How to build a better grape

Dr. Debbie Inglis Dr. Jim Willwerth

by Dr. Debbie Inglis, CCOVI Director, Brock University, and Dr. Jim Willwerth, Viticulturist, CCOVI, Brock University. 

How to build a better grape?  That is a question commonly asked to researchers like ourselves at the Cool Climate Oenology and Viticulture Institute (CCOVI).  Can you create a grape that would be resistant to disease and insects, survive extreme cold temperatures in winter, fully ripen in our growing season (whether it is hot and dry, or cold and rainy), and then produce the best wine ever?  These are all the conditions we have in the erratic Ontario climate. Are we up for the challenge? You bet! 

We need to look at this from two perspectives: what can be done now to improve grapes that are already in production, designing wines around current climatic conditions that are even more appealing to consumers; and what can we plan for in the future, especially with the impact of climate change that we are already experiencing. What will our climate be like in 30+ years and how will we, and grapevines, adapt to this change?

One way to build a better grape is through breeding programs. The key to this strategy is to keep a high percentage of the high quality Vitis vinifera wine grape background in the new variety, but breed into this disease resistance and cold hardiness from native grapes that grow in harsh conditions. This process can take many years to develop and release new varieties. New technologies are helping to accelerate the process, especially as we learn the important genes in grapes that provide cold hardiness and disease resistance, but these are long-term projects that can take 15+ years.  It does not end there.  Did you know grapevines take five years once they are planted before they come into full production for wine?  In southern Ontario, vines seem to maintain good production levels for approximately 25 years before they need to be replaced.  So, these are long-term investments of time and money we are looking at. But planning for the future is vital to continue to grow our thriving Ontario wine industry. For this, we need to model what our climate will be like in 30 years so we can match grape varieties (or future varieties we develop) to this climate. You’ll have to check back with us once our climatic modeling is done so we can give you a snapshot of what to expect in our grape growing regions in 2045.

So what do we do in the interim to improve our high-quality grapevines that are currently in production to build a better grape? We need to develop innovative practices to improve vine health and create wines well suited to our current climate.  Canada’s winters are our biggest threat to grapevines. Grapevines that produce the best wine are not very tolerant to our sub-zero temperatures, so we have to figure out what growers can do in the vineyard to make vines as tolerant as they can be to cold.  Did you know that grapevines become more tolerant to cold temperatures as the temperatures start to drop in the fall and the daylight hours become fewer?  These are the signals to the vine to prepare for the winter months and cold temperatures ahead – their acclimation phase.  The vines eventually reach their maximum hardiness around January, where they can tolerate temperatures to about -20°C before damage occurs.  In the spring, the opposite occurs; they become less and less tolerant to cold temperatures as they prepare for bud break in the spring – their deacclimation phase. 

Our research follows grapevine cold hardiness throughout the entire dormant period from October through to April to allow us to understand factors that impact hardiness (crop load, disease and water stress, grape ‘hang time’ on the vine).  Through this research, we help grape farmers protect their vines in the winter by keeping track of how cold tolerant the vines are while they are dormant.  How does this help farmers?  If a cold weather event is forecasted to get colder than the measured hardiness level of the vine, we warn the growers so they can make management decisions such as using wind machines or flying helicopters to warm up the air and protect the vines so the temperature never gets to the danger zone. 

We have made these decisions easy for busy grape growers by creating an online database called VineAlert (http://www.ccovi.ca/vine-alert) that tells growers what temperature different varieties are able to tolerate based on their regional location and stage of dormancy.  Here’s what a VineAlert screen looks like.

CCOVI’s VineAlert
Figure 1.  Screenshot of CCOVI’s VineAlert depicting cold hardiness ratings of Chardonnay vines and minimum temperature data in the Four Mile Creek sub-appellation for the 2011/12 dormant season.  As seen in the graph, in late March of 2012, when the bud hardiness value of -6.5C (LTE10 in purple) approached the minimum temperatures that day (-6C), cold injury can result and growers will use protective measures such as wind machines.

 

All grape growers need to do is go to the website, scroll down to what varieties they grow, pick their location, and the information is displayed in an easy-to-access format.  We also send out email alerts to let them know when trouble may be near due to cold weather.  This way we are helping growers have healthier grapevines with good yields of quality fruit after our winter and spring months.

This season is the perfect illustration of the effectiveness of VineAlert. A few weeks ago in mid-late April, due to the warm weather that stimulated rapid deacclimation of grapevines, the vines were only hardy to about -6.5°C, about 3-4 weeks ahead of a normal year. A cold weather event was forecasted to go down to about -4 to -5°C, dangerously close to bud hardiness values (See Figure 1). The year before, at this same time, vines were hardy to around -17°C and growers would not be concerned about a -4°C event.  But in the spring of 2012, the vines had so rapidly deacclimated, they were in danger. We were able to share this data with the grower community throughVineAlert, and get an early warning out to them.  Growers were prepared and used wind machines and helicopters (see Figure 2 below) to warm up the air and protect their vines. 

Helicopter being used to protect grapevines
Figure 2.  Helicopter being used to protect grapevines from damage during a cold spring weather event in Niagara on the Lake on March 21, 2012.  The blades of the helicopter act similar to wind machines and mix warm air with the cold air near ground to keep temperatures from reaching critical values that will kill grapevine buds and other tissue.

 

The early spring frosts are continuing, and through VineAlert, we will continue to assist growers to manage cold events to avoid damage as pictured in Figure 3.

Healthy vines (far left) vs. vines with cold injury (right)
Figure 3.  Healthy vines (far left) vs. vines with cold injury (right) after the 2010/11 winter months.  These damaged vines do not have many live buds and are pushing shoots from their base.  These base shoots will need to be re-trained from the ground up to replace the dead trunks, leading to loss of income and more associated costs for the grower. It will take a couple of years to get them back into full production again.

 

Does building the perfect grape end at having the vine make it through the cold Canadian winter? Not at all–we are much more demanding than that.  The fruit quality must be there to produce wines that our consumers want.  We have research programs in this area too, but it will need to wait until our next blog where we can tell you all about how we can actually further ripen fruit off-vine using repurposed tobacco kilns and greenhouses to make “appassimento” wines or remove under-ripe green flavours from wine using our patent-pending technology. 

We are learning through research and innovative practices how to keep our vineyards flourishing and produce wines of consistent high quality no matter what Mother Nature has in store for us.  With the climate expected to change dramatically over the years, it is important to be prepared for the future to grow and sustain our incredible, home grown grape and wine industry in Ontario.  

Twitter: @CCOVIBrockU

http://www.brocku.ca/ccovi

Categories: Bio economy and clean tech Tags: , , , , , , ,

The opinions posted in this blog are not those of the Ontario government nor its staff, but those of the guest blogger.

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