UC Riverside citrus researcher Mikeal Roose is among 23 honorees across the University of California campuses to receive UC Regents Innovation Awards, the UC announced this week. Roose is credited with co-developing the seedless Tango mandarin.
This is the inaugural year for the awards, which recognize UC faculty members whose research has real-world impact. The awards have five categories, with winners chosen from the 10 UC campuses and three affiliated Department of Energy national laboratories.
Roose, who has been at UCR since 1982, is a citrus geneticist and past chair of the Department of Botany and Plant Sciences. He is now a faculty member in UCR’s Graduate Division. In 2006, he received the Award of Excellence for Exceptional Service to the California Citrus Industry.
Roose was among 11 honored in the Distinguished Lifetime Achievement Award category for “innovations that have led to long-term positive impacts on the lives of others and inspiring UC inventors and entrepreneurs.”
The text of Roose’s award reads: “Mikeal Roose used citrus genetics to develop several new mandarin varieties, including the virtually seedless Tango, an easy-to-peel fruit often found under the name Wonderful Halos®, Cuties®, or Delites® that has put the mandarin on pace to be the best-selling U.S. citrus. His research also targets huanglongbing (citrus greening), a major threat to the citrus industry worldwide.”
Roose co-developed the Tango with research associate Timothy Williams, an effort that began in the 1990s to develop a mandarin that would remain seedless regardless of what citrus was grown in proximity.
“It had all the qualities you want in a mandarin — easy to peel, rich color, great flavor, and very low seeded even when grown near other varieties,” Roose said in a UCR feature early this year. “That combination is very rare.”
The Tango has generated more than $70 million for UC Riverside, making it among the most successful innovations in University of California history. According to state figures, in 2024, the Tango accounted for nearly 20,000 acres — or 32% — of all mandarin acreage in the state, the largest share of a single mandarin variety.
Recently, the U.S. plant patent expired, allowing domestic growers to plant the variety without paying royalties.
The UC Regents Innovation Awards were announced in 2025 “to further encourage the UC community of faculty and researchers to solve the world’s most pressing challenges through use-inspired research, civically responsible entrepreneurship, and the translation of academic-based research into practical solutions having societal benefit.”
Nominations were accepted from Jan. 1- May 1, 2026, and each recipient receives a cash prize of at least $10,000.
