Vance Whitaker pauses to finger runners of strawberry plants in the greenhouse housing the lines he uses to make the crosses necessary to turn out new varieties.

“The Florida strawberry variety situation is changing a little bit,” says the University of Florida’s strawberry breeder at the Gulf Coast Research and Education Center at Baum.

He may look like an eager, fresh-faced high schooler working on a science project, but Whitaker has already been on the job three years.

Looking at the 378 strawberry selections currently in the greenhouse, change seems distinctly possible. Throw in the 10,000 seedlings he will evaluate this season, and it’s reasonable to think that one or two, at least, could someday be widely grown on Florida strawberry farms. These varieties in the pipeline toward release could be significantly different from those now being grown in the state.

Since the last few strawberry varieties released in Florida show relatively good disease resistance, fine shape and shipping characteristics, Whitaker can look at other things, like flavor.

“Because my predecessors made so much progress, I have more freedom to focus on flavor,” he says. “Most of the material I evaluate already has good shape and some disease resistance. This gives me freedom as a breeder to focus on other things.

“”I see that Florida is going to have to have a competitive edge with Mexican imports. If we ask what’s going to be the quality that gives Florida a bump in the marketplace, flavor is the obvious thing.”

Grower management will remain the key to producing good strawberries for the market. Better flavor, though, could differentiate them from competitors. Growers already realize that.

“In a recent survey, growers consistently put flavor in the top two traits they valued,” Whitaker says. “They have undergone a shift in their trait priorities, which was unexpected. I would have thought firmness, size, shape and shipping would be more important to them. It really surprised me.”

Consumers already know strawberries are good for them, so he questions whether breeding for incremental increases in attributes like antioxidants would be worthwhile.

“Instead of making it 10 percent more healthy, why not work to get a better-tasting berry? Then people might eat twice as many of them. I see improved flavor as a way to promote health, a way to get people to eat the amount of fruits they should be eating. I think the next frontier in strawberries is to add better flavor to the appearance, which is already good.”

Improved over time

Over the past couple of decades, the strawberries Florida grows have improved quite a bit, Whitaker thinks. That provides the base for his breeding program.

“Sweet Charlie, the first big University of Florida variety, was introduced in 1992. Festival came along in 2000 and was really a game changer; within a few years, it was the dominant variety and still has about 50 percent of the crop. Now a new variety, Radiance, has taken off and is doing well. This year, we have another one, Winterstar, that growers are definitely interested in growing.”

Winterstar, a 2005 selection initially released in 2011, deserves the attention it has recently been getting, he says. A cross between Radiance and Earlibrite, with large, deep red fruit, some think it sweeter than either of its parents.

“It’s one of our notable cultivars. The University of Florida has three cultivars out for this season, which is a reflection of the work done by the former breeders in this program,” Whitaker says.

“Don’t get me wrong. I think Festival and Radiance are decent tasting, very good strawberries. Some of the newer varieties coming along did better in group taste tests, where the testers used clickers. The two selections coming behind the released varieties far and away got more votes for taste.”

Taste, simple to recognize, gets scientifically complex. Food scientists’ work often focuses on taste. A strawberry releases 300 volatile chemical compounds that the human nose can sense, and some of these affect flavor either positively or negatively.

“Breeders can’t ignore volatiles,” he says. “We have to figure out which volatiles are affecting the sweetness.”

Developing new varieties based on taste requires precise work by the breeder. “It’s time-consuming; it’s tough,” Whitaker says. “There are no short cuts.”

He says he eats his share of strawberries, but taste panel opinions are more critical in picking winners among all the varietal options in the lab and field.

Flavor changes constantly during the season, depending on environmental factors, making his job even trickier.

“In this area, on average, soluble solids decline by half from January to March,” he says. “That explains why taste can be pretty good at the beginning of the season and not so good later in the season. The hotter the average temperatures, the lower the soluble solids. When it gets hot as we go into spring, there’s a 50 percent drop in sugars in the berry. That affects flavor.”

With that in mind, he tries to identify strawberry lines that do well in a wide temperature range.

“It’s possible to select for a high average and for flavor to be stable. I try to steer away from selections that react a lot to the environment. I want the Florida strawberry grower to keep the buyer with him throughout the season, rather than have the buyer switch to California berries because of flavor. The important thing is the stability of sugars as the season goes along.”

Inverse relationship

Sugar and strawberry yield have an inverse relationship, as well, and that makes the breeder’s task a little bit tougher.

“Yield and sugar are a trade off.We can get more than a 25 percent increase in yield in one generation, but get 9 percent less sugar,” Whitaker says.

“Unless the breeder takes this into account and chooses parents with good yield and good sugar, you’ll go backward in sugar. Now, whenever I choose parents I put a little more emphasis on sugar — I choose parents that only have positive values for both sugar and yield.”

If Florida growers use the new strawberry varieties to differentiate themselves from Mexican-grown berries, won’t Mexican farmers grow them, as well? After all, Mexico ships Festival strawberries, competing with Florida production.

“I think the university and the Florida Strawberry Growers Association will restrict Radiance and the other new varieties,” he says. “They will put safeguards in place. They previously did not restrict varieties going to Mexico, so the Mexicans grow a lot of Festival.

“Varieties have a way of getting out, despite the best efforts to protect them. That’s why it’s best to have a stream of new things coming along and being adopted by Florida growers before everybody else gets them. The reality is, we’ve got to keep replacing them with the next step up.”

The grower association is the domestic licensee for the university’s strawberry varieties, handling contracts with nurseries. The association retains part of the revenues from royalties, boosting research efforts with grant funding.

Grants very helpful

“This year, they gave over $400,000 in grants to work on strawberries,” Whitaker says. “The University of Florida got a lot of it. It’s very helpful. The international royalties far exceed domestic, though. Our varieties are now sold in 42 countries. Ekland Marketing Company of California handles international licensees and royalty collection outside the U.S. and Canada.”

Ekland deals with the university’s Fortuna, Festival, Sweet Charlie, Winter Dawn and Earlibrite varieties.

“Our varieties are being grown in the world’s major production areas,” he says. “Ekland works in concert with the Florida Strawberry Growers Association to make it happen.”

Whitaker, 32 years old, grew up in Oak Ridge, N.C., a small town in an area where tobacco was the major crop. His father was a land appraiser and lender for the Farm Credit Service. They lived on 20 acres outside town and Whitaker developed a love for gardening and landscaping.

He attended North Carolina State University and concentrated on ornamental horticulture, then got a Masters and Ph.D. from the University of Minnesota, where he focused on disease resistance in roses.

Roses and strawberries are related, members of the same family, and that led him to befriend those in the strawberry industry, which led to the University of Florida job.

“I’ve been blessed to get to do a job like this,” he says.. “It’s fun, and I’m doing something worthwhile — what more could anybody ask?”

Whitaker thinks the university could release a new strawberry variety, or possibly even two, in 2013.

“We’ll have a good idea what the top two are in February. We’ll look at grower trials, then go ahead and release them. We’ve got other material in the pipeline coming along behind these.

“When you consider how many seedlings we grow, for every success in strawberry breeding there are 15,000 to 20,000 failures. Is it firm enough? Is the flavor good enough? If there’s one thing wrong with a seedling, it goes on the trash heap.

“If it’s no better than the current one being grown, that may be enough to throw it out — as much as that hurts.”