Usually I hear "grafted," where you take one variety with strong roots, cut the top off of him, take another variety that makes the fruit you want, cut the roots off of him, and then put the good roots on the good fruit and tape them together. I've even seen one root stock grafted to several different species of fruit so the same tree grew apples, pears and pomegranates.

Apples don't breed true; a seeds out of a Gala apple won't grow a tree that makes Gala apples. They might be better, they might be worse, they won't be Galas. All commercial apple production is done by grafting branches of existing trees onto new root stocks.

I am just north of where peaches will properly grow. Doesn't stop people from trying. Every year in early spring there's a late cold snap, and every year people say "It's killin' my peaches." Every single individually wrapped year I hear that from someone.