Digital Commons Network^™

Characterizing Low Nutrient Stress Resistance In Crop Sunflowers (Helianthus Annus), Casey Croshaw

All Master's Theses

Historically agriculture has met global food production demands, but abiotic stresses are predicted to decrease crop yield in the context of climate change. In order to prevent losses in crop yield under conditions of increasing environmental stress and to reduce environmental damage from unsustainable farming practices, improvements must be made in crop breeding and bioengineering. However, these improvements require insight into the mechanisms of abiotic stress resistance. In this study, 60 different genetic sunflower (Helianthus annuus) lines were grown in the field under fertilized and unfertilized treatments to assess phenotypic traits associated with low nutrient stress resistance. Sunflowers …

Profile Of Genetically Modified Plants Authorized In Mexico, Mayra Teresa Garcia Ruiz, Aaron N. Knapp, Hernan Garcia Ruiz

Department of Plant Pathology: Faculty Publications

Mexico is a center of origin for several economically important plants including maize, cotton, and cocoa. Maize represents more than a food crop, has been declared a biological, cultural, agricultural and economic patrimony, and is linked to the national identity of Mexicans. In this review, we describe the historic and current use of genetically modified plants in Mexico and factors that contributed to the development of the biosafety regulation. We developed a database containing all permit applications received by the government to release genetically modified plants. A temporal and geographical analysis identified the plant species that have been authorized for …

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.

Apple Pomace Consumption Favorably Alters Hepatic Lipid Metabolism In Young Female Sprague-Dawley Rats Fed A Western Diet, Roy Chris Skinner, Derek C. Warren, Soofie N. Lateef, Vagner A. Benedito, Janet C. Tou

Faculty & Staff Scholarship

Apple pomace, which is a waste byproduct of processing, is rich in several nutrients, particularly dietary fiber, indicating potential benefits for diseases that are attributed to poor diets, such as non-alcoholic fatty liver disease (NAFLD). NAFLD affects over 25% of United States population and is increasing in children. Increasing fruit consumption can influence NAFLD. The study objective was to replace calories in standard or Western diets with apple pomace to determine the effects on genes regulating hepatic lipid metabolism and on risk of NAFLD. Female Sprague-Dawley rats were randomly assigned (n = 8 rats/group) to isocaloric diets of AIN-93G and …

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 …

Comparison Of The Genome Size, Endoreduplication, And Issr Marker Polymorphism In Eight Lotus (Fabaceae) Species, Erik Ducar, Monika Rewers, Iwona Jedrzejczyk, Pavol Martonfi, Elwira Sliwinska

Turkish Journal of Botany

Several species within the genus Lotus are important forage crops, and many are endangered or rare. Despite the high genetic diversity of the genus, identification of Lotus species is problematic because of the limited number of reliable morphological markers. In search of a quick, inexpensive, and steady method for species identification, genome size and cell cycle/endoreduplication intensity of 14 accessions belonging to eight Lotus species were estimated by flow cytometry. ISSR-PCR was also applied to find sensitive molecular markers for genetic diversity estimation. Genome size estimation revealed that Lotus species possess very small genomes and this characteristic enables the identification …

Interpopulation Variations In Morphochemical Characteristics Of Stevia Rebaudiana Bertoni, Neena Kumari, Ravinder Raina, Yash Pal Sharma

Turkish Journal of Botany

The present study was carried out with an aim to evaluate Stevia rebaudiana Bertoni segregants and to characterize them morphochemically to facilitate selection of superior genotypes for hybridization in breeding programs. Two identified strains named A and B and their segregant populations (F1 and F2) were evaluated with their morphological and chemical characteristics. Various qualitative and quantitative morphological characters including leaf shape, plant type (loose or compact), plant habit, plant height, and shoot collar diameter were considered. Simultaneously stevioside and rebaudioside-A content was evaluated. A few individuals were identified with rebaudioside-A content ranging from 5.11% to 8.55% and the ratio …

Waste Not, Want Not: Using Source-Separated Urine To Cultivate Maize In The Southern Highlands, Tanzania, Lucy Hatfield

