Plant Sciences Commons^™

Pyramiding Approaches For Potato Disease Resistance Breeding, Kristen M. Brown-Donovan

Electronic Theses and Dissertations

This study establishes the start of late blight genetic profiles for varieties and clones used as potato breeding material across the United States,and a Mendelian use of marker-assisted selection is employed to estimate allele dosage.

Potato is the fourth most important staple crop worldwide, with both high nutritional and economic values. Breeders seek improvements for many traits related to yield, dry matter, and surface and internal defects. Resistances to several diseases are also desired traits that breeders try to incorporate into their programs. The advent of DNA-based genetic technologies help breeding programs facilitate faster selection, including the use of marker-assisted …

Evaluating The Current Weed Community In Wild Blueberry Fields And Ipm Strategies For Spreading Dogbane (Apocynum Androsaemifolium), Anthony G. Ayers

Electronic Theses and Dissertations

Lowbush blueberry (Vaccinium angustifolium) is Maine’s third largest crop (USDA 2020 a). From 2017 – 2019 the three seasons yield average was 27,200 tons were harvested from 19,500 acres for a value of $22,468,000 (USDA 2020 c). Lowbush blueberries are managed on a two-year cycle. Every other year, lowbush blueberry fields are pruned to the ground either through the use of a tractor mounted flail mower or a prescribed burn (Yarborough 2009). Pruning is a necessary part of managing lowbush blueberries as the second-year growth produces the highest yield but steadily declines in subsequent years (Drummond et al. …

Microsite Requirements For Successful Regeneration In Lowland Northern White-Cedar (Thuja Occidentalis) Forests, Jeanette Allogio

Electronic Theses and Dissertations

Declines in stands of northern white-cedar (Thuja occidentalis L., hereafter cedar) have been observed as both shifts in species composition and reductions in cedar densities, particularly those stands in lowland sites (Curtis 1946, Boulfroy 2012). While several factors inhibiting cedar regeneration have been identified, a thorough understanding of the conditions that best promote regeneration is lacking. Our objectives for the first chapter were to characterize the site conditions associated with successful regeneration in lowland cedar stands and to describe how spatial patterns of various cedar size classes relate to site preference and to regeneration dynamics. These objectives were achieved …

Characterizing Patterns In Texas Gulf Coast Beach Dune Plant Species Composition, Cody Foster

Electronic Theses and Dissertations

Regional vegetation patterns of Texas beach plant communities were analyzed using cluster analysis, ANOSIM, SIMPER, NMDS, and ISA for fives zones representing the foredune complex of twenty Gulf Coast beaches. ANOVA revealed that zones differ in terms of percent bare sand, percent vegetative cover, and species richness. Cluster Analysis, ANOSIM, and SIMPER results indicate that Texas beaches can be divided into northern and southern regions based on differences in species composition of plant communities. Indicator Species Analysis (ISA) indicates that northern beaches are characterized by the presence of Rayjacksonia phyllocephala, Ambrosia Strophostyles, Ambrosia psilostachya, and Panicum amarum …

Evaluation Of Groundwater Sodium And Sodium Uptake In Taxodium And Its Hybrids On Galveston Island, Texas, Daniel Morgan

Electronic Theses and Dissertations

In September 2008, Hurricane Ike swept through the Gulf of Mexico striking the Gulf Coast, claiming hundreds of lives and causing billions of dollars in damage. The hurricane left behind elevated sea salt concentrations in the soil and groundwater, preventing the unaided return of live oaks and other species to the island. To determine effective ways to ameliorate the elevated Na⁺ concentrations in the soil, eight treatments were applied to the soil and combinations of three species of plants, live oak (Quercus virginiana), hybrid bald cypress (Taxodium ‘T406’), and yellow hibiscus (Hibiscus hamabo …

Congruence And Temporal Variation Of Floral Visitation And Pollen Transport Networks In Southern Appalachia, Daniel A. Barker

Electronic Theses and Dissertations

Observation of floral visitation is an accepted method to describe plant-pollinator interactions despite potential biases. Collecting pollen from pollinators offers new insights on the structure and function of plant-pollinator communities. Furthermore, the strength and frequency of plant-pollinator interactions can vary across temporal scales. However, within-season and within-day (morning vs. evening) variation in plant-pollinator networks has been little studied. By evaluating variation in network structure across these biologically relevant time scales, we will gain a better understanding of the factors that shape plant-pollinator communities. The objectives of this study are to 1) Compare the structure of plant-pollinator networks built on floral …

