Same place all modern commercial non-annual fruit comes from: there was one tree, bush, vine, whatever somewhere that had the desired characteristics and they graft buds from that plant onto root stock of other varieties. Doesn’t work for strawberries, etc, or to wild fruits, but all apples, grapes, oranges, pears, etc etc that you can buy in a nursery are produced this way.
Same place all modern commercial non-annual fruit comes from: there was one tree, bush, vine, whatever somewhere that had the desired characteristics and they graft buds from that plant onto root stock of other varieties. Doesn’t work for strawberries, etc, or to wild fruits, but all apples, grapes, oranges, pears, etc etc that you can buy in a nursery are produced this way.