Agronomy and Crop Sciences Commons^™

Plant Community Response To Disturbances In Nebraska Sandhills Upland Prairie, Josiah D. Dallmann

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

Historically, disturbances shaped prairie ecosystems both directly through events like fire and soil moving by animals, as well as indirectly through dynamic rainfall patterns and periodic flux in seed availabilities. We hypothesized that the implementation of several distinct disturbance events in Nebraska Sandhills upland prairie would have measurable effects on plant community composition. We implemented mid-spring fire, soil disturbance in the form of disking, seed addition of native forbs on disked plots, as well as early summer supplemental watering (to mimic minor rainfall events during abnormally dry periods) during 2016 and 2017. Plant community response during the first and second …

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 …

Corn Grain Yield Components And Nutrient Accumulation In Response To Nitrogen, Plant Density And Hybrid, Maria Julia Santoro

Theses and Dissertations--Plant and Soil Sciences

Modern maize hybrids exhibit higher yields, increased biomass production, stress tolerance and greater nitrogen (N) use efficiency. Increased biomass accumulation can influence nutrient uptake and lead to increased nutrient removal. Hybrids were tested at seeding rates (SR) of 74000 (low) and 148000 (supraoptimal) plants ha^-1 and at N rates of 0 (deficient) and 390 (non-limiting) kg N ha^-1. Plants were sampled at V7, V14, R3, R5 and R6 and separated into vegetative and reproductive fractions for determination of dry matter and N accumulation. Grain yield was harvested at R6.

The high SR and high N treatment combination …

Measured Soil Hydraulic Properties As Rzwqm2 Input To Simulate Soil Water Dynamics And Crop Evapotranspiration, Saadi Sattar Shahadha

Theses and Dissertations--Plant and Soil Sciences

Agricultural system models integrate many different processes that cannot all be measured in field experiments and help quantify soil water dynamics, crop evapotranspiration, and crop growth with high temporal resolution. Understanding soil water dynamics and crop evapotranspiration is essential to improve agricultural management of field crops. For example, the interaction between nitrogen application rate and water dynamics is not sufficiently understood. In most cases, model simulations deviate from field measurements, especially when model input parameters are indirectly and unspecifically derived. The extent to which measured soil hydraulic property inputs decrease the discrepancy between measured and simulated soil water status is …

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 …

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 F_3:6 and F_3:7 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 …

Improving Subtropical Grass Pastures On The South Coast Of Western Australia, Paul Sanford, Ron Master, Eric Dobbe

Bulletins 4000 -

This bulletin reports on the findings of a research project funded by DPIRD and MLA that investigated methods to improve legume content and increase production of both kikuyuand panic-based pastures on the south coast of WA.

Environmental Risk, Resource And Production, Nancye Gannaway

Farm Systems and Economics published reports

Plan Prepare Prosper - workshop

Aims

• To identify and plan for projected changes in weather patterns and in the physical resources that underpin the productivity of the farm enterprise.
• To develop initiatives to manage observed and likely threats from the environment to farm enterprises.
• To support the achievement of long-term economic viability of land under production

Today's content will help develop risk management strategies for agricultural production systems.

Genomic-Enabled Prediction Models Using Multi-Environment Trials To Estimate The Effect Of Genotype × Environment Interaction On Prediction Accuracy In Chickpea, Manish Roorkiwal, Diego Jarquin, Muneendra K. Singh, Pooran M. Gaur, Chellapilla Bharadwaj, Abhishek Rathore, Reka Howard, Samineni Srinivasan, Ankit Jain, Vanika Garg, Sandip Kale, Annapurna Chitikineni, Shailesh Tripathi, Elizabeth Jones, Kelly R. Robbins, José Crossa, Rajeev K. Varshney

Department of Agronomy and Horticulture: Faculty Publications

Genomic selection (GS) by selecting lines prior to field phenotyping using genotyping data has the potential to enhance the rate of genetic gains. Genotype × environment (G × E) interaction inclusion in GS models can improve prediction accuracy hence aid in selection of lines across target environments. Phenotypic data on 320 chickpea breeding lines for eight traits for three seasons at two locations were recorded. These lines were genotyped using DArTseq (1.6 K SNPs) and Genotyping-by-Sequencing (GBS; 89 K SNPs). Thirteen models were fitted including main effects of environment and lines, markers, and/or naïve and informed interactions to estimate prediction …

Gene Expression Profiling Of Iron Deficiency Chlorosis Sensitive And Tolerant Soybean Indicates Key Roles For Phenylpropanoids Under Alkalinity Stress, Brian M. Waters, Keenan Amundsen, George L. Graef

