake under various environmental conditions, …

Establishment And Spread Of A Single Parthenogenic Genotype Of The Mediterranean Arundo Wasp, Tetramesa Romana, In The Variable Climate Of Texas, John A. Goolsby, John F. Gaskin, Daniel V. Tarin, Alan E. Pepper, Don C. Henne, Allan Auclair, Alexis Racelis, Kenneth R. Summy, Patrick J. Moran, Donald B. Thomas

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

As part of a biological control program for the invasive weed, Arundo donax L., several genotypically unique populations of the parthenogenetic stemgalling wasp, Tetramesa romana Walker (Hymenoptera: Eurytomidae), from Spain and France were released in an infested riparian zone along the Rio Grande from Brownsville to Del Rio, TX. An adventive population of the wasp of unknown origin with limited distribution in Texas was also discovered, evaluated, and released as part of the program. More than 1.2 million wasps representing the mixture of genotypes were aerially released from 2009 to 2011. Wasps dispersed from their original release locations and now …

Potential For Optical Sensor-Based Nitrogen Fertilization In Grain Sorghum (Sorghum Bicolor L. Moench) In Arkansas, Kamil H. Rosales Rodriguez

Graduate Theses and Dissertations

Ground-based active-optical (GBAO) crop sensors have become an effective tool to improve nitrogen (N) use efficiency and to predict yield early in the growing season, particularly for grass crops. Commercially available canopy sensors calculate the normalized difference vegetative index (NDVI) by emitting light in the red and near infrared range of the electromagnetic spectrum. The NDVI is used to evaluate vigor status and to estimate yield potential. However, few studies have been conducted to compare the performance of commercially available sensors. Therefore, a study was conducted using the most common crop canopy sensors: i) N-Tech's GreenSeeker^TM (GS), ii) Holland …

Switchgrass Cultivar, Harvest Frequency, Fertilizer Source, And Irrigation Effects On Near-Surface Soil Properties In West-Central Arkansas, Alayna A. Jacobs

Graduate Theses and Dissertations

Switchgrass (Panicum virgatum L.) has been identified as a model bioenergy feedstock crop and is expected to become an important feedstock for future renewable fuel generation. Agronomic management combinations that maximize monoculture switchgrass yield are generally well understood; however, little is known about corresponding effects of differing switchgrass management combinations on near-surface soil properties. The objective of this research was to determine the residual near-surface soil property effects of three years (2008 to 2011) of consistent management combinations to maximize switchgrass biomass production, including cultivar (‘Alamo’ and ‘Cave-in-Rock’), harvest frequency (1-cut and 2-cut systems per year), fertilizer source (poultry …

Screening Diverse Soybean Germplasm For Water-Logging Tolerance, John Franklin Carlin

Graduate Theses and Dissertations

Water-logging can be detrimental to soybean growth and development; effects range from chlorosis and stunting to yield loss and plant death. Soybean response to, and the effects of, water-logging are dependent on the growth-stage of the plant at the initiation of water-logging. The objectives of this study were to screen a diverse soybean germplasm collection for water-logging tolerance (WLT) at both the V5 and R1 growth stage and to develop a method to screen soybean for WLT in greenhouse. One hundred thirty five genotypes consisting of historical genotypes, PIs, drought and WLT tolerant breeding lines were screened for WLT in …

Winter Field Pea As A Leguminous Cover Crop In Corn Production, Matthew Carroll Marsh

Graduate Theses and Dissertations

Leguminous cover crops, which fix nitrogen (N) from the atmosphere and add to the N content of the soil, have the potential to replace or partially replace commercial nitrogen fertilizers. In this experiment, field pea (Pisum arvense) was used as the leguminous cover crop in a conventional tilled corn (Zea mays) production system. In a 2-yr experiment (2008 and 2009), conducted at two locations in Arkansas, field pea was planted on half the field in the fall and allowed to grow until late April to early May. Field pea biomass was recorded, N content of biomass determined and then the …

Integration Of Herbicide Programs With Cultural And Mechanical Practices For Managing Glyphosate-Resistant Palmer Amaranth (Amaranthus Palmeri) In Soybean (Glycine Max), Holden Bell

