Heirloom preservation is indeed highly laudable. Brogdale [1] in the UK has ~2400 apple, ~500 pear, ~300 cherry, and a huge range of other edibles -- a fascina

Heirloom preservation is indeed highly laudable. Brogdale [1] in the UK has ~2400 apple, ~500 pear, ~300 cherry, and a huge range of other edibles -- a fascinating place to walk around if you're ever in the area. But none of them are multi-grafted. Each apple variety has two physical specimens -- adjacent to each other, on semi-dwarfing stock, and they re-graft and relocate every ten years or so, IIRC. One of the researchers there told me that in the UK there used to be a known range of close to 10,000 unique apple varieties, but many are now simply lost in time. In Australia we've got a much smaller range available -- in the order of a few hundred I think -- but I don't believe anyone trying to maintain a collection is using (let alone relying on) multiple grafts on the same plant. [1] https://www.brogdalecollections.org/ https://www.brogdalecollections.org/