Agronomy and Crop Sciences Commons^™

Site-Specific Pest Management In Nebraska Corn And Soybean Production Systems, Zachary D. Rystrom

Doctor of Plant Health Program: Dissertations and Student Research

Site-specific management (SSM) is widely used by farm producers to fertilize their fields. However, whole field management is currently practiced in integrated pest management (IPM). Site-specific management and agricultural technology can improve IPM especially when precision application of inputs can reduce selection pressure on pest populations, benefit the environment, or save costs of inputs. There is potential for site-specific pest management (SSPM) where pests, or environments vary spatially, and recommended management practices can be applied with precision. Three case studies are evaluated for SSPM to be applied in Nebraska corn and soybean production systems including corn rootworm, preemergence herbicides, and …

Exploration Of Genes Controlling Grain Yield Heterosis In Hybrid Wheat (Triticum Aestivum L.) Utilizing 3ʹ Rna Sequencing, Nichole Lynn Miller

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

The implementation and future success of hybrid wheat (Triticum aestivum L.) is impacted by breeders’ inability to create consistent high yielding, high heterosis hybrids. This research addresses this problem by conducting an exploration of transcriptomes from hybrids and parent lines to determine what genes are active in heterotic or non-heterotic hybrids and how their level of expression can explain the phenotype of grain yield heterosis. Using hybrids that showed positive mid-parent heterosis (MPH), classified as heterotic in our study, and negative or no difference MPH hybrids, classified as non-heterotic, differentially expressed genes (DEGs) potentially related to heterosis and hybrid …

Winter Cover Crop Impacts On Weed Dynamics In Eastern And Central Nebraska, Elizabeth Ann Oys

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

Reducing tillage in cropping systems causes weed management to be dependent on chemical and cultural methods for weed control. Over time, herbicide-resistant weeds have developed due to the continuous selection pressures from herbicides, particularly in the Midwest Corn Belt. Integrated weed management strategies, such as cover crops, can be used to mitigate some of these issues. Cover crops are primarily known for their soil health benefits, but there is evidence that cover crops can suppress weeds. However, less research has been done at the field-scale level to address cover crop impacts on the weed seedbank and aboveground weeds during the …

Dicamba Tank Mixtures And Formulations And Their Effects On Sensitive Crops During Cleanout Procedures, Vinicius Velho

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

The introduction of dicamba-tolerant (DT) soybeans (Glycine max L. Merr) and cotton (Gossypium hirsutum L) in 2017 provided an additional tool for herbicide resistant weeds management. In the subsequent years, off-target movement of dicamba allegedly caused damage to sensitive crops and vegetation.

Possible causes of off-target movement include tank contamination, physical drift, and volatility. Additional products, such as herbicides to control grass, are often added to tank with dicamba, which is used to control broadleaf weeds, to increase the spectrum of control and application efficiency. Dicamba products registered for DT crops require the use of drift reducing …

Regional Plant Community Differences In The Nebraska Sandhills, Travis Millikan

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

The Nebraska Sandhills is very valuable to the state of Nebraska, representing one of the most in-tact and largest grassland ecosystems in temperate regions in the world. Rangeland managers must understand plant community dynamics across the Sandhills to better inform management decisions. The first objective of this study was to evaluate plant community variability on upland Sands ecological sites across different precipitation zones in the Nebraska Sandhills. The second objective of our study was to utilize the Rangeland Analysis Platform (RAP) to examine spatial and temporal variability in biomass production and cover on pastures of ranches analyzed in the first …

Chromosome-Level Thlaspi Arvense Genome Provides New Tools For Translational Research And For A Newly Domesticated Cash Cover Crop Of The Cooler Climates, Adam Nunn, Isaac Rodríguez-Arévalo, Zenith Tandukar, Katherine Anna Frels, Adrián Contreras-Garrido, Pablo Carbonell-Bejerano, Panpan Zhang, Daniela Ramos Cruz, Katharina Jandrasits, Christa Lanz, Anthony Brusa, Marie Mirouze, Kevin Dorn, David W. Galbraith, Brice A. Jarvis, John C. Sedbrook, Donald L. Wyse, Christian Otto, David Langenberger, Peter F. Stadler, Detlef Weigel, M. David Marks, James A. Anderson, Claude Becker, Ratan Chopra

