Life Sciences Commons^™

New Insights On Hybridization In Potamogeton Floridanus (The Florida Pondweed)), Kaitlyn R. Sampson

<strong> Theses and Dissertations </strong>

Freshwater ecosystems are some of the most important and highest threatened habitats in the world, and aquatic plants play an important, but often-overlooked, role in maintaining them. Potamogeton is a diverse and ecologically important aquatic plant genus well known for taxonomic difficulty and rampant hybridization. lbis study aimed to 1) test the hypothesis that Potamogeton jloridanus (Florida pondweed) is a hybrid between P. oakesianus and P. pulcher, and 2) to investigate correlations in ecological conditions for the focal species. This study revealed the discovery of a new population of P. jloridanus in Big Coldwater Creek in Santa Rosa Co., FL, …

Evaluating Past Progress And Assessing Prediction Breeding Strategies For Sustained Genetic Gains In The Louisiana Sugarcane Variety Development Program, Brayden A. Blanchard

LSU Doctoral Dissertations

The aim of this dissertation is to outline important considerations for the Louisiana Sugarcane Variety Development Program (LSVDP) as it pertains to historical progress, impact, goal setting, and new strategies for continued genetic gains. Industry progress was evaluated with robust regression models to quantify rates of productivity gains. Over the last 50 years, statistically significant productivity gains were identified in sucrose content (45%), cane yield (32.2%), and sugar yield (93%) while pairwise comparisons of decades showed that progress was incremental rather than rapid and sustained once achieved. The decade from 1990-1999 was identified as the only decade with a significant …

Identification Of Downy Mildew Resistance In Wild Arugula And Evaluation Of Downy Mildew Causing Pathogens And Management Practices, Reilly B. Blair

Master's Theses

Downy mildew has been a potentially devastating constraint to crop production within the Brassicaceae family worldwide (CABI, 2022) and on the Central Coast of California (Smukler, et al, 2008; Koike, et al. 2007). Downy mildew is a foliar disease, caused by the pathogens in the Hyaloperonospora genus on plants within the Brassicaceae family (Goker, et al, 2009). Downy mildew is a disease that is common in region of the world with Coastal climates that provide humidity and moderate temperatures (Sarahan, et al, 2017). Crops within the Brassicaceae family maintain a predominant role in agricultural systems worldwide (Cartea, et al, 2011) …

Agrobacterium-Mediated Transformation Of Hemp (Cannabis Sativa L.)., Carthel Tyler Newton

Masters Theses

Agrobacterium­-mediated transformation has long been utilized as a method of producing stable, transgenic plants. This project describes an attempt to develop a system of producing stably transformed hemp (C. sativa (L.)) plants. Because of its recalcitrance to in vitro tissue culture and regeneration, transformation studies of hemp have been severely limited. In this study, I combined media components that have been shown to improve tissue culture health and regeneration. Additionally, I used hemp cultivars and explant sources that have been reported to function well in in vitro systems. The results showed that the improved media components did not …

Identifying Physiological, Morphological, And Genetic Drivers Of Key Intermediary Phenotypic Traits Associated With Stalk Lodging Resistance Within Genetically Diverse Maize Germplasm And Sorghum, Norbert Bokros

Theses and Dissertations--Plant and Soil Sciences

Maize stalk lodging reduces grain yields due to the permanent breakage or deformation of stalk tissue before grain harvest. To reveal new insights into the complex problem of maize stalk lodging, this dissertation will examine three primary objectives. First, the direct, diurnal influence of turgor pressure will be shown to have only marginal effects on stalk bending strength, a key trait associated with stalk lodging resistance. Up to a dozen individual stalks, grown to physiological maturity within the same field, were tested using a DARLING testing device. In parallel, stalk turgor status as measured by leaf water potential and turgor …

Quantitative Trait Loci Influencing Elemental Content In Grapevine Leaves, Jesse L. Krokower

MSU Graduate Theses

In grapevine, the influence of the plant’s elemental composition (the ionome) on fruit and wine quality is well established, but its genetic underpinnings have received limited scientific attention. In this study, I analyzed the leaf ionome of 131 interspecific F1 hybrid progeny plants from a cross between a Vitis rupestris Scheele (♀) and a Vitis riparia Michx (♂) parents, which were replicated in four different environments: Southwest Missouri, Central Missouri, South Dakota, and New York. I sampled leaves at three different times during the growing season at all four locations and had the concentration of 20 elements measured using ICP-MS. …

