The question, of course, is more about open pollination than anything else. But what must be stressed is that hybridization isn't a bad thing, and questions like this (with apologies and all respect to Trish) let the misunderstanding about hybridization continue. There are a lot of people who don't know the difference between hybrids, including F1 hybrids, and GMOs.
F1 hybrids are plants that grow from seeds created by blending two pure strains, each with at least one desirable trait. The resulting offspring will have the desirable traits from both parents, making it a better plant in some ways. The drawback is that when openly pollinated, this plant will not necessarily breed true. While this is done to make some produce more user friendly for commercial growers, it is also done for home gardeners to develop both flowers and vegetables with unusual colors and enhanced flavors.
Heirlooms are plants that will reliably reproduce themselves when openly pollinated. They are not (generally) the original species, but rather hybrids that retain their traits when openly pollinated.
GMOs are plants whose genome has been altered by geneticists by splicing in the genes from other species or altering the genes to resist herbicides, for instance. One well known example would be carrot genes spliced into the rice genome to increase its nutritional value. Another is. of course, Round-Up ready corn and soybeans which have been made resistant to the killing power of Round-Up.
Personally, I find GMOs disturbing. Their general use has been pushed beyond the testing done on them and the consequences are being discovered as afterthoughts.
