This is doubtful. The pressures in cultivation are likely to be
very different. Different pests, different levels of light, different
competing plants, different climatic variations. I doubt the pressures in
cultivation resemble the selective pressures in the wild, except perhaps
for plants grown in an outdoor bog that come from your locale. Even
there, the plants competitors and pests are likely to be different.
> Ok, here's what I meant, Sorry for being less than clear on this
> important subject. If you take a small number of individauls
> out of a given population and sexaully progate them you will get
> new population that shows marked differences. This is because
> the original population has a number of "dominant" traits that
> may be shown in all or most of it's members. Now, all the plants
> will have some less "dominant" traits NOT shared by all members
> so when these are seperated from the rest these traits come become
> dominant, or more visible (to the genetic eye, if you will) of
> the new population. This is not evolution nor is it a loss of
> much diversity, just a re-shuffling of the deck. In this way,
> my population of plants will become more different since a much
> different % of my plants will have certain characteristics than
> the colony they came from. As will John's plants in Arizona be
> different than mine and the original population. Ahh, getting
> that cleared up feels so good.
I think we should be a little careful using terms like dominant
in discussing genetics. Dominant has a very precise meaning; plants
homozygous for a trait determined by a dominant allele will be identical
to plants heterozygous for that allele, for that trait. I think what is
referred to above is shuffling of mostly recessive alleles, which will
create new combinations of genes, and thereby increase diversity.
However, keep in mind diversity is increased only if the original parents
are also kept going. Whether this Rincreased diversityS is actually
desirable in terms of reintroducing plants into the wild is debatable. As
for the plants grown in Arizona being different from plants grown
elsewhere, that depends on whether the original parents were different
(if you start with plants from the same supplier, that were propogated by
cutting or tissue culture, then youUve started with genetically identical
plants). Also, who really knows what the chief sources of selective
pressure are in cultivation? It may be that your greenhouse and my little
fluorescent light set up are really selecting for the same traits, even
though they seem very different.
>
> Anyway, it would probably take a very long, long time before
> evolution makes cultivated plants unsuited for the wild (not
> counting hybrids, sports and other wierdies like that; and
> natural selection would make fast work of them anyway.) Now, if
> we can only ensure that there will be somewhere wild in a couple
> thousand years!
Not necessarily true. An extreme example: You dig up 1000 plants
of species X and take them home. One of them survives because it has the
particular genetic makeup to survive your conditions. In one generation,
you have selected for a plant that grows best under your conditions. That
plant may or may not be suitable for reintroduction at some future date.
Perhaps it would have died out before producing any progeny if left in
the wild. This is obviously an extreme scenario, but more subtle
variations might be happening with our collections. We pollinate a
particular species of plant, and plant the thousands of seeds. In many
cases, we only have room to keep a few of the seedlings, and therefore we
keep the healthiest, or biggest, or whatever. A very few generations of
this and we could end up with a very homogenous population of that
species.
My point remains the same. Cultivation of these plants is great
fun. But cultivation is a poor substitute for preserving wild
populations.
Wayne Forrester