Graduate Theses and Dissertations

Herbicide-resistant Palmer amaranth is the most troublesome weed in Arkansas row crops, causing producers to rely heavily on multiple mechanisms of action to reduce selection pressure for further evolution of herbicide resistance and to successfully produce a profitable crop. It is critical for the sustainability of weed management not only to adequately control this weed but also to reduce the soil seedbank using both non-chemical and chemical practices. Studies were conducted to determine the effect of soybean row spacing, seeding rate, and herbicide program on Palmer amaranth emergence, survival, and seed production in soybean, the effect of drill-seeded soybean population …

Comprehensive Characterization And Rna-Seq Profiling Of The Hd-Zip Transcription Factor Family In Soybean (Glycine Max) During Dehydration And Salt Stress, Vikas Belamkar, Nathan T. Weeks, Arvind K. Bharti, Andrew Farmer, Michelle A. Graham, Steven B. Cannon

Department of Agronomy and Horticulture: Faculty Publications

Background:

The homeodomain leucine zipper (HD-Zip) transcription factor family is one of the largest plant specific superfamilies, and includes genes with roles in modulation of plant growth and response to environmental stresses. Many HD-Zip genes are characterized in Arabidopsis (Arabidopsis thaliana), and members of the family are being investigated for abiotic stress responses in rice (Oryza sativa), maize (Zea mays), poplar (Populus trichocarpa) and cucumber (Cucmis sativus). Findings in these species suggest HD-Zip genes as high priority candidates for crop improvement.

Results:

In this study we have identified members of …

Economic Contribution Of Agriculture And Food To Arkansas' Gross Domestic Product 1997-2012, Leah English, Jennie Popp, Wayne Miller

AAES Research Reports and Research Bulletins

Agricultural production, processing, and retail industries are major contributors to the Arkansas economy in terms of GDP. Agriculture contributes to the economy through direct agricultural production, value-added processing, and agricultural retail activities, and it also plays an important role through its interactions with other sectors. The use of non-agricultural goods and services as inputs into the agricultural sector promotes diversified growth in Arkansas’ economy; thus agriculture remains a vital part of Arkansas’ economy. This report: 1) compares the relative size of the Agriculture and Food Sector in Arkansas with those of neighboring states, the Southeastern region of the United States, …

Assessing Positional Accuracy And Correcting Point Data For Digital Soil Mapping At Varying Scales, Minerva J. Dorantes

Open Access Theses

Accuracy, timeliness, and the effect of scale of soil maps are rarely assessed. The recent increase in the use of GIS technologies and modelling software in natural resources and land management, has increased the demand for soil information at a finer resolution worldwide. Most of the world's developing countries rely on soils information at a scale that is too coarse for practical planning, and have obstacles impeding collection of new data, such as civil war and a lack of collection resources. The United States has an exhaustive collection of soils data at a fine scale. However, its location information is …

Automatic Extraction Of Plots From Geo-Registered Uas Imagery Of Crop Fields With Complex Planting Schemes, Anthony A. Hearst

Open Access Theses

Complex planting schemes are common in experimental crop fields and can make it difficult to extract plots of interest from high-resolution imagery of the fields gathered by Unmanned Aircraft Systems (UAS). This prevents UAS imagery from being applied in High-Throughput Precision Phenotyping and other areas of agricultural research. If the imagery is accurately geo-registered, then it may be possible to extract plots from the imagery based on their map coordinates. To test this approach, a UAS was used to acquire visual imagery of 5 ha of soybean fields containing 6.0 m2 plots in a complex planting scheme. Sixteen artificial targets …

Defining Management Strategies To Maximize Net Soil Carbon And Nitrogen Retention In Turfgrass Systems, Quincy D. Law

Open Access Theses

Soil carbon (C) sequestration has been proposed as a method to reduce atmospheric carbon dioxide (CO2 ). Managed turf areas are both a source and a sink for greenhouse gases (GHGs) including CO 2 , methane (CH4 ), and nitrous oxide (N2 O), among others. Management practices, including turfgrass selection and mowing, influence the amount of C and N stored in the soil, as well as the direct and indirect GHG emissions. Thus, the objective of this research was to determine how turfgrass selection (both species and cultivar) and mowing practices (such as frequency and grass clipping management) influence the …

Analyzing The Importance Of Diversifying Beyond Tobacco For Small-Scale Farmers In Malawi, Mphatso Charity Mbulukwa

Open Access Theses

This thesis analyses potential agricultural alternatives to production and marketing of tobacco in Malawi. I study existing patterns of crop and income diversification and factors that limit crop diversification. I also provide an analysis of the current profitability of different important cash crop alternatives that are commonly grown among smallholder farmers and compare their profitability to that of tobacco.

