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Articles 631 - 660 of 1801

Full-Text Articles in Botany

Book Reviews: Force Of Nature: George Fell, Founder Of The Natural Areas Movement. Arthur Melville Pearson., James R. Herkert Jun 2018

Book Reviews: Force Of Nature: George Fell, Founder Of The Natural Areas Movement. Arthur Melville Pearson., James R. Herkert

The Prairie Naturalist

Arthur Melville Pearson’s Force of Nature is a book that tells two very interesting and intertwined stories. One is a story of how perseverance and determination can drive an individual to accomplish great things. And the other is a story of how the modern day natural areas movement came to be. Fortunately for those interested in conservation and natural areas protection, those two stories were combined in the life of George Fell (1916-1994). In Fell’s home state of Illinois, where his impact is widely known, his name is synonymous with conservation. In other places where his impact is less well …

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Spatiotemporal Distribution Of Waterfowl Disease Outbreaks In Kansas, Usa, Thomas A. Becker, Adam A. Ahlers, Shane Hesting, David A. Haukos Jun 2018

Spatiotemporal Distribution Of Waterfowl Disease Outbreaks In Kansas, Usa, Thomas A. Becker, Adam A. Ahlers, Shane Hesting, David A. Haukos

The Prairie Naturalist

Causes and impacts of disease outbreaks in wild bird populations are rarely studied beyond documentation of large epizootic events. In Kansas, USA, a central disease surveillance and reporting protocol currently does not exist within the Kansas Department of Wildlife, Parks and Tourism, which has led to a lack of available knowledge of disease occurrences that could be used to predict and manage future outbreaks. We compiled historic records of documented waterbird disease outbreaks in Kansas from 1967–2014 and related the frequency of outbreaks with light geese (Ross’s goose [Anser rossii]; Snow goose [A. caerulescens]) populations from 1970–2014. We found 32 …

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Impacts Of Cover Crop And Residue Removal On Soil Hydraulic And Thermal Properties, Michael T. Sindelar Apr 2018

Impacts Of Cover Crop And Residue Removal On Soil Hydraulic And Thermal Properties, Michael T. Sindelar

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

Large-scale crop residue removal for livestock or biofuel production may negatively affect soil and water resources. A combination of management practices could be the key to manage such resources under increasingly variable climate. For instance, use of cover crops (CCs) could offset the negative impacts that corn (Zea mays L.) residue removal may have on soil water and energy balance. We studied: 1) the effect of corn residue removal (56%) with and without winter rye (Secale cereale L.) CC on soil hydraulic and thermal properties including water infiltration, water retention, pores-size distribution, thermal conductivity, specific heat capacity, and …

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Vegetation And Soil Responses To Concrete Grinding Residue Application On Highway Roadsides Of Eastern Nebraska, Ana Wingeyer, Martha Mamo, Walter H. Schacht, Dennis L. Mccallister, Pamela Sutton Apr 2018

Vegetation And Soil Responses To Concrete Grinding Residue Application On Highway Roadsides Of Eastern Nebraska, Ana Wingeyer, Martha Mamo, Walter H. Schacht, Dennis L. Mccallister, Pamela Sutton

Department of Agronomy and Horticulture: Faculty Publications

As a precautionary principle, the National Pollutant Discharge Elimination System (NPDES) permit establishes that the primary pollutant in concrete grinding residue (CGR) is its alkalinity and restricts CGR roadside discharge to 11 Mg ha−1 or the agronomic liming rate, whichever is lower. We evaluated the effect of CGR application on roadside soil chemical properties, existing vegetation, and rainfall runoff. Five CGR rates (0, 11, 22, 45, and 90 dry Mg ha−1) were tested on roadsides slopes at two different locations in eastern Nebraska. Vegetation, soil, and runoff characteristics were evaluated before CGR application and 30 d and …

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A Systems Modeling Approach To Forecast Corn Economic Optimum Nitrogen Rate, Laila A. Puntel, John E. Sawyer, Daniel W. Barker, Peter J. Thorburn, Michael J. Castellano, Kenneth J. Moore, Andy Vanloocke, Emily A. Heaton, Sotirios V. Archontoulis Apr 2018

A Systems Modeling Approach To Forecast Corn Economic Optimum Nitrogen Rate, Laila A. Puntel, John E. Sawyer, Daniel W. Barker, Peter J. Thorburn, Michael J. Castellano, Kenneth J. Moore, Andy Vanloocke, Emily A. Heaton, Sotirios V. Archontoulis

