Virus in bulbs

David Fenwick cf018a3312@blueyonder.co.uk
Mon, 03 Mar 2003 15:53:20 PST
Hi Jane,

>>>>>>I've also noticed that two nurseries in this region that specialize in
variegated
plants (Collectors and Terra Nova) frequently find variegated forms of
other plants arising in their collections; can these be the result of
viruses jumping from the variegated plants to other species and genera?
What does this mean, for example, for those who grow hosta cultivars --
should they worry about infection reaching their other liliaceous plants?

Dave here,
In my experience I have found that all cultivated / named viral variegations
to be safe and free from risk of spread, perhaps the most unusual of these
was Helleborus foetidus 'Variegatus' which just has 5 or 6 yellow spots
about 8mm across on each leaf.

There are numerous other reasons for plants to produce variegation. Seeds
can be treated with x-rays, but usually it can be as common as an unstable
gene which produces a variegated chimera. If the variegation is sectoral (a
partly variegated leaf) the variegation will usually be unstable, if
meristematic (variegation around the entire edge of the leaf) the
variegation is normally stable.

I failed to omit genetic stability in my earlier mail as this is another
problem that can lead people to think a plant has a virus. Genetic
instability can be quite common with bulbs that have been overly bred and
developed. eg. one or two Crocosmia have cycles where the flower colour may
change slightly every second or third year, genetics is the only reason I
can see for it.

I know someone with a sectorally variegated Kniphofia northiae at the
moment. We've dug it up and potted it and have laid the pot flat on the
floor with the variegated side uppermost, hopefully a shoot will arise from
the variegated section thus making it meristematic and stable. It has the
potential to make a superb plant.

Best Wishes,
Dave


Websites:
http://www.theafricangarden.com/
http://www.crocosmiaheritage.com/

Address:
David Fenwick
NCCPG National Collection of Crocosmia with Chasmanthe and Tulbaghia
The African Garden
96 Wasdale Gardens
Estover
Plymouth
Devon
England
PL6 8TW

----- Original Message -----
From: "Jane McGary" <janemcgary@earthlink.net>
To: "Pacific Bulb Society" <pbs@lists.ibiblio.org>
Sent: Monday, March 03, 2003 10:14 PM
Subject: Re: [pbs] Virus in bulbs


> This discussion reminds me that I would like to ask the experts some
> questions that have occurred to me over the past few years.
>
> 1. Is Colchicum 'Waterlily' (the widely sold double form) afflicted with
> some virus or other disease? I have not been able to keep it here, and
have
> given up on it.
>
> 2. Are commercial stocks of Fritillaria imperialis virused? Again, I
cannot
> establish them here and note that emerging foliage is distorted, but this
> can be caused by frost as well as disease, so I have not been sure. I no
> longer order bulbs of this species in any form and am trying to grow some
> stock from seed, but it is very slow and shows poor germination.
>
> 3. It has not been mentioned much, but some viruses affecting bulbous
> plants (and other plants) commonly can be transmitted between genera. The
> best-known example in bulbs is tulip viruses affecting lilies, so one is
> often advised not to grow tulips anywhere near valuable lilies. I've also
> noticed that two nurseries in this region that specialize in variegated
> plants (Collectors and Terra Nova) frequently find variegated forms of
> other plants arising in their collections; can these be the result of
> viruses jumping from the variegated plants to other species and genera?
> What does this mean, for example, for those who grow hosta cultivars --
> should they worry about infection reaching their other liliaceous plants?
>
> 4. The discussion of the decision whether to preserve an infected hybrid
or
> other clone points up the importance of maintaining a wide gene pool both
> in nature and in cultivation. By such means, populations can be constantly
> renewed, the unhealthy stock discarded and replaced by new, possibly
> resistant clones in great variety. This is the principle underlying the
> Lily Species Preservation Society, for which disease-free stocks are now
> being grown from seed in large numbers. It is more important to preserve a
> wild plant community with its inherent variation than to cosset a single
> hybrid clone, however pretty it may be.
>
> Therefore, we should all (a) support habitat preservation efforts like
> those of the Nature Conservancy, and (b) GROW MANY PLANTS FROM SEED, and
> participate in seed exchanges.
>
> Jane McGary
> Northwest Oregon
>
>
> _______________________________________________
> pbs mailing list
> pbs@lists.ibiblio.org
> http://www.pacificbulbsociety.org/list.php


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