Population Structure And Reproductive Biology Of Monilinia Vaccinii-Corymbosi (Reade) Honey In Lowbush Blueberry In Maine, Katherine A. Ashley

Electronic Theses and Dissertations

Lowbush blueberry, Vaccinium angustifolium Aiton, is both an economically and culturally important crop in Maine, being one of the few endemic crops to North America. The fungus Monilinia vaccinii-corymbosi (Mvc) causes mummy berry disease and is a significant pathogen of both highbush (Vaccinium corymbosum) and lowbush blueberries. While impacts of this disease are not regularly documented, it is estimated that 30-50% of the yield in an unmanaged field can be lost because of Mvc. This disease is typically managed with fungicides or burning of the field during years when the field is pruned, however, the impacts to the …

Effects Of Increased Atmospheric Carbon Dioxide Levels On Tobacco Mosaic Virus And Root-Knot Nematodes In Genetically Resistant And Susceptible Tomato Plants, Angie Nicholas

Electronic Theses and Dissertations

Rising atmospheric carbon dioxide (CO₂) may affect plant/pathogen interactions. This study focused on the effects of elevated CO₂ on Root-Knot Nematode (Meloidogyne arenaria) and Tobacco Mosaic Virus (TMV) infection in genetically resistant versus susceptible tomatoes (Solanum lycopersicum). Both resistant and susceptible tomatoes were grown in chambers with either ambient CO₂ or CO₂ elevated to 750 ppm and infected with M. arenaria or TMV. Measurements were taken at regular intervals to determine the effects of the pathogens on the plants. Resistant plants infected with M. arenaria maintained resistance while susceptible plants remained …

Role Of Plant Volatile Organic Compounds (Vocs) In Seed Priming And Plant-Herbivore Interactions., Abhinav Kumar Maurya

Electronic Theses and Dissertations

This dissertation explores and expands the existing knowledge on the role of plant volatiles in facilitating seed priming and providing direct defense against herbivore. Although the roles of plant volatiles in priming a plant’s defenses and providing direct defense against pests is well known, information regarding their effects on seed and the fitness of future plants and direct toxicity to herbivores is understudied. This dissertation does a thorough examination of these two understudied aspects of plant volatiles and provides novel insight into the role of plant volatiles in seed priming and direct defense (Chapter I). Seeds in the soil can …

Aboveground-Belowground Interactions: Roles Of Soil Biotic And Abiotic Factors On Switchgrass's (Panicum Virgatum) Growth, Defense Against Herbivory And Cell Wall Chemistry., Binod Basyal

Electronic Theses and Dissertations

Plants constantly interact with their biotic and abiotic soil environments. Most terrestrial plants form beneficial associations with soil microbes such as arbuscular mycorrhizal (AM) fungi, which are widely known for their ability to transfer soil phosphorus and nitrogen to the host plants. They help plants tolerate drought stress and improve plant defense against herbivores such as plant-parasitic nematodes (PPNs). This dissertation investigates the role of AM fungi on switchgrass’s (Panicum virgatum) growth, cell wall chemistry, and defense against PPNs using a combination of growth chamber and field studies. Switchgrass is a native warm-season species which is gaining traction as candidate …

Development Of A Near Infrared Reflectance Spectroscopy (Nirs) Platform For Rapid Wheat Quality Analysis, Lily Schimke

Electronic Theses and Dissertations

Wheat is a valuable cereal grain in terms of its growability, versatility, and multifunctional nutritional components. Research into the genetic characteristics and growing conditions of the grain is advantageous to wheat breeders, farmers, food scientists, food processors, and consumers. Optimizing the quality of the wheat grain is important to yielding a crop with the most desirable traits. Analytically obtaining data on the quality attributes of wheat is a lengthy and resource intensive process. Near infrared reflectance spectroscopy (NIRS) technology is rapid, cost-effective, and a powerful analytical tool that can be harnessed to create predictive calibrations for estimations of wheat parameters. …

Characterization Of Bacterial Endophytes Isolated From Brassica Carinata And Their Potential Use To Decrease Nutrient Requirements In Crops, Alex Soupir

Electronic Theses and Dissertations

Bacterial endophytes have the capability to enhance plant growth by producing plant growth hormones, solubilizing phosphates, suppressing pathogenic fungi, and reducing plant stress hormones. These capabilities make them desirable limiting the amount of nutrients and pesticides that are applied to crops. Through these assays and isolations, it is possible to identify novel bacterial species. In-vitro testing had shown 9 of the 20 isolates possess the ability to produce indole-3-acetic acid (IAA) with Pantoea agglomerans BC09 producing a concentration of 30.2 ng/μl over 4 days. BC09, Bacillus subilis BC10, and Pantoea sp. BC12 were able to solubilize calcium phosphate, 7 endophytes …

