If you’re a Florida grower seeking better tasting, higher-yielding, more disease resistant tomatoes, you’ll be glad to hear that the University of Florida’s tomato breeding program has doubled its efforts to produce just that—with help from a Paul J. DiMare Foundation endowment.

Sam Hutton has signed on as an assistant professor in the horticultural sciences department at the Gulf Coast Research and Education Center in Wimauma to serve as the department’s second tomato breeder. Jay Scott, a horticulture professor at the center, is the department’s other tomato breeder.

Hutton spent six years working as a graduate student, then as a post-doctoral researcher, in the university’s tomatobreeding program before being hired in November. His research focused on resistance to tomato yellow leaf curl virus and to bacterial leaf spot.

Hutton’s hiring was welcome news to Reggie Brown, manager of the Maitlandbased Florida Tomato Committee.

The tomato industry contributes up to $750 million to Florida’s economy every year, he says.

With increasing competition from growers in Mexico and Canada, cost management and productivity are important to maintain a viable tomato industry in the state, he says.

“That’s why a breeding program has been consistently supported by the industry.”

Funding Hutton’s position made sense for DiMare Inc. of Homestead, Fla., says Paul DiMare, president of the 82-year-old familyowned business.

“We couldn’t do that type of research, so we try to support the systems that have supported the industry over the years,” he says. “The University of Florida is one of the well-known ag centers in the country.”

Hutton already has made progress in several research areas.


“Tomato yellow leaf curl virus is a major problem for Florida production,” DiMare says.

If the leaves of your tomato plants curl and turn yellow, and if the overall growth of the plant is stunted, there’s a good chance they’ve been hit by TYLCV. The younger the plant is when it’s infected, the more pronounced the symptoms and the greater the yield loss.

The disease is transmitted by whiteflies, some of which have developed a tolerance to insecticides.

Researchers successfully have bred resistance genes from wild tomatoes into cultivated tomatoes to make a product that’s resistant to TYLCV, Hutton says. The bad news is that the resistance genes can be accompanied by genes that adversely impact yields and horticultural characteristics, a condition known as linkage drag.

The good news is, Hutton has made progress toward eliminating linkage drag from one of the major resistance genes—Ty-3—and he now is incorporating this newly developed material into all of his best plant material. He also is working with the university’s office of technology and licensing to get it into the hands of other tomato breeders.

Bacterial leaf spot

Hutton is dealing with two major challenges from bacterial leaf spot.

One is the fact that, after three decades of breeding efforts to combat the disease, new pathogens continue to emerge that overcome resistant genes. Hutton says he believes he has developed an approach that finally may resolve this issue.

The other is dealing with the “nonblighting” trait—which helps a plant to maintain its green leaves even after it’s infected. Hutton says he also believes he is making progress understanding the non-blighting trait, including how many genes control it and where those genes are.

“Knowing their location will then allow more efficient breeding by using molecular markers to identify and select non-blighting plants, even while they are seedlings,” he says. “We’re not quite there, but we’re making progress.”

The university’s tomato-breeding program also has research emphasis in several other areas, including graywall resistance, bacterial wilt resistance and flavor/quality, Hutton says.


Graywall is a cosmetic condition that causes gray blotchiness on the outer skin of a tomato. When the fruit is sliced, there may be brown tissue on the inside of the outer wall. The symptoms typically are not evident until the fruit ripens.

The big problem with finding a cure for graywall is that the cause is not known, Hutton says. However, it seems to show up more often when the weather is cool and in low-light conditions.

Knowing the locations of the resistance genes would help the breeding efforts, he says. Hutton is collaborating on a genetic study, which he hopes will provide a better understanding of graywall resistance.

Bacterial wilt

Bacterial wilt is a problem in some areas of Florida, Hutton says, but it’s actually more of a problem on the East Coast and in other parts of the world.

With bacterial wilt, pathogens get into a plant’s phloem tissue that transports water and basically plugs it so the plants start wilting, especially during the hottest time of the day.

As the infection progresses, the disease eventually kills the plant, Hutton says.

Tomato varieties have been released that are resistant to bacterial wilt, but they produce mostly small to medium fruit. Hutton says he hopes to soon be getting out some tolerant varieties with large fruit.

The university’s tomato breeding program “has made tremendous headway in this regard,” he says.

Flavor traits

One of the most common gripes from anyone who eats tomatoes is their lack of flavor.

“Everybody complains about flavor,” Hutton says.

But breeding for improved flavor is not simple. And since growers typically get paid by how many tomatoes they sell, not by how good they taste, there is less incentive to breed for flavor than for other traits, he says.

Still, the university’s breeding program is working to develop high-yielding varieties with improved flavor quality, Hutton says.

One of the goals is to identify and breed for key “flavor volatiles” that produce a favorable fruity taste, he says.

Since consumers tend to buy with their eyes, Hutton also has a side project focusing on breeding for high outside color. He says he hopes to combine an attractive appearance with good flavor, which will lead to repeat sales.

$2 million chair

DiMare Inc. put up $1 million to support the breeding program, DiMare says. The university matched it, resulting in a $2 million chair at the university for tomato plant breeding.

Taste is the No. 1 concern with tomatoes today, DiMare says. And breeding tomatoes that are resistant to pests and diseases can slash a grower’s expenses.

“If you can do that, you’d save a lot of money because the most expensive thing in farming today is spraying,” he says.

Brown says he believes Hutton is the right man for the job, characterizing him as having a “21st century skill set with the common sense that comes from being a 20th century horticulturist.”

“We’re looking forward to some great opportunities to improve the industry,” he says.