Following a review and synthesis of available literature on alternatives to tobacco, analysis is presented that relies upon data collected in 2009 from 380 households in Kasungu and Machinga districts of Malawi. Simpsons Index of diversification was used to measure the …

Creating Initial Digital Soil Properties Map Of Afghanistan, Shams R. Rahmani

Open Access Theses

Afghanistan is a country with a population of more than 31 million people and is located in south central Asia. The total arable land in the country is 12%, 5% is irrigated and the remaining 7% is rainfed. Due to the lack of available soil information, poor farming practices and land management planning severely affect the yield of agriculture products. In order to ensure sustainable agriculture and prevent land degradation problems, understanding spatial variability of soil is crucial. The overall objective of this research study was to use digital soil mapping techniques to identify the soil resources and generate a …

Liquid Swine Manure Application Timing And Instincttm Impacts On Net Soil Nitrogen Mineralization And Corn Yield, Min Xu

Open Access Theses

Nitrogen (N) is one of the most expensive variable input costs for corn production. Optimized manure management is essential to ensure maximum crop N utilization and to reduce the risk of N loss. A field study was conducted in central Indiana from 2011-2013 to assess liquid swine ( Sus scrofa L.) manure N availability when applied at different times or co-applied with InstinctTM , a microencapsulated form of nitrapyrin. Soil inorganic N contents, soil N mineralization, corn yield, grain N content, whole plant N concentrations of corn at the V6 growth stage, and ear leaf N concentrations of corn at …

Combining And Mapping Qtl For Fusarium Head Blight (Fhb) Resistance In Wheat, Jin Sun

Open Access Dissertations

Fusarium head blight (FHB) has become one of the most damaging wheat diseases in humid and semi-humid regions around the world. Single gene resistance to FHB in wheat provides only partial resistance and also the disease severity is highly influenced by environment. Consequently multiple genes are required for effective resistance. Our hypothesis is that identifying DNA markers for type I resistance will be very beneficial for selection, and combining type I and type II FHB resistance will be more effective than either type alone. The objectives of this project are to 1) combine type I resistance from cultivars Goldfield, INW0412, …

Selection And Genetic Drift In North American Maize, Collin Lamkey

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

Characterizing the impact of selection and genetic drift in the formation of heterotic groups and patterns in maize can reveal important insights into the mechanism underlying adaptation, and the relative importance of each force in defining population structure. The objectives were to characterize the role selection for hybrid performance had in defining population structure in both a reciprocal full-sib selection (RFS) program and a large collection of historically important inbred lines.

The Illumina GoldenGate Assay was used to genotype the University of Nebraska-Lincoln Replicated Recurrent Selection (UNL-RpRS) program. Eight cycles of S1-progeny and RFS selection were conducted for an index …

Msh1-Induced Non-Genetic Variation Provides A Source Of Phenotypic Diversity In Sorghum Bicolor, Roberto De La Rosa Santamaria, Mon-Ray Shao, Guomei Wang, David O. Nino-Liu, Hardik Kundariya, Yashitola Wamboldt, Ismail M. Dweikat, Sally Ann Mackenzie

Department of Agronomy and Horticulture: Faculty Publications

MutS Homolog 1 (MSH1) encodes a plant-specific protein that functions in mitochondria and chloroplasts. We showed previously that disruption or suppression of the MSH1 gene results in a process of developmental reprogramming that is heritable and non-genetic in subsequent generations. In Arabidopsis, this developmental reprogramming process is accompanied by striking changes in gene expression of organellar and stress response genes. This developmentally reprogrammed state, when used in crossing, results in a range of variation for plant growth potential. Here we investigate the implications of MSH1 modulation in a crop species. We found that MSH1-mediated phenotypic variation in Sorghum bicolor …

