Agronomy and Crop Sciences Commons^™

Genetic Resistance To The Downy Mildew Pathogen And Breeding Towards Durable Disease Management In Spinach, Bazgha Zia

Graduate Theses and Dissertations

Spinach (Spinacia oleracea) is a self-pollinated, dioecious winter crop. Prevalent challenges to the production of spinach include disease pressure imposed by downy mildew, which is caused by Peronospora effusa (=P. farinosa f. sp. spinaciae [Pfs]). A total of 19 new races of P. effusa have emerged, imposing serious challenges to the disease management in spinach production. Accordingly, this study was designed to explore the genetic components for establishing the basis of durable disease resistance development against the downy mildew pathogen (P. effusa 13) in spinach, through the use of various genome engineering approaches.

Our results have led (Chapter 2) to …

Developing A Lab-Scale Fluidized Bed Dryer System To Enhance Rough Rice Drying Process, Kaushik Luthra

Graduate Theses and Dissertations

For more than half of the world's population, rice (Oryza sativa L.) is a staple meal. However, rice growers encounter difficulties supplying this demand, particularly in developing nations, where rice is susceptible to spoilage if the moisture content is not lowered to a safe level soon after harvest. As a result, traditional drying methods, such as sun drying and natural air drying, are commonly used by rice growers, particularly in underdeveloped nations. However, these procedures are time-consuming and can lead to rice spoilage. On the other hand, fluidized bed drying is a well-established technology that might give rice growers a …

Efficacy Of Conditional And Constitutive Crispr/Cas9 In Rice Genome, Zahra Alizada

Graduate Theses and Dissertations

Constitutive expression of Cas9 leads to a higher editing efficiency; however, it also increases the chances of off-target mutations. Thus, transient expression of Cas9 is a desirable approach to achieve higher targeting efficiency and to curb the off-target effects. It was previously shown that heat-inducible expression of Cas9 had an editing efficiency of 45% as compared to the strong constitutive expression, and the heat-shock induced mutations were inherited by the next generation. In this study, cold-inducible promoter, AtRD29a, was used for driving Cas9 expression, and evaluated for its editing efficiency upon cold-treatment on the GUS transgene loci. The expression analysis …

Arkansas Corn And Grain Sorghum Research Studies 2020, Victor Ford, Jason Kelley, Nathan Mckinney Ii

Arkansas Agricultural Experiment Station Research Series

The 2021 edition of the Arkansas Corn and Grain Sorghum Research Studies Series includes research results on topics pertaining to corn and grain sorghum production, including weed, disease, and insect management; economics; sustainability; irrigation; post-harvest drying; soil fertility; mycotoxins; cover crop management; feral hog control; and research verification program results. Our objective is to capture and broadly distribute the results of research projects funded by the Arkansas Corn and Grain Sorghum Board. The intended audience includes producers and their advisors, current investigators, and future researchers. The Series serves as a citable archive of research results. Reports in this publication are …

Summaries Of Arkansas Cotton Research 2020, Fred Bourland

Arkansas Agricultural Experiment Station Research Series

In the five years before 2020, cotton acreage in Arkansas had steadily increased from an all-time low of 210,000 acres in 2015 to 610,000 planted acres in 2019. One reason for the increase can be attributed to a downturn in prices received by producers for commodities such as corn and soybean, which compete for acres with cotton. With the worldwide COVID-19 pandemic, cotton mill use dropped significantly during the first half of 2020 https://www.cottongrower.com/market-analysis/ncc-cotton-demand-returning-as-u-s-and-world-economies-rebound/. This disruption of the cotton supply chain was felt across the entire cotton industry. The resulting downturn of cotton prices prior to planting impacted producers planting …

Assessing Impacts Of Winter-Hay Feeding On Soil And Forage Nutrient Dynamics In A Rotationally-Grazed Pasture System In Arkansas, Lawrence Gordon Berry Iv

Graduate Theses and Dissertations

More than 38 % of United States’ rural land area was used for grazing (i.e., pastureland or rangeland) ruminant animals in 2017, constituting the largest private land use group. The expansive nature of these lands means that grazing and pasture management decisions have potential to impact water quality as well as profit margins. As a result, beef producers are under increased pressure from economic and environmental standpoints to limit application of nutrients beyond those required to grow the forage needed for animal consumption. At the same time, a large amount of nutrients is recycled back to pasture systems directly from …

