Growing tomatoes in Florida’s hot, humid climate isn’t always easy. Too hot and the fruit won't set. Too much rainfall and the fruit cracks, or the plants develop diseases and lose their leaves.

These problems have been largely solved with the introduction of Solar Fire, a heat-tolerant variety developed by researchers at the University of Florida’s Institute of Food and Agricultural Sciences.

"Solar Fire is our best bet yet for a tomato that can set fruit at warm temperatures," said Jay Scott, a professor of horticultural sciences at UF’s Gulf Coast Research and Education Center in Bradenton. "Most tomatoes that can set fruit at higher temperatures have small fruit, but this one is different. And you can plant this variety earlier in the fall growing season than other varieties."

Solar Fire has medium to large-sized fruit, just above 6 ounces, with an attractive red color and gloss. Each vine bears a lot of fruit, so crop yields are good. It is a firm tomato, an important factor when shipping produce, he said.

“It's best when eaten fresh in salads or sandwiches, rather than cooked or canned,” Scott said. “I like it on bruschetta with pecans and blue cheese.”

Solar Fire is resistant to races 1, 2 and 3 of Fusarium wilt, as well as Verticillium wilt race 1 and gray leafspot. It has moderate resistance to fruit soft rot, a bacterium that attacks damp tomatoes after the fruit has been harvested.

"Until now, if you wanted to plant tomatoes in Florida from July through August you’ve been pretty much out of luck," said Tony DiMare, vice president of DiMare Ruskin Inc., one of the state’s largest tomato producers. “There are a few varieties such as Florida 91 that can be planted in early fall, but summer heat has always meant the fruit won’t set. We're glad to see the introduction of a new heat-tolerant variety."

Growers are invited to see the new varieties, usually on someone's farm, DiMare said. "A small amount of seed is offered to growers so they can plant single rows of the tomato, called strip trials. If growers like the way the tomato performs, they'll plant a couple of acres to see how the plant fares under commercial production techniques."

Commercial production has become a science, he said, and new varieties come under close scrutiny.

"We check the moisture in the soil and monitor the nutrition we add to the plant," DiMare said. "We analyze the sap from the petiole of one of the tomatoes in the field for nitrogen and potassium levels to see if we need to add fertilizer. When the fruit is ripe, we check density, color, interior color and texture. We also look for flavor - consumers don’t want tomatoes that taste like cardboard."

Once the varieties are accepted for further production, they are named - often for the characteristic for which they were bred - such as Solar Fire's tolerance for heat, DiMare said.

Reggie Brown, director of the Florida Tomato Committee, an industry group based in Orlando, said tomatoes are the most valuable vegetable crop grown in Florida. A winter cash crop in Florida since the 1870s, tomatoes now bring more than $400 million into the state annually.

"We think this tomato will extend the tomato season in Florida, and will prove to be a significant addition to the fresh tomato business in the state," Brown said.