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Modelling The Influence Of Crop Density And Weather Conditions On Field Drying Characteristics Of Switchgrass And Maize Stover Using Random Forest, Amit Khanchi, Stuart J. Birrell, Robert B. Mitchell 2018 Iowa State University

Modelling The Influence Of Crop Density And Weather Conditions On Field Drying Characteristics Of Switchgrass And Maize Stover Using Random Forest, Amit Khanchi, Stuart J. Birrell, Robert B. Mitchell

Agricultural and Biosystems Engineering Publications

Field drying trials were conducted using both field baskets as well as grab sampling techniques to study drying behaviour of switchgrass and maize (corn) stover (CS). Environmental conditions such as hourly solar radiation, vapour pressure deficit (VPD), average wind speed, rainfall amount, harvesting method, and field operations such as swath density were used as variables for model development. A powerful classification-based algorithm, which uses a collection of decision trees called random forest (RF) was utilised to predict moisture content (MC) of switchgrass and CS on wet basis. RF predicted the MC of switchgrass and CS with a coefficient of determination ...


Genome-Wide Association Studies Of Doubled Haploid Exotic Introgression Lines For Root System Architecture Traits In Maize (Zea Mays L.), Darlene L. Sanchez, Sisi Liu, Rania Ibrahim, Michael Blanco, Thomas Lubberstedt 2018 Iowa State University

Genome-Wide Association Studies Of Doubled Haploid Exotic Introgression Lines For Root System Architecture Traits In Maize (Zea Mays L.), Darlene L. Sanchez, Sisi Liu, Rania Ibrahim, Michael Blanco, Thomas Lubberstedt

Agronomy Publications

Root system architecture (RSA) is becoming recognized as important for water and nutrient acquisition in plants. This study focuses on finding single nucleotide polymorphisms (SNPs) associated with seedling RSA traits from 300 doubled haploid (DH) lines derived from crosses between Germplasm Enhancement of Maize (GEM) accessions and inbred lines PHB47 and PHZ51. These DH lines were genotyped using 62,077 SNP markers, while root and shoot phenotype data were collected from 14-day old seedlings. Genome-wide association studies (GWAS) were conducted using three models to offset false positives/negatives. Multiple SNPs associated with seedling root traits were detected, some of which ...


Annual Net Returns To Cover Crops In Iowa, Alejandro Plastina, Fangge Liu, Wendiam Sawadgo, Fernando E. Miguez, Sarah Carlson, Guillermo Marcillo 2018 Iowa State University

Annual Net Returns To Cover Crops In Iowa, Alejandro Plastina, Fangge Liu, Wendiam Sawadgo, Fernando E. Miguez, Sarah Carlson, Guillermo Marcillo

Economics Working Papers

Despite the active promotion of cover crops as a key conservation practice, their adoption is very limited. We developed a series of partial budgets based on a statewide survey of Iowa farmers to evaluate the changes in net returns resulting from the incorporation of cover crops into a corn or soybean production system. The average net returns to cover crops use for farmers that did not use cover crops for grazing livestock or forage were consistently negative across different planting and termination methods, tillage practices, and experience levels. Only farmers that used cover crops for grazing livestock or forage, and ...


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 2018 University of Nebraska-Lincoln

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

Agronomy & 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 ...


Portable Canopy Chamber Measurements Of Evapotranspiration In Corn, Soybean, And Reconstructed Prairie, Chenyi Luo, Zhuangji Wang, Thomas J. Sauer, Matthew J. Helmers, Robert Horton 2018 Iowa State University

Portable Canopy Chamber Measurements Of Evapotranspiration In Corn, Soybean, And Reconstructed Prairie, Chenyi Luo, Zhuangji Wang, Thomas J. Sauer, Matthew J. Helmers, Robert Horton

Agricultural and Biosystems Engineering Publications

Evapotranspiration (ET) is a vital component of a field water balance. Canopy chambers are a promising method for determining crop ET because they are portable and applicable at a relatively small plot (m2) scale. Although a variety of canopy chamber designs have been proposed, field tests are still necessary to evaluate chamber performance for measuring crop ET. The objectives of this study are (1) to construct and use an improved canopy chamber to measure ET of three crops [corn (Zea mays, L.), soybean (Glycine max), and reconstructed mixed prairie] and (2) to compare the canopy chamber measurements with flux tower ...