Dissertations, Master's Theses and Master's Reports

In Sub-Saharan African countries, soil fertility is low due to unsustainable agricultural practices and little to no access to chemical fertilizer. Poor yields have resulted in many of these countries struggling to produce enough food to feed their growing populations. Human urine has been used as an effective, low-cost alternative to chemical fertilizers in greenhouse and plot trials on a variety of vegetables, but its effects on elemental grain composition in cereal crops are largely unknown. Here we tested whether diluted human urine applied as a fertilizer can increase maize crop growth, yield and nutritional content on small family-owned plots. …

The Effects Of Mycorrhizal Inoculant And Micronutrients On Early Plant Establshment During A Tallgrass Prairie Reconstruction, Christopher L. Barber

Dissertations and Theses @ UNI

Symbiotic relationships between mycorrhizal fungi and land plants are one of the most widespread examples of symbiosis on Earth yet there is still much to discover about their ecological impacts.

Prairie reconstructions are often done on highly disturbed sites such as reclaimed cropland, turf grass, and road rights-of-way. Disturbed soils often lack adequate quantities of both mycorrhizal fungi and micronutrients. I hypothesized that inoculated seeds with mycorrhizal spores or micronutrient seed treatments will aid in the early establishment of a tallgrass prairie.

To test this hypothesis four treatments (T1 control, T2 mycorrhizal, T3 micronutrient, and T4 mycorrhizal and micronutrient) were …

Tor-Autophagy Branch Signaling Via Imp1 Dictates Plant-Microbe Biotrophic Interface Longevity, Guangchao Sun, Christian Elowsky, Gang Li, Richard Wilson

Department of Plant Pathology: Faculty Publications

Like other intracellular eukaryotic phytopathogens, the devastating rice blast fungus Magnaporthe (Pyricularia) oryzae first infects living host cells by elaborating invasive hyphae (IH) surrounded by a plant-derived membrane. This forms an extended biotrophic interface enclosing an apoplastic compartment into which fungal effectors can be deployed to evade host detection. M. oryzae also forms a focal, plant membrane-rich structure, the biotrophic interfacial complex (BIC), that accumulates cytoplasmic effectors for translocation into host cells. Molecular decision-making processes integrating fungal growth and metabolism in host cells with interface function and dynamics are unknown. Here, we report unanticipated roles for the M. …

Wheat Streak Mosaic Virus: A Century Old Virus With Rising Importance Worldwide, Khushwant Singh, Stephen N. Wegulo, Anna Skoracka, Jiban Kumar Kundu

Department of Plant Pathology: Faculty Publications

Wheat streak mosaic virus (WSMV) causes wheat streak mosaic, a disease of cereals and grasses that threatens wheat production worldwide. It is a monopartite, positive-sense, single-stranded RNA virus and the type member of the genus Tritimovirus in the family Potyviridae. The only known vector is the wheat curl mite (WCM, Aceria tosichella), recently identified as a species complex of biotypes differing in virus transmission. Low rates of seed transmission have been reported. Infected plants are stunted and have a yellow mosaic of parallel discontinuous streaks on the leaves. In the autumn, WCMs move from WSMV-infected volunteer wheat and other grass …

Mapping Rootable Depth And Root Zone Plant-Available Water Holding Capacity Of The Soil Of Sub-Saharan Africa, John G. B. Leenaars, Lieven Claessens, Gerard B. M. Heuvelink, Tom Hengl, Maria Ruiperez Gonzalez, Lenny G. J. Van Bussel, Nicolas Guilpart, Haishun Yang, Kenneth G. Cassman

Department of Agronomy and Horticulture: Faculty Publications

In rainfed crop production, root zone plant-available water holding capacity (RZ-PAWHC) of the soil has a large influence on crop growth and the yield response to management inputs such as improved seeds and fertilisers. However, data are lacking for this parameter in sub-Saharan Africa (SSA). This study produced the first spatially explicit, coherent and complete maps of the rootable depth and RZ-PAWHC of soil in SSA. We compiled georeferenced data from 28,000 soil profiles from SSA, which were used as input for digital soil mapping (DSM) techniques to produce soil property maps of SSA. Based on these soil properties, we …