Identification And Confirmation Of Loci Associated With Canopy Wilting In Soybean Using Genome-Wide Association Mapping, Siva K. Chamarthi, Avjinder S. Kaler, Hussein Abdel-Haleem, Felix B. Fritschi, Jason D. Gillman, Jeffrey D. Ray, James R. Smith, Arun P. Dhanapal, Charles A. King, Larry C. Purcell

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Drought causes significant soybean [Glycine max (L.) Merr.] yield losses each year in rain-fed production systems of many regions. Genetic improvement of soybean for drought tolerance is a cost-effective approach to stabilize yield under rain-fed management. The objectives of this study were to confirm previously reported soybean loci and to identify novel loci associated with canopy wilting (CW) using a panel of 200 diverse maturity group (MG) IV accessions. These 200 accessions along with six checks were planted at six site-years using an augmented incomplete block design with three replications under irrigated and rain-fed treatments. Association mapping, using 34,680 …

Recurrent Selection With Sub-Lethal Doses Of Mesotrione Reduces Sensitivity In Amaranthus Palmeri, Jason K. Norsworthy, Vijay K. Varanasi, Muthukumar Bagavathiannan, Chad Brabham

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Amaranthus palmeri, ranked as the most prolific and troublesome weed in North America, has evolved resistance to several herbicide sites of action. Repeated use of any one herbicide, especially at lower than recommended doses, can lead to evolution of weed resistance, and, therefore, a better understanding of the process of resistance evolution is essential for the management of A. palmeri and other difficult-to-control weed species. Amaranthus palmeri rapidly developed resistance to 4-hydroxyphenylpyruvate dioxygenase (HPPD) inhibitors such as mesotrione. The objective of this study was to test the potential for low-dose applications of mesotrione to select for reduced susceptibility over …

Using Network-Based Machine Learning To Predict Transcription Factors Involved In Drought Resistance, Chirag Gupta, Venkategowda Ramegowda, Supratim Basu, Andy Pereira

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Gene regulatory networks underpin stress response pathways in plants. However, parsing these networks to prioritize key genes underlying a particular trait is challenging. Here, we have built the Gene Regulation and Association Network (GRAiN) of rice (Oryza sativa). GRAiN is an interactive query-based web-platform that allows users to study functional relationships between transcription factors (TFs) and genetic modules underlying abiotic-stress responses. We built GRAiN by applying a combination of different network inference algorithms to publicly available gene expression data. We propose a supervised machine learning framework that complements GRAiN in prioritizing genes that regulate stress signal transduction and …

Phenotyping Anther Extrusion Of Wheat Using Image Analysis, Zachary James Winn, Dylan Lee Larkin, Jamison Trey Murry, David Earl Moon, Richard Esten Mason

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Phenotyping wheat (Triticum aestivum L.) is time-consuming and new methods are necessary to decrease labor. To develop a heterotic pool of male wheat lines for hybrid breeding, there must be an efficient way to measure both anther extrusion and the size of anthers. Five hundred and ninety-four soft red winter wheat lines in two replications of randomized complete block design were phenotyped for anther extrusion, a key trait for hybrid wheat production. A device was constructed to capture images using a mobile device. Four heads were sampled per line when anthesis was evident for half the heads in the …

Evaluating Silicon Foliar Sprays As A Strategy To Improve Postproduction Performance Of Potted Basil (Ocimum Basilicum L.), Joshua Tebow

Horticulture Undergraduate Honors Theses

The objective of the study was to evaluate foliar silicon (Si) applications for effects on the growth and performance of container-grown basil during production and resistance to postproduction wilt in retail. Basil (Ocimum basilicum ‘Genovese’ L.) seedling plugs were transplanted into 10-cm diameter plastic containers with peat-based substrate and grown for 42 d in a polycarbonate greenhouse. Plants were irrigated with fertilizer solution consisting of a 17.0 nitrogen (N)-1.3 phosphorus-14.1 potassium water-soluble fertilizer dissolved in tap water at 150 mg∙L-1 N. Foliar sprays containing sodium silicate at 0, 50, 100, 200, and 400 mg∙L-1 Si mixed with deionized water were …

Characterization, Incidence, And Epidemiology Of Two Novel Strawberry Rhabdoviruses, Ava Wait

Graduate Theses and Dissertations

Strawberry is the most important berry crop, grown in most temperate regions around the world. In the early 2000s and in 2012-2013, viral disease devastated strawberry production in California and Florida respectively; causing multimillion dollar losses. This occurred because viruses were moving in the field undetected. The modern strawberry (Fragaria x ananassa Duch.) is tolerant to single and double infections; yet when several viruses infect plants, symptoms as severe as plant death can occur. To prevent future epidemics, the use of virus-tested planting materials is essential. In 2019, rhabdovirus-like sequences were detected in strawberry using a combination of high-throughput sequencing …