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 2018 Purdue University

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

Agronomy & 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 ...


Qtl Mapping In Three Connected Populations Reveals A Set Of Consensus Genomic Regions For Low Temperature Germination Ability In Zea Mays L., Xuhui Li, Guihua Wang, Junjie Fu, Li Li, Guangyao Jia, Lisha Ren, Thomas Lubberstedt, Guoying Wang, Jianhua Wang, Riliang Gu 2018 China Agricultural University

Qtl Mapping In Three Connected Populations Reveals A Set Of Consensus Genomic Regions For Low Temperature Germination Ability In Zea Mays L., Xuhui Li, Guihua Wang, Junjie Fu, Li Li, Guangyao Jia, Lisha Ren, Thomas Lubberstedt, Guoying Wang, Jianhua Wang, Riliang Gu

Agronomy Publications

Improving seed vigor in response to cold stress is an important breeding objective in maize that allows early sowing. Using two cold tolerant inbred lines 220 and P9-10 and two susceptible lines Y1518 and PH4CV, three connected F2:3 populations were generated for detecting quantitative trait locus (QTL) related to seed low-temperature germination ability. At 10°C, two germination traits (emergence rate and germination index) were collected from a sand bed and three seedling traits (seedling root length, shoot length, and total length) were extracted from paper rolls. Significant correlations were found among all traits in all populations. Via single-population ...


Integrating Management Zones And Canopy Sensing To Improve Nitrogen Recommendation Algorithms, Joel D. Crowther 2018 University of Nebraska-Lincoln

Integrating Management Zones And Canopy Sensing To Improve Nitrogen Recommendation Algorithms, Joel D. Crowther

Theses, Dissertations, and Student Research in Agronomy and Horticulture

Fertilizer nitrogen use efficiency (NUE) in maize (Zea mays L.) production is historically inefficient, presenting significant environmental and economic challenges. Low NUE can be attributed to poor synchrony between soil N supply and crop demand, applying uniform rates of N fertilizer to spatially variable landscapes, and failure to account for temporal variability in crop response to N. Innovative N management strategies, including crop canopy sensing and management zones (MZ), are tools that have proven useful in increasing NUE. Several researchers have proposed that the integration of these two approaches may result in further improvements in NUE and in profitability by ...


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 2018 University of Nebraska-Lincoln

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

Agronomy & 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 ...


Prairie Strips Improve Biodiversity And The Delivery Of Multiple Ecosystem Services From Corn–Soybean Croplands, Lisa A. Schulte, Jarad Niemi, Matthew J. Helmers, Matt Liebman, J. Gordon Arbuckle, David E. James, Randall K. Kolka, Matthew E. O'Neal, Mark D. Tomer, John C. Tyndall, Heidi Asbjornsen, Pauline Drobney, Jeri Neal, Chris Witte 2018 Iowa State University

Prairie Strips Improve Biodiversity And The Delivery Of Multiple Ecosystem Services From Corn–Soybean Croplands, Lisa A. Schulte, Jarad Niemi, Matthew J. Helmers, Matt Liebman, J. Gordon Arbuckle, David E. James, Randall K. Kolka, Matthew E. O'Neal, Mark D. Tomer, John C. Tyndall, Heidi Asbjornsen, Pauline Drobney, Jeri Neal, Chris Witte

Jarad Niemi

Loss of biodiversity and degradation of ecosystem services from agricultural lands remain important challenges in the United States despite decades of spending on natural resource management. To date, conservation investment has emphasized engineering practices or vegetative strategies centered on monocultural plantings of nonnative plants, largely excluding native species from cropland. In a catchment-scale experiment, we quantified the multiple effects of integrating strips of native prairie species amid corn and soybean crops, with prairie strips arranged to arrest run-off on slopes. Replacing 10% of cropland with prairie strips increased biodiversity and ecosystem services with minimal impacts on crop production. Compared with ...


