Re: Re: CULT:Sports--anyone?

From: "Jeff and Carolyn Walters" <jcwalters@bridgernet.com>

> From: "William Stone" <wstone@volcano.net>
> 
> Not being a expert or any thing the oldest Sport I know of is in the Rose
> Family " Austrian Copper "  When planted it should grow to be a red rose
> with some yellow infusion, But if you get a sport of it,  It will be a
light
> bright yellow rose.  I believe the origin of this rose is traced back to
B.
> C.

Bill,

Actually, the shrub rose known as AUSTRIAN COPPER is a sport of the
naturally occurring species, Rosa foetida, which bears bright yellow,
single flowers. Thus, when yellow flowers appear on AC, as they frequently
do, it represents a reverse sport or back mutation to the wild type. I have
never seen an established AC on which this does not happen. It has occured
several times on my AC in the fifteen years or more that I have been
growing it.

>     I note this as it is a sport which takes in the whole plant and not
just
> one shoot.  

In fact, as I have observed it, the reverse mutation to yellow flowers on
AC rose bushes occurs, like most sports, with a gene change in a single
cell at a growth point, such as in a newly emerging cane or in a new branch
growing on an existing cane. After the mutation has occurred, every cell
resulting from further division of the mutated mother cell will carry a
replicate of the mutated gene, and thus the whole branch or cane when it
blooms will bear yellow flowers rather than red-orange ones. I think the
wild type is more vigorous than the AUSTRIAN COPPER mutation, and thus, if
the canes bearing yellow flowers are not pruned out the whole shrub will
eventually appear to revert to the wild type Rosa foetida. This does not
happen overnight, however. There are many AC roses in this area that
continue to bear red flowers and yellow flowers on separate canes year
after year. 
           
I believe a similar process occurs in irises that sport. Maureen
hypothesized a series of gene changes as being responsible for a sport, but
in most cases it is probably just a single mutation in a single replicating
cell at a growth point in the plant that is proliferated as that cell and
its descendants continue to divide. 

Jeff Walters in northern Utah  (USDA Zone 4/5, Sunset Zone 2)
jcwalters@bridgernet.com


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