Quality Determinates Of Rice Price In Open Bag Markets In Sub-Saharan Africa, Bailey Peterson-Wilhelm

Graduate Theses and Dissertations

Weaknesses in the grades and standards system in low-income countries across Sub-Saharan Africa undermine the transparency of agricultural markets. In the Democratic Republic of the Congo (DRC), Ghana and Mozambique rice is predominately sold in open bags and if rice price does not reflect its quality, then inefficiencies may lead to consumer welfare losses. Importantly, it is possible that impoverished communities are priced out of the market due to inflated and inefficient prices. The objective of this study is to examine determinates of rice price by estimating the impact of selected rice quality attributes on rice prices in DRC, Ghana …

Long-Term Changes In Soil Surface Properties As Affected By Management Practices In A Wheat-Soybean, Double-Crop System, Machaela Morrison

Crop, Soil and Environmental Sciences Undergraduate Honors Theses

Long-term agricultural sustainability and productivity are controlled by the integrative effects of different management practices on the soil. Many Arkansas producers use the double-crop system to grow soybeans [Glycine max (L.) Merr] and wheat (Triticum aestivum L.). Studying combinations of different, non-traditional, alternative agricultural techniques may help producers better understand the long-term implications of various management practice options on sustainability and productivity. The objective of this study was to evaluate the effects of agricultural management practices, including residue level, tillage, irrigation, and burning, and soil depth on the change in various soil properties from 2010 to 2020 in …

Baseline Sensitivity To Dmi Fungicides In Cercospora Spp. And Corynespora Spp. In Arkansas Soybeans, Evan Buckner

Crop, Soil and Environmental Sciences Undergraduate Honors Theses

Cercospora spp. and Corynespora spp. are two common foliar fungal pathogens in Arkansas amongst other soybean producing areas. Two primary diseases caused by Cercospora spp. are Cercospora Leaf Blight (CLB, caused mainly by C. kikuchii) and Frogeye Leaf Spot (C. sojina). Both diseases affect foliage, and when lesions collapse, leaves may fall prematurely resulting in yield loss. In the specific case of CLB, this is a disease on the rise since 2000, and also causes seed infection reducing seed quality. Target spot is a disease caused by Corynespora cassiicola, and is of less damaging for farmers in larger …

Resistance Screening And Association Mapping For Resistance To The Downy Mildew Pathogen Of Spinach, Dotun Olaoye

Graduate Theses and Dissertations

Spinach is an important cool leafy vegetable cultivated around the world, with large scale production in California and Arizona in the U.S. Spinach is a highly nutritious vegetable beneficial in the human diet. Spinach is affected by a number of biotic stressors. Downy mildew, caused by the oomycete pathogen Peronospora effusa, is a major threat to spinach as it affects the leaf quality and impacts the economic value of spinach. Several efforts have led to the development of resistant genotypes/cultivars to this pathogen. However, few studies have examined the genetics of resistance to the downy mildew pathogen in detail. This …

Suppression Of Erecta Signaling Impacts Agronomic Performance Of Soybean (Glycine Max (L) Merril) In The Greenhouse, Yasmin Vasques Berchembrock, Flavia Barbosa Silva Botelho, Vibha Srivastava

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

The ERECTA (ER) family of genes, encoding leucine-rich repeat receptor-like kinase (RLK), influences complex morphological and physiological aspects of plants. Modulation of ER signaling leads to abiotic stress tolerance in diverse plant species. However, whether the gain in stress tolerance is accompanied with desirable agronomic performance is not clearly known. In this study, soybean plants potentially suppressed in ER signaling were evaluated for the phenotypic performance and drought response in the greenhouse. These plants expressed a dominant-negative Arabidopsis thaliana ER (AtER) called ΔKinase to suppress ER signaling, which has previously been linked with the tolerance to water …

Estimating Irrigation In Rice Fields With A Water Balance Approach, Kristen Trinh

Biological and Agricultural Engineering Undergraduate Honors Theses

Global food production must increase to meet the demand associated with increased population growth, so irrigation water use will continue to rise. Therefore, it is important to monitor water usage particularly when an irrigation flowmeter is unavailable. A field water balance was created for a selection of rice fields in East-central Arkansas under observation in 2018 and 2019. From those, irrigation inputs are deduced from the water balance alone. First, each field had sensors that collected water table level (WTL) data. Next, other water inputs and outputs such as precipitation and evapotranspiration (ET) were collected from two modeled sources. The …

