From my three weeks as a Columbia River, Washington apple picker in the 70's,
This means he has maintained living samples of the trees themselves. Seems obvious, he has all those apples, eh?
Because
apple strains don't grow true to the seed, only to the wood.
To grow a tree that produces say, Jonathans, wood from a Jonathan-producing tree must be grafted on to some starter stock.
So, you can't just preserve Jonathan seeds up there in
Svalbard, they won't ever make true Jonathans, rather some variant.