Department of Agronomy and Horticulture: Faculty Publications

Historically crop models have been used to evaluate crop yield responses to nitrogen (N) rates after harvest when it is too late for the farmers to make in-season adjustments. We hypothesize that the use of a crop model as an in-season forecast tool will improve current N decision-making. To explore this, we used the Agricultural Production Systems sIMulator (APSIM) calibrated with long-term experimental data for central Iowa, USA (16-years in continuous corn and 15-years in soybean-corn rotation) combined with actual weather data up to a specific crop stage and historical weather data thereafter. The objectives were to: (1) evaluate the …

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Review Of Genome-Wide Association Studies: From Polymorphism To Personalized Medicine, Jinliang Yang Mar 2018

Review Of Genome-Wide Association Studies: From Polymorphism To Personalized Medicine, Jinliang Yang

Department of Agronomy and Horticulture: Faculty Publications

Genome-wide association studies (GWAS) has become a powerful tool in the area of quantitative genetics to map the relationship between trait and genomic variations. This volume provides a great resource for beginners to learn about the recent advances in GWAS and for domain experts to identify the gaps in the area. The first part of the volume lays out the statistical background of GWAS. I really liked the article by Yang et al., Introduction to Statistical Methods in Genome-Wide Association Studies. In this chapter, the authors talked about the missing heritability issue and introduced ways to calculate heritability using the …

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An Epigenetic Breeding System In Soybean For Increased Yield And Stability, Sunil K. Kenchanmane Raju, Mon-Ray Shao, Robersy Sanchez, Ying-Zhi Xu, Ajay Sandhu, George L. Graef, Sally A. Mackenzie Feb 2018

An Epigenetic Breeding System In Soybean For Increased Yield And Stability, Sunil K. Kenchanmane Raju, Mon-Ray Shao, Robersy Sanchez, Ying-Zhi Xu, Ajay Sandhu, George L. Graef, Sally A. Mackenzie

Department of Agronomy and Horticulture: Faculty Publications

Epigenetic variation has been associated with a wide range of adaptive phenotypes in plants, but there exist few direct means for exploiting this variation. RNAi suppression of the plant-specific gene, MutS HOMOLOG1 (MSH1), in multiple plant species produces a range of developmental changes accompanied by modulation of defence, phytohormone and abiotic stress response pathways along with methylome repatterning. This msh1-conditioned developmental reprogramming is retained independent of transgene segregation, giving rise to transgene-null ‘memory’ effects. An isogenic memory line crossed to wild type produces progeny families displaying increased variation in adaptive traits that respond to selection. This study …

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Inheritance Of Mesotrione Resistance In An Amaranthus Tuberculatus (Var. Rudis) Population From Nebraska, Usa, Maxwel C. Oliveira, Todd A. Gaines, Amit J. Jhala, Stevan Z. Knezevic Feb 2018

Inheritance Of Mesotrione Resistance In An Amaranthus Tuberculatus (Var. Rudis) Population From Nebraska, Usa, Maxwel C. Oliveira, Todd A. Gaines, Amit J. Jhala, Stevan Z. Knezevic

Department of Agronomy and Horticulture: Faculty Publications

A population of Amaranthus tuberculatus (var. rudis) evolved resistance to 4- hydroxyphenylpyruvate dioxygenase (HPPD) inhibitor herbicides (mesotrione, tembotrione, and topramezone) in Nebraska. The level of resistance was the highest to mesotrione, and the mechanism of resistance in this population is metabolism-based likely via cytochrome P450 enzymes. The increasing number of weeds resistant to herbicides warrants studies on the ecology and evolutionary factors contributing for resistance evolution, including inheritance of resistance traits. In this study, we investigated the genetic control of mesotrione resistance in an A. tuberculatus population from Nebraska, USA. Results showed that reciprocal crosses in the F1 families exhibited …

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Genome-Wide Analysis Of Grain Yield Stability And Environmental Interactions In A Multiparental Soybean Population, Alencar Xavier, Diego Jarquin, Reka Howard, Vishnu Ramasubramanian, James E. Specht, George L. Graef, William D. Beavis, Brian W. Diers, Qijian Song, Perry B. Cregan, Randall L. Nelson, Rouf Mian, J. Grover Shannon, Leah K. Mchale, Dechun Wang, William Schapaugh, Aaron J. Lorenz, Shizhong Xu, William M. Muir, Katy M. Rainey Feb 2018

Genome-Wide Analysis Of Grain Yield Stability And Environmental Interactions In A Multiparental Soybean Population, Alencar Xavier, Diego Jarquin, Reka Howard, Vishnu Ramasubramanian, James E. Specht, George L. Graef, William D. Beavis, Brian W. Diers, Qijian Song, Perry B. Cregan, Randall L. Nelson, Rouf Mian, J. Grover Shannon, Leah K. Mchale, Dechun Wang, William Schapaugh, Aaron J. Lorenz, Shizhong Xu, William M. Muir, Katy M. Rainey

