Are there "Identical Twin" plants?

Cereoid CEREOID at prodigy.net
Sat Dec 16 18:08:13 EST 2000


Okay George, you've led us on long enough and you are starting to come
across as a troll.

Its time for the bottom line.

What is your point?


"George Hammond" <ghammond at mediaone.net> wrote in message
news:3A3BE786.5235C70 at mediaone.net...
> Wayne Parrott wrote:
> >
> > George Hammond wrote:
> >
> > > GH:  You've totally missed the point. I DON'T WANT TO CONTROL
ANYTHING.
> > >      What I want to know is, what is the Standard Deviation of plant
> > >      growth in the "real environment" when we are talking strictly
about
> > >      a crop of geneetically identical plants?
> > >        Now, somebody in agriculture must KNOW the answer to this, say
> > >      for potatoes, or onions or some other asexual crop plant.
> >
> > It depends on the variety and on the trait, and it depends if you are
talking
> > about the SD within a field or between fields.  For something like
flower color,
> > the SD would be close to zero.
>
> GH: Right, I understand that.
>
> > For something like height or yield, it would
> > fairly uniform within a field (barring spots which are overly wet/dry,
or
> > otherwise inappropropriate),
>
> GH: YES, this is what I'm talking about, "gross overall size",
>     I'm NOT concerned with "specific traits".
>       There is such a thing as a "growth curve" for
>     ALL plants and animals and the "plateau" of this
>     curve represents what we call "maturity", or
>     "terminal growth".
>       However, there is reason to believe that there is such
>     a thing as a "theoretical growth curve" for any given
>     genetic species, and that in fact, since a large cloned
>     plant population has a "terminal growth variance"; that very
>     few plants EVER achieve this "theoretical growth curve".
>       Would you agree with this speculation?
>
>  but could be quite large between fields, depending
> > on how distant they are.  Breeders generally call this genotype x
environment
> > interactions.  Genotypes are known which are more stable across
environments than
> > others.  In the end, the SD is difficult to predict without measuring
it.
>
> GH:  Yes, it is the "between fields" SD that I am talking about.
>      You apparently agree that such a thing exists and can be
>      measured.
>
> >
> > Keep in mind that plants need not reproduce vegetatively to be
genetically
> > identical.  Hybrids from inbred parents (as in a field of corn) are
genetically
> > identical.  So are inbred plants (as in a field of soybean) and
apomictic plants
> > (as in dandelions).
>
> GH:  yes, this is most interesting.  One researcher pointed
>      out that laboratory mice have been purposely inbred for
>      thousands of generations, so that within a strain, they
>      are virtually genetically identical.
>        My question would immediately be "how much of a growth curve
>      variance" could these genetically identical mice manifest.
>
>      You see; the question here is nothing but the old NATURE-NURTURE
>      discussion.... with a NEW TWIST.
>        It is now hypothesized that higher animals, and probably plants,
>      have something which we could call a "nominal maximum genetic
>      size", and that in the natural environment, very few IF ANY
>      individual specimens EVER ACHIEVE IT.
>        The object then, becomes the task of PROVING THIS CONJECTURE.
>
> >
> > Because of the variability that a given variety of genetically identical
plants
> > exists, seed companies generally avoid having a central breeding
station.
> > Instead, they depend on having multiple breeding stations, each one
breeding for
> > the immediate vecinity.
> >
>
> GH:  I see.  BTW, on the question of "nominal maximum genetic
>      size", I think it should be mentioned that "giant vegetables"
>      are a NATURE (genetic) effect and not a NATURE (environmental)
>      effect.  Seeds for "giant vegetables" have an altered "cell
>      division gene" that makes the cell-division much more rapid
>      and that accounts for their giant size.
>        This is further evidence, that for any GIVEN GENETIC SPECIES
>      there is such a thing as a "maximum genetic size" of
>      the adult.
>
> --
> BE SURE TO VISIT MY WEBSITE, BELOW:
> -----------------------------------------------------------
> George Hammond, M.S. Physics
> Email:    ghammond at mediaone.net
> Website:  http://people.ne.mediaone.net/ghammond/index.html
> -----------------------------------------------------------







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