Identifying the effect of clone and rootstock on viticultural performance, fruit composition and winemaking potential for Pinot Noir, Chardonnay and Riesling, in Niagara, Ontario.

Previous research globally has demonstrated that the performance of grapevine clone and rootstock combinations on vine performance and fruit quality are region-specific. Consequently, it is imperative for the Ontario wine industry to have locally-relevant information on the performance of vine combinations before these selections are purchased and established in vineyards. The objective of this research is to identify the influence of clone and rootstock combination on vine performance, fruit composition and oenological potential for core Ontario varieties: Pinot noir (clones: 113, 114, 115 and 777 on rootstock Riparia Gloire), Chardonnay (clones: 548, 96, 95 and 76 on rootstock Selektion Oppenheim 4), and Riesling (clones 9, 12 and 21 on rootstock SO4; clones 239, 49 and 21 on rootstock SO4; rootstocks 101-14, SO4 and 5C on clone 9; and rootstocks 3309C and SO4 on clone 21) over the course of multiple growing seasons and vintages, 2017 and 2018. Replicated blocks for each treatment were established in one of three commercial vineyards within the Niagara region. Vine performance was measured by timing of phenological stages, yield components, vine balance, disease and winter injury. Fruit composition was determined by measuring acid and soluble solid content of 100-berry samples taken from sentinel vines. Fruit was harvested from select research blocks and fermented into wine to evaluate oenological potential through must composition analysis, fermentation kinetics and finished wine composition analysis. Results indicate significant (p≤0.05) differences in all cultivars in both years, for the effects of clone and rootstock on vine performance, fruit composition and oenological potential in Niagara. However, trends were generally not consistent across years, indicating further vintages will be required to eliminate the weather-related differences between years. This project is limited by its duration of two years. Research from additional vintages is required in order to further understand the effects of clone and rootstock selection under Niagara vineyard conditions. Acknowledgements First, I would like to thank my academic advisors, Dr. Debbie Inglis and Dr. Jim Willwerth for their support and guidance through the course of this research. Their experience and insight guided me through this project and helped me to develop as a scientist and a professional. I would also like to thank my committee members Dr. Belinda Kemp and Dr. Vincenzo De Luca for their time and commitment, adding depth and understanding to my work. Secondly, I would like to thank our funding partners, the Natural Science and Engineering Research Council of Canada-Collaborative Research and Development and the Ontario Grape and Wine Research Inc and our industry partners. Their collaborative support has made this research possible. Thirdly, I would like to thank the faculty, staff and students at the Cool Climate Oenology and Viticulture Institute that contributed their hard work, time and knowledge towards this research, most notably, Andréanne Hébert-Haché, Stephanie Bilek, Fei Yang, Tony Wang, Tom Willwerth, Mark Willwerth, Cameron Green, Steven Trussler, Lisa Dowling, Shufen Xu, Elena Genkin, Jennifer Kelley, Margaret Thibodeau, Leah Felice del Renton, Brianne Dorin and Robin Holford. Finally, I would like to thank my family. Without their love and support this accomplishment would not have been possible.