Agronomy and Crop Sciences Commons^™

Influence Of Harvest Date On Seed Yield And Quality In Forage Kochia, Cody F. Creech, Blair L. Waldron, Corey V. Ransom, Dale R. Zobell, Joseph Earl Creech

Department of Agronomy and Horticulture: Faculty Publications

Forage kochia (Bassia prostrata) is used for rangeland reclamation and livestock and wildlife forage, but limited research has been conducted on its seed production. Therefore, this research evaluated the effect of harvest date on seed weight, germination, and seed yield of forage kochia subspecies virescens and grisea. Seed was harvested from individual plants for 3 years during October, November, and December. October harvest had the lightest 100-seed weights, with the November harvest slightly heavier than December, for most accessions. Cultivar Snowstorm and breeding line Sahsel, both subsp. grisea, had the greatest 100-seed weights in November, 155 …

Maize And Soybean Root Front Velocity And Maximum Depth In Iowa, Usa, Raziel A. Ordóñez, Michael J. Castellano, J. L. Hatfield, M. J. Helmers, Mark A. Licht, Matt Liebman, Ranae Dietzel, Rafael Martinez-Feria, Javed Iqbal, Laila A. Puntel, S. Carolina Córdova, Kaitlin Togliatti, Emily E. Wright, Sotirios V. Archontoulis

Department of Agronomy and Horticulture: Faculty Publications

Quantitative measurements of root traits can improve our understanding of how crops respond to soil and weather conditions, but such data are rare. Our objective was to quantify maximum root depth and root front velocity (RFV) for maize (Zea mays) and soybean (Glycine max) crops across a range of growing conditions in the Midwest USA. Two sets of root measurements were taken every 10–15 days: in the crop row (in-row) and between two crop rows (center-row) across six Iowa sites having different management practices such as planting dates and drainage systems, totaling 20 replicated experimental treatments. …

Sequences Involved In Plant Yield And Methods Of Using, Harkamal Walia, Dante Placido, Thomas E. Clemente

Department of Agronomy and Horticulture: Faculty Publications

Nucleic acid sequences involved in plant yield are provided, as are methods of using such nucleic acid sequences .

Building Resilience In Social-Ecological Food Systems In Vermont, Kristine Lien Skog, Stine Elisabeth Eriksen, Christy Anderson Brekken, Charles A. Francis

Department of Agronomy and Horticulture: Faculty Publications

There is an expanding interest in Local Food Systems (LFSs) in Vermont, United States, along with a growing effort to create adaptive governance to facilitate action. In this case study, we investigate how adaptive governance of LFS can provide ideas and act as a catalyst for creating resilience in other social-ecological systems (SESs). By participating in meetings and interviewing stakeholders inside and outside the Vermont LFS network, we found that consumers were highly motivated to participate by supporting environmental issues, the local economy, and interactive communities, as well as building social relationships. Farmers experienced better income and increased respect in …

Identification Of Quantitative Trait Loci Conferring Resistance To Tan Spot In A Biparental Population Derived From Two Nebraska Hard Red Winter Wheat Cultivars, Gayan K. Kariyawasam, Waseem Hussain, Amanda Easterly, Mary Guttieri, Vikas Belamkar, Jesse Poland, Jorge Venegas, Stephen Baenziger, Francois Marais, Jack B. Rasmussen, Zhaohui Liu

Department of Agronomy and Horticulture: Faculty Publications

Tan spot, caused by Pyrenophora triticirepentis (Ptr), is a destructive foliar disease in all types of cultivated wheat worldwide. Genetics of tan spot resistance in wheat is complex, involving insensitivity to fungal-produced necrotrophic effectors (NEs), major resistance genes, and quantitative trait loci (QTL) conferring race-nonspecific and race-specific resistance. The Nebraska hard red winter wheat (HRWW) cultivar ‘Wesley’ is insensitive to Ptr ToxA and highly resistant to multiple Ptr races, but the genetics of resistance in this cultivar is unknown. In this study, we used a recombinant inbred line (RIL) population derived from a cross between Wesley and another …

Improving An Active-Optical Reflectance Sensor Algorithm Using Soil And Weather Information, G. M. Bean, N. R. Kitchen, J. J. Camberato, R. B. Ferguson, F. G. Fernandez, D. W. Franzen, C. A. M. Laboski, E. D. Nafziger, J. E. Sawyer, P. C. Scharf, J. Schepers, J. S. Shanahan

Department of Agronomy and Horticulture: Faculty Publications

Active-optical reflectance sensors (AORS) use light reflectance characteristics from a crop canopy as an indicator of the plant’s N health. However, studies have shown AORS algorithms used in conjunction with measured reflectance characteristics for corn (Zea mays L.) N fertilizer rate recommendations are not consistently accurate. Our objective was to determine if soil and weather information could be utilized with an AORS algorithm developed at the University of Missouri (ALG_MU) to improve in-season (~V9 corn development stage) N fertilizer recommendations. Nitrogen response trials were conducted across eight states over three growing seasons, totaling 49 sites with soils …

