American Chestnuts

Richard Winder rwinder at PFC.Forestry.CA
Fri Jan 7 16:05:41 EST 1994


In article <Phillipsj-cic-is-050194123332 at 136.205.11.44>, Phillipsj-cic-is at redstone-emh2.army.mil (Jimmy A. Phillips) writes:
>In article <wier.757726326 at qwerty-gw>, wier at md.fsl.noaa.gov (Stuart Wier)
>wrote:
>
>
>> Years ago the Northern Nut Growers were working on hardy strains which
>> could resist the Chestnut blight.  I do not have their address at
>> hand. They publish books so you might look in the back of 
>> books in print.
>> 
>> When I go I hope it is by a blithe.
>> 
>> Stu Wier
>
>Is the the blight still a problem today or has it been eradicated?
>
>
>Jim Phillips

Cryphonectria parasitica (if that's still the name of chestnut blight) isn't
likely to go away any time soon, since other trees are also occasionally 
susceptible in varying degrees to the fungus.  Among the chestnuts, American
is most susceptible, followed by European. Chinese and Japanese are fairly 
resistant.  Originally, hybridization with Asian chestnuts did not go well 
because the Asian forms are more bushy, with poorer timber quality.  
Eventually, some suitable hybrids were developed, but they are not adapted to
very wide site characteristics.  Most instances of apparent natural resistance
in American chestnut are due to escape or suppression by hypovirulent strains
of C. parasitica.  There has been quite a bit of work on the use of 
hypovirulence to control the disease, but I'm not sure where that stands
today.  I sat in on a seminar a fews years ago where someone was using 
molecular biology to look at some of the back-crossing done in the original 
hybridization work, and they found some major problems with it.  I can't 
remember the details, but they indicated to me that while it is possible to
come up with suitable hybrids, it will probably be centuries before
we will see them in place and fully recovering the former importance of the
species. An interesting side note to this is that chestnuts, as a more
reliable nut source than trees such as oak, could conceivably support much
larger wildlife populations in the forests of Eastern North America.  -RSW

  RICHARD WINDER                    Title: Visiting Fellow
  Forestry Canada                   Phone: (604) 363-0600
  Victoria, B.C.                    Internet: RWINDER at A1.PFC.Forestry.CA



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