Characterization Of Lignin Structural Variability And The Associated Application In Genome Wide Association Studies, Nathan D. Bryant

Doctoral Dissertations

Poplar (Populus sp.) is a promising biofuel feedstock due to advantageous features such as fast growth, the ability to grow on marginal land, and relatively low lignin content. However, there is tremendous variability associated with the composition of biomass. Understanding this variability, especially in lignin, is crucial to developing and implementing financially viable, integrated biorefineries. Although lignin is typically described as being comprised of three primary monolignols (syringyl, guaiacyl, p-hydroxyphenyl), it is a highly irregular biopolymer that can incorporate non-canonical monolignols. It is also connected by a variety of interunit linkages, adding to its complexity. Secondary cell wall …

A Genome Wide Association Study Of Heat Tolerance In Snap Bean (Phaseolus Vulgaris), Morgan Stone

All Theses

Bean production in the United States has decreased while the temperatures have been steadily increasing, reaching new highs each year. Heat stress is detrimental to common bean (also known as snap bean) production. Symptoms of heat stress include decrease in pollen viability, shriveling of pods, and pod abortion making them unmarketable. Pod production of 323 snap bean accessions from a large diversity panel was assessed in a randomized complete block design with field trials at two different times in the spring season. The results show a significant decrease in the number of pods produced per plant and weight of pods …

Enabling Breeding For Fruitlet Freeze Tolerance In Peach, Ufuk Caglar

All Theses

Climate change is affecting the production of temperate fruit crops, with cold temperatures emerging as a critical abiotic stressor that limits plant growth and performance. Freeze damage, particularly in spring, has resulted in significant economic losses in peach production in the southeastern United States. Research efforts in peach and other Prunus species have primarily focused on studying dormancy-related traits associated with bloom time, such as chill and heat requirement, with fruitlet freeze tolerance not equally represented. Breeding for climate resilience in peach requires a combination of these traits to allow for late bloom via targeted chill requirement and high heat …

A Robust Agroinfiltration Method, Bryce N. Trull

Masters Theses

Stable transformation of soybean (Glycine max) is a markedly slow and laborious process. Thus, a tool that enables rapid evaluation of genetic elements in planta is critical to advance complex research and genetic engineering in soybean. To that end, a substantially robust agroinfiltration method was innovated in this work. Agroinfiltration is a technique that leverages Agrobacterium-mediated transient transformation to deliver genetic elements to the cells of whole plant tissues, usually leaves. Several factors were found to be relevant to successful soybean leaf agroinfiltration, including genotype, surfactant, developmental stage, and Agrobacterium culture medium. The research represents not only …

Evaluation Of Oxyfluorfen For Use In Roxy Rice, Casey Hunter Arnold

Graduate Theses and Dissertations

Mid-southern U.S. rice (Oryza sativa L.) producers are challenged every year to control problematic barnyardgrass [Echinochloa crus-galli (L.) Beauv.] and weedy rice (Oryza sativa L.) because they have evolved resistance to most labeled herbicides. Oxyfluorfen is a Herbicide Resistance Action Committee (HRAC)/Weed Science Society of America (WSSA) Group 14 herbicide that inhibits protoporphyrinogen oxidase within the plant. Currently, there are no HRAC/WSSA Group 14 herbicides labeled for barnyardgrass or weedy rice control in midsouthern rice production. Therefore, oxyfluorfen is being evaluated for barnyardgrass and weedy rice control. Plant breeders at the University of California – Davis were able to breed …

Driscoll’S Water-Use Efficiency (Wue) Strawberry Breeding Trial, Aidan Inoue

Plant Sciences

California’s water supply is seeing stress and growers are increasingly under pressure to lower their water use. While reducing irrigation to strawberry plants can be used to raise sugars (°bx), research on the impact of deficit irrigation on plant growth, fruit yield and quality are not yet quantified. The purpose of this experiment is to observe the effects of a ~50% deficit irrigation treatment on tabletop strawberry plants where drainage measurements and plant absorption can be recorded. Results indicate that plant vigor and total marketable yield are predominantly treatment dependent whereas fruit characteristics, including culls and berry size are reliant …

Breeding Cotton For Determinate Growth Habit: Increasing Cotton Fiber Yield By Remobilization Of End-Of-Season Perennial Reserves, Salman Naveed

