Open Access. Powered by Scholars. Published by Universities.®

Agricultural Science Commons

Open Access. Powered by Scholars. Published by Universities.®

10,740 Full-Text Articles 11,106 Authors 1,709,746 Downloads 90 Institutions

All Articles in Agricultural Science

Faceted Search

10,740 full-text articles. Page 2 of 207.

Flood Adulterated Grain - Nutrient Supply To Crops When Land Applied, John E. Sawyer, Antonio Mallarino 2019 Iowa State University

Flood Adulterated Grain - Nutrient Supply To Crops When Land Applied, John E. Sawyer, Antonio Mallarino

John E. Sawyer

Flooding has been extensive in several areas of Iowa this spring. In some cases, stored grain has been affected by flood waters. Land application of flood adulterated grain as a nutrient source for a future crop may be an option for some. See the Iowa Dept. of Natural Resources (IDNR) and Iowa Dept. of Agriculture and Land Stewardship (IDALS) publication for Proper Management of Flooded Grain and Hay. That publication states “Farms disposing of spoiled grain and feed on their own property can land apply damaged grain at the following application rates: 146 bu corn/acre and 50 bu soybean ...


Anhydrous Ammonia Application -- Spring 2019, John E. Sawyer 2019 Iowa State University

Anhydrous Ammonia Application -- Spring 2019, John E. Sawyer

John E. Sawyer

It was a late harvest in fall 2018. Soils were wet and frozen when it was time to apply anhydrous ammonia. Those situations resulted in much less than normal anhydrous ammonia application last fall. Therefore, considerable anhydrous ammonia needs to be applied this spring. There is only so much capacity to switch from one nitrogen (N) fertilizer product to another. In Iowa, historically the two largest N fertilizers are anhydrous ammonia (largest) and urea-ammonium nitrate (UAN) solution, with granulated urea a distant third.


Springtime Precipitation – A Tool For Estimating Nitrogen Application Need For Corn, John E. Sawyer 2019 Iowa State University

Springtime Precipitation – A Tool For Estimating Nitrogen Application Need For Corn, John E. Sawyer

John E. Sawyer

Wet springtime conditions typically raise questions about the status of applied nitrogen (N). Or the question, do I need to apply additional N to my cornfields? At this time we do not know what the weather/precipitation will be for the entire springtime, but the extended period of wet conditions this spring is of concern. A summary of long-term N rate trials with continuous corn and corn rotated with soybean conducted at seven ISU research and demonstration farms in Iowa from 1999 to 2016 has been an on-going basis for indicating the potential for needing an N rate greater than ...


Nitrogen Fertilization Options With Delayed Or Rescue Applications, John E. Sawyer 2019 Iowa State University

Nitrogen Fertilization Options With Delayed Or Rescue Applications, John E. Sawyer

John E. Sawyer

It’s been a wait-go-stop (repeat) corn planting season this spring. Whether you planted early or are just now getting corn planted, it seems planting windows were short and rushed. In some cases this meant planting (corn/soybean) and worrying later about getting nitrogen (N) applied. And in some areas of Iowa, wetter than normal conditions are raising questions about supplemental N application. What are the options for sidedress N?


Effects Of Unharvested, Shattered, Or Hailed-Out Soybean Fields On Nutrient Supply For Corn, John E. Sawyer 2019 Iowa State University

Effects Of Unharvested, Shattered, Or Hailed-Out Soybean Fields On Nutrient Supply For Corn, John E. Sawyer

John E. Sawyer

Flooded fields and wet soil conditions in the fall 2018 meant some soybean fields were not, or are not going to be harvested. Also, some fields occasionally experienced significant shattering or a hailstorm in the fall where soybean seed is knocked from the plants and thus not harvested. When the grain is not harvested, nitrogen (N), phosphorus (P), and potassium (K) nutrients returned to the soil in the soybean grain can be accounted for when planning nutrient applications for the next crop. Other nutrients will also be returned, but most are not a fertilization need in Iowa soils. An estimate ...