Department of Agronomy and Horticulture: Faculty Publications

Genetic improvement toward optimized and stable agronomic performance of soybean genotypes is desirable for food security. Understanding how genotypes perform in different environmental conditions helps breeders develop sustainable cultivars adapted to target regions. Complex traits of importance are known to be controlled by a large number of genomic regions with small effects whose magnitude and direction are modulated by environmental factors. Knowledge of the constraints and undesirable effects resulting from genotype by environmental interactions is a key objective in improving selection procedures in soybean breeding programs. In this study, the genetic basis of soybean grain yield responsiveness to environmental factors …

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Overlapping Residual Herbicides For Control Of Photosystem (Ps) Ii- And 4-Hydroxyphenylpyruvate Dioxygenase (Hppd)-Inhibitor-Resistant Palmer Amaranth (Amaranthus Palmeri S. Watson) In Glyphosate-Resistant Maize, Parminder S. Chahal, Zahoor Ahmad Ganie, Amit J. Jhala Jan 2018

Overlapping Residual Herbicides For Control Of Photosystem (Ps) Ii- And 4-Hydroxyphenylpyruvate Dioxygenase (Hppd)-Inhibitor-Resistant Palmer Amaranth (Amaranthus Palmeri S. Watson) In Glyphosate-Resistant Maize, Parminder S. Chahal, Zahoor Ahmad Ganie, Amit J. Jhala

Department of Agronomy and Horticulture: Faculty Publications

A Palmer amaranth (Amaranthus palmeri S. Watson) biotype has evolved resistance to photosystem (PS) II- (atrazine) and 4-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicides (mesotrione, tembotrione, and topramezone) in maize seed production field in Nebraska, USA. The objectives of this study were to determine the effect of soil residual pre-emergence (PRE) herbicides followed by (fb) tank-mixture of residual and foliar active post-emergence (POST) herbicides on PS-II- and HPPD-inhibitor-resistant Palmer amaranth control, maize yield, and net economic returns. Field experiments were conducted in a grower’s field infested with PS II- and HPPD-inhibitor-resistant Palmer amaranth near Shickley in Fillmore County, Nebraska, USA in 2015 …

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Optimising The Identification Of Causal Variants Across Varying Genetic Architectures In Crops, Chenyong Miao, Jinliang Yang, James C. Schnable Jan 2018

Optimising The Identification Of Causal Variants Across Varying Genetic Architectures In Crops, Chenyong Miao, Jinliang Yang, James C. Schnable

Department of Agronomy and Horticulture: Faculty Publications

Association studies use statistical links between genetic markers and the phenotype variation across many individuals to identify genes controlling variation in the target phenotype. However, this approach, particularly conducted on a genome-wide scale (GWAS), has limited power to identify the genes responsible for variation in traits controlled by complex genetic architectures. In this study, we employ real-world genotype datasets from four crop species with distinct minor allele frequency distributions, population structures and linkage disequilibrium patterns. We demonstrate that different GWAS statistical approaches provide favourable trade-offs between power and accuracy for traits controlled by different types of genetic architectures. FarmCPU provides …

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Transcriptional Reprogramming Of Legume Genomes: Perspective And Challenges Associated With Single-Cell And Single Cell-Type Approaches During Nodule Development, Marc Libault Jan 2018

Transcriptional Reprogramming Of Legume Genomes: Perspective And Challenges Associated With Single-Cell And Single Cell-Type Approaches During Nodule Development, Marc Libault

Department of Agronomy and Horticulture: Faculty Publications

Transcriptomic approaches revealed thousands of genes differentially or specifically expressed during nodulation, a biological process resulting from the symbiosis between leguminous plant roots and rhizobia, atmospheric nitrogen-fixing symbiotic bacteria. Ultimately, nodulation will lead to the development of a new root organ, the nodule. Through functional genomic studies, plant transcriptomes have been used by scientists to reveal plant genes potentially controlling nodulation. However, it is important to acknowledge that the physiology, transcriptomic programs, and biochemical properties of the plant cells involved in nodulation are continuously regulated. They also differ between the different cell-types composing the nodules. To generate a more accurate …

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First Case Of Glufosinate-Resistant Rigid Ryegrass (Lolium Rigidum Gaud.) In Greece, Ilias S. Travlos, Nikolina Cheimona, Rafael De Prado, Amit J. Jhala, Demosthenis Chachalis, Eleni Tani Jan 2018

First Case Of Glufosinate-Resistant Rigid Ryegrass (Lolium Rigidum Gaud.) In Greece, Ilias S. Travlos, Nikolina Cheimona, Rafael De Prado, Amit J. Jhala, Demosthenis Chachalis, Eleni Tani

