World's Peaches, Plums Preserved In Unique Collection

From the repository's offices, laboratories and greenhouses at Davis, Calif., it's only a short drive to the research orchards at Winters, where about 750 peach trees and about 700 plums flourish.

Most of the peaches are varieties of Prunus persica, such as the historically important "Shanghai" and "J.H. Hale," two varieties that are in the parentage of nearly all of today's U.S.-grown peaches.

Other distinctive peaches include a white-fleshed cling peach from Korea named "Yumyeong," and the red-fleshed "Sanguine de Tardiff " from France.

Predominant in the plum collection are the European plum, Prunus domestica, produced as a fresh fruit or dried into prunes; and the Japanese plum, P. salicina, typically sold in this country as a dessert plum.

Among the most unusual: the squat, green-apple-flavored P. simonii from Asia; Europe's P. spinosa, of sloe gin fame; and the North American P. hortulana, a stately ornamental tree. Also distinctive: South Africa's "Laetitia," a P. salicina variety that bears large fruit, and "Sans Noay," a pit-free French P. domestica plum commonly dried into prunes.

From spring through fall, plant breeders inspect the collection to choose varieties they can incorporate into their own fruit-breeding programs. Researchers who are studying the genetic makeup of the world's plums use leaf samples from the repository to extract DNA for their research. ARS scientists at the repository conduct analyses of plum DNA as well, to be sure all the plums in the collection are correctly identified and catalogued.