Economic Contribution Of The Agricultural Sector To The Arkansas Economy In 2017, Leah English, Jennie Popp, Wayne Miller 2019 University of Arkansas, Fayetteville

Economic Contribution Of The Agricultural Sector To The Arkansas Economy In 2017, Leah English, Jennie Popp, Wayne Miller

Research Reports and Research Bulletins

Agriculture and associated agricultural activities are major contributors to the Arkansas economy. Agriculture is defined as the sum of agricultural production and processing activities, unless otherwise specified, and includes crop and animal production and processing, agricultural support industries, forestry and forest products, and textile goods. Agriculture contributes to the economy through direct agricultural production and value-added processing, and also leads to economic activity in other parts of the economy. This report is the eleventh in a series of reports examining agriculture’s economic contribution to the Arkansas economy. The total economic contribution of agriculture (direct, indirect, and induced effects) on ...


Herbicide Drift Influence On Amaranthus Spp. Herbicide Resistance Evolution, Bruno Canella Vieira 2019 University of Nebraska-Lincoln

Herbicide Drift Influence On Amaranthus Spp. Herbicide Resistance Evolution, Bruno Canella Vieira

Theses, Dissertations, and Student Research in Agronomy and Horticulture

The adverse consequences of herbicide drift towards sensitive crops have been extensively reported in the literature. However, no information is available on the consequences of herbicide drift onto weed species inhabiting boundaries of agricultural fields. Exposure to herbicide drift could be detrimental to long-term weed management as several weed species have evolved herbicide resistance after recurrent selection with low herbicide rates. Despite the herbicide drift exposure and its potential implications on resistance evolution and weed management, resistance prone weed species such as Palmer amaranth (Amaranthus palmeri) and waterhemp (Amaranthus tuberculatus) are often neglected and not properly managed in agricultural field ...


Have Our Scn Sorrows Been Drowned?, Gregory L. Tylka 2019 Iowa State University

Have Our Scn Sorrows Been Drowned?, Gregory L. Tylka

Integrated Crop Management News

Those looking for any bit of good news in all of the rain-soaked suffering we have endured this spring have asked if the extreme overabundance of moisture has drowned soybean cyst nematode (SCN). Unfortunately, the answer is no.


Tissue Testing For Field Crops Requires Cautious Use And Interpretation, Antonio Mallarino, John E. Sawyer 2019 Iowa State University

Tissue Testing For Field Crops Requires Cautious Use And Interpretation, Antonio Mallarino, John E. Sawyer

Integrated Crop Management News

In-season plant tissue testing can be useful in diagnosing nutrient deficiencies in field crops, but it must be used with caution. Extra care is needed this year given the unusual crop planting and growing conditions.


Climate Change Impacts On Winter Wheat Yield In Northern China, Xiu Geng, Fang Wang, Wei Ren, Zhixin Hao 2019 Chinese Academy of Sciences, China

Climate Change Impacts On Winter Wheat Yield In Northern China, Xiu Geng, Fang Wang, Wei Ren, Zhixin Hao

Plant and Soil Sciences Faculty Publications

Exploring the impacts of climate change on agriculture is one of important topics with respect to climate change. We quantitatively examined the impacts of climate change on winter wheat yield in Northern China using the Cobb–Douglas production function. Utilizing time-series data of agricultural production and meteorological observations from 1981 to 2016, the impacts of climatic factors on wheat production were assessed. It was found that the contribution of climatic factors to winter wheat yield per unit area (WYPA) was 0.762–1.921% in absolute terms. Growing season average temperature (GSAT) had a negative impact on WYPA for the ...


Transcriptome Analyses And Virus Induced Gene Silencing Identify Genes In The Rpp4 -Mediated Asian Soybean Rust Resistance Pathway, Aguida A.M.P. Morales, Jamie A. O'Rourke, Martijn van de Mortel, Katherine T. Scheider, Timothy J. Bancroft, Aluizio Borem, Rex T. Nelson, Daniel S. Nettleton, Thomas J. Baum, Randy C. Shoemaker, Reid D. Frederick, Ricardo V. Abdelnoor, Kerry F. Pedley, Steven A. Whitham, Michelle Graham 2019 Universidade Federal de Vicosa

Transcriptome Analyses And Virus Induced Gene Silencing Identify Genes In The Rpp4 -Mediated Asian Soybean Rust Resistance Pathway, Aguida A.M.P. Morales, Jamie A. O'Rourke, Martijn Van De Mortel, Katherine T. Scheider, Timothy J. Bancroft, Aluizio Borem, Rex T. Nelson, Daniel S. Nettleton, Thomas J. Baum, Randy C. Shoemaker, Reid D. Frederick, Ricardo V. Abdelnoor, Kerry F. Pedley, Steven A. Whitham, Michelle Graham

