Plant Sciences Commons^™

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 …

Validation Of Soil-Test-Based Phosphorus And Potassium Fertilizer Recommendations For Rice And Soybean, Matthew Scott Fryer

Graduate Theses and Dissertations

The science of soil-testing for nutrient management and fertilizer recommendations is widely accepted among scientists and agronomists. Although this science is unsurpassed in predicting soil nutrient availability, soil-test interpretations are seldom validated. Major research objectives for irrigated soybean [Glycine max (L.) Merr.] and direct-seeded, delayed-flood rice (Oryza sativa L.) were to: i) validate the accuracy of Mehlich-3 soil-test P (STP) and K (STK) interpretations and ii) published critical tissue-P and -K interpretations in predicting the yield response to fertilizer at different significance levels (p≤0.05 to 0.25), iii) examine how seed nutrient concentrations are influenced by fertilization and crop response to …

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 …

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 …

Soybean Planting And Risk-Return Tradeoffs In The Mid-Southern United States, Weston Weeks

Graduate Theses and Dissertations

This thesis is comprised of two studies on the effects of soybean (Glycine max (L.) Merr.) planting date (PD) and maturity group (MG) selection on producer expected returns. Having to replant soybean after early-season planting because of poor stand establishment is costly for producers. Replanting costs have increased in the last ten years as seed and other input costs for soybean have increased. Using five years of field trial results from two locations in Arkansas, the yield response to early and late season plant population density has been estimated to determine yield and future revenue potential for the purpose of …

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, …

Distribution Of Herbicide-Resistant Shattercane And Johnsongrass Populations In Sorghum Production Areas Of Nebraska And Northern Kansas, Rodrigo Werle, Amit J. Jhala, Melinda K. Yerka, J. Anita Dille, John L. Lindquist

Department of Agronomy and Horticulture: Faculty Publications

Overreliance on acetolactate synthase (ALS)-inhibiting herbicides for weed control during the 1990s resulted in selection of ALS-resistant shattercane [Sorghum bicolor (L.) Moench ssp. drummondii (Nees ex Steud.) de Wet ex Davidse] biotypes in Nebraska. The objective of this study was to assess the baseline presence of ALS-resistance in 190 shattercane and 59 johnsongrass [Sorghum halepense (L.) Pers.] populations collected across northern Kansas, northwestern Missouri, and southern Nebraska in 2013. In 2014, a preliminary field experiment was conducted to evaluate the presence of herbicide resistance in the aforementioned populations. Treatments consisted of four herbicides (clethodim {2-[1-[[(E)-3-chloroprop-2-enoxy]amino] propylidene]-5-(2-ethylsulfanylpropyl)cyclohexane-1,3-dione}, glyphosate [N-(phosphonomethyl) …

Canola: A Modern Crop For A Modern Era, Kenneth J. Roché

Doctor of Plant Health Program: Dissertations and Student Research

The University of Nebraska-Lincoln Doctor of Plant Health program is a professional doctorate program with a comprehensive approach to plants and agriculture. The program emphasizes a broad interdisciplinary education across all plant-related disciplines, practical learning, research, and experience through internships. For my final required internship, I worked as a senior agricultural research intern with Research Designed for Agriculture (RD4AG) in Montana. RD4AG is a contract research organization based in Yuma, AZ with over thirty-years of experience. During my three month internship at RD4AG in Montana, a large portion of my responsibilities centered on managing regulated canola trials that were undertaken …

Genetic Control Of Morphometric Diversity In The Maize Shoot Apical Meristem, Samuel Leiboff, Xianran Li, Heng-Cheng Hu, Natalie Todt, Jinliang Yang, Xiao Li, Xiaoqing Yu, Gary J. Muehlbauer, Marja C.P. Timmermans, Jianming Yu, Patrick S. Schnable, Michael J. Scanlon

Department of Agronomy and Horticulture: Faculty Publications

The maize shoot apical meristem (SAM) comprises a small pool of stem cells that generate all above-ground organs. Although mutational studies have identified genetic networks regulating SAM function, little is known about SAM morphological variation in natural populations. Here we report the use of high-throughput image processing to capture rich SAM size variation within a diverse maize inbred panel. We demonstrate correlations between seedling SAM size and agronomically important adult traits such as flowering time, stem size and leaf node number. Combining SAM phenotypes with 1.2 million single nucleotide polymorphisms (SNPs) via genome-wide association study reveals unexpected SAM morphology candidate …

Residue Harvest Effects On Irrigated, No-Till Corn Yield And Nitrogen Response, Charles S. Wortmann, Charles A. Shapiro, Marty R. Schmer