Active-Optical Reflectance Sensing Corn Algorithms Evaluated Over The United States Midwest Corn Belt, G. M. Bean, N. R. Kitchen, J. J. Camberato, R. B. Ferguson, F. G. Fernandez, D. W. Franzen, C. A. M. Laboski, E. D. Nafziger, J. E. Sawyer, P. C. Scharf, J. Schepers, J. S. Shanahan

Department of Agronomy and Horticulture: Faculty Publications

Uncertainty exists with corn (Zea mays L.) N management due to year-to-year variation in crop N need, soil N supply, and N loss from leaching, volatilization, and denitrification. Activeoptical reflectance sensing (AORS) has proven effective in some fields for generating N fertilizer recommendations that improve N use efficiency, but locally derived (e.g., within a US state) AORS algorithms have not been tested simultaneously across a broad region. The objective of this research was to evaluate locally developed AORS algorithms across the US Midwest Corn Belt region for making in-season corn N recommendations. Forty-nine N response trials were conducted across …

Lignocellulosic-Based Bioenergy And Water Quality Parameters: A Review, Bharat Sharma Acharya, Humberto Blanco-Canqui

Department of Agronomy and Horticulture: Faculty Publications

High rates of crop residue removal as biofuel feedstocks could increase losses of nonpoint source pollutants, negatively affecting water quality. An alternative to residue removal can be growing dedicated bioenergy crops such as warm season grasses (WSGs) and short-rotation woody crops (SRWCs). Yet, our understanding of the implications of growing dedicated bioenergy crops on water quality is limited. Thus, we (i) synthesized and compared the impacts of crop residue removal, WSGs, and SRWCs on water quality parameters (i.e., sediment and nutrient runoff, and nutrient leaching) and (ii) identified research gaps for growing dedicated energy crops. Literature indicates that residue removal …

Hops On A Quarter-Acre, Stacy A. Adams

Department of Agronomy and Horticulture: Faculty Publications

This publication presents information on how to develop a quarter-acre hop yard, suitably sized to explore the unique production methods associated with this specialty crop. Emerging growers with an interest in growing hop should gain knowledge about its unique plant growth and development, culture, common pests and diseases, and harvest handling. Using information in this publication, growers should be able to experiment with hop production and harvesting so that they can develop a measured vision for future production of this crop.

Epigenomic Plasticity Of Arabidopsis Msh1 Mutants Under Prolonged Cold Stress, Sunil Kumar Kenchanmane Raju, Mon-Ray Shao, Yashitola Wamboldt, Sally A. Mackenzie

Department of Agronomy and Horticulture: Faculty Publications

Dynamic transcriptional and epigenetic changes enable rapid adaptive benefit to environmental fluctuations. However, the underlying mechanisms and the extent to which this occurs are not well known. MutS Homolog 1 (MSH1) mutants cause heritable developmental phenotypes accompanied by modulation of defense, phytohormone, stress‐response, and circadian rhythm genes, as well as heritable changes in DNA methylation patterns. Consistent with gene expression changes, msh1 mutants display enhanced tolerance for abiotic stress including drought and salt stress, while showing increased susceptibility to freezing temperatures. Despite changes in defense and biotic stress‐response genes, msh1 mutants showed increasing susceptibility to the bacterial pathogen Pseudomonas syringae. …

Can Bangladesh Produce Enough Cereals To Meet Future Demand?, J. Timsina, J. Wolf, N. Guilpart, L G. J. Van Bussel, P. Grassini, J. Van Wart, A. Hossain, H. Rashid, S. Islam, M. K. Van Ittersum

Department of Agronomy and Horticulture: Faculty Publications

Bangladesh faces huge challenges in achieving food security due to its high population, diet changes, and limited room for expanding cropland and cropping intensity. The objective of this study is to assess the degree to which Bangladesh can be self-sufficient in terms of domestic maize, rice and wheat production by the years 2030 and 2050 by closing the existing gap (Yg) between yield potential (Yp) and actual farm yield (Ya), accounting for possible changes in cropland area. Yield potential and yield gaps were calculated for the three crops using well-validated crop models and site-specific weather,management and soil data, and upscaled …

Parallel Altitudinal Clines Reveal Trends In Adaptive Evolution Of Genome Size In Zea Mays, Paul Bilinski, Patrice S. Albert, Jeremy J. Berg, James A. Birchler, Mark N. Grote, Anne Lorant, Juvenal Quezada, Kelly Swarts, Jinliang Yang, Jeffrey Ross-Ibarra

Department of Agronomy and Horticulture: Faculty Publications

While the vast majority of genome size variation in plants is due to differences in repetitive sequence, we know little about how selection acts on repeat content in natural populations. Here we investigate parallel changes in intraspecific genome size and repeat content of domesticated maize (Zea mays) landraces and their wild relative teosinte across altitudinal gradients in Mesoamerica and South America. We combine genotyping, low coverage whole-genome sequence data, and flow cytometry to test for evidence of selection on genome size and individual repeat abundance. We find that population structure alone cannot explain the observed variation, implying that …

Genomic Prediction Accuracy For Switchgrass Traits Related To Bioenergy Within Differentiated Populations, Jason D. Fiedler, Christina Lanzatella, Serge J. Edme, Nathan A. Palmer, Gautam Sarath, Rob Mitchell, Christian M. Tobias

Department of Agronomy and Horticulture: Faculty Publications

Background: Switchgrass breeders need to improve the rates of genetic gain in many bioenergy-related traits in order to create improved cultivars that are higher yielding and have optimal biomass composition. One way to achieve this is through genomic selection. However, the heritability of traits needs to be determined as well as the accuracy of prediction in order to determine if efficient selection is possible.

