Re: CULT:Mosiac Virus

wmoores wrote:
> 
> > > >
> > >    How do you tell the difference between mosaic virus and the
> > > striping , stippling  or flecking in MING DYNASTY,
> > > HUMORESQUE, OFF BROADWAY, many arilbreds and some with
> > > broken color?
> 
>     Dallas Patterson wrote:
> 
> > Some viruses alter the genome of the Iris progeny, i.e. re-writes a
> > portion of the genetic code which governs the form and development of
> > the organism. Tulips, Iris, and many other plants have distinctive
> > color patterns as the consequence of such genetic alterations caused
> > by viruses. Once a plant is conceived with the altered genetic code,
> > genome, no further virus infection is required to produce the special
> > color pattern.>> The color pattern is fixed in the genetic code, with or
> > without the presence of any viruses>>
> 
>   If the color pattern is fixed w or w/o viruses, why worry?
> 
>   Is ti mosaic virus that causes the markings in the above cultivars?
> 

The answer depends on the meaning of your question. MING DYNASTY,
HUMORESQUE, OFF BROADWAY, and others ARE NOT exhibiting the marking
patterns because they are currently infected by a mosaic virus. They ARE
exhibiting the marking patterns because they have inherited genes which
cause such marking patterns. The genes which cause such marking patterns
may or may not have been altered by a mosaic virus infection or other
virus infection in a pod parent, pollen parent, or other ancestral
plant. The genes which cause such marking patterns may have been altered
by common solar radiation (i.e. sunlight), chemical exposures, viruses,
or other agents in a pod parent, pollen parent, or other ancestral
plant.

> >. These viruses make the organism ill, just
> > as people are made ill by the influenza viruses.
> 
>     The above cultivars I mentioned are not ill.  They have been
> around for years and need no pampering.
> 

That's correct. Their markings are the result of their genetic
inheritance, and not a current virus infection. 

Nonetheless, that does not mean they are virus free, either. Just like
their self colored cousins, the unusually marked Iris can be infected
with a mosaic iris without exhibiitng the symptoms. In such cases, their
markings have nothing whatsoever to do with the current presence or
non-presence of a virus infection.

Tulip growers faced the same problem. Tulip growers have sometimes had a
problem exporting certain tulips with broken colors. The broken colors
were caused by a virus in the parent plant/s. Although the children
plants were not necessarily infected by the virus which caused the
broken colors in the genetic inheritance, in actual fact, many of the
plants were infected by the virus because of their culture. In other
words, the soil in which they were grown and the plants where they were
grown transmitted the damaging viruses. Today, these broken color Tulips
may or may not be infected by a damaging virus, depending on the
circumstances of their culture, and not because of their genetic
inheritance. 

Again, the inherited color pattern is not indicative of a virus
infection. Only current and abnormal changes to the normal coloring of
the Iris is an indicator of a possible virus infection. 

Also, the absence of abnormal coloring in the foilage and blossom does
not necessarily mean any plant is virus free, either, no matter what its
coloring may be. Plants which are resistant to a particualr virus may
exhibit no symptoms as a result of its virus infection, yet the infected
plant remains capable of transmitting the virus to less resistant
plants.

> > 1) as "Light and dark green mottling and yellow stippling of foliage.
> > Mottling and stippling are especially prominent on young leaves.
> > Mosaic is most severe on bulbous iris and some rhizomatous species.
> > Iris germanica and its hybrids are only slightly stunted and sometimes
> > exhibit no symptoms...Oncocylus iris and their hybrids can be severely
> > damaged."
> >
>   I have seen light and dark green mottling only on a few Louisiana iris leaves not on
> the same cultivar and not every year.  It doesn't seem to spread to the entire patch.
> I have never seen  any mosaic virus in the flower of any LAs.
> 

I certainly hope not.

> > Exposing Iris to tobacco, Nicotiana plants, or infected bulbous and
> > rhizomatous plants is evidently a risky proposition from the
> > standpoint of disease control among Iris.
> 
>    I spoke of the tobacco juice in jest, but the replies have brought
> up interesting information, though I am not convinced the flecking
> in the blooms is any kind of virus.
> 
>   Walter Moores
>   Enid Lake, MS USA 7/8

Inherited color patterns like the normal flecking in the blooms are
unrelated to the current presence or non-presence of a virus.

Yes, the tobacco juice was humor, but the funny thing is that
grasshoppers love tobacco so much they're a tobacco pest <grin>. 

"The most common disease, insect, and weed pests were arbitrarily
identified as those affecting 50% or more of the fields planted in a
given crop...Tobacco fields reported Tobacco hornworm, Tobacco budworm,
Grasshopper, and Aphids as the most common insects. (Kentucky Integrated
Pest Management, Annual Summary 1993, University of Kentucky Integrated
Pest Management
<http://www.uky.edu/Agriculture/IPM/sponsprj/annsum93.htm>."

Ever picked those fat tobacco hornworms out of a tobacco patch??? Ever
watch grasshoppers chew tobacco? Yuck!!!

Dallas Patterson
nye@fidalgo.net

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