Department of Agronomy and Horticulture: Faculty Publications

Crop residue harvest occurs on about 40% of Nebraska’s 3,700,000 ha of corn (Zea mays L.) land, primarily for feeding of beef cattle. Immobilization of applied N is expected to be less with residue harvest due to reduced microbial activity for digestion of high C/N ratio organic material. Residue reduction may affect subsequent crop yield and response to applied N. Field research was conducted at three locations over 2 yr in eastern Nebraska for irrigated, no-till corn following corn to determine residue harvest effects on yield and the economically optimal nitrogen rate (EONR). Study sites had deep silt loam …

Evidence Of Field-Evolved Resistance To Bifenthrin In Western Corn Rootworm (Diabrotica Virgifera Virgifera Leconte) Populations In Western Nebraska And Kansas, Adriano E. Pereira, Haichuan Wang, Sarah N. Zukoff, Lance Meinke, B. Wade French, Blair Siegfried

Department of Entomology: Faculty Publications

Pyrethroid insecticides have been used to control larvae or adults of the western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, a key pest of field corn in the United States. In response to reports of reduced efficacy of pyrethroids in WCR management programs in southwestern areas of Nebraska and Kansas the present research was designed to establish a baseline of susceptibility to the pyrethroid insecticide, bifenthrin, using susceptible laboratory populations and to compare this baseline with susceptibility of field populations. Concentration-response bioassays were performed to estimate the baseline susceptibility. From the baseline data, a diagnostic concentration (LC99) was determined and …

Herbicides Applied At Or Shortly After Seeding Are Effective For Weed Control In Seedling Buffalograss, Luqi Li, Matthew D. Sousek, Zachary Reicher

Department of Agronomy and Horticulture: Faculty Publications

Herbicides applied shortly after seeding of buffalograss [Buchloe dactyloides (Nutt.) Engelm.] can help reduce weed pressure and maximize establishment of buffalograss. This study evaluated 12 relatively recently developed herbicides for turf safety and weed control when applied at seeding or 0 or 2 weeks after emergence (WAE) of ‘Bowie’ or ‘Sundancer’ buffalograss. Primary weed species on the site were common purslane (Portulaca oleracea L.), redroot pigweed (Amaranthus retroflexus L.), and/or yellow foxtail [Setaria lutescens (Weigel ex Stuntz) F.T. Hubb.]. Regardless of cultivar, untreated checks had53% weed cover by 6 WAE, whereas most of the herbicide treatments resulted …

Synfind: Compiling Syntenic Regions Across Any Set Of Genomes On Demand, Haibao Tang, Matthew D. Bomhoff, Evan Briones, Liangsheng Zhang, James C. Schnable, Eric Lyons

Department of Agronomy and Horticulture: Faculty Publications

The identification of conserved syntenic regions enables discovery of predicted locations for orthologous and homeologous genes, evenwhennosuchgeneispresent.Thiscapabilitymeansthatsynteny-basedmethodsarefarmoreeffectivethansequencesimilaritybased methods in identifying true-negatives, a necessity forstudying gene loss and gene transposition. However, the identification of syntenicregionsrequirescomplexanalyseswhichmustberepeatedforpairwisecomparisonsbetweenanytwospecies.Therefore,as the number of published genomes increases, there is a growing demand for scalable, simple-to-use applications to perform comparative genomic analyses that cater to both gene family studies and genome-scale studies. We implemented SynFind, a web-based tool that addresses this need. Given one query genome, SynFind is capable of identifying conserved syntenic regions in any set of targetgenomes.SynFindiscapableofreportingper-geneinformation,usefulforresearchersstudyingspecificgenefamilies,aswellas genome-wide data sets of syntenic gene and predicted gene …

A Population Structure And Genome-Wide Association Analysis On The Usda Soybean Germplasm Collection, Nonoy Bandillo, Diego Jarquin, Qijian Song, Randall L. Nelson, Perry Cregan, James Specht, Aaron Lorenz

Department of Agronomy and Horticulture: Faculty Publications

Population structure analyses and genome-wide association studies (GWAS) conducted on crop germplasm collections provide valuable information on the frequency and distribution of alleles governing economically important traits. The value of these analyses is substantially enhanced when the accession numbers can be increased from ~1,000 to ~10,000 or more. In this research, we conducted the first comprehensive analysis of population structure on the collection of 14,000 soybean accessions [Glycine max (L.) Merr. and G. soja Siebold & Zucc.] using a 50KSNP chip. Accessions originating from Japan were relatively homogenous and distinct from the Korean accessions. As a whole, both Japanese and …

Arkansas Corn And Grain Sorghum Performance Tests 2015, R. D. Bond, J. A. Still, D. G. Dombek

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.

