In a dusty notebook filled with careful handwriting, Thomas Toyama recorded every cross, every seedling, every bloom—meticulous details that are now helping Washington State University breed better cherries a generation later.
For 22 years, from 1963 to 1985, Toyama served as WSU's cherry breeder, developing 11 cultivars that would become cornerstones of the Pacific Northwest's fruit industry. Many people know Chelan, probably the region's most beloved variety, but Toyama's work also gave the world Tieton, Kiona, Glacier, Benton, and Selah. What made his program remarkable wasn't just the number of cultivars released—it was the systematic, almost archaeological approach that Cameron Peace and his colleagues at WSU are now taking to understand his legacy.
In a paper published in Fruit Research, Peace's team used Toyama's hand-written records to trace the precise genetic heritage of those 11 cultivars. The work revealed something elegant: most of Toyama's successful varieties stemmed from just two basic genetic sources. The first was Stella, a self-fertile cultivar that could reliably produce fruit without cross-pollination. The second was a pair of French varieties chosen specifically because they fruited earlier in the season. By combining these proven traits in different ways, Toyama achieved his breeding goals with precision that modern researchers can now map and learn from.
The scale of Toyama's work becomes clear when you see the raw numbers. To create those 11 cultivars, he used 103 unique parent plants across 241 cherry families, pollinating more than 88,000 flowers and germinating at least 5,182 seeds. That wasn't trial-and-error—that was deliberate genetic architecture. And now, with a graduate student named Duygu Caymaz painstakingly analyzing Toyama's notebooks, Peace wants to transform those records into something even more powerful: a digitized database that today's breeders can access and build upon.
Why does this matter? Modern cherry growers and consumers want the same things Toyama was breeding for decades ago: larger fruit, disease resistance, and an extended growing season. But without understanding the genetic source of each trait, breeders can waste years trying to combine varieties that might carry the same genetic factors for size, which wouldn't yield larger fruit at all. "We can use this information to identify where particular genetic factors come from," Peace explains. If two promising varieties both get their big-fruit trait from the same ancestor, crossing them won't improve size. But if they come from different genetic sources, the combination could be even better. That knowledge changes everything.
Per McCord, WSU's current cherry breeder, sees Toyama's work as validation. "My increased use of my own cultivar selections mirrors what Dr. Toyama was doing," McCord said. "This reinforces that I am on the right track." He's already using large-fruited offspring of Selah in his own breeding program, continuing the conversation that Toyama started four decades ago.
As Peace works to digitize Toyama's notebook, he's opening a door that many breeding programs never bothered to keep unlocked. Most programs have a general idea of their history, but few have bothered with "such specific numbers," as Peace notes. By honoring what Toyama left behind and making it accessible, WSU is showing that the best innovations aren't always new—sometimes they're waiting quietly in an old notebook, ready to help grow a better future.