Department of Agronomy and Horticulture: Faculty Publications

Thlaspi arvense (field pennycress) is being domesticated as a winter annual oilseed crop capable of improving ecosystems and intensifying agricultural productivity without increasing land use. It is a selfing diploid with a short life cycle and is amenable to genetic manipulations, making it an accessible field-based model species for genetics and epigenetics. The availability of a high-quality reference genome is vital for understanding pennycress physiology and for clarifying its evolutionary history within the Brassicaceae. Here, we present a chromosome-level genome assembly of var. MN106-Ref with improved gene annotation and use it to investigate gene structure differences between two accessions (MN108 …

Agricultural Intensification Can Help Protect The Amazon Forest And Reduce Global Warming / Protecting The Amazon Forest And Reducing Global Warming Via Agricultural Intensification, Fabio R. Marin, Alencar J. Zanon, Juan P. Monzon, José F. Andrade, Evandro H.F.M. Silva, Gean L. Richter, Luis A.S. Antolin, Bruna S.M.R. Ribeiro, Giovanna G. Ribas, Rafael Battisti, Alexandre B. Heinemann, Patricio Grassini

Department of Agronomy and Horticulture: Faculty Publications

The Amazon basin includes 550 M ha covered with rainforests, with 60% of this area being in Brazil. Conversion of rainforest for soybean production raises concerns about the degree to which Brazil can reconcile production and environmental goals. Here we investigated the degree to which intensification could help Brazil produce more soybean without further encroachment of the Amazon Forest. Our analysis shows that continuation of current trends in soybean yield and area would lead to conversion of additional 5.7 M ha of forests and savannas during the next 15 years, with an associated 2550 Mt of CO2eq released into the …

Climate Change And Management Impacts On Soybean N Fixation, Soil N Mineralization, N2O Emissions, And Seed Yield, Elvis F. Elli, Ignacio A. Ciampitti, Michael J. Castellano, Larry C. Purcell, Seth Naeve, Patricio Grassini, Nicolas C. La Menza, Luiz Moro Rosso, André F. De Borja Reis, Péter Kovács, Sotirios V. Archontoulis

Department of Agronomy and Horticulture: Faculty Publications

Limited knowledge about how nitrogen (N) dynamics are affected by climate change, weather variability, and crop management is a major barrier to improving the productivity and environmental performance of soybean-based cropping systems. To fill this knowledge gap, we created a systems understanding of agroecosystem N dynamics and quantified the impact of controllable (management) and uncontrollable (weather, climate) factors on N fluxes and soybean yields. We performed a simulation experiment across 10 soybean production environments in the United States using the Agricultural Production Systems sIMulator (APSIM) model and future climate projections from five global circulation models. Climate change (2020–2080) increased N …

Two Fingerprinting Sets For Humulus Lupulus Based On Kasp And Microsatellite Markers, Mandie Driskill, Katie Pardee, Kim E. Hummer, Jason D. Zurni, Keenan L. Amundsen, Annette Wiles, Claudia Wiedowi, Josef Patza, John A. Henningi, Nahla V. Bassili

Department of Agronomy and Horticulture: Faculty Publications

Verification of clonal identity of hop (Humulus lupulus L.) cultivars within breeding programs and germplasm collections is vital to conserving genetic resources. Accurate and economic DNA-based tools are needed in dioecious hop to confirm identity and parentage, neither of which can be reliably determined from morphological observations. In this study, we developed two fingerprinting sets for hop: a 9-SSR fingerprinting set containing high-core repeats that can be run in a single PCR reaction and a kompetitive allele specific PCR (KASP) assay of 25 single nucleotide polymorphisms (SNPs). The SSR set contains a sex-linked primer pair, HI-AGA7, that was used …

Variation In Bacterial Community Structure Under Long-Term Fertilization, Tillage, And Cover Cropping In Continuous Cotton Production, Ning Duan, Lidong Li, Xiaolong Liang, Aubrey Fine, Jie Zhuang, Mark Radosevich, Sean M. Schaeffer

