For standard sized apple trees, it can take up to eight years for them to start producing. One common solution is to graft them onto a dwarfing rootstocks which makes them mature in just a few years.
Some of the early cropping techniques done in own-root fruit trees include: Tying down 1 and 2 year old branches to the horizontal Summer pruning while avoiding winter pruning Withholding nitrogen Root pruning https://www.cooltemperate.co.uk/own-root-project/
The techniques don't seem very common, and it sounded too good to be true for seed grown standard sized apples to bear fruits in only a few years. How long should we expect to wait until we see fruits if we followed the techniques?