Hi everybody...let me avoid my Friday work deadline by jumping into this.
The key excerpt in Tyrus' link was...
Unfortunately, with all this controversy floating about, sometimes home gardeners don’t realize that hybrids has nothing at all to do with genetic engineering, which is a very different thing.
As teat says, pretty close to no veggies are gm. Twenty or so years ago there was a flavor saver tomato that was a dismal failure. It could be picked ripe and then not rot as quickly. Trouble came in shipping a ripe tomato.
Think of heirlooms as a super race type concept. For open pollinating plants you've got to grow them separate from the rest of the plant world (if their progeny are to remain the same generation after generation) or they'll take in genes from their neighbors.
Hybridization is I think about 70 yeras old. The concept is that the progeny have traits from two complimentary but different parents. Stictly a conventional breeding concept. Interestingly, hybridization ( like pasteurization) was not legal in parts of Europe for many years.
The "heirloom" varieties that modern society embraces today, are products popularized and developed by industrial agriculture 50 or whatever yeras ago. Industry moved passed these products for many reasons, many of those dictated by the grocery stores.
We plant heirloom tomatoes and we like replanting a variety or two each year. But we appreciate the fact that conventional products are there to feed us the other 10 mos. of the year.