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Utilizing Mitotalens To Investigate Large Repeats In The Arabidopsis Thaliana Mitochondrial Genome, Cambelle Johnson Aug 2023

Utilizing Mitotalens To Investigate Large Repeats In The Arabidopsis Thaliana Mitochondrial Genome, Cambelle Johnson

Honors Theses

Mitochondria are a silly place to store the genetic code. In spite of the ever-present threat of oxidative DNA damage, plant mitochondrial genomes are expansive in size and include noncoding repeat sequences, a small number of which are greater than 1kilobase (kb), known hereafter as “large repeats” (LR). This theme of one or more large repeat pairs is shared across most flowering plants, lending to the belief that they somehow contribute to the plant’s fitness. These repeats exhibit high rates of rearrangement and recombination. Studying repeats in vivo could have large scale implications in hybrid crop production enhancement including eliminating …


Exploring Gene Expression Patterns For Resilient Maize Lines Under Nitrogen Stress, Alice Guo May 2023

Exploring Gene Expression Patterns For Resilient Maize Lines Under Nitrogen Stress, Alice Guo

Honors Theses

Nitrogen plays a major role in the proper growth and development of maize and is therefore essential to crop production, being the most critical nutrient for achieving optimal yield. In previous field and greenhouse studies, we have found maize lines that differ in their resiliency to nitrogen stress. To identify the potential genomic regions associated with the differences in nitrogen deficiency resilience, Genome-Wide Association Studies (GWAS) were conducted. Based on a previous study, the most consistently resilient maize inbred lines within the Goodman-Buckler diversity panel have been identified as the lines A619 and A661, while the non-resilient inbred lines have …


A Small Stem Assay Using Hypovirulent Cryphonectria Parasitica To Screen Castanea Dentata Backcross F2 Families May Set The Stage For Long-Term Survival, Trish Nguyen May 2023

A Small Stem Assay Using Hypovirulent Cryphonectria Parasitica To Screen Castanea Dentata Backcross F2 Families May Set The Stage For Long-Term Survival, Trish Nguyen

Honors Theses

By combining the results of blight resistance breeding and the application of hypovirulence as a biocontrol, populations of resistant hybrid trees could be deployed together with a less pathogenic strain of Cryphonectria parasitica (Murr.) Barr. I used a small stem assay to screen seedlings in thirteen half-sibling backcross F2 families with an attenuated strain of C. parasitica containing the Cryphonectria parasitica hypovirus-1 (CHV-1) Euro7 virus. The experiment was set up as a randomized complete block design in 2-gallon containers. Measurements of canker length and morphology were gathered at 90 days post-inoculation. Although statistically significant differences were seen between canker lengths …


Oxalic Acid Leaf Disk Soak Assay Is A New Possibility In Screening For Blight Resistance In Castanea Species, Kaitlyn Harden May 2023

Oxalic Acid Leaf Disk Soak Assay Is A New Possibility In Screening For Blight Resistance In Castanea Species, Kaitlyn Harden

Honors Theses

Chestnut blight is a disease caused by the ascomycete fungus Cryphonectria parasitica in the Castanea species. The fungus uses oxalic acid (OA) to attack the tree’s cells. Castanea dentata, the American chestnut, was wiped out by chestnut blight in the early to mid-20th century, but several East Asian Castanea species appear highly resistant to the fungus. To breed resistant American type trees, screening methods are used to enable selection of interspecific hybrids. The alternative small stem assay (aSSA) is a method of screening container-grown hybrid seedlings during their first growing season by directly infecting them with C. parasitica. Some plant …


Bryophytes Of Goochland County, Virginia, Mikayla Quinn Apr 2023

Bryophytes Of Goochland County, Virginia, Mikayla Quinn

Honors Theses

Bryophytes are non-vascular land plants that include mosses, liverworts, and hornworts. Although easier to overlook because of their smaller size, bryophytes are a fundamental part of the ecosystem. As such, maintaining record of their biodiversity is important. Yet, records of bryophyte species in Goochland County, VA were low compared to more thoroughly documented counties such as Prince Edward County. This study expands the documentation of bryophyte flora and presents a checklist of bryophyte species found Virginia’s Goochland County from 2020-2023. Fieldwork conducted at public and privately-owned properties throughout the county between January 2020 and March 2023 yielded 702 specimens that …


Systematic Review: Effect Of Cover Crop On Working Farm, Noella A. Bahatsi Mar 2023

Systematic Review: Effect Of Cover Crop On Working Farm, Noella A. Bahatsi

Honors Theses

On-farm research is when research techniques such as randomized, replicated treatments strips and large-scale techniques are used on actual farms or ranches. Due to a great deal of interest and curiosity among farmers and researchers who wish to make their farming methods more profitable, efficient, and/or sustainable, this type of research has been conducted more frequently each year. On-farm research has contributed to economic growth and the transfer of knowledge to farmers because of fresh discoveries and upgraded technology (Lacoste et al., 2022). This is also where farmers collaborate with researchers to test new management practices and technologies providing unbiased …


Changes In Ecosystem Processes And Functional Traits Over An Elevational Gradient, Tiana Issa Jan 2023

Changes In Ecosystem Processes And Functional Traits Over An Elevational Gradient, Tiana Issa

Honors Theses

Elevation gradients have been used to understand how climate change impacts various ecosystems processes by substituting distance across elevation with time, reflecting a previous, colder climate. To monitor the changes in soil organic carbon (SOC), plant community, and functional traits across time in the face of climate change, this study used space-for-time substitution to emulate a long-term study with elevational gradients and revisited the same gradient for nearly two decades to monitor elevational effects across time. With this research, I aim to answer the following questions: (1) How does elevation impact ecosystem processes and alpine plant traits? (2) How does …


Heading For A Breakdown: Assessing Evolution Through The Hybridization Of Two Sexual Systems, Diamanda A. Zizis Jan 2023

Heading For A Breakdown: Assessing Evolution Through The Hybridization Of Two Sexual Systems, Diamanda A. Zizis

Honors Theses

Hybridization is an important evolutionary pathway that has contributed to the world’s vast biodiversity. In plants, especially angiosperms, hybridization is known to be an important mechanism for speciation, phenotypic divergence, and changes in reproductive systems. Solanum species present an ideal system to investigate how hybridization between two different sexual systems impacts the reproductive and phenotypic biology of the hybrid progeny. Hybrid seeds were acquired from crosses between Australian Solanum species Solanum dioicum (dioecious) and S. ultraspinosum (andromonoecious) in order to track what happens when you cross two plants with different sexual systems. Vegetative and floral morphological measurements were conducted, and …