Re: HYB: genetic drift (was daylength vs temperature & bloom initiation)


From: "David G. Holm" <sherlock@amigo.net>

On 5 Apr 99, at 9:05, Linda Mann wrote:
 
> There is a perception that source of plant material affects the rate of
> acclimatization & the more similar the climate the better plants will do
> the first year or so.  Thinking that the older the cultivar, the more
> likely something like this would be, I bought ROSY WINGS from several
> sources throughout the country last year California, Nebraska, and Texas.
> They have grown in relation to when the arrived here rather than where
> they came from: California has done the best.

Linda:

If you were to repeat this experiment this year the results may have been 
different.  The "environmental" memory should not last more than a year.  If 
there were to be a consistent source plant location effect this would be 
interesting and should be investigated further.  It is known that certain plant 
biochemical components are influenced by environment.  Distinguishing 
between specific location effects vs atypcial growing effects on these 
compents would be interesting and complicated.  It would be complicated 
because creating certain consistent environmental conditions over time 
would be next to impossible.  Growth chambers are helpful but not the real 
world.

 
> Also, potatos certainly have been vegetatively propagated for decades -
> any evidence of genetic drift?

The only way "genetic drift" can occur is via a mutation.  There may be 
mutations occuring that do not result in any obvious visual plant change 
that may affect performance of the plant.  Accumulation of these mutations 
over several generations may be referred to as "genetic drift".  That is why it 
is very important that plant propagators, both field propagators or lab 
propagators, try to employ methods to verify they the cultivars they are 
producing and selling have not mutated.  In potatoes the seed crop is 
routinely rogued (sp?) and inspected to assure that mutations are 
eliminated.

Some cultivars are more prone to mutations and in some environments 
mutations are more easily observable.

Dave


Dave Holm
Professor of Horticulture (Potato Breeding)
Colorado State University
sherlock@amigo.net

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