Enhancing The Effectiveness Of Biological Control Programs Of Invasive Species By Utilizing An Integrated Pest Management Approach, Invasive Species Advisory Committee

National Invasive Species Council

Conclusion

Biological control has been shown on many occasions to be the most cost-effective invasive species management tool available. However, integrating biological control projects with the full breadth of other integrated pest management (IPM) tools, expanding post-re- lease monitoring to maximize efficacy, adaptive management, and incorporating new and innovative ecological, and genetic technologies may provide private and public land managers greater opportunities for long-term success in suppression of established invasive species.

Switchgrass Germplasm Resources, Michael D. Casler, Kenneth P. Vogel, Melanie Harrison

Department of Agronomy and Horticulture: Faculty Publications

Switchgrass (Panicum virgatum L.) is an important native grass and dominant member of the tallgrass prairie ecosystem. It is used for conservation, restoration, livestock feed production, and bioenergy feedstock production. The purpose of this review is to describe the biological and geographical basis for switchgrass germplasm diversity and to provide a resource for scientists and outreach personnel to find switchgrass germplasm to meet their needs. Upland and lowland ecotypes represent the most important polymorphism in switchgrass, with distinct but overlapping geographic distributions. Variation in ploidy exists within both ecotypes, with 2n = 4x = 36 the dominant ploidy …

Adding Genetically Distant Individuals To Training Populations Reduces Genomic Prediction Accuracy In Barley, Aaron Lorenz, Kevin P. Smith

Department of Agronomy and Horticulture: Faculty Publications

One of the most important factors affecting genomic prediction accuracy appears to be training population (TP) composition. The objective of this study was to evaluate the effect of genomic relationship on genomic prediction accuracy and determine if adding increasingly unrelated individuals to a TP can reduce prediction accuracy. To accomplish this, a population of barley (Hordeum vulgare L.) lines from the University of Minnesota (lines denoted as MN) and North Dakota State University (lines denoted as ND) breeding programs were used for model training. Predictions were validated using two independent sets of progenies derived from MN  MN crosses …

Community Seed Banks: Origins, Evolution, And Prospects, Charles A. Francis

Department of Agronomy and Horticulture: Faculty Publications

As a survey of contemporary community-level seed banks, this is an excellent compilation and instructive guide. The first section provides an overview of how seed banks originated, their varied goals and activities, several contrasting forms of management, and how they organize and perform to meet these goals. An intriguing claim in the book is that the concept of “seed banks is only some three decades old,” while in fact the practice of saving, preserving, and exchanging seed within a community is probably as old as human communities themselves.

Organized seed banks often serve specific functions: preserving seeds, providing seed access …

Assessing Multiple-Herbicide Resistance In A 2,4-D Resistant Waterhemp (Amaranthus Tuberculatus) Biotype From Nebraska – Student Research, Roberto Crespo

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

A waterhemp biotype was recently reported resistant to 2,4-D in Nebraska. In addition to the repeated use of 2,4-D, atrazine and imazathapyr were reported to be frequently used to control broadleaf weeds. Greenhouse experiments were conducted to confirm 2,4-D resistance and test for resistance to growth regulator herbicides and other herbicide modes-of-action (MoA). A single dose-response experiment showed reduced sensitivity in all three waterhemp biotypes to atrazine, imazethapyr and lactofen; therefore, they were generally considered resistant to those three herbicide MoA. None of the biotypes contained the Ser264 target-site mutation. Since the ametryn dose-response experiment resulted in all susceptible biotypes, …

Economic Contribution Of Agriculture And Food To Arkansas' Gross Domestic Product 1997-2013, Leah English, Jennie Popp, Wayne Miller

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; 2) provides an overview of Arkansas’ economy …

Screening Of Olive Cultivars For Tolerance To Fusicladium Oleagineum In South Africa, Zakhele Cyril Msimango

Professional Agricultural Workers Journal

Abstract

This study evaluated commercial olive cultivars for resistance to olive leaf spot (OLS). A growth chamber trial was undertaken with one temperature treatment (16°C) applied during inoculation while a relative humidity (RH) of above 80% was maintained. Plants were kept for 48 hours at 99% RH after inoculation and then moved to shade netted area for disease development at a temperature of 25±5°C. The results were used for categorizing the eight olive cultivars evaluated in this study according to their OLS susceptibility. ‘Frantoio’ was categorized as most tolerant; ‘Nandi’ and ‘Leccino’ were found to be moderately tolerant, and ‘Nocellara …

Summaries Of Arkansas Cotton Research 2014, Derrick M. Oosterhuis

Arkansas Agricultural Experiment Station Research Series

No abstract provided.