All Dissertations

Cotton (Gossypium spp.) is a major export commodity for the U.S. Despite advances in plant breeding and management practices, the cotton yield gains in the U.S. have stagnated. Therefore, to increase cotton fiber yield, we undertook a novel approach by altering the growth habit of cotton from perennial to annual. In this effort, eight genotypes showing strong expression alleles for five floral induction and meristem identity genes were selected from 44 Upland cotton mini-core collection genotypes and genetically crossed in various combinations to stack the strong expression alleles in a genotype. These efforts have allowed us to develop high-yielding, …

Identifying Genetic Sources Of Anthracnose Resistance In Global Sorghum Lines, Mary-Frances Behnke

All Theses

Anthracnose of sorghum (causal agent: Colletotrichum sublineola) is the most detrimental disease of sorghum (Sorghum bicolor) worldwide, significantly reducing grain yield. This study includes a literature review of the disease and a meta-analysis of genome-wide association studies (GWAS) of anthracnose-resistance in sorghum as means to elucidate genetic sources of the trait. The meta-analysis includes genotypic and phenotypic data from 5 unique studies and 1,071 sorghum lines. Original genotyping-by-sequencing data from were obtained primarily from National Center for Biotechnology Information’s Sequence Read Archive (NCBI-SRA) and prepared and processed using the Tassel 5 GBS v2. pipeline. Phenotypic data were …

Genetic Dissection Of Alkalinity Tolerance In Rice (Oryza Sativa L.), Lovepreet Singh

LSU Doctoral Dissertations

Alkaline stress is a major threat to rice production globally. The resources for genetic improvement of alkalinity tolerance in rice are limited. We performed genome-wide association study (GWAS) and QTL mapping integrated with whole genome sequencing and expression analysis to identify and confirm QTLs and candidate genes. We developed a near-isogenic line (NIL) population to fine map the two important QTLs. In GWAS experiment, we genotyped and phenotyped a panel of indica and japonica genotypes for alkalinity tolerance and identified genomic regions and candidate genes conferring alkalinity tolerance. Principal component analysis revealed that alkalinity tolerance score, shoot dry weight, and …

Genome-Wide Association Study For Agronomic Traits In Bermudagrass (Cynodon Spp.), Lovepreet Singh

Theses and Dissertations

Bermudagrass (Cynodon spp.) breeding and cultivar development is hampered by limited information regarding its genetic and phenotypic diversity. A germplasm collection of 206 bermudagrass accessions from 29 countries was genotyped with high-throughput genotyping-by-sequencing technique. Genomic diversity in this diverse germplasm panel was assessed with multifaceted approaches including population structure, phylogenetic analysis, principal component analysis, and genetic diversity parameters. This study revealed substantial genetic variation in the Cynodon accessions, demonstrating the potential of this germplasm panel for further genetic studies and cultivar development in breeding programs. Another critical issue in turfgrass breeding is the lack of information regarding the genetic …

Evaluation Of Early Maturing Cultivars, Optimal Harvest Timing, And Canopy Reflectance Of Peanut To Maximize Grade And Yield, Joseph Bryan Whittenton

Theses and Dissertations

Peanut digging timing is difficult to predict due to indeterminate growth and peanut pods maturing underground, resulting in the need to research methods that provide consistent measurements, while reducing time and effort for farmers and researchers. Experiments were conducted to evaluate the accuracy of the Maturity Index 1 and Maturity Index 2 in predicting peanut grade, the accuracy of the North Carolina 2 degree day method in predicting peanut yield, and remote sensing vegetative indices sensitivity equivalence (SEq) to peanut Maturity Index 2 and harvest grade (TSMK) for cultivars IPG-914 and Georgia-06G in Mississippi.

Maturity Index 1 and …

Understanding Host-Microbe Interactions In Maize Kernel And Sweetpotato Leaf Metagenomic Profiles., Alison K. Adams

Doctoral Dissertations

Functional and quantitative metagenomic profiling remains challenging and limits our understanding of host-microbe interactions. This body of work aims to mediate these challenges by using a novel quantitative reduced representation sequencing strategy (OmeSeq-qRRS), development of a fully automated software for quantitative metagenomic/microbiome profiling (Qmatey: quantitative metagenomic alignment and taxonomic identification using exact-matching) and implementing these tools for understanding plant-microbe-pathogen interactions in maize and sweetpotato. The next generation sequencing-based OmeSeq-qRRS leverages the strengths of shotgun whole genome sequencing and costs lower that the more affordable amplicon sequencing method. The novel FASTQ data compression/indexing and enhanced-multithreading of the MegaBLAST in Qmatey allows …

