North American Fruit Explorers mailing list at ibiblio

[Jwlehman@aol.com]

In a message dated 12/7/2005 5:34:24 PM US Eastern Standard Time, yarrylo@hotmail.com writes:
> Has anyone tried or considered D. lotus as an alternative to D. virginiana 
> as a rootstock for American persimmon?
> I understand that D. lotus is less cold hardy than D.V. but still supposedly
> hardy to zone 5, so would its use still present a hardiness problem in zones 
> 6 and higher?
> Also noting some growers' observations of the significant variability of
> persimmon variety traits on different individual D.V. rootstocks, might D. 
> lotus rootstock allow a more consistent _expression_ of the graft (as it apparently
> does for D. kaki for which it is the preferred rootstock in some locations),
> thereby possibly improving cultivar evaluations?
> And is it reasonable to expect a somewhat dwarfed or shrubier plant to grow
> on lotus stock and would these qualities be desirable for harvesting
> considerations?
> Might also the naturally resistant D. lotus provide some protection from
> persimmon wilt?
> But back to basics, will this graft even take?!
> Thanks
> Alan Stei
n 

Hello Alan,

Yes, there is significant variability in D. virginiana that causes problems comparing  
clones in test blocks. I'd also believe this would hold true for D. lotus seedlings. And because of having one species on another, the over all variability may even be greater.  Strictly guessing! 

What we need is a method to clone Diospyros rootstocks and Purdue is working on that and have succeeded somewhat. We could than test on uniform understocks. The system isn't perfected and hopefully lack of funds will not halt the work. One plant propagator has said they would produce rootstocks if invitro propagation is perfected. 

I have lotus growing here in Indiana and they freeze to the ground every year, except one in the past 8 years. I think maybe two are still alive. If D. lotus were used as understock here, Zone 5b, I'd suggest the graft would need be made low, below ground level. But then kaki would still suffer winter damage in zone 5 and even zone 6. 

Yes, lotus is used as understock for kaki and recommended in the South. Lotus is less tap rooted and have more laterals making it theoretically a better rootstock. I have no experience to speak from. But they are graft compatible. Some nurseries use lotus as an understock. 

Have no idea if lotus would offer resistance for persimmon wilt also called KSD. Keep in mind this writer believes there could be more than one cause or combination of causes for sudden death and shepherd hooking is a symptom of dying kaki from one or more causes. 

Now if KSD is caused from Manganese poising as has been speculated, then lotus could be a preventative if the uptake of Manganese is less than with virginiana or kaki as I've seen reports that kaki on kaki can also exhibit KSD. 

We know some varieties within a given species have more resistance to certain viruses. For example, at the USDA, Beltsville, where they test incoming plant material for viruses one of the first steps is graft Prunus to virus sensitive rootstocks. If the rootstock dies, the material is virus infected. No need to test further. If one of the causes of KSD is a virus then virginiana must be tolerant of it. Would lotus impart resistance to grafted kaki? Have no idea. Virginiana certainly doesn't seem to and acts more like a carrier.  See Lester Davis input on the subject 12/02/05, subject title: Kaki sex. 

There you have it, much verbiage, no conclusion. 

Jerry