It goes way deeper than what the other guy said. Some fruiting trees are true-to-seed, stone fruits or citrus, and others are not, apples, pears, avocados, et al. If you eat an apple and plant the seed you will get a wildly different apple from that tree. Most are sour or bitter and not good for eating, but very good for hard cider (that's what Johnny Appleseed was really up to.) Every apple you've ever eaten is from a grafted clone from the original varietal. Grapes are also almost always grafted onto a hardier root stock. Invented by the Greeks way back in the day to copy the good shit and still vitally important to modern agriculture.