Department of Agronomy and Horticulture: Faculty Publications

Repeated applications of the same herbicide(s), which are characterized by the same mode of action, increase selection pressure, which in turn favours the evolution of herbicide-resistant weeds. Glufosinate is a broad-spectrum non-selective herbicide being used for weed control for many years around the world. Rigid ryegrass (Lolium rigidum Gaud.) is an economically important grass weed in Greece. Recent complaints by growers about control failure of rigid ryegrass with glufosinate require further investigation and have been the basis of this study. The objectives of this study were to confirm the existence of glufosinate-resistant L. rigidum in Greece and evaluate the …

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Empowerment And Tech Adoption: Introducing The Treadle Pump Triggers Farmers’ Innovation In Eastern Ethiopia, Shimelis Beyene, Teshome H. Regassa, Belaineh Legesse, Martha Mamo, Tsegaye Tadesse Jan 2018

Empowerment And Tech Adoption: Introducing The Treadle Pump Triggers Farmers’ Innovation In Eastern Ethiopia, Shimelis Beyene, Teshome H. Regassa, Belaineh Legesse, Martha Mamo, Tsegaye Tadesse

Department of Agronomy and Horticulture: Faculty Publications

In 2013, thirty-eight treadle pumps (TPs) were installed as low-cost technology introduction for small-scale irrigation in eastern Ethiopia. This pilot project also trained six farmers on tube well excavation, as well as the installation and maintenance of pumps. In June 2015, researchers visited nine of the thirty-eight TP villages and found only two TPs functioning as originally installed. The rest were replaced with a new technology developed by the trained farmers. Farmers, empowered by training, gained more control in developing technology options tailored to local needs and conditions of their communities. Adopters of the new technology stated that the limited …

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Beyond The Plot: Technology Extrapolation Domains For Scaling Out Agronomic Science, Juan I. Rattalino Edreira, Kenneth G. Cassman, Zvi Hochman, Martin K. Van Ittersum, Lenny Van Bussel, Lieven Claessens, Patricio Grassini Jan 2018

Beyond The Plot: Technology Extrapolation Domains For Scaling Out Agronomic Science, Juan I. Rattalino Edreira, Kenneth G. Cassman, Zvi Hochman, Martin K. Van Ittersum, Lenny Van Bussel, Lieven Claessens, Patricio Grassini

Department of Agronomy and Horticulture: Faculty Publications

Ensuring an adequate food supply in systems that protect environmental quality and conserve natural resources requires productive and resource-efficient cropping systems on existing farmland.Meeting this challenge will be difficult without a robust spatial framework that facilitates rapid evaluation and scaling-out of currently available and emerging technologies. Here we develop a global spatial framework to delineate ‘technology extrapolation domains’ based on key climate and soil factors that govern crop yields and yield stability in rainfed crop production. The proposed framework adequately represents the spatial pattern of crop yields and stability when evaluated over the data-rich US Corn Belt. It also facilitates …

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Is Conservation Agriculture A Potential Option For Cereal-Based Sustainable Farming System In The Eastern Indo-Gangetic Plains Of Nepal?, Dipendra Pokharel, Raj Kant Jha, Thakur Prasad Tiwari, Mahesh Kumar Gathala, Hari Krishna Shrestha, Dinesh Panday Jan 2018

Is Conservation Agriculture A Potential Option For Cereal-Based Sustainable Farming System In The Eastern Indo-Gangetic Plains Of Nepal?, Dipendra Pokharel, Raj Kant Jha, Thakur Prasad Tiwari, Mahesh Kumar Gathala, Hari Krishna Shrestha, Dinesh Panday

Department of Agronomy and Horticulture: Faculty Publications

A decline in land and water productivity, increase in the cost of cultivation, and labor-intensive practices are affecting the cereal-based farming system in Nepal, particularly in the Indo-Gangetic Plains (IGP). Conservation agriculture (CA) practices have been found to be the climate-, energy-, and labor-smart and sustainable agricultural production technologies. Sustainable and Resilient Farming System Intensification (SRFSI) has been working since 2014 in response to the sustainability of the cereal-based (rice–wheat and rice–maize) farming in Sunsari and Dhanusha districts of Nepal. This study was conducted to assess the adoption and scaling up of CA in addition to input usage, production, net …

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Impact Of Drought On Chemical Composition And Sugar Yields From Dilute-Acid Pretreatment And Enzymatic Hydrolysis Of Miscanthus, A Tall Fescue Mixture, And Switchgrass, Amber Hoover, Rachel Emerson, Allison Ray, Daniel Stevens, Sabrina Morgan, Marnie Cortez, Robert Kallenbach, Matthew Sousek, Rodney Farris, Dayna Daubaras Jan 2018

