Virus in bulbs

David Fenwick cf018a3312@blueyonder.co.uk
Mon, 03 Mar 2003 16:21:53 PST
Hi John,

>>>>>I read with interest your omments regarding virus. It seems to me that,
if there is a rare species or historically important cultivar with
virus, propagation by meristem culture might result in the production of
a virus free plant. Not all plants are able to be propagated by such
means, but an effort should be made to preserve such important plants in
this way.

I fully agree, sadly Crocosmia do not microprop so well, this is why I said
that 'post micropropagation trial' may be neccessary, to select the closest
clone to the original plant. Basically Crocosmia are genetically unstable
when micropropagated, one grower I know got three distinct hybrids when he
tried to microprop one of his new hybrid, he gave up in the end.

>>>>It might not be possible to get an establishment to undertake such work,
but if of such importance an effort should be made. Are there such
establishments which could undertake such work?

Yes there are establishments that could do it, either universities or
commercial facilities, I think my role though is basically to promote the
need for this to be done. I'll let you know if it's ever offered.

>>>> it seems to me every effort should be made in this regard rather than
destroy important collections.

What we have to look at is the number of hybrids that have been developed in
the past by our forefathers, sometimes these are referred to as heirlooms in
the US. In the UK there were many fantastic advances in the production of
garden worthy hybrids from the Victorian era until the outbreak of war in
1939. This makes it historically important to conserve, and for the sake of
the 'gene pool', for it could be used now to make further advances in
hybridisation.

This 'gene pool' may also be medicinally important. One example of this is
in the case of Germany. As Germany could not get good supplies of medicinal
herbs in the early 20th century, and they embarked on a breeding program to
develop their own, one genus developed in particular was Aconitum. The
plants that were produced contained highly increased levels of  'active
ingredient' than any other hybrids produced at that time. Hence on finding
and conserving these plants we may now find plants that could be cost
effectively used at the moment, either by large companies, or third world
countries.

If found these latter plants would be the first to have their viruses
eradicated through micropropagation, it's all down to economics at the end
of the day..

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: "John Bryan" <johnbryan@worldnet.att.net>
To: "Pacific Bulb Society" <pbs@lists.ibiblio.org>
Sent: Monday, March 03, 2003 6:14 PM
Subject: Re: [pbs] Virus in bulbs


