BUSINESS

3 Amigos on the vanguard of the fight against citrus greening in Lake Alfred

Kevin Bouffard
kevin.bouffard@theledger.com
From left, Fred Gmitter, Bill Castle and Jude Grosser are sometimes referred to as the Three Amigos in the industry because of their decades-long collaboration on breeding new citrus trees at the UF/IFAS Citrus and Research Education Center in Lake Alfred. [ SCOTT WHEELER/THE LEDGER ]

LAKE ALFRED – Science works through collaboration, with practitioners sharing their discoveries through papers published in professional journals or swapping ideas at academic conferences.

But not many are as much fun as the collaboration among Bill Castle, emeritus professor of horticulture, and Fred Gmitter and Jude Grosser, both professors of citrus genetics and breeding, at the University of Florida’s Citrus Research and Education Center in Lake Alfred.

The three scientists have worked as a team since the 1990s in a program to develop new citrus varieties in Florida to meet various citrus industry needs – for example, the fresh fruit industry’s need for easy-peeling, seedless fruit popular with consumers.

Although Castle, Gmitter and Grosser had worked together and shared ideas since the mid-1980s, when Grosser came to the Lake Alfred center, they didn’t become a team until the following decade.

At the time, scientists were being encouraged to develop team research projects, which had a better chance to get funding, and Harold Browning, the center’s director, encouraged them to collaborate formally. It worked.

“It solidified what we had been doing,” Gmitter said.

The collaboration was immediately successful.

“Originally, we recognized we wanted to bring different types of skills and perspectives together,” Castle said. “Each one of us has a skill set and a place on the team. It’s not competitive. We each have our roles.”

On the skill level, Gmitter, 67, is the expert in citrus genetics. He was part of an international team that mapped the citrus genome, a pivotal map that guides breeding and other research to this day.

Grosser, 63, is a leading global expert in a breeding technique known as “cell fusion,” for breeding new plant varieties at the molecular level. He introduced the new technology into Lake Alfred’s citrus breeding program when he was hired in 1984.

Castle, 76, a 2016 inductee into the Florida Citrus Hall of Fame, evaluates the potential new citrus varieties developed in his partners’ labs in the field, testing their ability to thrive in Florida’s soil and climate environments.

Each of the three scientists contributes his unique personality to the team.

Gmitter excels at evaluating and shaping ideas.

“One of the things I appreciate about Fred is, if you have an idea you think will change the world and you miss something obvious, he’s the one to point that out,” Grosser said. “He’s the safety valve.”

Grosser brings his passion and enthusiasm to the job.

“Jude is a man with a mission,” Castle said.

Castle brings a more practical perspective to the work.

“Bill is the thoroughness,” Grosser said.

“He keeps us grounded,” Gmitter added.

None of the scientists plays a commanding role, however.

“Years ago, the administration pushed and kicked us to determine a leader,” Gmitter said. “There never was one, and there will never be one.”

Castle and Grosser agreed.

“I think that comes out of the respect we have for each other,” Grosser said.

The team has just a couple of simple ground rules.

In disputes, they’ve agreed on the “two-out-of-three rule.” If there’s dissent on an issue, the majority vote prevails.

The rule came into play when The Ledger asked about the team’s widely known nickname in the Florida citrus industry – the Three Amigos.

Castle didn’t want it mentioned in this article, but Gmitter and Grosser didn’t mind. Grosser even liked it.

The second rule is that all three scientists, even the dissenter, supports team decisions, especially when one is called into question.

“If one doesn’t agree, he doesn’t throw the others under the bus,” Gmitter said.

Working with growers is a characteristic all three share.

“All three of us have been blessed to get on the same wavelength with growers,” Grosser said.

Pete Spyke, a Fort Pierce grower who went on the South African trip, agreed.

“There’s not a single grove planted in the state of Florida that does not reflect the work he (Castle) has done. He’s touched everything,” Spyke said. “The work he did for the industry definitely moved the needle, and he also served as a leader for other researchers in how to structure their programs.”

“I’ve traveled around the world (and) went to many citrus conferences and met with many people in the citrus industry,” wrote Greg Murray, a former executive with the Coca-Cola Co. based in Australia, in an email to The Ledger. “One thing that always impressed me was the high regard and respect held worldwide for Jude and his colleagues (Gmitter and Castle).”

The Castle-Gmitter-Grosser team’s mission changed in 2005 with the discovery of the fatal bacterial disease citrus greening, which has led to shrinkage of more than 70 percent in Florida’s annual citrus harvest.

While nearly a decade of research has developed some greening counter-measures that extend a citrus tree’s life, such as more effective fertilization and pest control, nothing has arrested the disease’s fatal march. The conventional wisdom is that no single weapon will work against greening but that a truly effective strategy must include a new variety that is either tolerant – or even better, resistant – to the disease.

Tolerance means an infected tree will not suffer as severely as current varieties do. Resistance means a tree will show no effects to infection.

One of the problems with tolerance is that there’s no standard definition, the scientists agreed. In other words, how much of an improvement in overcoming symptoms constitutes “tolerance”?

If the team discovers a new citrus tree that grows normal-size fruit but in smaller numbers, is that sufficiently tolerant, Castle asked.

Whatever the definition, there are already some new varieties, such as the Sugar Belle tangerine and the Valquarius orange, that show improved tolerance to infection and are being planted in significant numbers in Florida, they said.

Resistance, however, will be a bigger problem. Some varieties appear resistant in the lab, but that’s a long way away from the propagation and release of a commercial tree.

“It’s not so easy. Greening is a complicated disease,” Gmitter said. “It affects every part of how a plant grows.”

Grosser offered the hope of using new fertilizer techniques that could transform a tolerant tree into a resistant one. He acknowledged, however, Gmitter is still challenging him on the concept.

“I have total confidence in the team,” Grosser said. “The pressure is to get everything (research) paid for.”