Impact Of Drought On Chemical Composition And Sugar Yields From Dilute-Acid Pretreatment And Enzymatic Hydrolysis Of Miscanthus, A Tall Fescue Mixture, And Switchgrass, Amber Hoover, Rachel Emerson, Allison Ray, Daniel Stevens, Sabrina Morgan, Marnie Cortez, Robert Kallenbach, Matthew Sousek, Rodney Farris, Dayna Daubaras

Department of Agronomy and Horticulture: Faculty Publications

Environmental factors like drought impact the quality of biomass entering a bioconversion process. Drought often reduces the sugar content in lignocellulosic biomass, which could have economic impacts, particularly when compounded with losses in dry biomass yield; however, the effects on conversion efficiency are not completely understood. This study investigated how drought may impact biomass composition and sugar yields from dilute-acid pretreatment and enzymatic hydrolysis of Miscanthus, a tall fescue mixture, and switchgrass from Nebraska, Missouri, and Oklahoma, respectively, grown as part of Regional Feedstock Partnership field trials. Samples were grown and harvested in 2010 during non-drought conditions and in …

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Impaired Phloem Loading In Zmsweet13a,B,C Sucrose Transporter Triple Knock-Out Mutants In Zea Mays, Margaret Bezrutczyk, Thomas Hartwig, Marc Horschman, Si Nian Char, Jinliang Yang, Bing Yang, Wolf B. Frommer, Davide Sosso Jan 2018

Impaired Phloem Loading In Zmsweet13a,B,C Sucrose Transporter Triple Knock-Out Mutants In Zea Mays, Margaret Bezrutczyk, Thomas Hartwig, Marc Horschman, Si Nian Char, Jinliang Yang, Bing Yang, Wolf B. Frommer, Davide Sosso

Department of Agronomy and Horticulture: Faculty Publications

Crop yield is critical for human nutrition, yet the underlying machinery that ultimately determines yield potential is still not understood. Crop productivity under ideal conditions is determined by the efficiency with which plants intercept light, convert it into chemical energy, translocate photosynthates and convert these to storage products in harvestable organs (Zhu et al., 2010). In many crops, sucrose is the primary form for translocation inside the conduit (i.e. the phloem). A combination of SWEETmediated efflux from phloem parenchyma and subsequent secondary active sucrose import by SUT sucrose/H+ symporters is thought to create the driving force for pressure gradient-driven …

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Tetracycline And Sulfonamide Antibiotic Resistance Genes In Soils From Nebraska Organic Farming Operations, Marylynn Cadena, Lisa M. Durso, Daniel N. Miller, Heidi M. Waldrip, B. L. Castleberry, Rhae A. Drijber, Charles S. Wortmann Jan 2018

Tetracycline And Sulfonamide Antibiotic Resistance Genes In Soils From Nebraska Organic Farming Operations, Marylynn Cadena, Lisa M. Durso, Daniel N. Miller, Heidi M. Waldrip, B. L. Castleberry, Rhae A. Drijber, Charles S. Wortmann

Department of Agronomy and Horticulture: Faculty Publications

There is widespread agreement that agricultural antibiotic resistance should be reduced, however, it is unclear from the available literature what an appropriate target for reduction would be. Organic farms provide a unique opportunity to disentangle questions of agricultural antibiotic drug use from questions of antibiotic resistance in the soil. In this study, soil was collected from 12 certified organic farms in Nebraska, evaluated for the presence of tetracycline and sulfonamide resistance genes (n = 15 targets), and correlated to soil physical, chemical, and biological parameters. Tetracycline and sulfonamide antibiotic resistance genes (ARGs) were found in soils from all 12 …

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Sifting And Winnowing: Analysis Of Farmer Field Data For Soybean In The Us North-Central Region, Spyridon Mourtzinis, Juan I. Rattalino Edreira, Patricio Grassini, Adam C. Roth, Shaun N. Casteel, Ignacio A. Ciampitti, Hans J. Kandel, Peter M. Kyveryga, Mark A. Licht, Laura E. Lindsey, Daren S. Mueller, Emerson D. Nafziger, Seth L. Naeve, Jordan Stanley, Michael J. Staton, Shawn P. Conley Jan 2018

Sifting And Winnowing: Analysis Of Farmer Field Data For Soybean In The Us North-Central Region, Spyridon Mourtzinis, Juan I. Rattalino Edreira, Patricio Grassini, Adam C. Roth, Shaun N. Casteel, Ignacio A. Ciampitti, Hans J. Kandel, Peter M. Kyveryga, Mark A. Licht, Laura E. Lindsey, Daren S. Mueller, Emerson D. Nafziger, Seth L. Naeve, Jordan Stanley, Michael J. Staton, Shawn P. Conley