The Influence Of Singlet Oxygen And Loss Of Function Of Fatty Acid Desaturase 7 In The Chloroplast On Aphid Resistance In Arabidopsis Thaliana, Hillary Donna Fischer

Graduate Theses and Dissertations

Fatty Acid Desaturase 7 (FAD7) is a chloroplast-localized enzyme that alters the fatty acid content of photosynthetic membranes, and that negatively regulates plant defenses against aphids. Previous studies in the model organism Arabidopsis (Arabidopsis thaliana) have shown that loss-of-function mutations in FAD7 decrease population growth of the green peach aphid (GPA; Myzus persicae Sulzer). This study further characterized the effects of a fad7 null mutant on aphids, and investigated the role of reactive oxygen species (ROS), including singlet oxygen (1O2), in plant responses to aphid resistance in fad7 as well as in wild type plants and a mutant with heightened …

Starter Nitrogen Source And Preflood Nitrogen Rate Effects On Rice Grown On Clay Soils, Linda Rachelle Martin

Graduate Theses and Dissertations

Seedling rice (Oryza sativa L.) grown on clayey-textured soils generally develops slowly as compared to loamy-textured soils. Our research examined the effects of starter-N source and preflood-N rates on canopy closure, total aboveground N uptake, and grain yield of rice grown on clayey-textured soils. Eleven field trials were established in Arkansas and Mississippi including five trials with a hybrid cultivar and six trials using a pure-line cultivar. Starter-N sources included no starter-N (NONE), ammonium sulfate (AMS), diammonium phosphate (DAP), and urea (UREA) applied at 24 kg N ha-1 at the rice 2-leaf stage and five preflood-N rates ranging from 0-224 …

Short-Term Effects Of Winter Cover Crops On Soil Properties, Yield, And Partial Returns In A No-Tillage Soybean Rotation, Drew Dillon Kirkpatrick

Graduate Theses and Dissertations

Cover crops have the potential to provide many benefits including weed suppression, erosion control, and improvements to soil quality. These benefits can be affected by species, biomass accumulation, and management practices. Although large amounts of biomass are good for maximizing benefits, it can result in problems for establishing the subsequent crop. Soybean [Glycine max (L.) Merr.] accounts for over 50% of Arkansas crop hectares annually; therefore, understanding the effect that a cover crop can have on the following soybean crop is crucial to the successful implementation of cover crops within the state. A study was established to evaluate winter cover …

Screening And Breeding Soybean For Flood Tolerance, Maria Roberta De Oliveira

Graduate Theses and Dissertations

Waterlogging can be detrimental to soybean [Glycine max (L.) Merr.] growth and development, with effects ranging from chlorosis and stunting to yield loss and plant death. Soybean responses to, and the effects of, waterlogging are dependent on the growth stage of the plant at the initiation of waterlogging. The objectives of this study were: (1) to assess the effectiveness of Genomic Selection (GS), Marker Assisted Selection (MAS) and Phenotypic Selection for flood tolerance at the progeny row stage as compared to random selection, for the development of high-yielding flood-tolerant lines; and (2) to compare field-screening and hydroponic greenhouse screening methodologies …

Evaluation Of Irrigation And Nutrient Management Strategies In Rice Using Alternative Irrigation Methods, Justin Lee Chlapecka

Graduate Theses and Dissertations

As water resources gain value across the Mid-South, alternative irrigation strategies of rice (Oryza sativa L.) have garnered increasing attention. In 2015, an estimated 1.7% of Arkansas rice hectarage used alternate wetting and drying (AWD) irrigation and 0.9% used furrow irrigation. As of 2020, 2.5% used AWD and 16.9% used furrow irrigation, the latter accounting for near 99,000 ha in Arkansas. Little information exists in the scientific literature in relation to management of rice grown in the Mid-South without a conventional flood. This fact coupled with the rapid adoption rate, especially for furrow-irrigated rice (FIR), during the last five years …

Crop Response To Low-Dose Dicamba, Mason Castner

Graduate Theses and Dissertations

The introduction of dicamba-resistant (DR) soybean [Glycine max (L.) Merr.] and cotton (Gossypium hirsutum L.) followed by a label allowing over-the-top applications of dicamba in the 2017 provided growers an additional option for broadleaf weed control. Because non-DR soybean is sensitive to low concentrations of dicamba, postemergence dicamba applications present growers choosing to plant non-DR soybean with concerns of damage from off-target movement through physical drift and volatilization of the herbicide as well as tank-contamination from prior dicamba application. Consequences of low-dose dicamba exposure on sensitive vegetative and reproductive soybean have been well researched, but little is known regarding the …