Lowland Rice Nutrient Responses For The Guinea And Sudan Savannas Of Nigeria, Christogonus K. Daudu, Enemona M. Ugbaje, Eunice Y. Oyinlola, Bitrus D. Tarfa, Adamu A. Yakubu, Ishaku Y. Amapu, Charles S. Wortmann

Department of Agronomy and Horticulture: Faculty Publications

Yield response of irrigated lowland rice (Oryza sativa L.) to nutrient application was determined to improve the information base for fertilizer use in the Sudan and Southern Guinea Savannas of Nigeria. Economically optimal rates (EOR) and agronomic efficiency (AE) were determined. Five N levels and four levels each P, K, and Zn were evaluated with two varieties at two locations. Nitrogen effects varied by variety and location but mean paddy yield with 0 kg ha^–1 N was 3.4 Mg ha^–1 and was increased by 1.3 Mg ha^–1 with 40 kg ha^–1 N. The mean EOR …

Lowland Rice Nutrient Responses For The Guinea And Sudan Savannas Of Nigeria, Christogonus K. Daudu, Enemona M. Ugbaje, Eunice Y. Oyinlola, Bitrus D. Tarfa, Adamu A. Yakubu, Ishaku Y. Amapu, Charles S. Wortmann

Department of Agronomy and Horticulture: Faculty Publications

Copyright © 2018 by the American Society of Agronomy

This is an open access article

doi:10.2134/agronj2017.08.0469

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 …

Mapping Rootable Depth And Root Zone Plant-Available Water Holding Capacity Of The Soil Of Sub-Saharan Africa, Johan G. B. Leenaars, Lieven Claessens, Gerard B.M. Heuvelink, Tom Hengl, Maria Ruiperez Gonzalez, Lenny G.J. Van Bussel, Nicolas Guilpart, Haishun Yang, Kenneth G. Cassman

Department of Agronomy and Horticulture: Faculty Publications

In rainfed crop production, root zone plant-available water holding capacity (RZ-PAWHC) of the soil has a large influence on crop growth and the yield response to management inputs such as improved seeds and fertilisers. However, data are lacking for this parameter in sub-Saharan Africa (SSA). This study produced the first spatially explicit, coherent and complete maps of the rootable depth and RZ-PAWHC of soil in SSA. We compiled georeferenced data from 28,000 soil profiles from SSA, which were used as input for digital soil mapping (DSM) techniques to produce soil property maps of SSA. Based on these soil properties, we …

Phosphate Deficiency Negatively Affects Early Steps Of The Symbiosis Between Common Bean And Rhizobia, Mariel C. Isidra-Arellano, Maria Del Rocio Reyero-Saavedra, Maria Del Socorro Sanchez-Correa, Lise Pingault, Sidharth Sen, Trupti Joshi, Lourdes Girard, Norma A. Castro-Guerrero, David G. Mendoza-Cozatl, Marc Libault, Oswaldo Valdes-Lopez

Department of Agronomy and Horticulture: Faculty Publications

Phosphate (Pi) deficiency reduces nodule formation and development in different legume species including common bean. Despite significant progress in the understanding of the genetic responses underlying the adaptation of nodules to Pi deficiency, it is still unclear whether this nutritional deficiency interferes with the molecular dialogue between legumes and rhizobia. If so, what part of the molecular dialogue is impaired? In this study, we provide evidence demonstrating that Pi deficiency negatively affects critical early molecular and physiological responses that are required for a successful symbiosis between common bean and rhizobia. We demonstrated that the infection thread formation and the expression …

Root And Shoot Contribution To Carbon And Nitrogen Inputs In The Topsoil Layer In No-Tillage Crop Systems Under Subtropical Conditions, Marciel Redin, Sylvie Recous, Celso Aita, Bruno Chaves, Ismael Cristiano Pfeifer, Leonardo Mendes Bastos, Getulio Elias Pilecco, Sandro Jose Giacomini

