Sanjay Gupta started tracking the genetics of a potato in 1998.

His research, which is the first of its kind, began hundreds of miles away in a lab at the University of Minnesota. But the first fruits of his labor will be realized in south-central Idaho.

The University of Idaho potato physiologist is on the verge of solving one of the industries most costly obstacles - storing potatoes in cold climates.

In Idaho and across the nation, harvested potatoes are in the early days of a storage season that could continue through next August.

When held at temperatures below 45 degrees Fahrenheit, they develop cold-induced "sweetening" - a process in which sugars within spuds produce dark fries that are unacceptable to consumers. They're also more likely to sprout, lose moisture and develop diseases.

But Gupta said growers could continue cold-stored potatoes and enjoy eating them, too.

He teamed with Richard Novy, Aberdeen-based USDA Agricultural Research Service potato breeder, and two Midwestern scientists to select breeding lines that would resist cold-induced sweetening.

Potatoes that could be stored at or below 42 degrees Fahrenheit and still fry up light wouldn't need as many sprout inhibition treatments, Gupta said. As living seed, they would respire less at colder temperatures, thereby retaining moisture and weight, and would be less prone to plant diseases.

"That would be a very significant improvement," he said. "Cold sweetening has been a problem for the potato industry for a very long time."

While at the University of Minnesota, Gupta began developing two biochemical markers that reveal a potato's ability to tolerate cold storage.

One of the biochemical markers is a protein called UDP-Glucose pyrophosphorylase that controls the formation of sucrose from the potatoes' starches; the other, acid invertase, controls the formation of the reducing sugars glucose and fructose from sucrose. Together, they indicate not only how well a variety can be stored at lower temperatures but for how long.

Gupta refined the markers at the University of Idaho's Kimberly Research and Extension Center.

Along with Martin Glynn of the USDA-ARS in East Grand Forks and Joe Sowokinos of the University of Minnesota, he then used the markers to screen about 300 experimental clones and commercial varieties from a dozen North American breeding programs. The markers predicted with about 90 percent accuracy a potato's response to storage temperatures.

"Understanding the underlying mechanism of cold-sweetening is a big benefit to breeders," said Novy.

He said that crossing different varieties of cold-resistent potatoes can create offspring that are more resistant than current varieties.

By choosing the right parents, breeders could significantly accelerate the development of potatoes with the level of cold-sweetening resistance the market seeks, Gupta said.

Joshua Palmer may be reached at jpalmer@magicvalley.com