This summer, farmers in Montana and North Dakota are growing a new variety of potato developed by renowned breeder and plant geneticist Christian Thill.

The MonDak Gold, a red-skinned potato with a yellow flesh named for the region in which it is being grown, is in its first commercial growing season this year. It is the latest breed of specialty potato to come from the University of Minnesota researcher and professor of horticultural science who died unexpectedly of a heart-related ailment Aug. 7 at age 53.

"His life was potatoes," said Chuck Gunnerson, president of the Northern Plains Potato Growers Association. "He was a very passionate potato breeder. He was highly respected. He pretty much gave all his time to improving the variety of potatoes for processors."

Thill, of Minneapolis, grew up in the Buffalo, N.Y., area and after high school enrolled at St. Bonaventure University to study accounting. His interest in biology led him to transfer to Marquette University in Milwaukee, where he earned his undergraduate degree and met his wife, Mary. Her father, Martin, was a potato breeder at Frito Lay, where Thill took a job as a research assistant after college and developed his interest in potatoes, said his wife of 25 years.

After a stint at Monsanto, Thill earned his master's and doctoral degrees in plant breeding and genetics from the University of Wisconsin-Madison. He was hired at the U in 1997 where he worked to develop varieties that could withstand disease, produce high yield and were of good quality.

"He had a deep love for what he did," said Jeff Miller, a former plant pathologist at the U who is now president of Miller Research, an agricultural firm in Idaho. "He'd try to understand their needs and then try to develop [what] was better for growers. When it came to variety, he was the expert."

Thill taught vegetable breeding courses at the U and supervised several students who earned master's and doctorate degrees, said Gary Gardner, who hired Thill when he was chairman of the U's Horticultural Science department. Thill shared his research at conferences nationwide and in places as far away as Australia, China, Germany and Italy.

"The legacy of a plant breeder is in those plant varieties they worked on, and I think he left us a strong legacy," Gardner said.

Thill was most at home working with students in the greenhouse or in the fields where he wore his trademark farm boots and at times pink clogs to keep things light, said Susie Thompson, a former colleague who is now a professor in the potato breeding program at North Dakota State University.

"He was always fun," she said. "He was a very creative person who thought outside the box. He loved teaching and was gifted."

Described by friends and colleagues as brilliant yet humble, Thill often volunteered at Burroughs Community School, the Minneapolis grade school his daughters attended. He'd also bring home potatoes right out of the research fields and share them with neighbors or bring them to local food shelves.

Besides his wife, Thill is survived by three daughters, Abigail, Grace and Erin Thill, all of Minneapolis; his father and stepmother, Robert and Elizabeth Thill, his mother, Jean Elsinghorst; sisters Paula Elsinghorst, Rebecca Thill Nicometi and Janice Ward, all of the Buffalo, N.Y., area, and another sister, Donna Thill Moore, of Springfield, Ill.; brothers Timothy Thill, Richard Thompson and Andrew Thompson, all of the Buffalo, N.Y., area, and Eric Elsinghorst, of Lawrence, Kan., and several nieces and nephews. Services have been held.