Department of Agronomy and Horticulture: Faculty Publications

Field trials are commonly used to estimate the effects of different factors on crop yields. In the present study, we followed an alternative approach to identify factors that explain field-to-field yield variation, which consisted of farmer survey data, a spatial framework, and multiple statistical procedures. This approach was used to identify management factors with strongest association with on-farm soybean yield variation in the US North Central (NC) region. Field survey data, including yield and management information, were collected over two crop growing seasons (2014 and 2015) from rainfed and irrigated soybean fields (total of 3568 field-year observations). Fields were grouped …

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Application Of Machine Learning Methodologies For Predicting Corn Economic Optimal Nitrogen Rate, Zhisheng Qin, D. Brenton Myers, Curtis J. Ransom, Newell R. Kitchen, Sang-Zi Liang, James J. Camberato, Paul R. Carter, Richard B. Ferguson, Fabian G. Fernandez, David W. Franzen, Carrie A. M. Laboski, Brad D. Malone, Emerson D. Nafziger, John E. Sawyer, John F. Shanahan Jan 2018

Application Of Machine Learning Methodologies For Predicting Corn Economic Optimal Nitrogen Rate, Zhisheng Qin, D. Brenton Myers, Curtis J. Ransom, Newell R. Kitchen, Sang-Zi Liang, James J. Camberato, Paul R. Carter, Richard B. Ferguson, Fabian G. Fernandez, David W. Franzen, Carrie A. M. Laboski, Brad D. Malone, Emerson D. Nafziger, John E. Sawyer, John F. Shanahan

Department of Agronomy and Horticulture: Faculty Publications

Determination of in-season N requirement for corn (Zea mays L.) is challenging due to interactions of genotype, environment, and management. Machine learning (ML), with its predictive power to tackle complex systems, may solve this barrier in the development of locally based N recommendations. The objective of this study was to explore application of ML methodologies to predict economic optimum nitrogen rate (EONR) for corn using data from 47 experiments across the US Corn Belt. Two features, a water table adjusted available water capacity (AWCwt) and a ratio of in-season rainfall to AWCwt (RAWCwt), were …

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Managing Wicked Herbicide-Resistance: Lessons From The Field, Jill Schroeder, Michael Barrett, David R. Shaw, Amy B. Asmus, Harold Coble, David Ervin, Raymond A. Jussaume Jr., Michael D. K. Owen, Ian Burke, Cody F. Creech, A. Stanley Culpepper, William S. Curran, Darrin M. Dodds, Todd A. Gaines, Jeffrey L. Gunsolus, Bradley D. Hanson, Prashant Jha, Annie E. Klodd, Andrew R. Kniss, Ramon G. Leon, Sandra Mcdonald, Don W. Morishita, Brian J. Schutte, Christy L. Sprague, Phillip W. Stahlman, Larry E. Steckel, Mark J. Vangessel Jan 2018

Managing Wicked Herbicide-Resistance: Lessons From The Field, Jill Schroeder, Michael Barrett, David R. Shaw, Amy B. Asmus, Harold Coble, David Ervin, Raymond A. Jussaume Jr., Michael D. K. Owen, Ian Burke, Cody F. Creech, A. Stanley Culpepper, William S. Curran, Darrin M. Dodds, Todd A. Gaines, Jeffrey L. Gunsolus, Bradley D. Hanson, Prashant Jha, Annie E. Klodd, Andrew R. Kniss, Ramon G. Leon, Sandra Mcdonald, Don W. Morishita, Brian J. Schutte, Christy L. Sprague, Phillip W. Stahlman, Larry E. Steckel, Mark J. Vangessel

Department of Agronomy and Horticulture: Faculty Publications

Herbicide resistance is ‘wicked’ in nature; therefore, results of the many educational efforts to encourage diversification of weed control practices in the United States have been mixed. It is clear that we do not sufficiently understand the totality of the grassroots obstacles, concerns, challenges, and specific solutions needed for varied crop production systems. Weed management issues and solutions vary with such variables as management styles, regions, cropping systems, and available or affordable technologies. Therefore, to help the weed science community better understand the needs and ideas of those directly dealing with herbicide resistance, seven half-day regional listening sessions were held …

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Growth, Fitness, And Overwinter Survival Of A Shattercane (Sorghum Bicolor Ssp. Drummondii) × Grain Sorghum (Sorghum Bicolor Ssp. Bicolor) F2 Population, Jared J. Schmidt, Melinda K. Yerka, Jeffrey F. Pedersen, John L. Lindquist Jan 2018

