SR9150 - Improved Wine Grape Cold Hardiness and Disease Tolerance Through Variety Development

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Researcher:

Dr. John Zandstra, Ridgetown College - University of Guelph

Objectives:

1. Document the virus status of grape plants imported from Italy, Austria, Switzerland and Germany.
   
2. Evaluate the cold tolerance of European grape cultivars when grown under Ontario conditions.
   
3. Document the disease tolerance (mildews, botrytis) of European grape cultivars when grown under Ontario conditions.
   
4. Document the production characteristics of new grape cultivars when grown under Ontario conditions.
   
5. Evaluate wine quality of new grape cultivars.

Expected Benefits:

The continual adoption of new varieties which show improvements in characteristics such as yield, maturity, food quality, pest resistance or environmental tolerance are crucial to any agricultural plant industry. The researchers are working in cooperation with the Center for Plant Health by streamlining the virus screening process so relatively large numbers of grape vines can be released under quarantine after a 5-6 month initial virus screening program for field evaluations. The project will provide timely data on the performance of promising cold tolerant and disease resistant varieties not presently available in North America.

Summary of Research Results:

While grape and wine production in Ontario is a dynamic and expanding industry, winter injury, especially to vinifera vines continues to be a concern. Some degree of low temperature injury is present every year and many management strategies are geared towards reducing this type of injury. Regardless, damage can be severe after hard winters, as was seen in 1994 and 2003. Proper site selection is a management strategy directed towards reducing low temperature injury, and good grape sites are often located near large bodies of water in order to take advantage of the moderate climate. Associated with this close proximity to water are periods of high humidity, which promote the incidence of major grape diseases including powdery mildew and botrytis bunch rot.

Having wine grape varieties with improved cold hardiness and disease tolerance would be of value to the Ontario industry. At the request of the grape and wine industry in southwestern Ontario, a project was initiated in 2000 to evaluate cold hardy and disease tolerant vinifera grape varieties from across Europe. In 2000, eight cold hardy varieties were imported from Italy, in 2005 four vinifera grape selections bred specifically for tolerance to grape diseases were imported from Germany and Austria, and in 2007 five varieties were received which originated from the country of Georgia. In all cases the vines are imported under the supervision of the Canadian Food Inspection Agency, who screen them for regulated pathogens and release them under quarantine. Presently, only the Italian varieties have produced a crop.

Of all the Italian varieties, Tocai Friulano was the most cold tolerant as determined by spring bud survival. While not statistically better than Auxerrios (which was included as a relatively cold tolerant vinifera), it had numerically greater bud survival counts 3 years out of 4. It is a white grape variety which matures in late September in Southwestern Ontario; in its first year of production (2005) it produced 1.2 tons of grapes/acre at 20.9o Brix. Small batches of wine have been prepared which are being evaluated by local wineries. No major disease problems have been noted with this variety.