160 years of Cornell potato breeding: local collaboration & national impact

Robert Plaisted, professor emeritus of plant breeding and genetics, oversaw Cornell’s potato breeding program for almost half a century, from 1956-2000. The biggest challenge he addressed was protecting potatoes from the invasive golden nematode, a microscopic worm that feeds on potato roots, stunting growth and drastically reducing yield. The nematode was first discovered in Long Island in 1941. 

“At the time, the control method was fumigation,” Plaisted said. “But a few years into the program, they discovered on the research farm that the well from which the irrigation water was being pumped had signs of the fumigant. The well water on Long Island is sacred, so they immediately prohibited the further application of the nematicide.”

Along with breeders at Cornell and in Maine, Plaisted acquired wild South American potato varieties resistant to nematodes, and crossed them with Scottish seeds, better adapted for New York’s long daylight growing periods. The researchers began releasing golden nematode-resistant varieties that effectively controlled the pest, without the fumigant pesticide. 

Since then, almost every Cornell variety released includes such resistance, De Jong said. And because Cornell varieties are so widely grown across the country, they are now used as breeding stock in other programs, so that resistant varieties are also being released by other breeders, he said. In the U.S., careful monitoring and regulation have prevented the pest from spreading outside New York – for now.

“If golden nematodes ever do appear someplace else, there are resistant varieties being used everywhere,” De Jong said. “Out of everything our program has done, I’m most proud that we’ve spread nematode resistance across the country – it’s almost the equivalent of a vaccination.”

"I’m most proud that we’ve spread nematode resistance across the country."

The Mahany family understands better than most the devastation that can result from potato pests and diseases. The Irish potato famine of 1845 led Cain Mahany to immigrate from Ireland to North America, where he began a new potato farm in Maine. His descendants relocated to Arkport, New York in the mid-20th century, where the current Mahany Farms grows 2,300 acres of primarily potatoes, field corn and wheat. 

For at least 55 years, Mahany Farms has collaborated with Cornell potato breeders to test potential new varieties in real-world conditions, said grower Gary Mahany. In 1997, Plaisted named a new variety Reba after Gary’s mother, to honor the family’s long-term support of the program and all women in the potato industry, Mahany said. 

Participating in plant breeding trials means that almost every year, Cornell researchers come to the farm and provide seed potatoes of 10-12 potential new varieties. The growers watch for yield, pest and disease resistance, drought tolerance, storage quality, and factors important to their processors. The Mahanys grow potatoes for the Wise company, and for chipping, potatoes need to be small, round, not easily bruised, and have low water content, Mahany said. The family makes time in its busy schedule to participate in growing trials “because it matters,” he said. 

“We want to get a look at the new varieties as quick as we can, not just for ourselves but for other growers who don’t necessarily take the time,” Mahany said. “That’s the best way you can have input into whether a variety stays around or whether the breeding program drops it. It’s not just for us, it’s for everybody.”

The success of Cornell’s breeding program comes in large part from the researchers’ active engagement with industry and growers, said Chris Hansen, general manager of CSS Farms in Bliss, NY. The Bliss farm has collaborated on testing new varieties for at least 30 years, and De Jong released a 2023 variety “Bliss” in honor of that relationship. The farm produces 70,000 tons of potatoes on 4,400 acres, and their crops go into Cape Cod, Kettle, Utz, Herr’s and Middlesworth potato chips. 

Hansen also participates in the Variety Development Committee Cornell established to bring together growers and processors with potato breeders. The group has met every year for decades. 

“We’re able to give Walter feedback about what we need, what we want to see, and he listens and values our input – that’s been the success of the program, is everyone collaborating together and Walter making decisions based on that feedback,” Hansen said. “In my opinion, it’s the best program in the nation.”

“In my opinion, it’s the best program in the nation.”

Cornell has supported potato breeding efforts almost since the university’s founding in 1865, as New York’s land grant university. Long-term, dedicated support to agricultural research is crucial for making the kinds of breakthroughs that powered the Green Revolution, such as developing varieties that are higher yielding, disease-resistant and best-adapted to various climates, said Margaret Smith, outgoing associate dean and director of the Cornell University Agricultural Experiment Station (Cornell AES). The station manages many of the farms and greenhouses where the university’s plant breeders conduct initial trials. Since 1887, Cornell AES has also distributed federal capacity funding (currently from the U.S. Department of Agriculture’s National Institute for Food and Agriculture) for states to perform research relevant to agriculture, environmental protection and community well-being. 

Plant breeding in particular requires consistent funding to maintain, because new variety development can take 10 years or more, and plant materials will die without facilities and staff to maintain them, Smith said. 

“You can’t just stop a breeding program and pick it up next year. When plants in a breeding nursery die, you’ve lost genetic materials that you can never recreate,” said Smith, who is also a corn breeder. 

“You can’t just stop a breeding program and pick it up next year. When plants in a breeding nursery die, you’ve lost genetic materials that you can never recreate.”

The USDA also supports multi-state research projects, which enable researchers across state borders and disciplines to work together to address regional problems, said Toni DiTommaso, incoming associate dean and director of Cornell AES. Cornell’s potato breeders have participated in multi-state projects for many years, and De Jong currently serves on a collaborative potato breeding and variety development research group tasked with enhancing farm sustainability throughout the Eastern U.S. 

“Having that federal funding as a stable backdrop over time allows researchers to continue and progress with their work, which is critical because it often takes many years to achieve results,” DiTommaso said. “Like with agriculture itself, agricultural research requires a lot of patience and commitment.” 

Krisy Gashler is a freelance writer for the Cornell University Agricultural Experiment Station.