03-02-2004, 04:16 PM
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Pollination question
(Becca) wrote in message m...
Sherwin Dubren wrote in message ...
I have often seen descriptions of certain fruit trees, specified as self
fertile, that their productivity can be increased by having two or more
trees of the same variety nearby. I can't understand what is the
genetic difference between pollen from the same tree and pollen from an
identical species nearby. Is there some other mechanism at work here?
Sherwin Dubren
Due to Google delay this post may show up long after better & more
relevant statements have been made.
Hey Sherwin,
Basically, you and your wife (or ex-girlfriend, potential mate, etc.)
are of the same species. But you clearly still have genetic
differences (assuming you don't have a "domestic partnership" with an
identifcal twin).
Generally, offspring with more genetic diversity do better due to a
phenomenom called inbreeding depression.
However, plants are a little more crazy in their mating requirements
than humans (maybe it has to do with being rooted in one spot?).
Plants can fertilize themselves within the same flower, they can swap
pollen between flowers on the same plant, they can swap pollen between
clones, and they can swap pollen between two genetically different
plants (out-crossing - like human mating).
For most organisms, out-crossing leads to greater offspring success.
More genetic diversity leads to better ability to adapt to
environments. Think of the few health problems with mutt dogs
compared to the breed specific health problems of pure bred dogs.
The same is true of the trees. My guess is that the trees can
self-fertilize, but they usually have some sort of inbreeding
depression. This means you get less fruit if your trees are selfing
than if they are being fertilized by other species.
bleh! I'm just jamming along on the species vibe, while totally
ignoring the grafting aspect. I don't know what to tell you about
that...
~becca
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