Investigating Effect Of Seed Source And Developing Germination Protocols To Improve Success In Restoration Of Arkansas Tallgrass Prairies, Rhiannon Spencerosa

Graduate Theses and Dissertations

American tallgrass prairie has faced losses estimated at 87-98% of original land area since European settlement. Native seeds are often used to supplement struggling or extinct plant populations in tallgrass prairie restoration and establishment sites. Two main considerations in restoration and establishment are from where to source seed and how to obtain high germination rates. In order to determine the effect of seed source, a common garden experiment was performed in Fayetteville, Arkansas in 2022 with five prairie species: Andropogon gerardii (big bluestem), Bouteloua curtipendula (sideoats grama), Panicum virgatum (switchgrass), Schizachyrium scoparium (little bluestem), and Sorghastrum nutans (Indiangrass). Seed was …

Analysis And Installation Of A Demonstration Agroforestry Orchard For Californian Mediterranean Plant Communities, Brandon Hurd

Master of Science in Environmental Sciences and Management Projects

Climate-appropriate agroforestry can provide low-input food security and ecosystem services for local Californian Mediterranean climates, while conserving natural resources (e.g., water, nitrogen, etc.). This project showcases a variety of agroforestry methods for five common plant communities of California and other analogous Mediterranean climates at the CAFES Experimental Farm on the campus of Cal Poly San Luis Obispo. Plant community species and their ethnobotanical uses were analyzed to mimic and incorporate aspects of native flora. Agricultural plants were also characterized to represent each of the five selected plant communities. GIS was used to assess the project site for soil, slope, and …

The Trojan Horse Of The Paddy Field: Determining The Genetic Origins Of Seed Shattering In Spanish Weedy Rice, Eric Heinze

Undergraduate University Honors Capstones

Weedy rice, or red rice, is an agricultural weed that has evolved independently in different parts of the world from cultivated rice. Significant crop damage has resulted from weed infestations, leading to a loss of income for farmers and a severe reduction in crop yield. Seed shattering is one of the most distinctive and problematic characteristics of weedy rice, as it allows seeds to disperse and persist in soil for long periods and limit the effectiveness of current weed control efforts. While previous studies have identified a mutation causing a reduction in shattering between wild and cultivated rice, the exact …

Comparative Genomics Of The Putatively Asexual Powder Lichens Lepraria And Other Lecanoromycete Lichens, Bubba Pfeffer

EWU Masters Thesis Collection

No abstract provided.

Improving Baking Quality Of Soft Red Winter Wheat In Kentucky Through Breeding And Sulfur-Nitrogen Fertility Management, Maria Paula Castellari

Theses and Dissertations--Plant and Soil Sciences

Soft Red Winter (SRW) wheat is an important crop grown on about 400,000 acres in Kentucky as a pivotal cash crop in the 3-crops-in-2-years rotation of corn, wheat, and soybean. The humid environment of Kentucky generates a high yielding wheat crop, with low protein concentration and weak gluten strength. This wheat is mainly sold to millers and used by the industry for cakes, pastries, cookies, and crackers. Conversely, there is a rapidly growing interest in identifying other value-added markets for this wheat different to commodity commercialization, such as artisan-baked goods and craft-distilled beverages. Evaluating the quality characteristics of wheat grown …

Winter Rye (Secale Cereale L.) Management And Production Profitability In Kentucky, And Heritability Of Sensory Attributes, Elzbieta Szuleta

Theses and Dissertations--Plant and Soil Sciences

Winter rye (Secale cereale L.) is a small grain crop characterized by outstanding tolerance to drought, low temperatures, soil salinity and relatively low nutritional requirements. Rye is widely used as a cover crop, well known for its deep root system and outstanding nitrogen scavenging ability. This crop is widely used as a feed for livestock but also it is beneficial in human nutrition. Because of its versatile use, nutritional benefits and unique aroma and flavor, especially for bread and whiskey, there is an increasing interest in this crop in the United States. Unfortunately, rye grain production in the United …

Morphological And Genetic Analysis Of The Root System In Two American Grapevines (Vitis Species), Parinaz Mohtasebi