Influence Of Soybean Management Decisions On The Subsequent Rice Crop's Response To Nitrogen, Carrie C. Ortel, Trenton L. Roberts, Kyle A. Hoegenauer, Jarrod T. Hardke

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Little is known about the effects of soybean [Glycine max (L.) Merr.] management practices on the success of the subsequent rice (Oryza sativa L.) crop. A study was initiated to determine how rice was affected by the preceding soybean crop's maturity group (MG) and planting date when grown in rotation on silt loam and clay soils. Optimum and late soybean planting dates and MGs (3.5, 4.7, 5.4, and 5.6) were followed by a rice crop. The results differed by soil texture, with the planting date and MG selection of the previous soybean crop more influential to the rice …

Leaf Nitrogen Sufficiency Level Guidelines For Midseason Fertilization In Corn, Caio Luiz Dos Santos, Trenton L. Roberts, Larry C. Purcell

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Improving N management guidelines in corn (Zea mays L.) production systems can reduce fertilization costs and potential negative environmental impacts. This study was conducted to assess the effectiveness of leaf nitrogen (LN) concentration as a tool to improve midseason N management in corn production. The experiment was conducted on 8 site-years with furrow irrigation. There were 11 N fertilization regimes with season total N rates ranging from 0 to 257 kg N ha⁻¹. Split-applications were made at pre-plant, the 10th collared leaf stage (V10), the 12th collared leaf stage (V12), and tasseling (VT). The uppermost fully collared …

Soil Quality Indices As Affected By Long-Term Burning, Irrigation, Tillage, And Fertility Management, Helen C.S. Amorim, Amanda Ashworth, Kristofor R. Brye, Brian J. Wienhold, Mary C. Savin, Phillip R. Owens, Sergio Silva

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Understanding the impacts of long-term agricultural practices on soil quality (SQ) is key for sustaining agroecosystem productivity. This study investigated conventional and no-tillage (NT), residue burning and no burning, residue level (high and low), and irrigation (irrigated and dryland) effects on soil properties, SQ, and crop yields following 16 yr of a wheat (Triticum aestivum L.)–soybean [Glycine max (L.) Merr.] double-crop system via the Soil Management Assessment Framework (SMAF). A field experiment was conducted in the Lower Mississippi River Delta region on a silt-loam soil. Bulk density, soil organic C (SOC), total N (TN), pH, electrical conductivity (EC), …

Wayne E. Sabbe Arkansas Soil Fertility Studies 2020, 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. The studies described within will allow producers to compare their practices with the university’s research efforts. Additionally, soil-test data and fertilizer sales are presented to allow comparisons among years, crops, and other areas within Arkansas.

Recurrent Selection With Low Herbicide Rates And Salt Stress Decrease Sensitivity Of Echinochloa Colona To Imidazolinone, Lariza Benedetti, Vivian Ebeling Viana, Pamela Carvalho-Moore, Vinicios Rafael Gehrke, Gustavo Maia Souza, Edinalvo Rabaioli Camargo, Luis Antonio De Avila, Nilda Roma-Burgos

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Weeds represent an increasing challenge for crop systems since they have evolved adaptability to adverse environmental conditions, such as salinity stress. Herbicide effectiveness can be altered by the quality of water in which the weed is growing. This research aimed to study the combined effect of salt stress and recurrent selection with a sublethal dose of imidazolinone herbicides in the shifting of the sensitivity of Echinochloa colona (L.) Link (junglerice) to imidazolinone herbicides. This study was divided into two experiments; in experiment I, three recurrent selection cycles were conducted in Pelotas/RS/Brazil with imazapic + imazapyr at 0.125× the field rate; …

Mechanism Of Resistance To S-Metolachlor In Palmer Amaranth, Gulab Rangani, Matheus M. Noguera, Reiofeli Algodon Salas-Perez, Lariza Benedetti, Nilda Roma-Burgos

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Herbicides are major tools for effective weed management. The evolution of resistance to herbicides in weedy species, especially contributed by non-target-site-based resistance (NTSR) is a worrisome issue in crop production globally. Glyphosate-resistant Palmer amaranth (Amaranthus palmeri) is one of the extremely difficult weeds in southern US crop production. In this study, we present the level and molecular basis of resistance to the chloroacetamide herbicide, S-metolachlor, in six field-evolved A. palmeri populations that had survivors at the recommended field-dose (1.1 kg ai ha⁻¹). These samples were collected in 2014 and 2015. The level of resistance was …