REPLY: [pbs] permanent clones??
Lee Poulsen
wlp at Radar-Sci.Jpl.Nasa.Gov
Wed Jul 7 14:30:14 EDT 2004
I know that at the US Dept. of Agric./Univ. of Calif. Riverside citrus
research center they have perfected the technique they use to obtain
virus-free versions of various citrus cultivars. They actually graft
and grow the virused cultivar in pots in a large room that is an oven
where they raise the temperature to a certain point and keep it there
continuously (somewhere between 100 and 120 deg. F. but I can't
remember exactly what). Then when new growth appears, they take just
the growing tip and tissue culture from that.
They discovered that above a certain temperature, viruses are unable to
migrate into the newly grown cells. Thus they are able to clone
completely virus-free plants. I've read that this method was used to
clean up the 'Meyer' lemon variety some years ago.
I don't know if this technique would work for lilies or other geophytes
as well.
--Lee Poulsen
Pasadena area, California, USDA Zone 9-10
On Jul 7, 2004, at 9:37 AM, John Bryan wrote:
> Thanks for your message. Rather than an inner scale, I think the very
> tip of the growing point is better in order to obtain virus free cells.
> Hopefully they are taken before the virus can get to them, this would
> be
> even more the case if the tissue was taken from a plant that was
> growing
> rapidly, i.e. with added warmth to stimulate fast growth.
>
> DaveKarn at aol.com wrote:
>> Judith Freeman (of Columbia-Platte Lilies and The Lily Garden) has
>> said the
>> issue is that meristem culture did not remove all the virus particles
>> in the
>> bulbs multiplied by meristem culture. The remaining few particles
>> were too few
>> to be detected by ELISA tests. For that reason, it is necessary to
>> periodically repeat these tests to have any assurance of virus
>> freedom. What, in
>> effect, is happening with these supposedly virus-free lilies is that
>> the
>> undetectable virus gradually works itself back up to levels that
>> present the standard
>> symptomology. I would imagine to get a truly virus free lily, one
>> would have to
>> continuously to incubate sections of the innermost scales.
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