From: LariAnn <AROIDIAN at worldnet.att.net> on 2009.09.06 at 18:01:41(19947)
Peter,
Interesting thoughts - I would think that if a variety, cultivar or
hybrid has stabilized to such an extent that it comes true to seed and
functions as a species, as you described, then wouldn't that mean it has
actually become a new species, in effect? Isn't that one way that
speciation manifests itself? Whether it took 100 years or 1000 years,
that should not make it any less of a new species, should it?
Regarding the barriers to crossing, all of the barrier factors you
mentioned, with the exception of genetic incompatibility, are factors
that can be overcome by judicious hybridization work. I can preserve
pollen to make up for flowering time differences, I can grow the plants
together even though in habitat they may be very far away from each
other, I can do my pollinations at different times of day in order to
find the right time, and, of course, I can learn how to be the right
pollinator myself. What I cannot do in traditional hybridization is to
overcome a genetic or biochemical barrier to the production of viable
pollen or ovules, or to the growth of the pollen on the stigma. However,
as a result of my work, I've done some hybridizations that I actually
thought were genetically impossible. The most remarkable example is my
hybrid of A. odora and A. reginula. Predictably, the progeny are
sterile, but the plants are beautiful. Perhaps, in time, the plant may
stabilize genetically and manifest fertility.
Kind regards,
LariAnn
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