Are All Thompson Grapes Seedless?

Question

Are all Thompson grapes seedless?

Answer 1

There are several sources of the seedlessness trait, and essentially all commercial cultivators get it from one of three sources: Thompson Seedless, Russian Seedless, and Black Monukka, all being cultivars of Vitis vinifera. There are currently more than a dozen varieties of seedless grapes. Several, such as Einset Seedless, Benjamin Gunnels's Prime seedless grapes, Reliance and Venus, have been specifically cultivated for hardiness and quality in the relatively cold climates of northeastern United States and southern Ontario.
I did not find any referance to a seeded Thompson Grape, so I assume that all Thompson Grapes are seedless.