Featured Graduate Students

Vivian Bernau

Vivian Bernau is a PhD Candidate in the department of Horticulture and Crop Science. She earned undergraduate degrees in agronomy and horticulture from Iowa State University and began her PhD program in 2014 after spending a few years gaining research experience with the USDA National Plant Germplasm System and abroad at the International Center for Tropical Agriculture (CIAT).

Under the guidance of her co-advisors, Dr. Kristin Mercer and Dr. Leah McHale, Bernau is exploring drought resistance in chile germplasm collected in the Mexican states of Oaxaca and Yucatan across temperature and precipitation gradients. Bernau hopes to identify an evolutionary and genetic basis for drought resistance, centering on the hypothesis that local adaptation to precipitation and temperature gradients has led to physiological adaptations, and thus genetic differences, in cultivated landraces and wild populations. In 2016, Bernau was awarded a US Borlaug Global Food Security Fellowship. Through this program she is expanding her dissertation research to investigate the effect of simulated drought stress on highland maize landraces from throughout Latin America at the International Maize and Wheat Improvement Center (CIMMYT) in El Batan, Mexico.

Through her PhD program, Bernau is working towards a career as a germplasm curator. At OSU, she has served as chair of the annual HCS Graduate Research Retreat and she’s developed teaching and grant writing skills—essential for a future in public research. Additionally, Bernau appreciates being a part of the plant research community at OSU and making connections in and beyond Kottman Hall through the Center for Applied Plant Sciences and the department of Evolution, Ecology, and Organismal Biology.

Top of page

Katherine D’AmicoKatherine D'Amico

Advisor: Jonathan Fresnedo Ramirez

Research: Non-infectious bud-failure in almond (Prunus dulcis) as a model to study plant aging and its effects in perennial species

Katherine D’Amico is a PhD candidate in the Translational Plant Sciences (TPS) graduate program. She is currently working in the department of Horticulture and Crop Science in Wooster, OH. Katherine’s dissertation research goal is to better understand plant aging and its effects in perennial species. To accomplish this, she is using non-infectious bud-failure in almond (Prunus dulcis), hypothesized to be an age-related disorder, as a model system. Her research aims to identify epigenetic mechanisms associated with exhibition of bud-failure in different cultivars and clones of almond. Approaches include comparing telomere length, examining gene expression patterns and performing epi-genotyping-by-sequencing using important almond cultivars and clones exhibiting distinct degrees of bud-failure. This work will help us to better understand the deterioration of key biological processes that occurs as plants age, particularly in perennial species.

Katherine received her B.S. in biology with a minor in computer science from John Carroll University. She earned an M.S. in conservation biology from the SUNY College of Environmental Science and Forestry where her research focus was on the potential non-target impacts of a transgenic American chestnut with enhanced blight resistance. After completing her Masters, Katherine worked for the USDA Agricultural Research Service at Cornell University in a Pseudomonas systems biology lab where her research focus was on small RNAs and their impacts on pathogen virulence in both tomato and Arabiodopsis models. She is excited to return to her “roots” at Ohio State working on a tree nut crop and is grateful for the opportunities afforded by the TPS program, the HCS department and the Fresnedo Ramirez lab.

Top of page


Cassidy Gedling

Lab: Dr. Anne Dorrance

Research: Mechanisms of quantitative resistance towards Phythophthora sojae and Fusarium graminearum in soybean

Cassidy Gedling is a PhD candidate in the Department of Plant Pathology, advised by Dr. Anne Dorrance. Her research focuses on identifying mechanisms and candidate genes for quantitative resistance towards two pathogens of soybean, Fusarium graminearum and Phythophtora sojae. Currently, fine mapping, gene expression analysis, and long range sequencing of the quantitative trait loci (QTL) are under way for identification and analysis of candidate genes for resistance towards F. graminearum. In an additional study she is conducting an expression quantitative trait (eQTL) analysis to identify defense response pathways and narrow putative candidate genes for quantitative resistance to P. sojae. Untimely, the goals of these studies are to incorporate resistance genes for these two pathogens into future breeding programs.

While completing multiple internships in her undergrad in unrelated fields, she found a passion for plant science through a remediation of natural flora internship at Indiana University Southeast. Gedling earned her B.A. in biology with a minor in plant science from Indiana University Southeast in 2014, and started graduate school directly after finishing her undergraduate degree. After completing graduate school, she hopes to continue her career in industry as a plant pathologist.

Top of page

Stephanie KarhoffStephanie Karhoff, PhD candidate

Lab: Dr. Leah McHale (co-advised by Dr. Anne Dorrance)

Research: Breeding for quantitative resistance to Phytophthora root and stem rot in soybean

Karhoff is a third year PhD candidate in the Translational Plant Sciences graduate program, co-advised by Drs. Leah McHale and Anne Dorrance. Her research goals are to assess a major quantitative trait loci (QTL) for Phytophthora root and stem rot in soybean and identify the gene(s) conferring resistance.  She is currently testing the QTL against multiple Phytophthora sojae isolates and in a separate experiment, testing the QTL’s effect in multiple genetic backgrounds.  She's also selecting candidate genes associated with the QTL based on both gene expression and fine-mapping results.  The long term goal of this study is to incorporate the resistance source into soybean cultivars.

Karhoff received her B.S. in Agriculture from The Ohio State University and has completed internships with the Ohio Soybean Performance Trials, AgReliant Genetics, Monsanto Company, and most recently Beck’s Hybrids. After graduate school, she hopes to pursue a career either as an extension educator, breeder, or agronomist. When she is not in the lab or field she enjoys applying her plant knowledge to her garden and spoiling her nieces and nephews.

Top of page


Matthew Willman

Advisor: Jonathan Fresnedo Ramirez

Research: Genetic characterization of black raspberry (Rubus occidentalis) breeding germplasm

Matthew Willman is a Masters student in the department of Horticulture and Crop Science. His research goals include estimation of genetic effects and identification of quantitative trait loci (QTLs) for important horticultural and fruit quality traits in black raspberry. Matthew’s work involves close collaboration with university and USDA researchers in Oregon, North Carolina, New York, and Ohio. He is currently analyzing phenotypic and genotypic data generated by these collaborators with the goal of characterizing and improving black raspberry breeding stock through the incorporation of wild germplasm. Matthew also maintains black raspberry germplasm at Ohio State which he is expanding through seed collection and propagation.

Matthew received his B.S. in Agriculture from The Ohio State University and completed an internship at the Boyce Thompson Institute at Cornell. His interest in plant science began in a restaurant kitchen, where he learned to cook using fine local ingredients before pursuing his bachelor’s degree. His work experience also includes apprenticeship and management in small-scale fruit and vegetable production systems for direct to consumer sales.

Top of page