Generation Of Maize (Zea Mays) Doubled Haploids Via Traditional Methods, Kimberly Vanous, Adam Vanous, Ursula Frei, Thomas Lubberstedt 2018 Iowa State University

Generation Of Maize (Zea Mays) Doubled Haploids Via Traditional Methods, Kimberly Vanous, Adam Vanous, Ursula Frei, Thomas Lubberstedt

Thomas Lubberstedt

Commercial maize hybrid production has corroborated the usefulness of producing inbred lines; however, the delivery of new lines has always been a major time constraint in breeding programs. Traditional methods for developing inbred lines typically require 6 to 10 generations of self-pollination to obtain sufficient homozygosity. To bypass the time and costs associated with the development of inbred lines, doubled haploid (DH) systems have been widely adopted in the commercial production of maize. Within just two generations, DH systems can create completely homozygous and homogeneous lines. A typical maize DH system, utilizing anthocyanin markers R1-nj or Pl1 for haploid selection ...


Discrimination Of Haploid And Diploid Maize Kernels Via Multispectral Imaging, Gerald N. De La Fuente, Jens Michael Carstensen, Michael A. Edberg, Thomas Lubberstedt 2018 Iowa State University

Discrimination Of Haploid And Diploid Maize Kernels Via Multispectral Imaging, Gerald N. De La Fuente, Jens Michael Carstensen, Michael A. Edberg, Thomas Lubberstedt

Thomas Lubberstedt

The use of doubled haploids (DHs) in maize has become ubiquitous in maize breeding programmes as it allows breeders to go from cross to evaluation in as little as 2 years. Two important aspects of the in vivo DH system used in maize are as follows: (i) the identification of haploid progeny and (ii) doubling of the haploid genome to produce fertile inbred lines. This study is focused on the first step. Currently, identification of maize haploid progeny is performed manually using the R1-nj seed colour marker. This is a labour-intensive and time-consuming process; a method for automated sorting of ...


Aac Penhold Canada Prairie Spring Red Wheat, R. D. Cuthbert, R. M. DePauw, R. E. Knox, Asheesh K. Singh, T. N. McCaig, B. McCallum, T. Fetch, B. L. Beres 2018 Agriculture and Agri-Food Canada

Aac Penhold Canada Prairie Spring Red Wheat, R. D. Cuthbert, R. M. Depauw, R. E. Knox, Asheesh K. Singh, T. N. Mccaig, B. Mccallum, T. Fetch, B. L. Beres

Asheesh Singh

AAC Penhold, an awned hard red spring wheat (Triticum aestivum L.) cultivar, yielded significantly more grain than 5700PR while maturing 2 days earlier, and 7.5 cm shorter stature. The seed size was significantly larger than 5700PR and 5701PR, with a test weight significantly heavier than both checks. AAC Penhold expressed resistance to prevalent races of leaf rust and common bunt, and moderate resistance to fusarium head blight and stem rust. AAC Penhold had higher grain and flour protein than the checks and improved Hagberg Falling Number, amylograph viscosity, and water absorption. AAC Penhold is eligible for grades of the ...