Dan Nettleton

Rpp4 (Resistance to Phakopsora pachyrhizi 4) confers resistance to Phakopsora pachyrhizi Sydow, the causal agent of Asian soybean rust (ASR). By combining expression profiling and virus induced gene silencing (VIGS), we are developing a genetic framework for Rpp4-mediated resistance. We measured gene expression in mock-inoculated and P. pachyrhizi-infected leaves of resistant soybean accession PI459025B (Rpp4) and the susceptible cultivar (Williams 82) across a 12-day time course. Unexpectedly, two biphasic responses were identified. In the incompatible reaction, genes induced at 12 h after infection (hai) were not differentially expressed at 24 hai, but were induced at 72 hai. In contrast, genes ...


Soybean Homologs Of Mpk4 Negatively Regulate Defense Responses And Positively Regulate Growth And Development, Jian-Zhong Liu, Heidi D. Horstman, Edward J. Braun, Michelle Graham, Chunquan Zhang, Duroy Navarre, Wen-Li Qiu, Yeunsook Lee, Dan Nettleton, John H. Hill, Steven A. Whitham 2019 Iowa State University

Soybean Homologs Of Mpk4 Negatively Regulate Defense Responses And Positively Regulate Growth And Development, Jian-Zhong Liu, Heidi D. Horstman, Edward J. Braun, Michelle Graham, Chunquan Zhang, Duroy Navarre, Wen-Li Qiu, Yeunsook Lee, Dan Nettleton, John H. Hill, Steven A. Whitham

Dan Nettleton

Mitogen-activated protein kinase (MAPK) cascades play important roles in disease resistance in model plant species such as Arabidopsis (Arabidopsis thaliana) and tobacco (Nicotiana tabacum). However, the importance of MAPK signaling pathways in the disease resistance of crops is still largely uninvestigated. To better understand the role of MAPK signaling pathways in disease resistance in soybean (Glycine max), 13, nine, and 10 genes encoding distinct MAPKs, MAPKKs, and MAPKKKs, respectively, were silenced using virus-induced gene silencing mediated by Bean pod mottle virus. Among the plants silenced for various MAPKs, MAPKKs, and MAPKKKs, those in which GmMAPK4 homologs (GmMPK4s) were silenced displayed ...


Parallel Genome-Wide Expression Profiling Of Host And Pathogen During Soybean Cyst Nematode Infection Of Soybean, Nagabhushana Ithal, Justin Recknor, Dan Nettleton, Leonard Hearne, Tom Maier, Thomas J. Baum, Melissa G. Mitchum 2019 University of Missouri

Parallel Genome-Wide Expression Profiling Of Host And Pathogen During Soybean Cyst Nematode Infection Of Soybean, Nagabhushana Ithal, Justin Recknor, Dan Nettleton, Leonard Hearne, Tom Maier, Thomas J. Baum, Melissa G. Mitchum

Dan Nettleton

Global analysis of gene expression changes in soybean (Glycine max) and Heterodera glycines (soybean cyst nematode [SCN]) during the course of infection in a compatible interaction was performed using the Affymetrix GeneChip soybean genome array. Among 35,611 soybean transcripts monitored, we identified 429 genes that showed statistically significant differential expression between uninfected and nematode-infected root tissues. These included genes encoding enzymes involved in primary metabolism; biosynthesis of phenolic compounds, lignin, and flavonoids; genes related to stress and defense responses; cell wall modification; cellular signaling; and transcriptional regulation. Among 7,431 SCN transcripts monitored, 1,850 genes showed statistically significant ...


Sequence Mining And Transcript Profiling To Explore Cyst Nematode Parasitism, Axel A. Elling, Makedonka Mitreva, Xiaowu Gai, John Martin, Justin Recknor, Eric L. Davis, Richard S. Hussey, Dan Nettleton, James P. McCarter, Thomas J. Baum 2019 Iowa State University

Sequence Mining And Transcript Profiling To Explore Cyst Nematode Parasitism, Axel A. Elling, Makedonka Mitreva, Xiaowu Gai, John Martin, Justin Recknor, Eric L. Davis, Richard S. Hussey, Dan Nettleton, James P. Mccarter, Thomas J. Baum

Dan Nettleton

Background: Cyst nematodes are devastating plant parasites that become sedentary within plant roots and induce the transformation of normal plant cells into elaborate feeding cells with the help of secreted effectors, the parasitism proteins. These proteins are the translation products of parasitism genes and are secreted molecular tools that allow cyst nematodes to infect plants.

