> The September 27, 1999 "Feedstuffs" contains a long
> article entitled "GMO corn has impact on feed consumption."
> ....Table 6 reports "Percent yield drag" for several high-oil
> corns tested in Iowa State University....
The high-oil corn varieties currently marketed are not transgenic or
genetically engineered in the sense usually conveyed by the the term "GMO."
They are derived from a long-term recurrent selection project at the
University of Illinois, a type of "conventional" breeding.
What is unique (and risky) about most varieties of high oil corn is the use
of a topcross pollinator to directly insert the trait into the grain right
in the farmers field. This allows the use of agronomically inferior
varieties of corn as pollinators, the seed of which is mixed with an
agronomically sound, intentionally sterile hybrid. The extreme,
grain-trait-contributor varieties, if ploughed into the conventional
pure-line breeding method, produce many undesirable characteristics.
Topcross is an innovative attempt to have-your-cake-and-eat-it-too, to
obtain a useful grain trait, while avoiding the agronomic drag that it (or
associated genes) would cause in regular corn breeding. Also, this approach
has some big logistical benefits in terms of reliable seed supply and
time-to-market for new varieties.
> I share this data not to question the possibility that high-oil
> varieties can or do deliver net economic benefits, but to simply
> reinforce the fact that most modifications of plants that result
> in a substantial change in the content of some desirable, basic
> (or newly introduced) component of the plant come at some
> physiological cost to the plant, and that yield drag is
> one manifestation of such costs.
But high-oil corn is not a good example. In this case, yield-drag (for want
of a better term) is mostly caused by failure to achieve adequate
pollination of the sterile hybrid in the mix. Sometimes environmental
factors cause the high-oil pollinator to flower at a slightly different time
than the sterile grain parent, reducing yield. It is not a subtle
physiological effect.
> As a result, plants can experience unanticipated
> developmental or immune system problems in response to
> certain combinations of environmental factors and pest
> pressure. Understanding and overcoming the sources of
> such instability in gene expression remains a major,
> ongoing challenge for genetic engineers and seed companies..
Most of this action takes place inside the seed company before the new
variety is released. Trying to do anything new genetically (transgenic or
not) produces 99.9% garbage. Only a tiny sliver of truly better (we hope!)
products get through all the internal screening.
IMO both the seed industry and the small-farmer community have a lot to gain
in the decommodification of grain. I think the development of specialty
grain products, perhaps by the topcross method, or by regular breeding is a
good thing. The unique challenges that some of these new technologies
create, may provide good niches for particular environments and special
kinds of TLC that smaller farmers can provide.
Dale
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