Identifying New Sources Of Resistance To Brown Stem Rot In Soybean, Chantal E. McCabe, Asheesh K. Singh, Leonor F. Leandro, Silvia R. Cianzio, Michelle A. Graham 2018 Iowa State University

Identifying New Sources Of Resistance To Brown Stem Rot In Soybean, Chantal E. Mccabe, Asheesh K. Singh, Leonor F. Leandro, Silvia R. Cianzio, Michelle A. Graham

Asheesh Singh

Brown stem rot (BSR), caused by the fungus Phialophora gregata f. sp. sojae (Allington & D.W. Chamberlain) W. Gams (syn. Cadophora gregata), causes yield losses up to 38%. Three dominant BSR-resistant genes have been identified: Rbs1, Rbs2, and Rbs3. Additional BSR resistance loci will complement breeding efforts by expanding the soybean [Glycine max (L.) Merr.] genetic base. The objective of this research was to determine if PI 594637, PI 594638B, PI 594650A, and PI 594858B contained novel BSR resistance genes. The accessions were crossed to three genotypes with known BSR resistance genes and populations were developed for allelism studies. A ...


Leveraging Genomic Prediction To Scan Germplasm Collection For Crop Improvement, Leonardo de Azevedo Peixoto, Tara C. Moellers, Jiaoping Zhang, Aaron J. Lorenz, Leonardo L. Bhering, William D. Beavis, Asheesh K. Singh 2018 Federal University of Vicosa

Leveraging Genomic Prediction To Scan Germplasm Collection For Crop Improvement, Leonardo De Azevedo Peixoto, Tara C. Moellers, Jiaoping Zhang, Aaron J. Lorenz, Leonardo L. Bhering, William D. Beavis, Asheesh K. Singh

Asheesh Singh

The objective of this study was to explore the potential of genomic prediction (GP) for soybean resistance against Sclerotinia sclerotiorum (Lib.) de Bary, the causal agent of white mold (WM). A diverse panel of 465 soybean plant introduction accessions was phenotyped for WM resistance in replicated field and greenhouse tests. All plant accessions were previously genotyped using the SoySNP50K BeadChip. The predictive ability of six GP models were compared, and the impact of marker density and training population size on the predictive ability was investigated. Cross-prediction among environments was tested to determine the effectiveness of the prediction models. GP models ...


Advancing Our Understanding Of Charcoal Rot In Soybeans, Martha P. Romero Luna, Daren Mueller, Alemu Mengistu, Asheesh K. Singh, Glen L. Hartman, Kiersten A. Wise 2018 Purdue University

Advancing Our Understanding Of Charcoal Rot In Soybeans, Martha P. Romero Luna, Daren Mueller, Alemu Mengistu, Asheesh K. Singh, Glen L. Hartman, Kiersten A. Wise

Asheesh Singh

Charcoal rot [Macrophomina phaseolina (Tassi) Goid] of soybean [Glycine max (L.) Merr.] is an important but commonly misidentified disease, and very few summary articles exist on this pathosystem. Research conducted over the past 10 yr has improved our understanding of the environment conducive to disease development, host resistance, and improved disease diagnosis and management. This article summarizes the currently available research with an emphasis on disease management.


Delayed Senescence In Soybean: Terminology, Research Update, And Survey Results From Growers, C. J. Harbach, T. W. Allen, C. R. Bowen, J. A. Davis, C. B. Hill, M. Leitman, B. R. Leonard, D. S. Mueller, G. B. Padgett, X. A. Phillips, R. W. Schneider, E. J. Sikora, A. K. Singh, G. L. Hartman 2018 University of Illinois at Urbana-Champaign

Delayed Senescence In Soybean: Terminology, Research Update, And Survey Results From Growers, C. J. Harbach, T. W. Allen, C. R. Bowen, J. A. Davis, C. B. Hill, M. Leitman, B. R. Leonard, D. S. Mueller, G. B. Padgett, X. A. Phillips, R. W. Schneider, E. J. Sikora, A. K. Singh, G. L. Hartman

Asheesh Singh

The terms used to describe symptoms of delayed senescence in soybean often are used inconsistently or interchangeably and do not adequately distinguish the observed symptoms in the field. Various causes have been proposed to explain the development of delayed senescence symptoms. In this article, we review published reports on delayed senescence symptoms in soybean, summarize current research findings, provide examples of terms related to specific symptoms, and present an overview of the results of a multi-state survey directed to soybean growers to understand their concerns about delayed soybean senescence. Some of these terms, such as green bean syndrome and green ...