Crop Rotations And Cover Crops Influences On Soil Biochemical Properties, Root Characteristics And Economic Performance, Hanxiao Feng

Electronic Theses and Dissertations

Introducing cover crops (CC) and increasing crop diversity in agricultural systems are beneficial in improving the soil health and crop production. However, limited research has been conducted that focuses the influence of CC and crop rotation on soil ecosystem, root growth and development, crop production, and economic returns. The objectives of this study were to (i) assess the impacts of CC management on soil enzyme activities and soil microbial community structure changes, (ii) evaluate the crop rotation management on crop root growth and development, nutrient storage in crop grain and biomass, and crop yield, and (iii) investigate the crop rotation …

Predicting Farinograph Stability Of Wheat Flour With Mixograph And Glutomatic Tests, Brooke Shumate

Electronic Theses and Dissertations

Hard red spring wheat (Triticum aestivum L.; HRSW) flour is typically used to produce wheat-based foods where dough strength is a key quality component. Maintaining acceptable levels of dough strength is an important goal in the development of new HRSW cultivars. In a commercial setting, dough strength is often measured as Farinograph stability, though due to various resource constraints, stability is often predicted in breeding programs via other methods like the Mixograph. The objective of this research was to combine Glutomatic with Mixograph data to determine whether Farinograph stability predictions might be improved over the use of Mixograph data …

Use Of Unmanned Aerial System (Uas) For High Throughput Evaluation Of Forage Yield In Oat Breeding Nurseries, Prakriti Sharma

Electronic Theses and Dissertations

Current strategies for phenotyping (for traits like biomass) numerous breeding lines under field conditions demand significant investment in both time and labor. Unmanned aerial systems (UAS) can be used to collect vegetation indexes (VI) with high throughput and could provide an efficient way to predict forage yield in breeding nurseries with accuracy. The main objective of the study was to evaluate the use of VIs derived from UAV collected images for estimating crop biomass. For this study, forage trials consisting of 35 oat genotypes were carried out at three locations in 2018 and four locations in 2019. Unmanned aerial vehicles …

Subalpine Forest Tree Seedling Response To Drought, Alex Goke

Electronic Theses and Dissertations

Knowledge of tree species’ ability to tolerate drought is necessary to anticipate future forest dynamics with climate change, especially at the seedling stage given their role in shaping forest structure. We used precipitation reduction shelters to mimic drought for subalpine conifer seedlings (A. lasiocarpa and P. engelmannii) in the Rocky Mountains and compared survivorship and morphological and physiological responses to assess relative degrees of drought tolerance. We detected no significant investment in morphological tolerance traits (e.g. root biomass, leaf:stem area ratio) but substantial reductions in net photosynthesis. While shading partially ameliorated drought effects when precipitation reduction was moderate, …

Determining The Effects Of Plant Extracts And Saltro Nematicide On Hatching, Mortality And Reproduction Of The Soybean Cyst Nematode (Heterodera Glycines), Bishnu Prasad Dhital

Electronic Theses and Dissertations

Soybean cyst nematode (SCN) is a microscopic worm that infects and feeds from the soybean roots, hence robbing the plant of nutrients, and entry wounds may facilitate other pathogens to infect the roots. Current SCN management practices include cultural, chemical, and biological methods. Cultural practices such as, crop rotation with non-host and different tillage practices are not efficient due to the persistent nature of SCN in the soil. Chemical nematicides, though effective, can be expensive, and some are not environmentally sound. SCN resistant soybean varieties are mainly derived from one source, PI 88788 and SCN population have already evolved to …

Developing Microbial Based Process To Produce High Value Natural Antimicrobial (Glyceollin) In Soybeans And Pullulan From Sucrose, Andrea Zavadil

Electronic Theses and Dissertations

Glyceollin is a secondary metabolite produced under stress conditions by soybean to act as a plant defender to pathogen attack. The antimicrobial nature of glyceollin makes it a promising natural alternative to antibiotics if incorporated into livestock feed. However, production of glyceollin is highly variable, dependent on soybean variety, and fungal elicitor used as inoculum. Our study compares two fungal spore elicitors, Trichoderma reesei and Aspergillus sojae on soybeans of diverse maturity level, and fungal susceptibility to determine highest glyceollin titer. Spore inoculation with T. reesei elicited highest glyceollin titers of 2.42±0.20 mg/g at 120 h, while A. sojae elicited …