> Dear Dave:
> I read with interest your omments regarding virus. It seems to me that,
> if there is a rare species or historically important cultivar with
> virus, propagation by meristem culture might result in the production of
> a virus free plant. Not all plants are able to be propagated by such
> means, but an effort should be made to preserve such important plants in
> this way. I remember we propagated the Lilium 'Enchantment' by this
> means and raised good quantities of this virus free plant.
> It might not be possible to get an establishment to undertake such work,
> but if of such importance an effort should be made. Are there such
> establishments which could undertake such work? it seems to me every
> effort should be made in this regard rather than destroy important
> collections. Cheers, John E. Bryan
> David Fenwick wrote:
> >
> > >>>>>There is a lot of virused material in the trade and
> > several nurseries have a few cultivars of Crocosmia that are terribly
> > virused. Any comments Dave? In my opinion it was viruses who wiped out
all
> > those fabulous Crocosmias you mentioned of late.
> >
> > Dave here,
> > Yes, Alberto I'd like to raise a few points.
> >
> > I hate to contradict you but I sincerely doubt viruses were responsible
for
> > wiping out many of the old Crocosmias, bad winters and Adolf Hitler were
> > primarily the two main causes; but I am considering 'disease' also and
for
> > reasons I will discuss.
> >
> > It my opinion that the commercial popularity of a genus, any genus, and
its
> > sale, has a direct relationship between the spread and increase of pest
> > populations and disease. Hence the more people that grow Crocosmia, the
> > higher the level of disease and increase in pests, many of which will be
> > virus vectors. Given that when plants are propagated, pests can be too,
and
> > transfered as unseen eggs, instars or larvae, and fungi, bacteria and
> > viruses transmitted unseen systemically.
> >
> > In my case, as a national collection holder it is very important for me
to
> > continually seek healthy stock, or know where I can get it from, and
mainly
> > because any collection of this size and of same genus can be considered
a
> > monocrop. In some respects monocrops are much easier to look after and
> > manage, however, pests which translocate viruses have a devastating
> > potential, and thus the correct proceedures need to be taken regarding
pest
> > and disease management, and crops need to be continuously supervised.
> >
> > Having followed Crocosmia hybrid development very closely from the
breeding
> > of Crocosmia x crocosmiiflora in 1879 it is possible to see a pattern
emerge
> > in the development of hybrids, their fashion trends and decline. However
> > this pattern is greatly masked by both the first and second world wars,
but
> > I am certainly looking into the fact that the higher the sale and
fashion,
> > the quicker the decline and probable extinction, but this is difficult
when
> > you have to consider two world wars. It is more probable though that
plants
> > have suffered because of changes in the economy, garden ownership, harsh
> > winters, and lack of time before and between wars to release these
hybrids
> > commercially.
> >
> > This commercial frequency, the dates plants were sold, from specific
> > nurseries, eg. such as with Lemoine, France, can be recorded in his
> > catalogues from 1879 - 1908, and may give an indication of resistance to
> > pests and disease, and thus eventual hardiness, if combined with
evidence on
> > parentage for that hybrid. This data could also be used as an aid to
> > identify un-named forms, as graphs can easily be prepared and the
evidence
> > collated.
> >
> > Getting back to viruses. It is obvious for in general, if we can't cure
the
> > plants, we must kill them. However there is a case whereby we are
condemning
> > plants to possibly extinction by killing them. Alberto mentions national
> > collections and specifically, the Canna collection. To answer this, one
must
> > firstly consider the plants importance, its rarity, its place within the
> > garden, potential vectors of viruses in the local vacinity, the
management
> > of these vectors, and the risk of spread to other plants by mechanical
means
> > (by human or leaf contact), and of course correct quaranteen proceedures
> > when plants enter collections of this type. But please don't condemn me
for
> > my honesty when I believe there is a case for conserving plants with
virus,
> > and yes there is a very good case for this to be done.
> >
> > We have to look at the types of viruses that our plants may have, their
> > symptoms, the vectors in each specific case, their ease of tramsmittion,
and
> > how virulent the viruses are. It is very important that when talking
about
> > conservation issues and viruses, that we do not generalise, as each case
is
> > important, and each case must be considered by scientific determination.
> >
> > I have only ever had one really badly infected virused Crocosmia ever
sent
> > to me, and this was destroyed. In conserving old hybrids it is obviously
> > highly probable that many plants contain viruses that can be considered
> > latent, have little or no effect on plant growth, and low risk of
spread. It
> > is threfore for us as an organisation dedicated to bulbs both to
educate,
> > neccessitate, facilitate and promote further scientific study in this
area,
> > and in our own countries.
> >
> > It is also possible that through micropropagation, and by post
> > micropropagation selection, we may eventually be able to distribute
> > certified virus free stocks.
> >
> > 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: "Alberto Castillo" <ezeizabotgard@hotmail.com>
> > To: <pbs@lists.ibiblio.org>
> > Sent: Monday, March 03, 2003 2:22 PM
> > Subject: [pbs] Virus in bulbs
> >
> > > Dear Mary Sue:
> > >                           You are wrong: not all panic at viruses. You
can
> > > still see remarks like "well, it has virus but I like it anyway" too
> > often.
> > > Fortunately there is a growing concern and you have growers like
Diana,
> > Dirk
> > > Wallace and Dash Geoghegan that spend lots of time and money in taking
> > every
> > > precaution to sell healthy material.  With time (and no doubt with
more
> > > valuable collections destroyed by viruses) people will learn that it
is a
> > > poor bargain to keep a diseased incurable plant against the rest of
the
> > > collection. We did not invent virus: it is a terrible occurrence that
we
> > can
> > > encounter during our experience as bulb growers. Right now, before our
> > very
> > > noses, one of the most fantastic projects of our time, the assembling
of a
> > > huge Canna collection has been put to an end by this. Most of you know
> > about
> > > the National Collections scheme in England. Well, there was a fabulous
> > > collection of them being assembled and the owner was very happy to
have
> > > found in France 52 cultivars most of which would prove new
introductions
> > (to
> > > the 140 others he was already growing). BUT, in came the Trojan horse!
> > Among
> > > those plants from France some had a virus that rapidly spread to other
so
> > > far healthy ones. That virus was masked by the plants' inherent vigor.
> > When
> > > the owner noticed  the appearance of uncommon yellow mottling in many
> > plants
> > > had them tested and it gave bean yellow  mosaic and Canna viruses. As
a
> > > result 70 cultivars (yes, 70!) had to be destroyed at once and the
news
> > were
> > > that he had discontinued the project altogether. So remember this
short
> > tale
> > > every time something shows symptoms and you decide to keep it. In my
> > > experience in most cases this is a common plant that sooner or later
you
> > > could replace!
> > > One can never overemphasize the need of a quarantine period . Do
maintain
> > > your newly introduced plants away from your collection for a time (two
> > weeks
> > > at last). Virus symptoms can be masked (there are symptomless and
latent
> > > viruses) but under periods of serious stress (like when you take a
plant
> > > from its "home" and take it somewhere else) symptoms can appear. They
are
> > > more visible (at times ONLY visible) in new growth so watch for the
tips
> > of
> > > new leaves. If they are uniformly green you have many chances that the
> > plant
> > > is healthy. If it shows mottling in a different shade of green be very
> > > worried. If you are not convinced do not let it close to your healthy
> > > collection. For instance if you live in Halifax, send it to Vancouver
for
> > > safety!.
> > >                        You are right in that there is so little in the
web
> > > on virus symptoms images. In the Ball Guides there are a few images of
> > > viruses in Liliums, Agapanthus, Canna and in  a number of dicots.
> > >                         There is a lot of virused material in the
trade
> > and
> > > several nurseries have a few cultivars of Crocosmia that are terribly
> > > virused. Any comments Dave? In my opinion it was viruses who wiped out
all
> > > those fabulous Crocosmias you mentioned of late.
> > > Regards
> > > Alberto
> > >
> > >
> > >
> > >
> > >
> > >
> > > _________________________________________________________________
> > > Charla con tus amigos en lĂ­nea mediante MSN Messenger:
> > > http://messenger.yupimsn.com/
> > >
> > > _______________________________________________
> > > pbs mailing list
> > > pbs@lists.ibiblio.org
> > > http://www.pacificbulbsociety.org/list.php
> >
> > ---
> > Outgoing mail is certified Virus Free.
> > Checked by AVG anti-virus system (http://www.grisoft.com/).
> > Version: 6.0.459 / Virus Database: 258 - Release Date: 25/02/03
> >
> > _______________________________________________
> > pbs mailing list
> > pbs@lists.ibiblio.org
> > http://www.pacificbulbsociety.org/list.php
> _______________________________________________
> pbs mailing list
> pbs@lists.ibiblio.org
> http://www.pacificbulbsociety.org/list.php


---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com/).
Version: 6.0.459 / Virus Database: 258 - Release Date: 26/02/03


More information about the pbs mailing list