Results: We present here the expression patterns of all previously described parasitism genes of the soybean cyst nematode, Heterodera glycines, in all major life stages except the adult male. These insights were gained by analyzing our gene expression dataset from experiments using the Affymetrix Soybean ...


Maize Inbreds Exhibit High Levels Of Copy Number Variation (Cnv) And Presence/Absence Variation (Pav) In Genome Content, Nathan M. Springer, Kai Ying, Yan Fu, Tieming Ji, Cheng-Ting Yeh, Yi Jia, Wei Wu, Todd Richmond, Jacob Kitzman, Heidi Rosenbaum, A. Leonardo Iniguez, W. Brad Barbazuk, Jeffrey A. Jeddeloh, Daniel S. Nettleton, Patrick S. Schnable 2019 University of Minnesota

Maize Inbreds Exhibit High Levels Of Copy Number Variation (Cnv) And Presence/Absence Variation (Pav) In Genome Content, Nathan M. Springer, Kai Ying, Yan Fu, Tieming Ji, Cheng-Ting Yeh, Yi Jia, Wei Wu, Todd Richmond, Jacob Kitzman, Heidi Rosenbaum, A. Leonardo Iniguez, W. Brad Barbazuk, Jeffrey A. Jeddeloh, Daniel S. Nettleton, Patrick S. Schnable

Dan Nettleton

Following the domestication of maize over the past ∼10,000 years, breeders have exploited the extensive genetic diversity of this species to mold its phenotype to meet human needs. The extent of structural variation, including copy number variation (CNV) and presence/absence variation (PAV), which are thought to contribute to the extraordinary phenotypic diversity and plasticity of this important crop, have not been elucidated. Whole-genome, array-based, comparative genomic hybridization (CGH) revealed a level of structural diversity between the inbred lines B73 and Mo17 that is unprecedented among higher eukaryotes. A detailed analysis of altered segments of DNA conservatively estimates that ...


Flor Revisited (Again): Eqtl And Mutational Analysis Of Nb-Lrr Mediated Immunity To Powdery Mildew In Barley, Roger P. Wise, Priyanka Surana, Gregory S. Fuerst, Ruo Xu, Divya Mistry, Julie A. Dickerson, Dan Nettleton Dr. 2019 United States Department of Agriculture

Flor Revisited (Again): Eqtl And Mutational Analysis Of Nb-Lrr Mediated Immunity To Powdery Mildew In Barley, Roger P. Wise, Priyanka Surana, Gregory S. Fuerst, Ruo Xu, Divya Mistry, Julie A. Dickerson, Dan Nettleton Dr.

Dan Nettleton

Genes encoding early signaling events in pathogen defense often are identified only by their phenotype. Such genes involved in barley-powdery mildew interactions include Mla, specifying race-specific resistance; Rar1 (Required for Mla12-specified resistance1), and Rom1 (Restoration of Mla-specified resistance1). The HSP90-SGT1-RAR1 complex appears to function as chaperone in MLA-specified resistance, however, much remains to be discovered regarding the precise signaling underlying plant immunity. Genetic analyses of fast-neutron mutants derived from CI 16151 (Mla6) uncovered a novel locus, designated Rar3 (Required for Mla6-specified resistance3). Rar3 segregates independent of Mla6 and Rar1, and rar3 mutants are susceptible to Blumeria graminis f. sp. hordei ...


Biphasic Gene Expression Changes Elicited By Phakopsora Pachyrhizi In Soybean Correlate With Fungal Penetration And Haustoria Formation, Katherine T. Schneider, Martijn van de Mortel, Timothy J. Bancroft, Edward J. Braun, Dan Nettleton, Rex T. Nelson, Reid D. Frederick, Thomas J. Baum, Michelle Graham, Steven A. Whitham 2019 United States Department of Agriculture

Biphasic Gene Expression Changes Elicited By Phakopsora Pachyrhizi In Soybean Correlate With Fungal Penetration And Haustoria Formation, Katherine T. Schneider, Martijn Van De Mortel, Timothy J. Bancroft, Edward J. Braun, Dan Nettleton, Rex T. Nelson, Reid D. Frederick, Thomas J. Baum, Michelle Graham, Steven A. Whitham

Dan Nettleton

Inoculation of soybean (Glycine max) plants with Phakopsora pachyrhizi, the causal organism of Asian soybean rust, elicits a biphasic response characterized by a burst of differential gene expression in the first 12 h. A quiescent period occurs from 24 to 48 h after inoculation, in which P. pachyrhizi continues to develop but does not elicit strong host responses, followed by a second phase of intense gene expression. To correlate soybean responses with P. pachyrhizi growth and development, we inoculated the soybean cultivar Ankur (accession PI462312), which carries the Rpp3 resistance gene, with avirulent and virulent isolates of P. pachyrhizi. The ...


