Thomcord grape is a hybrid of Thompson Seedless grape (Vitis vinifera, or Sultanina), which is popular in 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.
In 1983, research horticulturist David W. Ramming and technician Ronald L. Tarailo—Californian grape breeders working for the ARS, the chief scientific research agency of the USDA—crossed Thompson Seedless and Concord in order to answer a technical question about a newly developed procedure for breeding novel, superior seedless grapes. The researchers wanted to demonstrate that plants created from embryo culture were derived from fertilized eggs (zygotic) instead of the maternal tissue (somatic). From 1231 emasculations (removal of male flower parts to control pollination) of Thompson Seedless, the researchers produced 130 ovules using embryo rescue procedures. From these, 40 embryos developed and three seedlings were planted. The original seedling of Thomcord was planted in 1984 in plots in cooperation with California State University, Fresno. It was later selected in 1986 by Ramming and Tarailo and tested in the San Joaquin Valley under the name A29-67, and was introduced as “Thomcord.”