Department of Agronomy and Horticulture: Faculty Publications

Alkaline soils comprise 30% of the earth and have low plant-available iron (Fe) concentration, and can cause iron deficiency chlorosis (IDC). IDC causes soybean yield losses of $260 million annually. However, it is not known whether molecular responses to IDC are equivalent to responses to low iron supply. IDC tolerant and sensitive soybean lines provide a contrast to identify specific factors associated with IDC.We used RNA-seq to compare gene expression under combinations of normal pH (5.7) or alkaline pH (7.7, imposed by 2.5mM bicarbonate, or pH 8.2 imposed by 5mM bicarbonate) and normal (25μM) or low (1μM) iron conditions from …

Plant Probiotic Bacteria Bacillus And Paraburkholderia Improve Growth, Yield And Content Of Antioxidants In Strawberry Fruit, Mosaddiqur Rahman, Abdullah As Sabir, Julakha Akter Mukrta, Mohibul Alam Khan, Mohammed Mohi-Ud-Din, Giashuddin Miah, Mahfuzur Rahman, M. Tofazzal Islam

Faculty & Staff Scholarship

Strawberry is an excellent source of natural antioxidants with high capacity of scavenging free radicals.

This study evaluated the effects of two plant probiotic bacteria, Bacillus amylolequefaciens BChi1 and Paraburkholderia fungorum BRRh-4 on growth, fruit yield and antioxidant contents in strawberry fruits. Root dipping of seedlings (plug plants) followed by spray applications of both probiotic bacteria in the field on foliage significantly increased fruit yield (up to 48%) over non-treated control. Enhanced fruit yield likely to be linked with higher root and shoot growth, individual and total fruit weight/plant and production of phytohormone by the probiotic bacteria applied on plants. …

Crop Residue Harvest Impacts Wind Erodibility And Simulated Soil Loss In The Central Great Plains, Yuxin He, Deann R. Presley, John Tatarko, Humberto Blanco-Canqui

Department of Agronomy and Horticulture: Faculty Publications

Crop residue removal can affect the susceptibility to soil wind erosion in climates such as those of the Central Great Plains, United States. Six on-farm trials were conducted in Kansas from 2011 to 2013 to determine the effects of winter wheat (Triticum aestivum L.), corn (Zea mays L.), and grain sorghum (Sorghum bicolor (L.) Moench), residue removal at 0, 25, 50, 75, and 100% of initial height on soil wind erosion parameters. Those parameters include soil surface random roughness (RR), and wind erodible fraction (EF; aggregates -¹ for three hours. Threshold wind velocity required to initiate …

Genetic Diversity And Population Structure Of F3:6 Nebraska Winter Wheat Genotypes Using Genotyping-By-Sequencing, Shamseldeen Eltaher, Ahmed Sallam, Vikas Belamkar, Hamdy A. Emara, Ahmed A. Nower, Khaled F. M. Salem, Jesse Poland, Peter S. Baenziger

Department of Agronomy and Horticulture: Faculty Publications

The availability of information on the genetic diversity and population structure in wheat (Triticum aestivum L.) breeding lines will help wheat breeders to better use their genetic resources and manage genetic variation in their breeding program. The recent advances in sequencing technology provide the opportunity to identify tens or hundreds of thousands of single nucleotide polymorphism (SNPs) in large genome species (e.g., wheat). These SNPs can be utilized for understanding genetic diversity and performing genome wide association studies (GWAS) for complex traits. In this study, the genetic diversity and population structure were investigated in a set of 230 genotypes …

An Efficient And Improved Method For Virus-Induced Gene Silencing In Sorghum, Dharmendra Kumar Singh, Hee-Kyung Lee, Ismail M. Dweikat, Kirankumar S. Mysore

Department of Agronomy and Horticulture: Faculty Publications

Background: Although the draft genome of sorghum is available, the understanding of gene function is limited due to the lack of extensive mutant resources. Virus-induced gene silencing (VIGS) is an alternative to mutant resources to study gene function. This study reports an improved and efficient method for Brome mosaic virus (BMV)-based VIGS in sorghum.

Methods: Sorghum plants were rub-inoculated with sap prepared by grinding 2 g of infected Nicotiana benthamiana leaf in 1 ml 10 mM potassium phosphate buffer (pH 6.8) and 100 mg of carborundum abrasive. The sap was rubbed on two to three top leaves of sorghum. Inoculated …

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 …