A woman works with white potato blossoms
Beth Plummer, scientific technician at the Aroostook Research Farm in Presque Isle, collects potato blossom pollen to be used to start a new variety. Credit: Paula Brewer / Star-Herald

PRESQUE ISLE, Maine — Maine potato researchers have 45,000 new varieties in various testing stages each year, but now they are grappling with breeding tubers that can weather a warming climate.

Today’s spuds are bred to have certain attributes — disease and pest resistance, proper moisture levels for processing and more. Changing climate trends have sparked a greater urgency to create varieties that can grow better with the warmer temperatures and increased rain predicted for Maine.

For Gregory Porter, professor of crop ecology and management at the University of Maine and the leader of UMaine’s potato breeding program, it’s a long but rewarding process that begins at the Aroostook Farm research facility in Presque Isle. Scientists say warmer and wetter weather is coming, and since potatoes are traditionally a cooler-weather crop, both breeders and growers will have to be more innovative than ever to keep Maine’s top crop vigorous.

At the Aroostook Research Farm in Presque Isle, part of the University of Maine potato breeding program, Assistant Scientist Paul Ocaya prepares planting beds for true potato seed on May 5. Credit: Paula Brewer / The Star-Herald

The warmer forecast is a mixed bag, Porter said Wednesday. Higher temperatures could bring a longer growing season, but too much warmth at nighttime could actually hurt quality and yield.

“Warmer temperatures in general will probably not greatly hurt us, but if temperatures result in periods of much higher temperatures during a few key weeks in the season, it could reduce production, particularly if it stays really warm at night,” he said.

Potatoes favor a climate with days in the 70s and low 80s and cool nights, he said. It all depends on when the moisture falls. Dry periods can result in drought conditions. Excessive rain can cause diseases and quality problems like rot and skin blemishes.  

Growers are already adapting to changing conditions in ways that will enable Maine’s potato industry to remain competitive, Porter said. Many are employing longer crop rotations and using technology to maintain consistent storage conditions, manage pests and apply fertilizer.

Adopting new varieties that fit the markets but are tolerant to stress conditions will help.

Researchers are constantly working to create new varieties, including those resistant to disease, such as Potato Virus Y that affected the quality of the state’s crop a few years ago.  

But the UMaine breeding program and the Aroostook Farm are also beginning to create strains that are more tolerant to heat stress and more resistant to diseases that can occur with greater prevalence in wet conditions, Porter said.

“There are some things that we can do to breed and select new varieties to tolerate conditions going forward,” he said. ”Breeding for tolerance to some of these diseases is possible and is underway.”

Potato plants blossom in a greenhouse at the Aroostook Farm research facility in Presque Isle on May 5. Credit: Paula Brewer / The Star-Herald

At the Aroostook Farm, part of the Maine Agricultural and Forest Experiment Station, Assistant Scientist Paul Ocaya and Scientific Technician Beth Plummer are among the team doing the painstaking work of growing tiny potato seedlings that will become test varieties. Both have worked there for more than 20 years.

In one of the greenhouses Thursday, Plummer used the vibrating nodule of an electric toothbrush to gently harvest pollen from potato blossoms, collecting it in a small vial. She will then pollinate other plants to create new varieties.

Ocaya prepared planting beds with vermiculite and topsoil for true potato seed — not seed cut from existing tubers, but small seeds carefully harvested from seed pods on the plants. The delicate seedlings will be transplanted in another greenhouse, then the tiny tubers will be planted as a trial in a field, Ocaya said. From those, Porter will select a group for a second-year trial.

Doing all this work in Aroostook County is important, because it’s where most of the state’s potato crop is grown.

“There’s no better way to select than in the place of production,” Porter said. “While it’s important to determine if they’re adaptive, the starting point needs to be selection based on our conditions — temperature, day length — that our farmers face each year.”

Beth Plummer, scientific technician at the Aroostook Farm potato research facility in Presque Isle, collects potato blossom pollen on May 5. Credit: Paula Brewer / The Star-Herald

The County operation, though small scale, is extremely successful, Porter said, due in large part to its dedicated staff. There is also extensive support from the potato industry for their work.

Though no new varieties are ready for release right now, one of the program’s most recent successes is the Caribou Russet. Released in 2015, the potato was developed and trialed at the Presque Isle facility.

It’s all labor-intensive, and creating a marketable potato variety from research to production can take years and cost hundreds of thousands of dollars, Porter said.

“But new varieties are worth millions of dollars per year to the potato industry for many, many years.”