Cover Crop Biomass Production And Water Use In The Central Great Plains, David C. Nielsen, Drew J. Lyon, Gary W. Hergert, Robert K. Higgins, Johnathon D. Holman

David C. Nielsen

The water-limited environment of the semiarid Central Great Plains may not produce enough cover crop biomass to generate benefits associated with cover crop use in more humid regions. There have been reports that cover crops grown in mixtures produce more biomass with greater water use efficiency than single-species plantings. This study was conducted to determine differences in cover crop biomass production, water use efficiency, and residue cover between a mixture and single-species plantings. The study was conducted at Akron, CO, and Sidney, NE, during the 2012 and 2013 growing seasons under both rainfed and irrigated conditions. Water use, biomass, and …

The Enhancement Of Wild Bees (Hymenoptera: Apoidea) For Pollination Security, Eric M. Venturini

Electronic Theses and Dissertations

The acreage of pollinator-dependent crops continues to expand across the globe. Simultaneously, honey bee hives – an annually rented commodity that growers rely on – are more expensive every year and in some cases, scarce. In response, pollinator-dependent growers seek alternative pollinators. One approach is installing bee pasture on farms, a strategy that enables systems-based farmers to become in-situ farm-scale habitat managers. This thesis first presents a review of the literature on bee pasture plantings and provides a brief overview of some methods for assessing their impacts on the pollinator community. There are three major gaps in current bee pasture …

Long-Term Tillage System Impacts On Soil Erodibility, Julianne R. Chechanover, Dennis C. Flanagan

The Summer Undergraduate Research Fellowship (SURF) Symposium

Conservation tillage practices, such as no-till agriculture, have the potential of reducing the erodibility of a soil compared to conventional agricultural practices. This research sought to determine whether long-term agricultural practices affect the baseline erodibility properties of a soil. Two soils from Throckmorton-Purdue Agricultural Center in Tippecanoe County, Indiana were used during this experiment. One soil was treated with a long-term conventional tillage (fall chisel, spring disk) system and the other soil was treated with a long-term no-till system. The soils’ interrill erodibility, and rill erodibility and critical hydraulic shear stress were measured under a rainfall simulator using soil boxes …

Weed Dynamics During Transition To Conservation Agriculture In Western Kenya Maize Production, Judith A. Odhiambo, Urszula Norton, Dennis Ashilenje, Emmanuel C. Omondi, Jay B. Norton

Agricultural and Environmental Sciences Faculty Research

Weed competition is a significant problem in maize (Zea mays, L.) production in Sub-Saharan Africa. Better understanding of weed management and costs in maize intercropped with beans (Phaseolus vulgaris, L.) during transition to conservation agricultural systems is needed. Changes in weed population and maize growth were assessed for a period of three years at Bungoma where crops are grown twice per year and at Trans-Nzoia where crops are grown once per year. Treatments included three tillage practices: minimum (MT), no-till (NT) and conventional (CT) applied to three cropping systems: continuous maize/bean intercropping (TYPICAL), maize/bean intercropping with relayed mucuna after bean …

Designing A Remote Aerial System To Image And Analyze The Health Of Grape Crops At Cal Poly San Luis Obispo, Alexander D. Vice, Dylan Benton, Adipratnia Asmady, Andrew Mercier, Andrew Meyer, Eric Belfield, Aaron Drake

STAR Program Research Presentations

In the last decade the prevalence of unmanned aerial vehicles (UAVs) has exploded; however, the presence of UAVs in research situations is still a relatively new and untested field. The autonomous flight lab (AFL) at Cal Poly San Luis Obispo is a new lab site that is dedicated to using UAVs to benefit research for all backgrounds. Before AFL was able to fly missions we first needed to actually receive our vehicles, create a lab space that would provide all of the necessary resources and equipment necessary to fly, and to be granted permission by the Federal Aviation Administration (FAA) …

B. R. Wells Arkansas Rice Research Studies 2014, R. J. Norman, K.A. K. Moldenhauer

Arkansas Agricultural Experiment Station Research Series

No abstract provided.

Arkansas Wheat Cultivar Performance Tests 2014-2015, R. E. Mason, R. G. Miller, D. E. Moon, J. P. Kelley

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.