Growth, Fitness, And Overwinter Survival Of A Shattercane (Sorghum Bicolor Ssp. Drummondii) × Grain Sorghum (Sorghum Bicolor Ssp. Bicolor) F2 Population, Jared J. Schmidt, Melinda K. Yerka, Jeffrey F. Pedersen, John L. Lindquist

Department of Agronomy and Horticulture: Faculty Publications

Although sorghum [Sorghum bicolor (L.) Moench ssp. bicolor] is the fifth most important grain crop in terms of global production, no commercial hybrids carry genetically engineered (GE) traits for resistance to insect pests or herbicides due to regulatory concerns about gene flow to weedy relatives. However, non-GE herbicide resistance currently is being developed in grain sorghum and will likely transfer to related weeds. Monitoring the impact of this new nuclear technology on the evolution and invasiveness of related weeds requires a baseline understanding of the population biology of grain sorghum genes once they transfer to in situ weed …

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Phenotypic Data From Inbred Parents Can Improve Genomic Prediction In Pearl Millet Hybrids, Zhikai Liang, Shashi K. Gupta, Cheng-Ting Yeh, Yang Zhang, Daniel W. Ngu, Ramesh Kumar, Hemant T. Patil, Kanulal D. Mungra, Dev Vart Yadav, Abhishek Rathore, Rakesh K. Srivastava, Rajeev Gupta, Jinliang Yang, Rajeev K. Varshney, Patrick S. Schnable, James C. Schnable Jan 2018

Phenotypic Data From Inbred Parents Can Improve Genomic Prediction In Pearl Millet Hybrids, Zhikai Liang, Shashi K. Gupta, Cheng-Ting Yeh, Yang Zhang, Daniel W. Ngu, Ramesh Kumar, Hemant T. Patil, Kanulal D. Mungra, Dev Vart Yadav, Abhishek Rathore, Rakesh K. Srivastava, Rajeev Gupta, Jinliang Yang, Rajeev K. Varshney, Patrick S. Schnable, James C. Schnable

Department of Agronomy and Horticulture: Faculty Publications

Pearl millet is a non-model grain and fodder crop adapted to extremely hot and dry environments globally. In India, a great deal of public and private sectors’ investment has focused on developing pearl millet single cross hybrids based on the cytoplasmic-genetic male sterility (CMS) system, while in Africa most pearl millet production relies on open pollinated varieties. Pearl millet lines were phenotyped for both the inbred parents and hybrids stage. Many breeding efforts focus on phenotypic selection of inbred parents to generate improved parental lines and hybrids. This study evaluated two genotyping techniques and four genomic selection schemes in pearl …

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Isolation And Analysis Of Microbial Communities In Soil, Rhizosphere, And Roots In Perennial Grass Experiments, Morgan R. Mcpherson, Peng Wang, Robert B. Mitchell, Daniel P. Schachtman Jan 2018

Isolation And Analysis Of Microbial Communities In Soil, Rhizosphere, And Roots In Perennial Grass Experiments, Morgan R. Mcpherson, Peng Wang, Robert B. Mitchell, Daniel P. Schachtman

Department of Agronomy and Horticulture: Faculty Publications

Plant and soil microbiome studies are becoming increasingly important for understanding the roles microorganisms play in agricultural productivity. The purpose of this manuscript is to provide detail on how to rapidly sample soil, rhizosphere, and endosphere of replicated field trials and analyze changes that may occur in the microbial communities due to sample type, treatment, and plant genotype. The experiment used to demonstrate these methods consists of replicated field plots containing two, pure, warm-season grasses (Panicum virgatum and Andropogon gerardii) and a low-diversity grass mixture (A. gerardii, Sorghastrum nutans, and Bouteloua curtipendula). Briefly, plants …

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Hunger In The Land Of Plenty: Local Responses To Food Insecurity In Iowa, Gabrielle E. Roesch-Mcnally, Jacqueline Ann Nester, Andrea D. Basche, Eric Christianson, Emily Zimmerman Jan 2018

Hunger In The Land Of Plenty: Local Responses To Food Insecurity In Iowa, Gabrielle E. Roesch-Mcnally, Jacqueline Ann Nester, Andrea D. Basche, Eric Christianson, Emily Zimmerman

Department of Agronomy and Horticulture: Faculty Publications

Story County (estimated population 92,406 in 2013) lies in the heart of central Iowa, a state renowned for its remarkable agricultural productivity. Iowa leads all states for production of corn, soybean, and hogs. Revenues from agricultural products in Iowa total more than $30 billion annually according the 2012 Agricultural Census (USDA-NASS 2014). This productivity stems from a favorable natural and political environment. The temperate climate, productive soils, and gentle topography are ideal for our production system of commodity agriculture facilitated by federal policies, which include subsidized crop insurance and commodity payments (Horrigan, Lawrence, and Walker 2002). Despite this productivity and …

