Growing-Grapes.org

Some seedless fruits are grown from grafts on existing trees. Seedless grapes are not technically seedless, although they are seedless for practical purposes. Seedless grapes are different than most seedless fruits because the seeds initially develop but abort when they are very tiny embryos. So, in seedless grapes, normal fertilization does occur. You can often see
the remains of the aborted seed in the mature fruit. Seedless grape breeders can remove the tiny embryos before they abort and grow them in tissue culture to produce a mature plant. This is termed embryo rescue.

Not seeds…grafts.

There are no seeds. They take cuttings from one plant to grow another. The cuttings are rooted. They are not grafted.

Many "seedless" fruits aren’t truely seedless. They either have very small or very few seeds.

They grow seedless grapes from cutting, rather than from seeds. Some vegetables, such as cucumbers, have been bred to only produce female flowers as long as they are grown in optimum conditions. If you grow them under stress, they will produce male flowers as well, so you can then gather seeds.

They grow them from cuttings from the original plants.

grape vines