Re: Yet More on Genetic Engineering

Recently, it was commented that:

"Until the start of GE [genetic engineering] all plant breeding _was_
natural, in that it never went outside the bounds of natural
possibility. Any of the crosses that were carried out could conceivably
have happened without any human intervention. That they didn't, was
often because the particular species involved did not normally occur in
the same territory, but if they were introduced to one another by any
circumstance (not always planned human intervention) it was still
perfectly possible for nature to arrange a marriage."

It should be noted that these comments are accurate (up to a point) only
for *primary* hybrids. That is, hybrids between two species. The
comments are not true for complex hybrids as they are known in many
plant groups from aloes to zinnias and everything in between.

In orchids, artificial hybrids have been made that incorporate up to 7
different genera. Even if the 7 genera all occurred in the same area, it
is highly unlikely that "nature" would ever produce a 7-genus
intergeneric hybrid on its own. Likewise, cacti enthusiasts are now
producing multigeneric hybrids of large, brightly colored epiphytic
cacti that are beginning to rival those of orchids in genetic
complexity. And I have read (but no longer remember the source) that
complex multigeneric hybrids have also been produced in the grass
family.

Within the last few years, very complex hybrids have been produced in
the genus Aloe. For example Aloe 'Cha-Cha' has the following parentage:
(A. descoingsii x A. jucunda) x ((A. descoingsii x A. parvula) x A.
boiteaui). Aloe 'Grande' has this bloodline: (A. descoingsii x A.
parvula) x (A. albiflora x A. bellatula) x (A.descoingsii x A. parvula).
It is extremely doubtful that, even if all the parent species were
growing together in one area for millenia, nature on its own would ever
produce an Aloe 'Cha-Cha' or an Aloe 'Grande.'

Looking at orchids once again, many of the more complex breeding lines
are highly sterile and it is only through extremely artifical and
advanced techniques that any viable progeny are produced. For example,
in Paphiopedilum, the seeds of complex breeding lines must be sown at
the green pod stage (when they are still embryos) on specialized sowing
media using workers who are highly skilled in modern laboratory
techniques. Of course, embryo culture of complex breeding lines that
would otherwise produce only inviable seeds is a wholly "unnatural"
process with no counterpart in the natural world.

Moira's comments focus on just one factor that prevents hybridization
(geographic separation). However, there are many other factors that
preclude hybridization amongst closely related plants occupying the same
geographic area (such as blooming at different times of the year, having
different pollination syndromes, having different shaped flowers so
that, although they may share the same pollinator, the pollen is placed
on different parts of the pollinator's body, etc.). Again, hybrids
between species that exhibit such isolating factors are extremely rare
in nature and their production in cultivation is an "unnatural" process.

I recently attempted to hybridize two Erythrina species. One species is
native to Florida and blooms in the spring and the other is non-native
and flowers in the summer. To hybridize them I had to store pollen from
the spring-bloomer in the refrigerator so I'd have it available during
the summer. I'd like to see nature do that little trick! *SMILE*

My attempt at hybridizing Erythrinas seems to be every bit as
"artificial" as genetic engineering since to cross these two Erythrinas
I needed to bring them together in the same garden (that required a
highly artifical and "unnatural" transportation infrastructure...or are
airports, airplanes and modern postal service part of nature?) and I had
to have refrigeration (which means modern technological inventions need
to exist as well as the necessary electric power grid to run those
inventions...or are kitchen appliances and power plants part of
nature?).

R. Xavier Osorio
http://www.wfnirvana.com
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