Strawberry genome may lead to cheaper berries

Farmers have long struggled with getting ripe strawberries to market in good shape, but scientists say the recent mapping of the wild strawberry's genome may help them produce berries that are cheaper and easier to grow and arrive in stores in peak condition.

The woodland strawberry has become one of only a handful of food plants to have its genetic sequence charted, and scientists said the map could help them cut years off the time that it would take to produce similar results with traditional plant breeding techniques. But farmers and researchers also say the strawberry's genome isn't likely to be used to its full potential because of consumers' concerns about genetically modified foods.

Nate Nourse, who grows strawberries and other berries in Whately, Mass., said he saw a lot of potential in the strawberry genome map. Many of the strawberries he sells are what he calls June strawberries - sweet, sugary and something special for the few summer weeks they're available.

"But you can't hardly ship them because of the sugar content in them. The more sugar, the less shelf life," he said. He added, "This genetic stuff is going to help people understand what it is to make the sugars better."

He hoped the sequencing of the woodland strawberry genome would speed up the breeding process and make more reliable work that he describes now as a crap shoot. But, he said, that work can't include any sort of genetic modification - his customers wouldn't buy it.

Kevin Folta, an associate professor of horticulture at the University of Florida and one of the scientists who helped map the strawberry's genome, said that was one reason the strawberry industry contributed very little of the $200,000 needed to pay for the project. Growers didn't want to create a public relations problem for themselves.

"Being involved in a sequencing project could give a false impression of doing genetically modified technology on strawberries," he said.

Researchers said they're most likely to use the genome to try to develop plants that resist diseases and produce berries that hold up better while being shipped, last longer on shelves and cost less to grow. Down the road, they may also aim for better-tasting berries, although Folta said better flavor isn't growers' first concern.

"You don't taste in the store," he said, but consumers might not buy packages of berries because they haven't held up well during shipping.

Janet Slovin, a U.S. Department of Agriculture plant molecular biologist who worked on the strawberry genome project, said the research also has potential for similar changes in a long list of other members of the Rosaceae family, including apples, plums, peaches, raspberries and pears. Researchers who focus on those fruits worked on the sequencing team because the strawberry is related closely enough to be a good stand-in for them.

"This is really the lab rat for strawberries," Slovin said.

Folta, Slovin and 73 other researchers scattered around the world started working on the woodland strawberry genome three years ago, looking for a way to speed up plant breeding aimed at building a better berry.

Breeders, working mainly in California and Florida, have bred berries that are harder and less likely to bruise during shipping or that easily separate from their stems for easier picking. At least one variety, Slavin said, is grown for the long sturdy stem that lets it be easily dipped in melted chocolate at weddings.

Traditional breeding, however, involves growing thousands of plants, crossing them with numerous others, then growing those crosses, and repeating the steps over and over for five, 10, even 15 years to find even one plant that exhibits the trait breeders want. Some research never pans out at all.

With the genome sequenced, Folta said, researchers can instead grow a plant to seedling size, check it for the gene that controls the trait they're looking for, and, if it's there, focus breeding efforts on that plant.

"The last decade has really been an explosion of resources in strawberry genomics; we've really advanced what we know about strawberries, but we've always had to take time to initiate a first step, essentially going on a hunt to find the genes of interest," Folta said, adding, "With the genome in hand, you don't have to take that first step."