Rootstock,Tree Vigour and Scions?

[GF3]

Hello.
This year I will be grafting scions of the varieties: Court of Wick, Limelight and Herefordshire Russet. They will be grafted onto a Katy Tree (MM106) Lord Lambourne (MM106) and Red Delicious (M26)
According to information on the Keepers-Nursery website:
The Scions:
Court of Wick - the variety is classed as "Vigorous"
Limelight - vigour is "Small"
Herefordshire Russet - vigour is "Moderate"

The Trees:
Katy is classed as "Vigorous"
Lord Lambourne "Moderate"
Red Delicious "Moderate"

What will have the biggest influence on the growth rate of the grafted scions? The vigour of the variety of Scion, Rootstock of the tree or the vigour of variety of the tree that the scion is grafted to?

[smallblueplanet]

I'm only guessing, but we bought a three apple variety family tree off ebay, must be about 11 years ago (blimey, time flies!).

Anyway the three varieties are: Falstaff/Fortune/Idared Family apple tree on M26.
I can't remember which of the three is which but basically one of them has done really well and almost taken over, the 2nd has one largish branch and the last one is almost just a small 'twig'.
So I would guess the vigour of the variety is important for amount of the whole tree and rootstock dictates the overall size of the tree - we keep ours topped to about 7 foot. As I say, just a guess.

[FB.]

Rootstock and scion seem to have roughly equal effects on tree vigour.
Some scion+rootstock combinations grow better (or worse) than expected, possibly due to partial incompatibility or exceptionally good compatibility of the scion and rootstock.

Some rootstocks or scions grow better in certain soil types (acid/neutral/alkaline/clay/sand/chalk) or certain climates (cool/mild/wet/dry/dull/sunny).

All these interactions can sometimes result in trees behaving very differently to what was expected.