With climate change heating up Canada’s crop land, identifying or developing new potato varieties that can grow in warmer temperatures is on the radar of Agriculture and Agri-Food Canada (AAFC) researchers, writes Rosalie Tennison in this article published by Potatoes in Canada.
Potatoes originated from and still grow wild in the cooler climate of the Andes of South America, and research scientists have often mined these varieties for traits desired in North American cultivars. Canada’s potato-growing areas mimic the cool 20 C daytime temperatures that make the wild varieties so hardy. But what happens when the heat gets turned up?
Xiu-Qing Li of AAFC in Fredericton noticed that warmer summers are creating heat stress in Canadian potato crops. He began studying Canada’s current varieties to see which are the most heat-tolerant. He also hopes to identify the genes responsible for heat tolerance and to incorporate them into future varieties, either through genetic crosses or directional mutation.
“Climate change threatens the future production of potatoes, but some varieties are more heat-tolerant than others,” Li explains. “We want to continue to grow potatoes, but we need to use varieties that can tolerate heat stress.”
Growers know that developing new cultivars can take a decade or more and, with predicted increases in temperature to be as much as two degrees by the end of the century, if not sooner, plant breeders need to start working towards varieties that can take the heat immediately.
Li and his team put 55 commercial cultivars under heat stress in a laboratory and studied leaf chlorophyll content, plant growth and tuber yield. There were variations in the cultivars’ tolerance to the heat stress but, overall, leaf size was stunted, chlorophyll-index estimates increased and tuber size was reduced. As a result, he says, they were able to identify the most heat-tolerant cultivars currently available to Canadian growers.
“We wanted to understand the impacts of high temperatures on potatoes in the northern climate,” Li explains. “It’s possible that potatoes could be grown farther north if the climate warms up, but the issue will be if they will have enough time to reach maturity. Perhaps we will need varieties that mature earlier.”