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Social–Ecological Landscape Patterns Predict Woody Encroachment From Native Tree Plantings In A Temperate Grassland, Victoria M. Donovan, Jessica L. Burnett, Christine H. Bielski, Hannah E. Birge, Rebecca Bevans, Dirac L. Twidwell Jr, Craig R. Allen Jan 2018

Social–Ecological Landscape Patterns Predict Woody Encroachment From Native Tree Plantings In A Temperate Grassland, Victoria M. Donovan, Jessica L. Burnett, Christine H. Bielski, Hannah E. Birge, Rebecca Bevans, Dirac L. Twidwell Jr, Craig R. Allen

Department of Agronomy and Horticulture: Faculty Publications

Afforestation is often viewed as the purposeful planting of trees in historically non-forested grasslands, but an unintended consequence is woody encroachment, which should be considered part of the afforestation process. In North America’s temperate grassland biome, Eastern redcedar (Juniperus virginiana L.) is a native species used in tree plantings that aggressively invades in the absence of controlling processes. Cedar is a well-studied woody encroacher, but little is known about the degree to which cedar windbreaks, which are advocated for in agroforestry programs, are contributing to woody encroachment, what factors are associated with cedar spread from windbreaks, nor where encroachment …

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Engineering Linear, Branched-Chain Triterpene Metabolism In Monocots, Chase Kempinski, Zuodong Jiang, Garrett Zinck, Shirley J. Sato, Zhengxiang Ge, Thomas E. Clemente, Joe Chappell Jan 2018

Engineering Linear, Branched-Chain Triterpene Metabolism In Monocots, Chase Kempinski, Zuodong Jiang, Garrett Zinck, Shirley J. Sato, Zhengxiang Ge, Thomas E. Clemente, Joe Chappell

Department of Agronomy and Horticulture: Faculty Publications

Triterpenes are thirty-carbon compounds derived from the universal five-carbon prenyl precursors isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP). Normally, triterpenes are synthesized via the mevalonate (MVA) pathway operating in the cytoplasm of eukaryotes where DMAPP is condensed with two IPPs to yield farnesyl diphosphate (FPP), catalyzed by FPP synthase (FPS). Squalene synthase (SQS) condenses two molecules of FPP to generate the symmetrical product squalene, the first committed precursor to sterols and most other triterpenes. In the green algae Botryococcus braunii, two FPP molecules can also be condensed in an asymmetric manner yielding the more highly branched triterpene, botryococcene. Botryococcene …

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Genomic Selection In Preliminary Yield Trials In A Winter Wheat Breeding Program, Vikas Belamkar, Mary J. Guttieri, Waseem Hussain, Diego Jarquin, Ibrahim El-Basyoni, Jesse Poland, Aaron J. Lorenz, P. Stephen Baenziger Jan 2018

Genomic Selection In Preliminary Yield Trials In A Winter Wheat Breeding Program, Vikas Belamkar, Mary J. Guttieri, Waseem Hussain, Diego Jarquin, Ibrahim El-Basyoni, Jesse Poland, Aaron J. Lorenz, P. Stephen Baenziger

Department of Agronomy and Horticulture: Faculty Publications

Genomic prediction (GP) is now routinely performed in crop plants to predict unobserved phenotypes. The use of predicted phenotypes to make selections is an active area of research. Here, we evaluate GP for predicting grain yield and compare genomic and phenotypic selection by tracking lines advanced. We examined four independent nurseries of F3:6 and F3:7 lines trialed at 6 to 10 locations each year. Yield was analyzed using mixed models that accounted for experimental design and spatial variations. Genotype-by-sequencing provided nearly 27,000 high-quality SNPs. Average genomic predictive ability, estimated for each year by randomly masking lines as missing …

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Transient Heat Stress During Early Seed Development Primes Germination And Seedling Establishment In Rice, Kevin Begcy, Jaspreet Sandhu, Harkamal Walia Jan 2018

Transient Heat Stress During Early Seed Development Primes Germination And Seedling Establishment In Rice, Kevin Begcy, Jaspreet Sandhu, Harkamal Walia

Department of Agronomy and Horticulture: Faculty Publications

Rice yield is highly sensitive to increased temperature. Given the trend of increasing global temperatures, this sensitivity to higher temperatures poses a challenge for achieving global food security. Early seed development in rice is highly sensitive to unfavorable environmental conditions. Heat stress (HS) during this stage decreases seed size and fertility, thus reducing yield. Here, we explore the transgenerational phenotypic consequences of HS during early seed development on seed viability, germination, and establishment. To elucidate the impact of HS on the developmental events in postzygotic rice seeds, we imposed moderate (35°C) and severe (39°C) HS treatments initiated 1 day after …

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