Introducing the Penn State wine & grapes graduate students’ team

By: Michela Centinari and her graduate student team

An exciting and rewarding part of my responsibilities as a faculty member is mentoring graduate students and helping them to achieve their career goals. This week I would like to take the opportunity to introduce three young and talented graduated students who have decided to focus their studies and research on wine grapes.

It is my pleasure to advise Maria Smith and to co-advise Annie Klodd and Laura Homich. Their backgrounds are diverse and they each bring something new and interesting to the table. They are working on research projects that will benefit the wine and grape industry, as well as advance our knowledge on several topics including:

  • Effect of crop load and intensity of pre-bloom fruit-zone leaf removal on yield components, disease incidence, cold hardiness, winter carbohydrates storage, and wine sensory perception.
  • Effect of the timing of fruit -zone leaf removal and cluster sunlight availability on grape and wine aroma profiles.
  • Impact of under-trellis cover crops on vine root distribution, morphological traits, soil nutrient and water availability in response to below-ground competition for resources and/or interference for space.
  • Effect of delayed bud–break on fruit ripening, yield components and wine sensory perception.
  • Physiological response to post-budbreak freeze events in Vitis vinifera and inter-specific hybrids winegrape varieties.

These collaborative research projects on wine grapes have strengthened ties among faculty and research staff members at the Penn State College of Agricultural Sciences, as well as fostered cooperative relationships with universities such as Cornell and Virginia Tech. Finally, I would like to point out that thanks to the students’ hard work and efforts, this fall, wine will be made from several research trials under the supervision of the Extension Enologist, Denise Gardner. This will allow industry members to assess if and how viticulture treatments imposed in the vineyard affected wine sensory perception.

Later this year the students will post updates about their research projects in this blog. This week I invited Annie, Laura and Maria to introduce themselves to the wine grape community:


Annie Klodd

Sep 2014_Annie

“Hi, my name is Annie Klodd, and I’m a 2nd-year Masters student in Plant Biology at Penn State, advised by Drs. David Eissenstat and Michela Centinari. I grew up on a 20-acre vineyard in Iowa, and once I outgrew my childhood distain for pruning in -10 degree winters, I developed a true passion for the US winegrape industry, particularly in the Midwest and mid-Atlantic.

My research aims at understanding how cover crops planted under the trellis affect grapevine growth, so we can make informed decisions about if and how to use cover crops in mid-Atlantic vineyards. In order to get to the bottom of that, we have to look beyond pruning weight and yield and dig deeper (no pun intended) into how cover crops affect the vine roots’ access to vital nutrients and water. My experiment is located at Virginia Tech’s Alson B. Smith Agricultural Research and Extension Center vineyard, where Tony Wolf’s team found that an under-trellis grass cover crop reduced vegetative growth and yield of Cabernet Sauvignon vines. To explore why, I am testing whether the resource demands of the grass tend to limit the water and nutrients available to the vine roots. So far, my data suggests that the shallow fescue roots limit the phosphorus available to the vine in shallow soil, and force the vine roots into deeper soil, where nitrogen and phosphorus are in tighter supply. To learn more about how the vines respond to nutrient limitation, I’ll spend the next few months in the lab testing whether the cover crop caused the vine roots to alter their anatomy or rely more on beneficial mycorrhizal fungi for the uptake of phosphorus.”


Laura Homich

Sep 2014_Laura 3 pics

“Hi, my name is Laura Homich, and I’m a first year Masters student in the Food Science Department under the direction of Dr. Ryan Elias and Dr. Michela Centinari. I began my exploration of enology and viticulture as an undergraduate Chemistry student at Penn State. Through my undergraduate research experience with Extension Enologist, Denise Gardner, I not only helped with processing and analysis of the NE-1020 varietal wine trials, but also worked on my own project investigating the effects of co-inoculation on wine quality of a high-acid, red hybrid, Chambourcin. I was given the opportunity to present my research findings at the 2014 PA Wine Marketing and Research Board Symposium, and at the 2014 American Society of Enology and Viticulture Conference.

My thesis work will explore the effects of viticulture practices on the rotundone content in Noiret grapes and wine. Rotundone is an aroma-impact compound found in the grape skin and is attributed to the black pepper notes most commonly associated with Australian Shiraz. Rotundone has been identified in an increasing number of Vitis vinifera cultivars, including Grüner Veltliner. Interestingly, approximately 20% of consumers are anosmic (the inability to perceive) to rotundone, while those who can detect this compound can identify it at concentrations as low as 16 ng/L in wine. Noiret is a hybrid variety suitable for growth in cool-climate regions and is known for its black pepper characteristics. This study will look at the effects of timing of fruit-zone leaf removal and cluster sunlight exposure on rotundone content at various time points across the grape ripening process. Through this project, I’m thrilled to learn about wine aroma analysis methods, to continue to gain experience in winemaking, and to obtain hands-on experience in the vineyard.”


Maria Smith

Sep 2014_Maria

“Hi, I am Maria Smith. I graduated magna cum laude in 2009 from Virginia Commonwealth University, with a B.S. in biology and minors in chemistry and Spanish. At VCU, I studied the molecular genetic basis of symbiotic relationships for nitrogen fixation in flowering plants. I received my M.S. in horticulture from Cornell University in 2013 working with Dr. Taryn Bauerle on the role of both above and belowground traits on invasive potential of woody plants. I recently moved from Washington, DC here to Penn State for a Ph.D. in viticulture with Dr. Michela Centinari.

Grapevine injury due to cold temperatures (winter and late spring) is a limiting factor to grape production in PA and other regions as well. The focus of my research centers on how canopy management practices impact vine cold hardiness and winter carbohydrate reserves in permanent organs. Additionally, I will be exploring the role varietal differences have in physiological responses to imposed frost events post-bud break in young vines. This work will be in conjunction with on-going projects at the PSU Lake Erie Regional Grape Research and Extension Center and the vineyard at Rock Spring experimental farm.”



 We would like to especially thank our collaborators at Penn State (Bryan Hed, Denise Gardner), at Cornell University (Dr. Justine Vanden Heuvel), and at Virginia Tech University (Dr. Tony Wolf). Additionally, we would like to extension a special thank you to the PSU Lake Erie Regional Grape Research and Extension Center staff and Don Smith for their technical support.


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