Ok, let's stick to apples then, for the purposes of discussion. You mentioned that yours are heirloom varietals. I live in Michigan, we grow a lot of good apples, I appreciate your point, they are good. So lets say that your variety was around, oh, 200 years ago, which is old, comparatively. But, was it around 500 years ago? How about a thousand? A few thousand? See, if you go back enough on the family tree of most species of plant that humans consume now, you'll notice a few things. Your apples, which are now, large, sweet (or tart), and delicious, were once a small, hard, bitter ball of cellulose and seeds. Now, this is still an apple, we still have varieties like this today, crabapples. Humans realized that, by breeding plants that have traits that they like, they can encourage changes. Selective breeding is a type of technology. So, humans, using technology, performed a change on the species.
GMO's are just skipping, in the case of some crops such as wheat (First cultivated 8000 BCE), thousands of years. Given enough time, we could, by selective breeding, probably create a strain of wheat that would grow well in cold climates. Hell, given enough time you could create a strain of rice whose vitamin content was pretty close to modern Golden Rice.
I happen to be against a lot of things related to crops that are genetically modified, but my problem is with patent laws, pesticide incompatibilities, and a lot of modern farm law. But I am not against the modification of existing organisms genetic material to create versions better suited for human needs.