Department of Agronomy and Horticulture: Faculty Publications

Recycling of carbon (C) and nitrogen (N) from plants into soils is decisive for maintaining soil organic matter and soil fertility. Therefore, we quantified plant biomass and C and N in the shoots and roots from the topsoil layer for a wide range of annual crops grown under subtropical conditions. We grew 26 species, 13 main crops, and 13 cover crops, in the field in standard sowing arrangements. Root biomass was recovered from the 0.00-0.20 m soil layer at flowering, and shoot biomass was measured at flowering for all crops and at maturity only for the main crops. Root dry …

Genome-Wide Association Study Reveals Novel Genomic Regions Associated With 10 Grain Minerals In Synthetic Hexaploid Wheat, Madhav Bhatta, P. Stephen Baenziger, Brian M. Waters, Rachana Poudel, Vikas Belamkar, Jesse Poland, Alexey Morgounov

Department of Agronomy and Horticulture: Faculty Publications

Synthetic hexaploid wheat (SHW; Triticum durum L. x Aegilops tauschii Coss.) is a means of introducing novel genes/genomic regions into bread wheat (T. aestivum L.) and a potential genetic resource for improving grain mineral concentrations. We quantified 10 grain minerals (Ca, Cd, Cu, Co, Fe, Li, Mg, Mn, Ni, and Zn) using an inductively coupled mass spectrometer in 123 SHWs for a genome-wide association study (GWAS). A GWAS with 35,648 single nucleotide polymorphism (SNP) markers identified 92 marker-trait associations (MTAs), of which 60 were novel and 40 were within genes, and the genes underlying 20 MTAs had annotations suggesting …

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. …

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 …

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 …

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.

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 …

Can Increasing Grass-Fungal Endophyte Symbiotic Diversity Enhance Grassland Ecosystem Functioning?, Mahtaab Bagherzadeh

Theses and Dissertations--Plant and Soil Sciences

The relationship between biodiversity and ecosystem functioning is important in maintaining agroecosystem sustainability. Plant-microbe symbioses, such as exists between the grass tall fescue (Schedonorus arundinaceum) and the asexual fungal endophyte Epichloë coenophiala, can be utilized to enhance agroecosystem functions, such as herbivore resistance. “Novel” E. coenophiala strains that vary in the production of mammal- and insect-toxic compounds have been identified, inserted into tall fescue cultivars, and are planted in pastures globally. Novel fungal endophyte-tall fescue associations may have divergent ecosystem function effects. This study assessed effects of different fescue-endophyte symbiotic combinations on pasture ecosystem function, including aboveground …

Butterfly, Dogwood Linked In Circle Of Life, W. John Hayden, Nicky Staunton

Biology Faculty Publications

What would it be like to live on a diet of nothing but flowers? From the perspective of human nutrition, conventional wisdom suggests that it would be difficult to obtain a well-balanced diet from flowers alone. We do, however, have the legend of the lotus-eaters, people encountered by Odysseus and his crew on their epic return journey from Troy. As recounted in the Odyssey, lotus-eaters lived life in a perpetual stupor, and the two crew members who sampled lotus flowers immediately lost all interest in returning to their homes in Ithaca. Upon seeing the danger of consuming these flowers—the botanical …

An Efficient Protocol For Root Studies In The Common Sunflower Using Composite Plants, Tyler Parks

Masters Theses

Sunflower, Helianthus annuus, is one of the most important oilseed crop in the world. Oil from the seeds is prized for its' exceptional quality and flavor. Despite this, sunflowers have been forced onto marginal lands often on semi-arid and non-fertile soil, due to disease pressures and economics making it critical to produce more resilient lines and varieties to withstand these new stresses. The recent availability of the sunflower genome can allow genome-wide characterization of gene families. Stable transformation protocols, which can be used for characterization studies, have been developed for H. annuus using Agrobacterium tumefaciens, but they produce …