I have received two cuttings each of four pears that are semi-dwarfing when used as rootstock, ohxf 40, 51, 266, 226. 

The 51 is the only one I can find info on for the gulf south, with a single texas gardenerer reporting excellent dwarfing, precocity, and disease resistance, the latter being a major concern down here in the land of fire blight and pet-eating fungi! 

All of the OHxF are reputedly disease resistant, but these varieties are otherwise uncharted territory down here, so I'm going to give it a go, since the more traditional dwarfing rootstock such as quince show very poor disease resistance.

THese clones also have a reputation for being tough to root, so I am considering using the branches of the intended scion to push the rooting.  I think I can fashion a graft that will keep the branch attached to the tree while also joined to the cutting, the bottom of which will be in rooting medium. 

Kind of a rooting/layering/grafting combination.

Does this seem more likely to result in a rooted cutting than traditional methods?  It also has the advantage of giving me the rootstock-scion combinations I want in one season instead of two.

the future rootstck would have a standard whip/tongue cut, and the branch a modified one

Interesting,is the scion dormant?

both the tree and the cutting are dormant currently, but I would wait until the tree starts to push buds in a month or so before trying this. 

Your diagram would seem to indicate you've lost contact with the xylem of
the branch.Ergo the rootstock would be supplying all nutrients to the scion.
By leaving the phloem associated with the branch one could argue any
photosynthates would seek the easier path back to the tree's roots negating
any advantage of the proposed process.

I would expect the grafted area to heal/callous, thus have the branch fuse to and sustain it, while also provide downstream hormonal stimulus for rooting.  Once rooted, the branch can be removed, in stages perhaps.

In real life, though, you could be right.  The upstream branch may instead just shift everything-metabolic to the small remaining connection to the tree.

Does anyone want to guess which result is more likely?

Can you air layer a pear root stock limb growing beneath the original graft?

I will also do some chip grafts of the rootstock cuttings onto a Bradford pear so that I can have some source material to try again next spring if I have no luck.

Hey it's worth a try. Don't know if it will work but I'd call it ingenious..!!

You might try grafting the rootstock on a branch as if it were a regular varietal graft. After it heals and pushes new growth, try air-layering it by girdling at the graft union and putting the "rootstock" portion in a rooting medium. Sort of like "stooling", but done above ground.

For each of the four rootstock varieties, I have at least one each of:

1. Grafted to a Southern Bartlett or a Biscamp cutting and stuck into rooting medium (microwaved dirt\potting soil) with the named variety above ground and wrapped in parafilm.  They are in the shadiest part of my yard and each pot has a clear plastic bag over it for moisture retention.

2. Grafted onto existing Bradford pear in my yard, for an assured future supply/availability, and possible future air layering depending on how successful my other efforts are.

3. The reverse graft that I drew above.  Also bagged and in the shade.

 



 




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