MSU Graduate Theses

The North American grapes species Vitis rupestris Scheele and Vitis riparia Michx have been the pillars of rootstock breeding for many decades. Though a large body of viticultural knowledge has been accumulated on their impact on grafted scions, the genetic basis of their root system architecture (RSA) has received limited scientific attention. In this study, I generated and analyzed adventitious root systems from dormant cuttings of 22 V. riparia and 19 V. rupestris accessions, as well as 162 interspecific F1 hybrid progeny from a cross between V. rupestris (♀) and V. riparia (♂). I photographed the roots and then extracted …

Sequencing Antisense Transcriptome Of Populus Through Antisense/Sense Transcript Pair Enrichment, Emma V. Burke

Dissertations, Master's Theses and Master's Reports

Past transcriptome research on plants focused primarily on protein coding genes, and only recently researchers began looking into the non-protein coding regions that may play significant roles in gene regulation. Antisense RNA transcripts that are found naturally in the cell share complementary sequence with sense transcripts and have been shown to regulate expression of their sense counterparts. Since antisense RNA has been largely under-studied and difficult to sequence because of their low relative abundance, new methods are needed to target antisense RNA for efficient genome-wide profiling. To address this gap in methods to efficiently and cost effectively enrich antisense RNA …

Genomics-Assisted Approaches To Improve Grain Yield And End-Use Quality In Hard Winter Wheat (Triticum Aestivum L.), Harsimardeep Singh Gill

Electronic Theses and Dissertations

Global wheat production needs to be increased by 60% to meet the future demand of feeding nine billion people by 2050. Simultaneously, it is important to improve the enduse quality to meet the requirements of producers, grain markets, processors, and consumers. Thus, the development of more productive wheat varieties with better enduse quality remains the primary focus for all wheat breeding programs. However, direct phenotypic selection for improving grain yield and end-use quality is difficult as it is highly influenced by environmental factors. This dissertation focuses on harnessing advancements in genomics applications, including genome-wide association studies (GWAS), for the genetic …

Intraspecific Hybrid Identification Of Black Walnuts Via Marker Assisted Selection, Makenna B. Thompson

MSU Graduate Theses

The improvement of Eastern black walnut (Juglans nigra L.) cultivars could increase market expansion. Improved cultivars with superior qualities would increase profitability for both the seller and the buyer. Agronomically and economically important traits such as heavier nut weight, disease resistance, tree structure integrity, and yearly nut production can be efficiently improved by breeding black walnuts via marker-assisted selection. Microsatellite/simple sequence repeat markers were used in this research to determine potential intraspecific hybrids between ‘Football’ and ‘Sparrow’ cultivars. Intraspecific is defined as of the same genus and species. This quality makes it more difficult to identify hybrids because the parent …

Micronutrient Concentration Effects On Lettuce Growth And Susceptibility To Pythium, Kalyn M. Helms

Graduate Theses and Dissertations

In hydroponic production waterborne pathogens such as Pythium are ubiquitous and continually threaten a wide range of Controlled Environment Agriculture (CEA) crops in hydroponic production, including but not limited to: lettuce, spinach, basil, arugula, cucumber, tomato, sweet pepper, roses, chrysanthemums, and cannabis (Sutton et al., 2006; Gull, 2002; McGehee and Raudales, 2021; Gillespie, 2020). Despite extensive sanitation measures, disease control in hydroponics is fallible and requires constant surveillance and management to minimize outbreaks (Sutton et al., 2006). A potential disease suppression strategy is to increase micronutrient concentrations within hydroponic systems to naturally strengthen plant defenses against pathogens such as Pythium. …

Functional Analysis Of Soybean Proteinase Inhibitor Genes And Cyst Nematode-Inducible Synthetic Promoters For Insects And Nematode-Resistance In Plants, Mst Shamira Sultana

Doctoral Dissertations

Proteinase inhibitors (PIs) from legumes have the potential for use as protectants in response to pests and pathogens. Soybean (Glycine max) contains two trypsin inhibitors (TIs): Kunitz trypsin inhibitor (KTI) and Bowman-Birk inhibitor (BBI). In this study, the possible role of soybean TIs in plant defense against insects and nematodes was investigated. In addition to the three known TIs (KTI1, KTI2 and KTI3), novel inhibitors KTI5, KTI7, and BBI5 were identified in soybean. Their functional role was further examined by overexpression in soybean and Arabidopsis. In vitro enzyme inhibitory assays showed significant increase in trypsin and chymotrypsin inhibitory …