Department of Agronomy and Horticulture: Faculty Publications

Agricultural practices alter the structure and functions of soil microbial community. However, few studies have documented the alterations of bacterial communities in soils under long-term conservation management practices for continuous crop production. In this study, we evaluated soil bacterial diversity using 16S rRNA gene sequencing and soil physical and chemical properties within 12 combinations of inorganic N fertilization, cover cropping, and tillage throughout a cotton production cycle. Soil was collected from field plots of the West Tennessee Agriculture Research and Education Center in Jackson, TN, United States. The site has been under continuous cotton production for 38 years. A total …

Soybean Gall Midge (Resseliella Maxima Gagné): Insecticide Efficacy And Seasonal Larval Abundance, Vilma Maria Montenegro Castro

Department of Entomology: Dissertations, Theses, and Student Research

Soybean gall midge, Resseliella maxima Gagné was recently identified as a new species injuring soybean in Nebraska, Iowa, South Dakota, Minnesota, and Missouri. Resseliella maxima injury is caused by its three instars that feed on tissues within the soybean stem. Infested plants exhibit a darkening of the stem, disrupting nutrient flow within the plant and can lead to wilting or death of plants. Total yield losses can occur in the first 30 m of the field in heavily infested sites. The biology and behavior of this newly described insects is not well understood and management strategies for the management of …

Evaluating Traits Influencing Hybrid Wheat Seed Production Using A Double Haploid Population Derived From Freeman × Camelot, Emre Karahan

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

Hybrid wheat (Triticum aestivum L.) cultivars are preferred for their advanced agronomic traits such as a yield improvement increase up to 20%. However, hybrid cultivars remain difficult to produce on a commercial scale due to inadequate pollen dispersal, the closed nature of the wheat floret and the high cost of inducing sterility or restoring fertility in cleistogamous wheat. Redesigning parent-specific traits and understanding their potential interactions with related agronomic traits are needed to breed improved male lines in hybrid seed production fields. To better understand the genetic control of anther extrusion (AE), 174 double haploid lines derived from Freeman …

Cattle Diet Selection During The Growing Season On Upland Sandhills Rangelands, Alejandro Orozco-Lopez

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

The Sandhills is a diverse and complex ecosystem comprised of different topographic positions (i.e. slopes and interdunes) that influence grazing distribution, plant species composition, and cattle diet selection. The first objective of this study was to evaluate how grazing intensity influences species composition on slopes and interdunes on native rangeland within the Hillside pasture (160 ha) at the UNL Gudmundsen Sandhill’s Laboratory (GSL). The second objective of this study was to evaluate forage quality of individual species from three plant functional groups (i.e. warm-season grasses, cool-season grasses, and forbs/shrubs) on native rangeland within the Hillside pasture (160 ha) at GSL. …

Fine Mapping And Cloning Of The Major Seed Protein Quantitative Trait Loci On Soybean Chromosome 20, Christina E. Fliege, Russell A. Ward, Pamela Vogel, Hanh Nguyen, Truyen Quach, Ming Guo, João Paulo Gomes Viana, Lucas Borges Dos Santos, James Specht, Thomas Clemente, Matthew E. Hudson, Brian W. Diers

Department of Agronomy and Horticulture: Faculty Publications

Soybean [Glycine max (L.) Merr.] is a unique crop species because it has high levels of both protein and oil in its seed. Of the many quantitative trait loci (QTL) controlling soybean seed protein content, alleles of the cqSeed protein-003 QTL on chromosome 20 exert the greatest additive effect. The high-protein allele exists in both cultivated and wild soybean (Glycine soja Siebold & Zucc.) germplasm. Our objective was to fine map this QTL to enable positional-based cloning of its underlying causative gene(s). Fine mapping was achieved by developing and testing a series of populations in which the chromosomal region surrounding …

Microbiome Variation Across Populations Of Desert Halophyte Zygophyllum Qatarensis, Abdul Latif Khan, Lucas Dantas Lopes, Saqib Bilal, Sajjad Asaf, Kerri M. Crawford, Venkatesh Balan, Ahmed Al-Rawahi, Ahmed Al-Harrasi, Daniel P. Schachtman