The Trehalose Pathway In Maize: Conservation And Gene Regulation In Response To The Diurnal Cycle And Extended Darkness, Clémence Henry, Samuel W. Bledsoe, Allison Siekman, Alec Kollman, Brian M. Waters, Regina Feil, Mark Stitt, L. Mark Lagrimini

Department of Agronomy and Horticulture: Faculty Publications

Energy resources in plants are managed in continuously changing environments, such as changes occurring during the day/night cycle. Shading is an environmental disruption that decreases photosynthesis, compromises energy status, and impacts on crop productivity. The trehalose pathway plays a central but not well-defined role in maintaining energy balance. Here, we characterized the maize trehalose pathway genes and deciphered the impacts of the diurnal cycle and disruption of the day/night cycle on trehalose pathway gene expression and sugar metabolism. The maize genome encodes 14 trehalose-6-phosphate synthase (TPS) genes, 11 trehalose-6-phosphate phosphatase (TPP) genes, and one trehalase gene. Transcript abundance of most …

Contrasting Metabolism In Perenniating Structures Of Upland And Lowland Switchgrass Plants Late In The Growing Season, Nathan Palmer, Aaron J. Saathoff, Christian M. Tobias, Paul Twigg, Yuannan Xia, Kenneth P. Vogel, Soundararajan Madhavan, Scott E. Sattler, Gautam Sarath

Department of Agronomy and Horticulture: Faculty Publications

Background: Switchgrass (Panicum virgatum L.) is being developed as a bioenergy crop for many temperate regions of the world. One way to increase biomass yields is to move southern adapted lowland cultivars to more northern latitudes. However, many southerly adapted switchgrass germplasm can suffer significant winter kill in northerly climes.

Materials and Methods: Here, we have applied next-generation sequencing in combination with biochemical analyses to query the metabolism of crowns and rhizomes obtained from two contrasting switchgrass cultivars. Crowns and rhizomes from field-grown lowland (cv Kanlow) and upland (cv Summer) switchgrass cultivars were collected from three randomly selected post-flowering …

Pengaruh Naungan Dan Konsentrasi Pupuk Organik Cair Terhadap Pertumbuhan Tanaman Anggrek Phalaenopsis Hasil Persilangan Kultivar Sayukudion X Taida Snow, Yayat Rochayat Suradinata

Jurnal Kultivasi

Percobaan ini bertujuan untuk menentukan persentase naungan dan konsentrasi pupuk organik cair yang terbaik terhadap pertumbuhan dan perkembangan tanaman anggrek Phalaenopsis hasil persilangan kultivar Sayukudion x Taida Snow. Dilaksanakan di Rumah Kaca Fakultas Pertanian Universitas Padjadjaran, Jatinangor, Sumedang, dengan ketinggian tempat 700 meter dpl, pada bulan Oktober 2011 sampai Januari 2012. Rancangan percobaan yang digunakan adalah Rancangan Petak Terbagi dengan dua faktor dan tiga ulangan. Petak utama adalah persentase naungan (55 %, 65 %, 75 %) dan anak petak adalah konsentrasi pupuk organik cair (1 ml L-1, 2 ml L-1, 3 ml L-1). Perlakuan persentase naungan dan konsentrasi pupuk organik …

Pengaruh Berbagai Komposisi Kompos Dalam Tiga Jenis Media Pembibitan Terhadap Pertumbuhan Bibit Asparagus Dalam Polibeg, F. Kholifah, Tino Mutiarawati Onggo, Wawan Sutari

Jurnal Kultivasi

Asparagus seeding need suitable medium composition in order that seedlings can grow well and proper to be planted.The experiment aims to study the effect of different seedlings medium and various compost compositions within the medium on growth of asparagus seedlings planted in polybag.The experiment was conducted in research station of Agriculture Faculty, Universitas Padjadjaran, Jatinangor, Sumedang, located at 730 m above the sea level, conducted from May 2013 up to August 2013. A factorial randomized blocks design was used with four replications. The First factor was different seedlings medium, which consisted of three levels: rice husk, rice husk charcoal and …