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Re: reply to Wytze on corn pollination



Hi Dale,
I think that we should make it clear that the plants double fertilization has an important impact. In plants the pollen fertilizes both the egg cell and  the endosperm nucleus to produce a triploid. In corn and many other grains the endosperm makes up a major part of the final crop. So unlike the embryo whose _expression_ is delayed to the next planting the endosperm  expresses the transgene  in the the immediate generation  fertilized by  5 plants in each 1000 plants produced. Those 5 transgenic plants  may fertilize as many  as 100 or more  of the  individual cobs on plants in their immediate vicinity  or for that mater a higher number. This spread of transgenes is independent of selection and effects the corn crop in the generation of the planting. Even more impact may be seen in wheat.
The five transgenic corn plants in a thousand  can and probably does   cause an unacceptable  pollution of the harvested crop. However, the bureaucrats can fall back on the  "official" notion that regulations of their making cannot allow endosperm to be polluted by transgenes from pollen. The bureaucrats and  Dale  never seem to  worry about such things as double fertilization and nature..
Sincerely, Joe

Dale Wilson wrote:
Joe and wytze,

wytze wrote:
  
if a 0,5% gmo treshold level is set for sowing seed, than how big
is the chance that the resulting harvest will consist of more
than 0,9% gmo's? Is the assumption correct that a 0,5% gmo content
in seeds will remain 0,5% at harvest?
      

Joe wrote:
  
I think that the 5 gm corn seeds
per thousand  would stay in equilibrium in the absence of selection.
However, with selection from, for example,insect pests with Bt corn
or roundup from roundup ready corn it would not take long to populate
a field with GM corn volunteers.
    

Unless one were trying to select for the transgene, it is unlikely the
transgenic fraction would increase in cultivated corn.  The reason Bt
would not increase (within that generation), is that pollen is
generally shed before the plants start to break off from ECB tunneling.
 Now, if you were saving seed from the crop year after year, you might
gradually and inadvertently select for the Bt gene.

Dale

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