Agronomy and Crop Sciences Commons^™

The Draft Genome Of The C3 Panicoid Grass Species Dichanthelium Oligosanthes, Anthony J. Studer, James C. Schnable, Sarit Weissmann, Allison R. Kolbe, Michael R. Mckain, Ying Shao, Asaph B. Cousins, Elizabeth A. Kellogg, Thomas P. Brutnell

Department of Agronomy and Horticulture: Faculty Publications

Background: Comparisons between C₃ and C₄ grasses often utilize C₃ species from the subfamilies Ehrhartoideae or Pooideae and C₄ species from the subfamily Panicoideae, two clades that diverged over 50 million years ago. The divergence of the C₃ panicoid grass Dichanthelium oligosanthes from the independent C₄ lineages represented by Setaria viridis and Sorghum bicolor occurred approximately 15 million years ago, which is significantly more recent than members of the Bambusoideae, Ehrhartoideae, and Pooideae subfamilies. D. oligosanthes is ideally placed within the panicoid clade for comparative studies of C₃ and C₄ grasses.

Results: …

Estimating Yield Potential In Temperate High-Yielding, Direct-Seeded Us Rice Production Systems, Matthew B. Espe, Haishun Yang, Kenneth Cassman, Nicolas Guilpart, Hussain Sharifi, Bruce A. Linquist

Department of Agronomy and Horticulture: Faculty Publications

Accurate estimation of a crop’s yield potential (Yp) is critical to addressing long-term food security via identification of the exploitable yield gap. Due to lack of field data, efforts to quantify crop yield potential typically rely on crop models. Using the ORYZA rice crop model, we sought to estimate Yp of irrigated rice for two widely used rice varieties (M-206 and CXL745) in three major US rice-producing regions that together represent some of the highest yielding rice regions of the world. Three major issues with the crop model had to be addressed to achieve acceptable simulation of Yp; first, the …

Yield Gap Analysis Of Us Rice Production Systems Shows Opportunities For Improvement, Matthew B. Espe, Kenneth Cassman, Haishun Yang, Nicolas Guilpart, Patricio Grassini, Justin Van Wart, Merle Anders, Donn Beighley, Dustin Harrell, Steve Linscombe, Kent Mckenzie, Randall Mutters, Lloyd T. Wilson, Bruce A. Linquist

Department of Agronomy and Horticulture: Faculty Publications

Many assessments of crop yield gaps based on comparisons to actual yields suggest grain yields in highly intensified agricultural systems are at or near the maximum yield attainable. However, these estimates can be biased in situations where yields are below full yield potential. Rice yields in the US continue to increase annually, suggesting that rice yields are not near the potential. In the interest of directing future efforts towards areas where improvement is most easily achieved, we estimated yield potential and yield gaps in US rice production systems, which are amongst the highest yielding rice systems globally. Zones around fourteen …

Impact Of Derived Global Weather Data On Simulated Crop Yields, Justin Van Wart, Patricio Grassini, Kenneth Cassman

Department of Agronomy and Horticulture: Faculty Publications

Crop simulation models can be used to estimate impact of current and future climates on crop yields and food security, but require long-term historical daily weather data to obtain robust simulations. In many regions where crops are grown, daily weather data are not available. Alternatively, gridded weather databases (GWD) with complete terrestrial coverage are available, typically derived from: (i) global circulation computer models; (ii) interpolated weather station data; or (iii) remotely sensed surface data from satellites. The present study’s objective is to evaluate capacity of GWDs to simulate crop yield potential (Yp) or water-limited yield potential (Yw), which can serve …

Global Nitrogen Budgets In Cereals: A 50-Year Assessment For Maize, Rice, And Wheat Production Systems, J. K. Ladha, A. Tirol-Padre, C. K. Reddy, Kenneth Cassman, Sudhir Verma, D. S. Powlson, C. Van Kessel, Daniel De B. Richter, Debashis Chakraborty, Himanshu Pathak

Department of Agronomy and Horticulture: Faculty Publications

Industrially produced N-fertilizer is essential to the production of cereals that supports current and projected human populations. We constructed a top-down global N budget for maize, rice, and wheat for a 50-year period (1961 to 2010). Cereals harvested a total of 1551 Tg of N, of which 48% was supplied through fertilizer-N and 4% came from net soil depletion. An estimated 48% (737 Tg) of crop N, equal to 29, 38, and 25 kg ha⁻¹ yr⁻¹ for maize, rice, and wheat, respectively, is contributed by sources other than fertilizer- or soil-N. Non-symbiotic N₂ fixation appears to be …

