Thomcord
Thomcord is a seedless table grape variety and a hybrid of the popular Thompson Seedless or Sultanina grape (a Vitis vinifera variety) and Concord grape (a Vitis labrusca variety). Thomcord was developed in 1983 by Californian grape breeders working for the Agricultural Research Service (ARS), an agency of the United States Department of Agriculture (USDA), as part of a test to better understand a new seedless grape breeding procedure. Its aromatic, "labrusca" flavor is similar to that of Concord, but mellowed by the mild, sweet taste from Thompson Seedless. Thomcord grows well in hot, dry climates, ripens between late July and mid-August, and tolerates powdery mildew. It is a productive variety, yielding an average of of grapes per vine, but has produced as much as per vine in grower trials. The berries weigh between and have a medium-thick, blue-black skin that adheres to the fruit, unlike Concord, which has a thick skin that can slip off the pulp easily. The aborted seeds in the fruit body are relatively small, but larger than those in Thompson Seedless. The plant is not restricted for propagation and distribution. Virus-free propagation material is available from the Foundation Plant Services (FPS) at the University of California, Davis, and its genetic material is archived at the National Plant Germplasm System. After 17 years of testing, it was declared ready for use in 2003. It is currently available in supermarkets. Description Thomcord grape is a hybrid of Thompson Seedless grape (Vitis vinifera, or Sultanina), which is popular in American (?) supermarkets during the summer, and seeded Concord grape (Vitis labrusca), commonly used to make grape juice and jelly. It is a plump, juicy, seedless table grape and is slightly firmer than Concord. Thomcord has a blue-black skin with medium thickness and a whitish bloom. Unlike Concord, whose tough skin separates easily from the fruit, Thomcord has a more edible skin that clings to the flesh, much like Thompson Seedless. It has an aromatic flavor, similar to the Concord in taste ("labrusca"), though lighter due to the sweet, mild taste from Thompson Seedless. Thomcord is suitable for hot, dry growing conditions, more so than Concord and other Concord seedless types. Its adaptability to hot dry climates was derived from Thompson Seedless. It grows well in California's vineyards, particularly the San Joaquin Valley, just like Thompson Seedless. The plant is tolerant of (but not resistant to) powdery mildew, and is less susceptible to the fungus than Ruby Seedless, but more susceptible than Mars, Venus, Niabell, and Cayuga White varieties. The fungus can affect its leaves, stems, rachis (stem of the grape cluster), and berries. The grape ripens in the summer (mid-season), between late July and mid-August. Production details Thomcord is a productive variety, with a yield comparable to Thompson Seedless. When two cordons (arms) of the vines are trained horizontally on wires ("bilateral-trained") and are pruned to remove most of the previous year's growth ("spur-pruned") during the winter, it can produce up to per vine, or an average of