Main And Epistatic Loci Studies In Soybean For Sclerotinia Sclerotiorum Resistance Reveal Multiple Modes Of Resistance In Multi-Environments, Tara C. Moellers, Arti Singh, Jiaoping Zhang, Jae Brungardt, Mehdi Kabbage, Daren S. Mueller, Craig R. Grau, Ashish Ranjan, Damon L. Smith, R. V. Chowdy-Reddy, Asheesh K. Singh 2018 Iowa State University

Main And Epistatic Loci Studies In Soybean For Sclerotinia Sclerotiorum Resistance Reveal Multiple Modes Of Resistance In Multi-Environments, Tara C. Moellers, Arti Singh, Jiaoping Zhang, Jae Brungardt, Mehdi Kabbage, Daren S. Mueller, Craig R. Grau, Ashish Ranjan, Damon L. Smith, R. V. Chowdy-Reddy, Asheesh K. Singh

Asheesh Singh

Genome-wide association (GWAS) and epistatic (GWES) studies along with expression studies in soybean [Glycine max (L.) Merr.] were leveraged to dissect the genetics of Sclerotinia stem rot (SSR) [caused by Sclerotinia sclerotiorum (Lib.) de Bary], a significant fungal disease causing yield and quality losses. A large association panel of 466 diverse plant introduction accessions were phenotyped in multiple field and controlled environments to: (1) discover sources of resistance, (2) identify SNPs associated with resistance, and (3) determine putative candidate genes to elucidate the mode of resistance. We report 58 significant main effect loci and 24 significant epistatic interactions associated with ...


Genetic Architecture Of Charcoal Rot (Macrophomina Phaseolina) Resistance In Soybean Revealed Using A Diverse Panel, Sara M. Coser, R. V. Chowda Reddy, Jiaoping Zhang, Daren S. Mueller, Alemu Mengistu, Kiersten A. Wise, Tom W. Allen, Arti Singh, Asheesh K. Singh 2018 Iowa State University

Genetic Architecture Of Charcoal Rot (Macrophomina Phaseolina) Resistance In Soybean Revealed Using A Diverse Panel, Sara M. Coser, R. V. Chowda Reddy, Jiaoping Zhang, Daren S. Mueller, Alemu Mengistu, Kiersten A. Wise, Tom W. Allen, Arti Singh, Asheesh K. Singh

Asheesh Singh

Charcoal rot (CR) disease caused by Macrophomina phaseolina is responsible for significant yield losses in soybean production. Among the methods available for controlling this disease, breeding for resistance is the most promising. Progress in breeding efforts has been slow due to the insufficient information available on the genetic mechanisms related to resistance. Genome-wide association studies (GWAS) enable unraveling the genetic architecture of resistance and identification of causal genes. The aims of this study were to identify new sources of resistance to CR in a collection of 459 diverse plant introductions from the USDA Soybean Germplasm Core Collection using field and ...


Arizona Registered Dietitians Show Gaps In Knowledge Of Bean Health Benefits, Donna M. Winham, Andrea M. Hutchins, Sharon V. Thompson, Mariah K. Dougherty 2018 Iowa State University

Arizona Registered Dietitians Show Gaps In Knowledge Of Bean Health Benefits, Donna M. Winham, Andrea M. Hutchins, Sharon V. Thompson, Mariah K. Dougherty

Donna Winham

Registered Dietitians (RDs) promote nutrition practices and policies and can influence food consumption patterns to include nutrient dense foods such as beans. Although many evidence-based health benefits of bean consumption (e.g., cholesterol reduction, glycemic control) have been demonstrated, there is limited research on the knowledge, attitudes, and perceptions of RDs regarding the inclusion of beans in a healthy diet. To fill this existing research gap, this cross-sectional survey explored the perceptions, knowledge, and attitudes of 296 RDs in Arizona, USA, toward beans. The RDs largely held positive attitudes toward the healthfulness of beans and were aware of many health ...


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