Grapes! Our Never-Ending Crush

Grapes! Our Never-Ending Crush

Maybe the first grape that you encountered was a rich, blue-black Concord, presented as sweet, squishy jelly in a deliciously gooey peanut butter and jelly sandwich. Later, you probably broadened your repertoire with chewy, wrinkly raisins; chilled grape juice; and fresh grapes—plump and crisp.

As a grown-up, maybe you have an occasional glass of wine, which some medical studies suggest may benefit your health.

With so many pleasurable ways to enjoy grapes, it’s no wonder they’re second only to oranges as America’s favorite fruit. We each eat a whopping 50 pounds or more of grapes in some delicious form or another every year.

Whether it’s Chardonnay or Merlot wine grapes, Thompson Seedless table grapes, or Muscat of Alexandria raisin grapes—the chocolate-coated ones you can buy at the movie theater snack counter—grapes of all kinds, from around the globe, hold the attention of Agricultural Research Service experts in laboratories from coast to coast.

These researchers are demystifying the genes that make grapes prosper and developing new and better ways to cultivate vines in varied ecosystems. Too, they’re creating novel tactics that help vulnerable vines fend off their worst insect and disease enemies. And, they’re probing the mostly mysterious but reportedly health-imparting compounds in these berries. (Technically, grapes are berries.)

Here’s a closer look at what’s happening at a handful of these laboratories and research vineyards.

Grape-Breeding Research Bears Delectable Fruit

Chances are good that some of those tasty seedless grapes you buy at the supermarket are the research progeny of ARS’s California-based grape-breeding team. Located in the San Joaquin Valley, one of the most productive agricultural regions on our planet, the world-class team has developed an impressive array of luscious, seedless red, white, and black beauties in a grape-breeding program that dates back to 1923.

Best-sellers among them include Flame Seedless, America’s favorite red seedless grape; and Crimson Seedless, planted on more than a million acres in California—the nation’s leading grape-producing state. Others within the California top 10: Autumn Royal black seedless, ranked fifth; and ninth-place Princess, a delectable white seedless grape.

To develop a successful new grape, these scientists carefully select parent grape plants, cross (also known as “hybridize”) them, then apply embryo rescue tactics (see "Embryo Rescue: Making the Impossible Happen" below ) to produce healthy seedlings. In 2 or 3 years, when the plants bear fruit, only about 1 of every 100 vines will be selected for further testing.

Finalists go through 8 to 10 years or more of scrutiny, including informal taste-testing and trials to see how they respond to current grape-growing practices. Grape plants have to wind their way through all these tests before researchers will make them available to nurseries and growers. That’s according to horticulturist David W. Ramming. He leads today’s grape-breeding team at the ARS San Joaquin Valley Agricultural Sciences Center in Parlier, California. The team’s most recent offerings include two top-notch red seedless grapes and a generously sized white seedless.

Lush, Sweet Scarlets

Ramming describes newcomer Sweet Scarlet as “a specialty grape” with crunchy flesh, raspberry-red skin, and a hint of muscat flavor.

Sweet Scarlet’s alluring color makes it brighter than many other red seedless grapes that ripen at the same time of year—about mid-August in California. In all, the mild and fruity muscat flavor, thin skin, and pleasant texture make Sweet Scarlet “a truly exceptional grape,” says Ramming.

Scarlet Royal grapevines bear large, seedless berries that are “sweet, firm, and meaty,” with a pleasing, dark-red color, says Ramming. By ripening in mid-August, these grapes handily fill a gap between the early-ripening Flame Seedless and the late-ripening Crimson Seedless.

“This grape is easy for growers to produce,” he adds. “They’ll get good yields of good-sized berries that have a full red color.”