By Gillian Beatson 

Summer is hitting us with a sweltering heat wave – but ironically, this is also the time researchers are immersed in field tests to help plants get strong for the inevitable winter deep freeze that will be here before we know.

For example, University of Guelph researchers at the Simcoe Research Station are field testing enhanced common wine-quality grape rootstocks in preparation for winter to determine if even more viticulture development can take place across Ontario. 

Prof. Adam Dale, Department of Plant Agriculture, and Dr. Alireza Rahemi, a postdoctoral researcher, want to know if certain varietals that are improved with hardier rootstocks (established root systems of a grape variety) will defy the harsh elements and survive the winter months in certain regions across Ontario. 

Commercial grape varietals that are commonly grown in Ontario – Riesling, Chardonnay, Cabernet Franc and Pinot Noir – are included in the trial. 

“The issue here about expanding the acreage is the winter hardiness,” says Dale. “We need grapes to live through the winter. Wineries do lose crops over the winter some years – it happens. Losing two crops out of the last four years is not bad, but if they could lose zero – that’s great.”

Through grafting, the researchers believe certain rootstocks can help other grape varietals by providing them with a hardier root system that is already resistant to pests or drought.

For example, Vitis ripariais a species of wine grape that is native to Ontario and already known for its cold hardiness and disease resistance. Dale and his research group are grafting other common commercial wine grape varietals in Ontario onto rootstocks of this resilient species, to see if they could grow in areas that may not have been possible before. 

For this research, Rahemi collected 900 Vitis ripariaclones, all genetically different, from sandy soil regions all over Ontario. This includes growing regions such as Prince Edward County, Kent County, Norfolk County and Elgin County. 

Twelve of these clones were selected to be grafted with commercial wine varietals because of their drought and cold tolerance and planted for trials at the Simcoe Research Station in Norfolk County. 

Dale says this will offer insight into how these grafted rootstocks would fare in unconventional growing regions of Ontario, outside of the already established wine regions.

 “We know it is cold here and we know the Vitis ripariarootstocks that grow here have been adapted to Ontario weather,” says Dale. “The soil type and climate of the Norfolk region is very unique to Ontario so the information from the trials will be crucial for expanding wine grape growth in certain areas of Ontario where they may not have grown before.”

Bolstering this business could be very fruitful as the wine industry contributes greatly to the economy of the province and country. The Canadian Vinters Association and the Winery & Grower Alliance of Ontario said in a report last year that the Ontario wine and grape industry contributes $4.4 billion to the Canadian economy. 

The sector also generates thousands of jobs for Ontarians in areas like retail, farming, and product development.  

“If these trials are successful, it will benefit Ontario wineries,” he says. “They will have greater winery productivity … grape crops will not be lost throughout the winter months.”

Trials are ongoing with the grafted rootstocks. Dale and his research group will continue to monitor the planted vines over a few more winter seasons.  

This research was funded by a grant through the OMAFRA-U of G Agreement and the Agricultural Adaptation Council, through the Growing Forward 2 program. It was conducted in conjunction with the Ontario South Coast Wineries and Growers Association and the Ontario Wine and Grape Research Inc.