Joe,
Regarding the most significant point double fertilization you seem to
be misunderstanding or just obfuscating the main point. In single
fertilizations or plants with little or no endosperm the transgenic
portion of the seed is limited to an immature embryo making up a
minute portion of the seed.
Single or double fertilization, if the ovule is fertilized with a
pollen grain containing a transgene, the whole embryo is transgenic.
In a soybean, for example, the embryo constitutes pretty much the whole
seed (now, this may be a moot point for soybean because generally the
flower is self-pollinated before opening).
In corn, the embryo (including the scutellum) is very large, making up
a substantial fraction of the kernel. In any case, if the corn ovule
is fertilized by a transgenic pollen grain, both the embryo and the
endosperm will be transgenic. The plant that arises from the kernel
will be transgenic, and if the kernel is tested, it will test
transgenic.
The GM plant with every cell containing
transgenes will not appear until the following season of growth of
the seed.
Except for the pericarp (hull) every cell in a kernel of corn arising
from a transgenic pollen grain that landed on a conventional
(nontransgenic) corn plant, will be transgenic. It is transgenic
through and through. Double fertilization is beside the point.
In
grain of the endosperm rich crops a large portion of the seed is
triploid endosperm containing transgenic cells. So in the crops
lacking endosperm the GM content of the crop is heavily laden with
transgenic material in the generation of the fertilization.
Well, yeah. And that is also the case in endospermic seeds.
Endospermic or non-endospermic, a seed fertilized by a transgenic
pollen grain will be transgenic through and through.
Joe, I don't understand what we are disagreeing about. I don't think
we are genuinely disagreeing about anything. Nothing of substance
anyhow.
The point you made about GM detection in kernels is strange to say
the least.
It is important if you are trying to sell grain into a market that
demands a certain maximum GMO contamination level.
The food
standards for GM content are not set for number of transgenic
kernels but for transgene content in the food!
If 5% of the kernels are transgenic, then the tortillas you make from
it are made from 5% trangenic corn. This doesn't seem very
complicated.
Again it is very unwise to
pretend that transgenic endosperm does not count in grain crops!
This is some sort of straw man argument you have cooked up. I am not
claiming that at all.
Farmers selling into markets that demand non-GMO corn need to look at
this on the basis of fraction of kernels contaminated. This is not
only the simplest way to look at the problem, it relates directly to
how seed and grain is tested.
Dale
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