How do organic growers produce seedless grapes without using GM technology?
There are no commercially grown GM grapes anywhere in the world. Seedless grapes are the result of selective breeding to develop varieties with very small seeds and in many of the grapes, no seeds at all. Most seedless grapes do have seeds at some point but they do not set and produce hard outer shells.
Because most plant production of perennial crops like grapes are now produced using grafting and cutting methods, which are effectively exact clones of the mother plant material, it is becoming easier to produce seedless varieties. Obviously if a plant relies on seed to reproduce then it would not be possible to produce seedless grapes. There will always be some seedless grapes that do contain seeds and this is more likely to be the case in organic grapes.
Non-organic growers use a product called giberellic acid to treat the grapes and ensure that no seeds at all will be found in the grapes. Organic growers cannot use this product. As a result organic seedless grapes may occasionally contain a few very small seeds, although these would be of a size that should not result in the need for them to be removed before eating.