Smokey Comes Of Age: Unmanned Aerial Systems For Fire Management, Dirac L. Twidwell Jr., Craig R. Allen, Carrick Detweiler, James Higgins, Christian Laney, Sebastian Elbaum

Department of Agronomy and Horticulture: Faculty Publications

During the past century, fire management has focused on techniques both to protect human communities from catastrophic wildfire and to maintain fire-dependent ecological systems. However, despite a large and increasing allocation of resources and personnel to achieve these goals, fire management objectives at regional to global scales are not being met. Current fire management techniques are clearly inadequate for the challenges faced by fire managers, and technological innovations are needed. Advances in unmanned aerial systems (UAS) technology provide opportunities for innovation in fire management and science. In many countries, fire management organizations are beginning to explore the potential of UAS …

Identification Of Markers Linked To Genes For Sprouting Tolerance (Independent Of Grain Color) In Hard White Winter Wheat (Hwww), Juthamas Fakthongphan, Guihua Bai, Paul St. Amand, Robert A. Graybosch, P. Stephen Baenziger

Department of Agronomy and Horticulture: Faculty Publications

Key message Hard red wheats can donate genes to hard white wheats for tolerance to preharvest sprouting, the effects are quantitative in nature, and may be tracked with previously described DNA markers.

Abstract Pre-harvest sprouting (PHS) of wheat (Triticum aestivum L.) can negatively impact end-use quality and seed viability at planting. Due to preferences for white over red wheat in international markets, white wheat with PHS tolerance has become increasingly desired for worldwide wheat production. In general, however, red wheat is more tolerant of sprouting than white wheat. The main objective of this study was the identification of PHS …

Soil Water Improvements With The Long-Term Use Of A Winter Rye Covercrop, Andrea D. Basche, Thomas C. Kaspar, Sotirios V. Archontoulis, Dan B. Jaynes, Thomas J. Sauer, Timothy B. Parkin, Fernando E. Miguez

Department of Agronomy and Horticulture: Faculty Publications

The Midwestern United States, a region that produces one-third of maize and one-quarter of soybean grain globally, is projected to experience increasing rainfall variability. One approach to mitigate climate impacts is to utilize crop and soil management practices that enhance soil water storage and reduce the risks of flooding as well as drought-induced crop water stress. While some research indicates that a winter cover crop in maize-soybean rotations increases soil water availability, producers continue to be concerned that water use by cover crops will reduce water for a following cash crop. We analyzed continuous in-field soil water measurements from 2008 …

Engaging Middle School Students Through Locally Focused Environmental Science Project-Based Learning, Andrea D. Basche, Vincent Genareo, Adah Leshem, Amy Kissell, Judith Pauley

Department of Agronomy and Horticulture: Faculty Publications

Increasing scientific literacy through education is one way to promote awareness of current environmental challenges, and can be enhanced through project-based learning (PBL), a pedagogical approach in which students explore authentic topics and demonstrate their learning publically. The National Science Foundation–funded GK–12 program at Iowa State University partnered doctoral-level graduate students (fellows) with middle and high school science teachers. This study analyzed results from one such middle school partnership in Iowa, where a PBL approach was implemented. Classroom practices focused on local environmental case studies of energy development, water pollution, soil science, climate change, plant biology, and ecology. Results from …

Impact Of Pre-Anthesis Water Deficit On Yield And Yield Components In Barley (Hordeum Vulgare L.) Plants Grown Under Controlled Conditions, Zakaria I. Al-Ajlouni, Ayed Al-Abdallat, Abdul Latief A. Al-Ghzawi, Jamal Y. Ayad, Jamal M. Abu Elenein, Nisreen A. Al-Quraan, P. Stephen Baenziger

Department of Agronomy and Horticulture: Faculty Publications

Drought at pre-anthesis stages can influence barley growth and results in yield losses. Therefore, it is important to understand how drought at pre-anthesis can affect different traits associated with yield reduction in barley. The objective of this study was to understand the relevance of the genetic background of major flowering time genes in barley plants subjected to pre-anthesis drought and its impact on yield and yield components. A glasshouse experiment using a Randomized Complete Block Design was conducted to investigate the effect of drought and its timing on yield and yield components on eleven barley genotypes, which were selected to …

Predicting Long-Term Cover Crop Impacts On Soil Quality Using A Cropping Systems Model, Fernando E. Miguez, Sotirios Archontoulis, Andrea D. Basche