Department of Agronomy and Horticulture: Faculty Publications

Microbial symbionts play a significant role in plant health and stress tolerance. However, few studies exist that address rare species of core-microbiome function during abiotic stress. In the current study, we compared the microbiome composition of succulent dwarf shrub halophyte Zygophyllum qatarensis Hadidi across desert populations. The results showed that rhizospheric and endosphere microbiome greatly varied due to soil texture (sandy and gravel). No specific bacterial amplicon sequence variants were observed in the core-microbiome of bulk soil and rhizosphere, however, bacterial genus Alcaligenes and fungal genus Acidea were abundantly distributed across root and shoot endospheres. We also analyzed major nutrients …

Microbiome Variation Across Populations Of Desert Halophyte Zygophyllum Qatarensis, Abdul Latif Khan, Lucas Dantas Lopes, Saqib Bilal, Sajjad Asaf, Kerri M. Crawford, Venkatesh Balan, Ahmed Al-Rawahi, Ahmed Al-Harrasi, Daniel P. Schachtman

Department of Agronomy and Horticulture: Faculty Publications

Microbial symbionts play a significant role in plant health and stress tolerance. However, few studies exist that address rare species of core-microbiome function during abiotic stress. In the current study, we compared the microbiome composition of succulent dwarf shrub halophyte Zygophyllum qatarensis Hadidi across desert populations. The results showed that rhizospheric and endosphere microbiome greatly varied due to soil texture (sandy and gravel). No specific bacterial amplicon sequence variants were observed in the core-microbiome of bulk soil and rhizosphere, however, bacterial genus Alcaligenes and fungal genus Acidea were abundantly distributed across root and shoot endospheres. We also analyzed major nutrients …

Seabem: An Artificial Intelligence Powered Web Application To Predict Cover Crop Biomass, Aime Christian Tuyishime, Andrea Basche

Honors Program: Senior Projects (Public)

SEABEM, the Stacked Ensemble Algorithms Biomass Estimator Model, is a web application with a stacked ensemble of Machine Learning (ML) algorithms running on the backend to predict cover crop biomass for locations in Sub-Saharan. The SEABEM model was developed using a previously developed database of crop growth and yield that included site characteristics such as latitude, longitude, soil texture (sand, silt, and clay percentages), temperature, and precipitation. The goal of SEABEM is to provide global farmers, mainly small-scale African farmers, the knowledge they need before practicing and benefiting from cover crops while avoiding the expensive and time-consuming operations that come …

A Global Soil Spectral Calibration Library And Estimation Service, Keith D. Sheperd, Rich Ferguson, David Hoover, Fenny Van Egmond, Jonathan Sanderman, Yufeng Ge

Department of Agronomy and Horticulture: Faculty Publications

There is growing global interest in the potential for soil reflectance spectroscopy to fill an urgent need for more data on soil properties for improved decision-making on soil security at local to global scales. This is driven by the capability of soil spectroscopy to estimate a wide range of soil properties from a rapid, inexpensive, and highly reproducible measurement using only light. However, several obstacles are preventing wider adoption of soil spectroscopy. The biggest obstacles are the large variation in the soil analytical methods and operating procedures used in different laboratories, poor reproducibility of analyses within and amongst laboratories and …

Southeast Asia Must Narrow Down The Yield Gap To Continue To Be A Major Rice Bowl, Shen Yuan, Alexander M. Stuart, Alice G. Laborte, Juan I. Rattalino Edreira, Achim Dobermann, Le Vu Ngoc Kien, Lưu Thị Thúy, Kritkamol Paothong, Prachya Traesang, Khin Myo Tint, Su Su San, Marcelino Q. Villafuerte Ii, Emma D. Quicho, Anny Ruth P. Pame, Rathmuny Then, Rica Joy Flor, Neak Thon, Fahmuddin Agus, Nurwulan Agustiani, Nanyan Deng, Tao Li, Patricio Grassini

Department of Agronomy and Horticulture: Faculty Publications

Southeast Asia is a major rice-producing region with a high level of internal consumption and accounting for 40% of global rice exports. Limited land resources, climate change and yield stagnation during recent years have once again raised concerns about the capacity of the region to remain as a large net exporter. Here we use a modelling approach to map rice yield gaps and assess production potential and net exports by 2040. We find that the average yield gap represents 48% of the yield potential estimate for the region, but there are substantial differences among countries. Exploitable yield gaps are relatively …

Editorial: Genomics-Enabled Triticeae Improvement, Xue-Feng Ma, Xianchun Xia, Shuyu Liu, P. Stephen Baenziger, Hakan Özkan

Department of Agronomy and Horticulture: Faculty Publications

No abstract provided.