Phytoremediation Of Saline-Sodic Soils In East Central South Dakota Utilizing Perennial Grass Mixtures, Douglas J. Fiedler

Electronic Theses and Dissertations

Several decades of above average precipitation in South Dakota has increased the area of saline and sodic soils, which reduce crop yields and inhibit sensitive plant growth. Saline and sodic soils are difficult to remediate using traditional agricultural crops. Establishing salt tolerant perennial species may restore productivity to salt affected areas. Two perennial grass mixtures (mix 1: slender wheatgrass, beardless wildrye; mix 2: slender wheatgrass, western wheatgrass, green wheatgrass, creeping meadow foxtail) were dormant frost seeded along a topographic gradient in Clark Co., SD. Soils were Forman-Cresbard loam and a Cresbard-Cavour loam with surface electrical conductivity (EC_1:1) that …

Crop Rotations, Tillage And Cover Crops Influences On Soil Health, Greenhouse Gas Emissions And Farm Profitability, Jasdeep Singh

Electronic Theses and Dissertations

This study assessed the effects of three levels of crop rotation: [2-yr; corn (Zea mays L.)- soybean (Glycine max L.), 3-yr; corn-soybean-oat (Avena sativa L.) or 4-yr; cornsoybean- oat-winter wheat (Triticum aestivum L.)], two tillage [conventional-till (CT) and no-till (NT)], and two winter cover cropping systems [cover crop (CC) or fallow control (NC)] on soil biochemical and physical properties, greenhouse gas emissions (GHG), microbial community composition, crop yield and farm profitability under silty clay loam soil of south eastern South Dakota. Experimental design was a randomized complete block design in a split-split plot treatment arrangement with four replications. Rotations, tillage …

The Impact Of Subsurface Physical Characteristics On The Effectiveness Of Subsurface Drainage In The Northern Great Plains, Mehmet Emin Budak

Electronic Theses and Dissertations

World-wide, salinity and sodicity problems are increasing in coastal, irrigated and dryland agricultural systems. Traditional reclamation techniques for saline sodic soils include improving soil drainage by installing subsurface drainage, leaching with high quality water, and applying a source of calcium. However, due to differences in the soil parent material these traditional approach treatments were ineffective in removing sodium and other salts out of the soil profile of South Dakota. Understanding how the surface and subsurface soil characteristics and management interact to affect the sustainability of these systems is the first step in remediation. Each region and soil have a slightly …

Exploring Phenotypic Diversity And Quantitative Trait Loci Mapping For Root Architecture, Freezing Tolerance, Chilling Fulfillment, And Photoperiod Traits In Grapevine Populations, Dilmini Alahakoon

Electronic Theses and Dissertations

Grapevine (Vitis species) is one of the most valuable fruit crops widely cultivated throughout the United States of America (USA). Grape and wine industries in the northern USA have been expanding rapidly with the demand for quality wine grapes that can be grown in Northern cold climate regions. As most popular cultivars are freezing sensitive, the development of new cultivars for the region continues through breeding. In this study, we evaluated grapevine root system architecture, freezing tolerance, and bud break in different genetic backgrounds in natural or controlled environments. The dissertation research objectives were to explore trait phenotypic variation and …

Utilizing Rhizospheric And Bacterial Endophytes For Use As Potential Bio-Fertilizers For Sustainable Agricultural Production, Vincent Peta

Electronic Theses and Dissertations

Brassica carinata crop production offers an exciting alternative approach to the energy crisis when looking at novel ways to power our motor vehicles. Bacterial endophytes, while residing in host-plant tissues, offer a wide array of plant growth promotion benefits such as nitrogen fixation to impart nitrogen (N) nutrition, phosphate (P) solubilization to make soil-bound phosphate more mobile in soil for plant uptake, can suppress pathogenic microbes such as fungus and produce plant growth hormones to offset stress incurred by the plant. Previous literature has shown that there is large interest in studying endophytes from economically important crops such as wheat, …

Management Implications Of A Rye Cover Crop On Nutrient Cycling And Soybean Production In Southeast South Dakota: Focus On Rye Seeding Rates And Termination Timing, Benjamin Brockmueller

Electronic Theses and Dissertations

Winter rye (Secale cereale L.) has become an important cover crop in South Dakota; yet, concerns over negative impacts on cash crop yields is one important limitation to the widespread adoption of winter rye in cropping systems. Two field studies were implemented at the Southeast Research Farm near Beresford, SD investigating the impacts of five seeding rates (0-90 kg ha^-1) and termination timings (April 19th- May31st) with the objectives of examining the roles of winter rye management practices on soybean production and yield from nutrient cycling of nitrogen (N) and sulfur (S) in the agroecosystem. Plant, residue, …

