North American Fruit Explorers mailing list at ibiblio

[tanis grif <tanisgrif@yahoo.com>]

A couple years ago I did a lot of googles for this info.  Be warned that by
searching "graft" & "callus" you get a lot of medical pages.  I think I 
finally hit
pay-dirt w/ "bench-graft callus" or "pome graft physiology".

Anyway, the key factors for callus & tissue differentiation success are 
moisture,
oxygen, & temperature.  Pear has the widest tolerance for these, the biggest 
window.
 (Was it Ed F or Lucky P who posted "just get pear scion & stock in the same 
room,
for graft success"?)  Apples are not quite as forgiving; I think the temp 
range was
30 to 90 farenheit, 55 to 65 optimium.  Sorry, I didn't read much about stone 
fruits
because I haven't dabbled there yet, but my recollection is the optimium was 
warmer.

I had some success, 66%, last year w/ bench grafts by callussing in temps 
which
fluctuated between 60 & 40-- chilly but not cold.  My research told me the 
idea is
to hold the plants at a temp which will give better callus formation at the 
graft
union, than dormancy break in the stock & scion.

Note I have my best graft success (apple and pear) in the nursery in mid to 
late
May.  Black rubber tape-- I don't want to know how hot those graft unions get 
in
mid-May to mid-June sunshine!


--- Ed Fackler <> wrote:

> James:
> 
>      Sorry I didn't realize the person was grafting anything other than
> apple, perhaps pear.  Normally (or commercially) stone fruits are budded
> using green buds.
> 
>     If you (or others) are grafting stone fruits they vary like crazy in
> regards to callus tissue formation.  Peaches/nectarines require around 70
> degrees.  Plums can be successful at temps similar to apple.  Don't have any
> experience with dormant grafting cherry or apricot.
> 
>      And since most stone fruits are green budded I doubt that any relavent
> research has been done to address any "optimum" conditions for dormant
> grafting, but I could be wrong.
> 
> ed
> 
> 
> On 3/19/07, Erdman, James <> wrote:
> >
> > Grafts of what?  Optimum temperatures vary for different species;  38
> > sounds reasonable for apples, but stone fruits need a higher temp, 60 
> > sounds
> > like optimal for apricots (but don't quote me, as I don't have any
> > references handy, so I might be off a few degrees).
> >
> > I would like to hear/see/read any recent detailed info/studies on the
> > subject of optimum temps for callusing.
> >
> > Jim
> >
> 


 
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