Source Of Off-Type Frequencies In Winter Wheat Varieties, Michaela Benes

Honors Program: Senior Projects (Public)

The enzyme polyphenol oxidase (PPO) is undesirable in most wheat products due to the discoloration it causes. Purifying wheat varieties through selective breeding is the best way at getting rid of PPO in a variety. The variety NW15443 was planted in both a field in McCook, NE, and in a greenhouse in Lincoln, NE. Individual heads were snapped from the field and the greenhouse seed was harvested in bulk. After completing a PPO test of the seed, it was determined that the percentages of off-type frequencies from the field seed and the greenhouse seed were 11% and 3.6%, respectively. Using …

Influence Of Fertilizer Rate On Swollen Stem Formation (“Bulbing”) And Vitamin C Content In Different Kohlrabi Cultivars, Mark Iradukunda, Paul E. Read

Honors Program: Senior Projects (Public)

Kohlrabi (Brassica oleracea Gongylodes Group) is a vegetable crop found in the Brassicaceae, and it is rich in antioxidants such as vitamin C. Vitamin C helps in oxidative damage repair and strengthens the immune system, so exploring vitamin C sources may contribute to improving human health. The objective of this study was to determine the effect of different fertilizer rates on kohlrabi yield, in terms of the swollen stem and the vitamin C content, and if those effects are similar in different kohlrabi cultivars. In this greenhouse study, we fertilized four potted kohlrabi cultivars with a common water-soluble greenhouse fertilizer …

No-Till Farming And Greenhouse Gas Fluxes: Insights From Literature And Experimental Data, S. J. Ruis, H. Blanco-Canqui, P. J. Jasa, V. L. Jin

Department of Agronomy and Horticulture: Faculty Publications

Tillage intensity may differently impact gaseous losses of C and N to the atmosphere, but data from long-term experiments are relatively few. Yet, this information is needed to better understand C and N losses and gains in agricultural systems. The objective of this study was to determine how tillage intensity affects soil greenhouse gas (GHG) fluxes (CO₂, N₂O, and CH₄) by comparing experimental data from moldboard plow (MP), chisel plow (CP), double disk (DD), and no-till (NT) soils after 38–40 yr of management in a rainfed corn (Zea mays L.)- soybean (Glycine …

Impacts Of Temperature And Carbon Dioxide On Boro Rice Production, Sabiha Ferdous

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

There are different anticipated impacts of climate change (CC) on agriculture all over the world. Bangladesh as a developing country has potential vulnerability and negative impacts on CC. This change in meteorological parameters creates negative impacts on agricultural production which is a threat to food security and economic development. The country has recently achieved food security in rice which is mainly due to increased yields and area coverage of irrigated dry season (Boro) rice over the last decades. It is necessary to predict the future Boro rice production in accordance with CC as well as take supplementary actions to ensure …

Hybrid Seed Set In Relation With Male Floral Traits, Estimation Of Heterosis And Combining Abilities For Yield And Its Components In Wheat (Triticum Aestivum L.), Samira El Hanafi, Souad Cherkaoui, Zakaria Kehel, Miguel Sanchez-Garcia, Jean-Benoit Sarazin, Stephen Baenziger, Wuletaw Tadesse

Department of Agronomy and Horticulture: Faculty Publications

Breeding hybrids with maximum heterosis requires efficient cross-pollination and an improved male sterility system. Renewed efforts have been made to dissect the phenotypic variation and genetic basis of hybrid floral traits, although the potential of tailoring the appropriate flower design on seed setting is less known. To this end, elite wheat genotypes were crossed using a chemical hybridizing agent at different doses. A total of 23 hybrids were developed from a partial diallel design; and planted in an alpha lattice design with their parents at two locations in Morocco, for two years, to evaluate for yield components, heterosis and combining …

