How are seedless grapes grown?
Since seedless grapes cannot reproduce in the conventional way that grapes usually do (i.e., dropping seeds), growers have to take cuttings from other seedless grape plants and root them. Although the exact origin of seedless grapes is unknown, they might have been first cultivated in present-day Iran or Afghanistan thousands of years ago. Initially the first seedless grape was a genetic mutation in which the hard seed casing failed to develop—the mutation is called stenospermoscarpy. One modern seedless grape commonly bought today is the green Thompson seedless grape, from which 90% of all raisins are made.