Scottish Rock Garden Club Forum

Specific Families and Genera => Iris => Topic started by: biodiversite on February 26, 2008, 06:47:09 PM

Title: a virused 'Katharine Hodgkin' ?
Post by: biodiversite on February 26, 2008, 06:47:09 PM
comparing our photos of 'Katharine Hodgkin' on my french forum, we saw different variations of colors, i. e. it seems that in acid soil colors are stronger : do you make the same conclusion ? Moreover, one of our membre has a form with some broken colors (at the bottom of this page : http://plantes-passion.forumactif.fr/les-bulbes-f7/iris-reticules-2008-t1386-15.htm sorry the photo is too big for this forum !) : do you think this plant could be virosed ?
Title: Re: a virosed 'Katharine Hodgkin' ?
Post by: David Shaw on February 26, 2008, 06:58:53 PM
It is certainly an unusual form, Biodiversite. I usualy associate virus with streaks on the petals, in this case the streaks are missing! I think your forumist should isolate the pot for the time being until you get an answere.
 See Dominique's 'Sheila Anne Germany' in the Reticulata thread.
Title: Re: a virosed 'Katharine Hodgkin' ?
Post by: mark smyth on February 26, 2008, 07:07:07 PM
here's the photo
Title: Re: a virosed 'Katharine Hodgkin' ?
Post by: biodiversite on February 26, 2008, 07:14:44 PM
thanks for the redimensionned photo and the answer : then, if not a virus, what could be responsible of such aspect ?
Title: Re: a virosed 'Katharine Hodgkin' ?
Post by: biodiversite on February 26, 2008, 07:20:04 PM
then, the answer is perhaps there : http://www.srgc.org.uk/smf/index.php?topic=1194.225
it could be 'Sheila Ann Germaney' virosed...
Title: Re: a virosed 'Katharine Hodgkin' ?
Post by: Ezeiza on February 26, 2008, 07:40:52 PM
Hi:
    That 'Katherine Hopkin' material was virused has been known for years but this is true of several Reticulatas. Virus in the foliage is highly evident.

    The images show unusual stripes but the emerging foliage will show unmistakingly if the plant has mosaic or not.

Regards
Title: Re: a virused 'Katharine Hodgkin' ?
Post by: ashley on February 26, 2008, 09:46:50 PM
Alberto,

So do you think that the converse is also true, i.e. that plants with apparently healthy foliage are probably not virussed (even if the flowers show some coloured streaks, as here for example)?
Title: Re: a virused 'Katharine Hodgkin' ?
Post by: biodiversite on February 27, 2008, 06:32:36 AM
moreover, iris viruses are specific or not ? I think for example to Tulipa platystigma witch is always infected when coming from Holland...
Title: Re: a virused 'Katharine Hodgkin' ?
Post by: Ezeiza on February 27, 2008, 12:45:04 PM
Hi Ashley:
             
               I wish things were different but in Iridaceae viruses show in the flowers and not in the folaige at times. There is a virus that affects Babiana, Sparaxis, Tritonia, Dierama, Watsonia, Freesia, etc. that shows as darker stripes in the flowers but no signs are seen in the leaves. It is highly infectious and would wipe the plants. There is at least one strain that passes through the seeds to new plants.

               Using high nitrogen, the leaves of many bulbs develop a dark green colour that masks the virus symptoms in the leaves.

Regards
Title: Re: a virused 'Katharine Hodgkin' ?
Post by: Maggi Young on February 27, 2008, 12:51:49 PM
Quote
There is at least one strain that passes through the seeds to new plants
AARRGH! Frightening prospect.
 Would you agree, though, that is is worth trying to take seed from most plants that one suspects with a virus, in order to get clean new stock?
How would the amateur grower recognise the particular virus which can be passed even through seed? ???
Title: Re: a virused 'Katharine Hodgkin' ?
Post by: Ezeiza on February 27, 2008, 01:27:04 PM
Hi Maggi:

              This particular strain was propagated in Southern England and the seeds were sown as "capable of reproducing the pretty markings in the flowers". The symptoms were darker color stripes at random along the veins.


              Of course, one can clean a particular species from "normal" viruses from seed. The problem is that when a plant shows visible symptoms it is already too weak to produce any seed.


Regards
Title: Re: a virused 'Katharine Hodgkin' ?
Post by: Maggi Young on February 27, 2008, 01:35:41 PM
Quote
  The problem is that when a plant shows visible symptoms it is already too weak to produce any seed.
Well, that's not always the case: we have quarantined plants of other genera and got good seed from them before destroying the affected plants and in the context of this thread, we have specifically done this with Iris winogradowii.
Title: Re: a virused 'Katharine Hodgkin' ?
Post by: biodiversite on February 28, 2008, 12:46:30 PM
Maggi, do you have photos of this infected Iris winogradowii ?
Title: Re: a virused 'Katharine Hodgkin' ?
Post by: Maggi Young on February 28, 2008, 01:01:08 PM
No, Bio, I regret I do not have such photos.
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