Post-Termination Effects Of Cover Crop Monocultures And Mixtures On Soil Inorganic Nitrogen And Microbial Communities On Two Organic Farms In Illinois, Eleanor E. Lucadamo, Ashley A. Holmes, Samuel E. Wortman, Anthony C. Yannarell

Department of Agronomy and Horticulture: Faculty Publications

Cover crops can continue to affect agricultural systems even after they have been terminated by influencing nitrogen dynamics and by altering soil microbial communities. These post-termination effects can influence soil fertility, weed pressure, and the dynamics of potential plant pathogens in the narrow window of time between cover crop termination and cash crop emergence. We evaluated the post-termination effects of 12 different spring-sown cover crop mixtures and monocultures on soil nitrogen and microbial communities on two different organic farms in Central Illinois (on Lawson silt loam soil) and Northern Illinois (on Virgil silt loam soil). In comparison to control plots …

Post-Termination Effects Of Cover Crop Monocultures And Mixtures On Soil Inorganic Nitrogen And Microbial Communities On Two Organic Farms In Illinois, Eleanor E. Lucadamo, Ashley A. Holmes, Samuel E. Wortman, Anthony C. Yannarell

Department of Agronomy and Horticulture: Faculty Publications

Cover crops can continue to affect agricultural systems even after they have been terminated by influencing nitrogen dynamics and by altering soil microbial communities. These post-termination effects can influence soil fertility, weed pressure, and the dynamics of potential plant pathogens in the narrow window of time between cover crop termination and cash crop emergence. We evaluated the post-termination effects of 12 different spring-sown cover crop mixtures and monocultures on soil nitrogen and microbial communities on two different organic farms in Central Illinois (on Lawson silt loam soil) and Northern Illinois (on Virgil silt loam soil). In comparison to control plots …

Practice Cost And Size Differences In Invasive Plant Management Strategies: An Empirical Analysis Of Us Great Plains States, Mazbahul G. Ahamad

Department of Agronomy and Horticulture: Faculty Publications

Grassland conservation of the Conservation Stewardship Program in the United States (US) is one of the largest cost-sharing initiatives for protecting grazing land from invasive and woody plants. The practice cost and unit size of various invasive and woody plant management strategies, such as mulching, brush management, and pre- scribed burning, are different from state to state. We aimed to compare and examine the association between practice cost ($/acre[ac]) and standard unit size of practice (acre) of mulching, brush management, and pre- scribed burning strategies in nine US Great Plains states, including Kansas, Montana, Nebraska, New Mexico, North Dakota, Oklahoma, …

Implementation Of Epigenetic Variation In Sorghum Selection And Implications For Crop Resilience Breeding, Dikungwa Ketumile, Xiaodong Yang, Robersy Sanchez, Hardik Kundariya, John F. Rajewski, Ismail M. Dweikat, Sally A. Mackenzie

Department of Agronomy and Horticulture: Faculty Publications

Crop resilience and yield stability are complex traits essential for food security. Sorghum bicolor is an important grain crop that shows promise for its natural resilience to drought and potential for marginal land production. We have developed sorghum lines in the Tx430 genetic background suppressed for MSH1 expression as a means of inducing de novo epigenetic variation, and have used these materials to evaluate changes in plant growth vigor. Plant crossing and selection in two distinct environments revealed features of phenotypic plasticity derived from MSH1 manipulation. Introduction of an epigenetic variation to an isogenic sorghum population, in the absence of …

Assessment Of Bacterial Inoculant Delivery Methods For Cereal Crops, Yen Ning Chai, Stephanie Futrell, Daniel P. Schachtman

Department of Agronomy and Horticulture: Faculty Publications

Despite growing evidence that plant growth-promoting bacteria can be used to improve crop vigor, a comparison of the different methods of delivery to determine which is optimal has not been published. An optimal inoculation method ensures that the inoculant colonizes the host plant so that its potential for plant growth-promotion is fully evaluated. The objective of this study was to compare the efficacy of three seed coating methods, seedling priming, and soil drench for delivering three bacterial inoculants to the sorghum rhizosphere and root endosphere. The methods were compared across multiple time points under axenic conditions and colonization efficiency was …