POTATOES FOR A CHANGING CLIMATE
Report of the Crop-Climate Trials 2014 – 2016
Climate change threatens food security globally and in Canada. Communities need to develop sustainable food systems as an adaptation to climate change. Crop biological diversity is a central element of food sustainability. Potatoes are the fourth most important food crop in the world and are widely grown in Canada.
We undertook a three-year field trial of twelve heritage and conventional potato varieties in a wide range of climatic regions across Canada. We used standard planting and observation methods to track potato development and yield while recording in-field weather variables.
Our trial sites experienced a great range of weather conditions including extreme drought, heat and precipitation representative of the variability of climate and weather anticipated with climate change. Potato plant development and yields varied widely across our trial sites and from year to year at each site, presumably in part because of the great weather differences.
Potatoes grew best at mean growing season temperatures between 14 °C and 17 °C, with monthly soil temperatures below 20 °C, and a well-distributed growing season precipitation of 100-150 mm. A minimum of 1000 Growing Degree Days (a measure of heat accumulation and a proxy for growing season length) were required for potato production, but higher yields were not obtained from regions with more accumulated heat. Soil temperatures above 20 °C resulted in poor yields and precipitation below 100 mm as experienced regularly on southern Vancouver Island strongly reduced yields. Even in the short season climate of Mayo, Yukon all varieties including heritage ones produced harvestable yields.
Several heritage varieties grew and yielded as well as some conventional varieties and at least one conventional variety yielded poorly at most sites. Three conventional varieties—Russet Burbank, Kennebec, and Chieftain—generally performed well at all sites but not always. The heritage variety, Ozette-Nootka, originally introduced by Spanish to Vancouver Island more than two hundred years ago. performed as well as conventional varieties in all regions and under the full range of growing season weather. Heritage varieties Sieglinde, Banana, Corne de Mouton, Russian Blue, and Mrs. Moehrle’s Yellow Fleshed also grew and yielded well in several trial sites. Yukon Gold, a popular commercial type, yielded poorly at most sites in most years.
We uncovered a uniquely Canadian heritage variety, Likely, and included it in our trails. Although not a strong yielding variety, it apparently has exceptional cold tolerance and performed especially well in the north. Tubers were sent to the Potato Gene Resources Centre in Fredericton where it was clonally propagated, cleaned of viruses and diseases and is now available for research and growing.
In addition to our formal trials, we received informal observations from casual growers that confirmed many of our trial observations. There was great interest from growers and gardeners in our project and our heritage varieties and we distributed thousands of tubers.
Using our results, we developed variety profiles for the twelve types we trialed. These can be used by growers to select potatoes suitable to their region tastes and growing techniques. One of our trial participants established production of several heritage varieties on a commercial scale.
We summarized several practical tips for people interested in growing potatoes as the climate changes. Observing and recording local weather, particularly first and last frost date, as well as extreme heat, humidity, and rainfall, will be increasingly important for ongoing understanding of potato growth and adaptation. Local knowledge of cultural practices, variety selection, soils, and weather are the indispensable foundation for food security – it should be shared widely, but also provides the basis for experimenting with new techniques and crops. Potatoes are highly vulnerable to pathogens that build up in the seed tubers: practice strict rotation, limit the number of years you grow from the same seed source, select only the best potatoes for future seed crops, and renew your personal seed sources regularly by purchasing certified seed.
The three-year field trials form the basis for moving forward. Access to a wider variety of clean seed potatoes can be supported by a network of regional living variety collections and tuber production centres. We recommend strengthening the network of climate stations, particularly in underserved areas in the north where potato production is likely to expand. We also encourage people to make the information available in a practical format that can help guide decision making about key adaptive practices in a rapidly changing foodscape. Continuing to distribute and test more varieties in more areas – and particularly food-insecure northern regions can engage local people, develop knowledge, and set in motion the local selection and adaptation process.
For the next two years we propose selecting 15 potato varieties to distribute three varieties each to 100 growers who are trained in simplified observation techniques. Growers not served by climate stations may also receive a simple weather recording instrument. Weather and variety performance data will be compiled to create new variety profiles.
Our project demonstrates that potatoes can be grown more widely across Canada than is common practice, particularly if heritage varieties are used. By planting several varieties growers and communities can establish reliable yields of a key food crop and develop food self-reliance in the face of changing and highly variable climate. Our Crop-Climate approach and methods may have wide application to other crops and other regions of the world.
Download the full report here:
Volunteer Grower-Observers wanted
Keeping heritage potatoes in cultivation is one way to conserve our agricultural biodiversity. Sharing knowledge of successes and failures is a key step to improving food security and adapting to climate change.
Here’s how you can help:
1. Contribute casual observations and stories about your favourite potato.
2. Request some Ozette-Nootka tubers for growing, observing and eating
I will send you 5 tubers of Ozette Nootka with an observation form for you to track during the growing season.
3. Grow and observe your favourite varieties through the growing season.
A simplified, standard observation form can be downloaded here. Post it on your fridge to remind you to fill it out.
4. Do you know of an unusual variety grown in your area that we need to know about?
Let us know about it. We would like to preserve as many local varieties as possible!
Potatoes and climate change in the news
To submit observations of heritage potato growth forms, please download and print this form for each variety:
Heritage Potato Observation Form 2018