Distinct Biphasic Mrna Changes In Response To Asian Soybean Rust Infection, Martijn van de Mortel, Justin C. Recknor, Michelle Graham, Dan Nettleton, Jaime D. Dittman, Rex T. Nelson, Claudia V. Godoy, Ricardo V. Abdelnoor, Alvaro M.R. Almeida, Thomas J. Baum, Steven A. Whitham 2019 Iowa State University

Distinct Biphasic Mrna Changes In Response To Asian Soybean Rust Infection, Martijn Van De Mortel, Justin C. Recknor, Michelle Graham, Dan Nettleton, Jaime D. Dittman, Rex T. Nelson, Claudia V. Godoy, Ricardo V. Abdelnoor, Alvaro M.R. Almeida, Thomas J. Baum, Steven A. Whitham

Dan Nettleton

Asian soybean rust (ASR), caused by Phakopsora pachyrhizi, is now established in all major soybean-producing countries. Currently, there is little information about the molecular basis of ASR–soybean interactions, which will be needed to assist future efforts to develop effective resistance. Toward this end, abundance changes of soybean mRNAs were measured over a 7-day ASR infection time course in mock-inoculated and infected leaves of a soybean accession (PI230970) carrying the Rpp2 resistance gene and a susceptible genotype (Embrapa-48). The expression profiles of differentially expressed genes (ASR-infected compared with the mock-inoculated control) revealed a biphasic response to ASR in each genotype ...


Developmental Transcript Profiling Of Cyst Nematode Feeding Cells In Soybean Roots, Nagabhushana Ithal, Justin Recknor, Dan Nettleton, Tom Maier, Thomas J. Baum, Melissa G. Mitchum 2019 University of Missouri

Developmental Transcript Profiling Of Cyst Nematode Feeding Cells In Soybean Roots, Nagabhushana Ithal, Justin Recknor, Dan Nettleton, Tom Maier, Thomas J. Baum, Melissa G. Mitchum

Dan Nettleton

Cyst nematodes of the genus Heterodera are obligate, sedentary endoparasites that have developed highly evolved relationships with specific host plant species. Successful parasitism involves significant physiological and morphological changes to plant root cells for the formation of specialized feeding cells called syncytia. To better understand the molecular mechanisms that lead to the development of nematode feeding cells, transcript profiling was conducted on developing syncytia induced by the soybean cyst nematode Heterodera glycines in soybean roots by coupling laser capture microdissection with high-density oligonucleotide microarray analysis. This approach has identified pathways that may play intrinsic roles in syncytium induction, formation, and ...


Comparison Of Transcript Profiles In Wild-Type And O2 Maize Endosperm In Different Genetic Backgrounds, Hongwu Jia, Dan Nettleton, Joan M. Peterson, Gricelda Vasquez-Carrillo, Jean-Luc Jannink, M. Paul Scott 2019 Monsanto

Comparison Of Transcript Profiles In Wild-Type And O2 Maize Endosperm In Different Genetic Backgrounds, Hongwu Jia, Dan Nettleton, Joan M. Peterson, Gricelda Vasquez-Carrillo, Jean-Luc Jannink, M. Paul Scott

Dan Nettleton

Mutations in the Opaque2 (O2) gene of maize (Zea mays L.) improve the nutritional value of maize by reducing the level of zeins in the kernel. The phenotype of o2 grain is controlled by many modifier genes and is therefore strongly dependent on genetic background. We propose two hypotheses to explain differences in phenotypic severity in different genetic backgrounds: (i) Specific genes are differentially (o2 vs. wild-type) expressed only in certain genotypes, and (ii) A set of genes are differentially expressed in all backgrounds, but the degree of differential expression differs in different backgrounds. To determine the extent to which ...


Digital Commons powered by bepress