How do apple trees reproduce ?

Brittany's answer is correct, but I will add a little to the question. As far as the apples you eat in the store, none of those came from a seed. Almost all trees that produce fruits or nuts have been grafted or budded. I won't get into all the details, but basically plant growers will take a branch or bud (the tiny area where leaves eventually emerge) and add it to an existing rootstock. Rootstocks are usually a member of the same genus, but always from the same family. These rootstocks are usually plants that are more hearty and have desirable characteristics such as nematode resistance or disease resistance, but don't have the quality of fruit people want. So the rootstock is usually grown from cuttings, and then cut down so people can graft or bud a scion (the desirable variety of plant that is what you mostly see and from which you get edible fruit). They get these from trees that are from the same variety as the one you desire, such as taking a branch from a "Granny Smith" ...  more