Tomato breeders have mastered the art of making produce that's durable, attractive and available year-round.

Making it tasty is another matter.

As American palates get more sensitive, seed companies and growers have heard a lot of complaints about grocery-store tomatoes—they look great but taste bland. So, agribusinesses are pouring millions into efforts to jazz up the staple fruit. They're holding focus groups to zero in on the traits that give a good tomato its zest and using new technology to speed up breeding.

But there are numerous obstacles—from balancing different concepts of what tastes good to identifying just what genes control flavor.

"I can see the light at the end of the tunnel," says Harry Klee, a plant geneticist and tomato specialist at the University of Florida. But, he adds, "we're not there yet."

Different Priorities

How did we get into the tunnel in the first place? For many years, breeders and seed companies have been breeding tomatoes for just about everything except taste. Retailers have wanted tomatoes that look good and have a long shelf life. Farmers, meanwhile, have wanted a plant with high yields.

Amid those clear-cut demands, consumer tastes, which are tough to define, have been less a priority. So, over the decades, taste has declined.

Some researchers, in fact, say they can pinpoint the moment things started to go downhill.

In June, a widely publicized study in the journal Science argued that a genetic mutation was discovered about 70 years ago and bred into tomatoes, because it made the plants turn a deep red and ripen uniformly. But according to the study, that same mutation also deactivated the gene responsible for sugars that give the tomato much of its flavor.

To be sure, people can still find tomatoes that are packed with flavor at farmers' markets, in backyard gardens and even in grocery stores, at times. But those varieties are typically more expensive, and they aren't bred to withstand the mass production and shipping endured by the tomatoes most often tossed in our salads or used on our hamburgers.

Kent Shoemaker, chief executive of Lipman , the world's largest field-tomato grower, says it's one thing to grow a dozen tomatoes in the backyard at the height of the growing season "and quite another to harvest millions of them year-round."

More Than Good Looks

Seed companies and growers say they know that people aren't satisfied. Mr. Shoemaker says his company has gotten the message from consumers that "they want more than just pretty produce." The company has responded, in part, by developing a tomato called the Vintage Ripe that the company claims is its tastiest yet.

Likewise, Consuelo Madere, president of the vegetable-seeds division of Monsanto Co., says she's keenly aware of the negative perceptions of regular tomatoes. "My friends and family all say, 'When are we going to have tomatoes that taste better?' " she says.

Among the projects at Monsanto, Ms. Madere says, is a long-term effort to breed cherry-tomato flavor components into regular field tomatoes.

The stakes, and the opportunities, are big. Tomatoes are the biggest seller in the $5 billion vegetable-seed market, accounting for about a quarter of sales, says Mark Nelson, an associate with Context Network, a Des Moines, Iowa, consulting firm.

The effort to improve taste is a long and slow process that involves conventional breeding. Despite the big splash earlier this year when the full tomato genome was published, there's no genetically modified tomato on the market.

Bayer AG, for instance, spent 10 years developing a fleshier tomato, called Intense, that claims to eliminate watery salsa and soggy sandwiches. The company also spent years on its most recent Marmande tomato, a sweet heirloom with green shoulders and a ribbed appearance, which was introduced in Spain in April.

Mr. Shoemaker of Lipman says his company can spend three years building a "library" of parents at the start of the breeding process for a new variety, followed by field experimentation that can last for years.

Even then, the variety may not make it to market. Mr. Shoemaker says the company recently abandoned one project after field trials because the tomatoes wouldn't produce enough sugars to balance out their acidity.

Accounting for Taste

One thing that may help the process along is molecular, or "marker-assisted," breeding, which is vastly accelerating the discovery process of genes that account for taste. The technique relies on genetic testing to identity which plants to crossbreed, all but eliminating the endless trial and error that has long been central to breeding.

That's a tremendous help, researchers say, because of the numbers involved. Despite the recent study in Science, they say, there are actually many genes together that account for taste.

Sugars, acids, aroma and texture all go into the perception of taste, says Ira Stein, head of the breeding-tomato operation at Nunhems, the vegetable-seed operation at Bayer.

Breeders can protect against diseases such as heat blight, for example, by focusing on one specific gene, says Dr. Klee of the University of Florida. But there are at least 20 different compounds that account for a tomato's flavor, and at least a dozen genes.

Dr. Klee has spent years conducting focus groups of 80 to 90 people each week, testing dozens of varieties to identify those that taste good. He takes the tomatoes the focus groups prefer and deconstructs them, trying to identify specific genes that make them tasty.

"If flavor was one gene," he says, "we'd be done."

Mr. Berry is a staff reporter in The Wall Street Journal's Chicago bureau. He can be reached at

Corrections & Amplifications
An earlier version of this article misspelled Consuelo Madere's name as Consuela.