Biomass And Morphological Development Of Miscanthus Compared With Native Grass In South Dakota, Ehsan J. Al Ainizi

Electronic Theses and Dissertations

Little is known about Miscanthus for bioenergy in the northern Great Plains. This study compared 10-year-old stands of Miscanthus x giganteus to switchgrass (Panicum virgatum L.) and prairie cordgrass (Spartina pectinata Link) for biomass on marginal cropland in eastern South Dakota. This study was conducted during 2017 and 2018 at Brookings, SD. Day of year (DOY), species, and N fertility were evaluated for effects on biomass yield and related components (tillers m-2, plant height, and weed biomass). All three variables had significant effects on biomass yield, tiller m-2, and tiller height in both years. N rate had no effect on …

In-Season Crop Management Effect On Soybean Yield And Grain Quality In Eastern South Dakota, Kelsey Bergman

Electronic Theses and Dissertations

Soybean [Glycine max (L.) Merr.] yield has increased over time by introduction of newer varieties and improved agronomic practices. However, grain protein concentration has been decreasing at the same time. New field studies in 2018 and 2019 investigated inseason crop management practices effect such as use of foliar protection application, fertilizer application, different maturity length or different planting dates on grain yield and grain quality. The studies were established near Brookings, SD and Beresford, SD. In-season treatments were targeting nutrient availability or protecting soybean canopy during the grain filling period. Such treatments included the use of fungicide, insecticide, or supplying …

Quantitative Imaging Of Cell-Level Auxin Cytokinin Outputs In Soybean And Model Plants, Paul Gaillard

Electronic Theses and Dissertations

Auxin and cytokinin are major plant hormones that orchestrate plant development. These hormones are involved in cell division and differentiation and their spatio‐temporal balance controls organ initiation and maturation. Even though independent transcriptional responses to these hormones have been characterized, their concomitant outputs have not been described. We developed methodology to determine auxin-cytokinin relative output (ACRO) ratios at cellular resolution. Hormone-specific fluorescent markers that localize to the nucleus were used to report transcriptional outputs of auxin and cytokinin. Multiphoton microscopy and image data processing were used to quantify their relative ratio at cellular level in three-dimensional tissue volumes. This strategy …

The Role Of Endophytes In Conferring Salinity Tolerance In Prairie Cordgrass And The Winter Wheat Mint Variety, Jeffery Bartel

Electronic Theses and Dissertations

Prairie Cordgrass (PCG) Spartina pectinata is a native grass to North America that survives saline conditions, can be harvested multiple times in a year, and can be used as biofuel. Endophytes are bacteria that reside in plant tissues and often have growthpromoting capabilities. They can assist plants by obtaining nutrients by improving the tolerance of plants against a broad range of stresses, such as plant pathogens, viruses, flooding, drought, acids, or bases. PCG can survive ocean levels of salinity. Endophytes that naturally bond with PCG may not only be able to not only help PCG but be transferred to other …

Understanding South Dakota Farmers’ Intentions To And Adoption Of Conservation Practices: An Examination Of The Theory Of Planned Behavior, Edem Avemegah

Electronic Theses and Dissertations

Conservation agriculture practice is a sustainable farming method based on three principle: crop diversification, minimal soil disturbance or movement and permanent or semi-permanent of soil cover. Government and stakeholders within the agricultural sector in the United States are promoting conservation farming practices but limited voluntary adoption still exists among producers at the farm level. This research study investigated the factors that influence the adoption of conservation practices among producers in the eastern and central parts of South Dakota (SD). A modified theory of planned behavior (TPB) is used as a framework alongside socioeconomic and demographic indicators to understand farmers’ current …

Soil Physical And Hydrological Properties, And Greenhouse Gas Emissions Under Integrated Crop-Livestock Agroecosystems, Navdeep Singh

Electronic Theses and Dissertations

Cover crops (CCs) and grazing play a critical role in successful implementation of the integrated crop-livestock system (ICLS) because they can have a direct impact on soils and greenhouse gas emissions. The objectives of this study were to (i) evaluate the short-term impacts of CCs [grass dominated cover crops (GdC) and legume dominated cover crops (LdC)] and grazed CCs and corn (Zea mays L.) residue under oat (Avena sativa L.)–CC–corn rotation on soil physical and hydrological properties; (ii) quantify the architecture of soil pores using X-ray computed tomography (CT) for soils managed under long-term ICLS, native grazed pasture and corn-soybean …