Department of Agronomy and Horticulture: Faculty Publications

Increased attention is being paid to cover crops as an option to reduce water pollution and decrease soil degradation in Iowa. More producers are experimenting with cover crops to increase soil productivity. However, when this project began there was little research to demonstrate the long-term impacts that cover crops have on crop yields. There were no estimates to quantify how much environmental benefit a cover crop could provide in terms of erosion and soil carbon changes. Such estimates are beneficial to demonstrate the long-term improvements that a cover crop affords in Iowa, particularly for corn-soybean rotations where the winter planting …

Corn Response To Nitrogen Management Under Fully-Irrigated Vs. Water-Stressed Conditions, Bijesh Maharjan, Carl J. Rosen, John A. Lamb, Rodney T. Venterea

Department of Agronomy and Horticulture: Faculty Publications

Characterizing corn (Zea mays L.) grain yield (GY) response to N is critical for maximizing profits, increasing N use efficiency and minimizing environmental impacts. Although a large database of GY response to N exists for highly productive soils, few data exist for less productive soils. While changes in precipitation are expected in the future, few studies have compared GY response to varying N management practices under conditions of varying water availability. We measured GY and basal stalk nitrate nitrogen (BSN) at harvest using split-applied urea at eight N rates under fully-irrigated (FI) and water-stressed (WS) conditions in a loamy …

Identification Of Evening Complex Associated Proteins In Arabidopsis By Affinity Purification And Mass Spectrometry, He Huang, Sophie Alvarez, Rebecca Bindbeutel, Zhouxin Shen, Michael J. Naldrett, Bradley S. Evans, Steven P. Briggs, Leslie M. Hicks, Steve A. Kay, Dmitri A. Nusinow

Department of Agronomy and Horticulture: Faculty Publications

Many species possess an endogenous circadian clock to synchronize internal physiology with an oscillating external environment. In plants, the circadian clock coordinates growth, metabolism and development over daily and seasonal time scales. Many proteins in the circadian network form oscillating complexes that temporally regulate myriad processes, including signal transduction, transcription, protein degradation and post-translational modification. In Arabidopsis thaliana, a tripartite complex composed of EARLY FLOWERING 4 (ELF4), EARLY FLOWERING 3 (ELF3), and LUX ARRHYTHMO (LUX), named the evening complex, modulates daily rhythms in gene expression and growth through transcriptional regulation. However, little is known about the physical interactions that …

Multidisciplinary Research And Extension Team Evolution: Processes, Outcomes, And Strategies, Daren Redfearn, Jay Parsons, Mary Drewnoski

Department of Agronomy and Horticulture: Faculty Publications

Team-based research is not an innovative concept; however, the current models of team research are based principally on self-formed teams with a defined duration. Current trends seem to point toward the development of administratively designed multidisciplinary teams. Although this seems logical, minimal guidelines exist to aid in team development or evaluate team outcomes. Critical processes in a team-based research atmosphere have not been identified, much less described, and strategies for successful implementation have not been proposed. The strength of this approach can be summarized as a unified focus during the course of problem definition and solution. Many trade-offs and obstacles …

Identification And Verification Of Qtl Associated With Frost Tolerance Using Linkage Mapping And Gwas In Winter Faba Bean, Ahmed Sallam, Mustapha Arbaoui, Mohamed El-Esawi, Nathan Abshire

Department of Agronomy and Horticulture: Faculty Publications

Frost stress is one of the abiotic stresses that causes a significant reduction in winter faba bean yield in Europe. The main objective of this work is to genetically improve frost tolerance in winter faba bean by identifying and validating QTL associated with frost tolerance to be used in marker-assisted selection (MAS). Two different genetic backgrounds were used: a biparental population (BPP) consisting of 101 inbred lines, and 189 genotypes from single seed descent (SSD) from the Gottingen Winter bean Population (GWBP). All experiments were conducted in a frost growth chamber under controlled conditions. Both populations were genotyped using the …

Modeling Shattercane Dynamics In Herbicide-Tolerant Grain Sorghum Cropping Systems, Rodrigo Werle, Brigitte Tenhumberg, John L. Lindquist

Department of Agronomy and Horticulture: Faculty Publications

Traditional breeding technology is currently being used to develop grain sorghum [Sorghum bicolor (L.) Moench ssp. bicolor] germplasm that will be tolerant to acetolactate synthase (ALS)-inhibiting herbicides. This technology (Inzen^TM, DuPont^TM) has the potential to improve sorghum production by allowing for the postemergence control of traditionally hard-to-control grasses. However, grain sorghum and shattercane [weedy Sorghum species; Sorghum bicolor (L.) Moench ssp. drummondii (Nees ex Steud.) de Wet ex Davidse] can interbreed and introduced traits such as herbicide tolerance could increase the weediness of the weedy relative. Our objective was to develop a simulation model …