Results: Using five distinct switchgrass populations comprised of three lowland, one upland and one hybrid accession, the accuracy of genomic predictions under different cross-validation strategies and prediction methods was investigated. Individual genotypes were collected using GBS …

Method For The Production Of High Saturated, Low Polyunsaturated Soybean Oil, Thomas E. Clemente, Hyunwoo Park, Edgar B. Cahoon, Hanh Nguyen

Department of Agronomy and Horticulture: Faculty Publications

Methods of genetically modifying soybean plants to alter the fatty acid properties of the oil are described.

Comparison Of Soil-Applied And Postemergence Herbicides With Multiple Sites Of Herbicidal Activity On Two Populations Of Herbicide-Resistant Palmer Amaranth In Kentucky, Nicholas J. Fleitz

Theses and Dissertations--Plant and Soil Sciences

With the introduction of herbicide resistant Palmer amaranth into Kentucky during the past 10 years there has been an increasing concern for effective control measures in grain production. Field trials were performed in 2016 and 2017 near Barlow and Paris, KY to determine efficacy of chemical control programs targeting herbicide resistant Palmer amaranth. Percent visual control, effects on plant density and plant height were measured in 2016 to determine treatment effectiveness. Treatments containing four different sites of herbicide activity achieved an average of 98% control. Treatments containing only 3, 2 or 1 site of activity only achieved 64%, 45% and …

Chemical Topping Burley Tobacco, Mitchell D. Richmond

Theses and Dissertations--Plant and Soil Sciences

The act of topping tobacco (Nicotiana tabacum L.) involves the removal of the terminal bud or inflorescence of the tobacco plant. This practice ordinarily is accomplished by manually removing the top of each tobacco plant in an entire field which is labor intensive and costly. Chemical topping utilizes sucker control products to inhibit the terminal bud and axillary bud growth without manually removing the top of the tobacco plant. There were several research objectives in order to determine the utility of a chemical topping system: 1) determine if burley tobacco could be chemically topped with currently registered suckercide products …

Ecophysiological Analysis Of Yield Determination In Soybean Of Different Relative Maturities, Maria Morrogh Bernard

Theses and Dissertations--Plant and Soil Sciences

Soybean yield differences are a combination of the genotype, environmental conditions, and management practices. Understanding how these factors interact through the analysis of the components involved in yield determination, provides a way to increase potential and actual yields in Kentucky.

Two irrigated experiments were conducted to quantify differences in the mechanisms of yield determination across soybean maturity groups (MG) 2 to 5 (Chapter 1), and to quantify management options (seeding rate and choice of MG cultivar) that increase yield potential of double crop soybean systems (Chapter 2).

Results showed that cultivars used different physiological strategies to achieve high yields, but …

Cc-Type Glutaredoxins Mediate Plant Response And Signaling Under Nitrate Starvation In Arabidopsis, Ji-Yul Jung, Ji Hoon Ahn, Daniel P. Schachtman

Department of Agronomy and Horticulture: Faculty Publications

Background: Nitrogen is an essential nutrient in plants. Despite the importance of nitrogen for plant growth and agricultural productivity, signal transduction pathways in response to nitrate starvation have not been fully elucidated in plants.

Results: Gene expression analysis and ectopic expression were used to discover that many CC-type glutaredoxins (ROXYs) are differentially expressed in response to nitrate deprivation. A gain-of-function approach showed that ROXYs may play a role in nutrient sensing through the regulation of chlorophyll content, root hair growth, and transcription of nitrate-related genes such as NRT2.1 under low or high nitrate conditions. Reactive oxygen species (ROS) …

Risks And Opportunities Of Gm Crops: Bt Maize Example, Andrea K. Carzoli, Siddique I. Aboobucker, Leah L. Sandall, Thomas T. Lubberstedt, Walter P. Suza

Department of Agronomy and Horticulture: Faculty Publications

The anticipated world population growth emphasizes a need to produce more food on less land. Cutting-edge technologies, including genetic engineering, can help to develop improved crop varieties and protect natural resources. In spite of the potential for genetically-modified (GM) crops to make crop production more efficient, they remain a polarizing issue due to safety concerns. This paper provides an overview of the risk assessment process. The safety of Bacillus thuringiensis (Bt) proteins is used as an example for how risk assessment is applied to GM crops. Risks associated with GM crops have proven to be low to non-existent. Developing countries …