Breeding Taste Back into Tomatoes

Some tomatoes, especially in winter, may look perfectly round and plump on store shelves, but a slice and bite at home may be disappointing.

Researchers at the University of Florida in Gainesville’s Plant Innovation Center are trying to change that by using genetics to breed in some of the flavor they said was lost over the years when tomatoes were bred for beauty, transportation hardiness, and shelf life.

“Modern tomatoes are bred for size, firmness, and to ship a long time. In the process, they lost their flavor,” says Denise M. Tieman, PhD, a research professor at the university and lead author of a paper in the January 26 edition of Science magazine.

“This is part of an ongoing study for 10 years. Earlier papers were on what makes tomato flavor, the biochemistry. Flavor is very hard to quantify,” she says. “This new paper looks at what makes it difficult to breed flavor. It’s possible to breed flavor back into modern tomatoes.”

She and her colleagues sequenced the genomes of different tomatoes and looked at the DNA in the versions that tasted good. They performed traditional cross-breeding. The goal is to only have to look at the genome of seedlings and pick the ones that will grow up tasty, saving months of having to grow the tomato in its full natural cycle.

Dr. Tieman is in the lab of Harry Klee, PhD, which is identifying the chemical combinations for better tomato flavor. The researchers are studying alleles, or gene variants, that give tomatoes specific traits like acidity, sweetness, and pest-resistance. They say they were able to use genetic analysis to replace bad alleles in modern tomato varieties with good alleles to improve taste.

Garden Gem tomatoes in the greenhouse. (Image credit: University of Florida)

“With traditional breeding, I have to wait a whole season—six months—for a tomato to produce a result. But if they [Dr. Klee’s lab] can look at genetics to see certain traits, they can create seeds and save time,” says Paul Cilia, owner of Hot N’ Humid Hydroponics, Tampa, Fla. He says he unofficially tests the lab’s tomato seeds and is enthused by the two varieties the lab currently sells, the Garden Gem and the Garden Treasure. He’s also growing some test seeds from the lab.

Cilia, who works for a large insurance company, has the small hydroponic business on the side, but grows enough to sell tomatoes to sell at farmers’ markets. He adds he is now certified as a nursery so he can sell plants.

He notes the smaller Garden Gem is hardy and produces a lot of tomatoes, while the larger Garden Treasure, “is the tastiest slicing tomato I’ve grown to date.” Cilia says the tomatoes last on his counter for two to three weeks in temperatures as high as 78 degrees Fahrenheit.

“These tomatoes also have excellent cold-weather resistance at 34 degrees,” he says. “Anything under 50 degrees can spoil them.”

The U.S. follows China in worldwide tomato production, according to the USDA. Florida and California account for two-thirds or more of commercially produced fresh tomatoes.

Still, breeding takes time and the scientists are studying more genes, so Dr. Klee says the genetic traits from his latest study may take three to four years to produce in new varieties of tomatoes.