Letter To The Editor Ws-2 Introgression In A Proportion Of Arabidopsis Thaliana Col-0 Stock Seed Produces Specific Phenotypes And Highlights The Importance Of Routine Genetic Verification, Mon-Ray Shao, Vikas Shedge, Hardik Kundariya, Fredric R. Lehle, Sally Ann Mackenzie

Department of Agronomy and Horticulture: Faculty Publications

Arabidopsis thaliana is an important model organism with a robust network of resources that has been of enormous value to the plant science research community. The use of isogenic material as a reference point or control is critical for many types of experiments in plant molecular biology and genetics. Recently, we noticed that some seed from a common source of the widely-used Columbia-0 (Col-0) strain gave rise to plants showing features atypical for this strain. Whole genome DNA-sequencing and allele-specific PCR assays confirmed that the abnormal individuals contain multiple introgressions from the ecotype Wassilewskija-2 (Ws-2), as described below. This emphasizes …

Optimization Of Doubled Haploid Production In Burley Tobacco (Nicotiana Tabacum L.), Ezequiel De Oliveira

Theses and Dissertations--Plant and Soil Sciences

Doubled haploidy (DH) is a plant breeding technique that is often utilized by plant breeders to minimize the time required to reach homozygosity in breeding lines. The first objective of this study was to compare two methods of generating DH lines in tobacco (Nicotiana tabacum L.). Inbred burley tobacco varieties TN 90LC and GR 149LC were used to produce both androgenic derived doubled haploids (ADDH) and maternally derived doubled haploids (MDDH). The relative agronomic performance of TN 90LC and GR 149 LC ADDH and MDDH lines was compared when used either as pure-line cultivars or when used for the …

Probing The Plant Cell Wall With Herbicides: A Chemical Genetics Approach, Chad B. Brabham

Theses and Dissertations--Plant and Soil Sciences

The primary cell wall is a highly organized multi-layered matrix of polysaccharides (cellulose, hemi-cellulose, and pectin). The ability of the rigid cell wall to sufficiently loosen to allow growth is a complex process that differs considerably between grasses monocots and dicots. Cellulose is the major structural component required for anisotropic cell expansion and is synthesized by CELLULOSE SYNTHASE A (CesA) proteins. Here, our objectives were two-fold: 1) dissect cell walls and cellulose biosynthesis in dicots and grasses using chemical biology and reverse genetic approaches 2) characterize and classify the inhibitory mechanisms of cellulose biosynthesis inhibitors (CBIs). A reverse genetics TILLING …

Irrigated Zea Mays Response To Nitrogen And High Plant Population Density In Narrow Rows, Julie Baniszewski

Theses and Dissertations--Plant and Soil Sciences

Modern genetics have improved maize hybrids to better tolerate stress, use nutrients more efficiently and potentially yield higher. Management practices, such as narrow row technology and high plant population density (PPD) may further improve yields in modern maize under irrigated, non-limiting conditions. High PPD (74, 99, 124, 148 K seeds ha^-1) were tested in narrow rows with up to four nitrogen (N) rates in three locations over two years in Kentucky with a modern maize hybrid in irrigated, non-limiting conditions. Results indicate that optimal seeding rates were 99,000 to 124,000 seeds ha^-1, providing maximum yield and …

Distribution And Characterization Of The Soybean Cyst Nematode, Heterodera Glycines (Hg) Types In South Dakota, Krishna Acharya

Electronic Theses and Dissertations

The soybean cyst nematode (SCN), Heterodera glycines Ichinohe, is an endoparasitic nematode and one of the major pests of soybean (Glycine max L.) in the United State and all over the world where soybean is grown. SCN is ranked first among the biological factors that cause yield loss in soybean. The estimated yield loss by this nematode is $1b annually in the United States alone. SCN is thought to have been first found in China. It was first identified in the United States in 1954 in North Carolina and in South Dakota in 1995. To date, SCN continues to spread …

Soil Salinity Study In Northern Great Plains Sodium Affected Soil, Tulsi P. Kharel

Electronic Theses and Dissertations

Climate and land-use changes when combined with the marine sediments that underlay portions of the Northern Great Plains have increased the salinization and sodification risks. The objectives of this dissertation were to compare three chemical amendments (calcium chloride, sulfuric acid and gypsum) remediation strategies on water permeability and sodium (Na) transport in undisturbed soil columns and to develop a remote sensing technique to characterize salinization in South Dakota soils. Fortyeight undisturbed soil columns (30 cm x 15 cm) collected from White Lake, Redfield, and Pierpont were used to assess the chemical remediation strategies. In this study the experimental design was …

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 …

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 …

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 …