How 'Bout Them Apples (to Beat Climate Change)

In the quest to make apple trees more resilient in a warming climate, some Michigan researchers are looking for a late bloomer. A native Michigan apple tree, the Malus coronaria, learned to fight frost by blooming two or three weeks later than the trees that produce cultivated varieties of apples like Honeycrisp or Red Delicious. "That doesn't sound like a lot, but almost always that's enough for the flowers to escape the killing spring frost," said Steve van Nocker, a Michigan State University professor and plant geneticist, per the AP.

• Goal: Van Nocker doesn't want to replace popular varieties like Fuji or Honeycrisp with M. coronaria apples, since the Michigan tree's fruit is small, green, and bitter. "They don't taste good at all," van Nocker says. Instead, he seeks to identify the genes that cause late blooming and create a genetic stock that breeders could use to develop commercial apples. Van Nocker also is sending seeds to the US Department of Agriculture so the genetic stock won't be lost if the tree continues to decline.
• Changing climate: Per a recent Washington State University study, major apple-growing counties in the top three US apple-producing states—Washington, Michigan, and New York—are seeing fewer cold days and more warm fall nights. Washington also is experiencing more extreme heat. The study, which examined climate data from 1979 to 2022, said temperature trends could alter bloom timing, bring trees out of dormancy too early, and increase the risk of sunburn, which hurts the appearance and quality of apples.

• Timeline: Making a later-blooming commercial apple could take decades. If an M. coronaria is crossed with a commercial apple tree to make a new hybrid, it would take four or five years for that tree to start producing apples. Crossbreeding would continue until researchers developed an apple with the desired traits of both varieties. But van Nocker says it's critical to try. "With climate change, it's quite possible that apples won't be able to be produced in Michigan in the future," he says.
• Similar projects: In Europe and South Korea, growers are experimenting with solar panels in vineyards and orchards. The panels protect fruit from hail and sun damage but also let in light and heat, says Jared Buono, director of Cornell University's Hudson Valley Research Lab. University of Maryland researchers recently announced the development of a more heat-tolerant apple variety. And at Penn State, a team built an unmanned vehicle with a propane-fueled heater that can roll through an orchard and warm trees.

(More apples stories.)