> How important is rapid genetic turnover to farmers... is rapid genetic
> turnover a fixation of the ag. research complex that is out of line with the
> goals of producers...
I believe the term is "hybrid vigor". Genetic line "A" (producing 35 bu/ac)
is crossed with genetic line "B" (producing 31 bu/ac) to produce a hybrid
line "C" that produces 38-40 bu/ac.
Unfortunately, such a cross may also make hybrid "C" exceptionally susceptible
to blight, or weed competition, or soil compaction. Livestock, say chickens,
may produce considerable quanties of meat on the breasts or legs, but their
bones may be so brittle that they break when the birds try to stand.
Check the ads for seed corn in any conventional farming magazine. The
seeds can produce exceptional yields (corn, soybeans, wheat, sorghum, etc).
But that productivity drops if the plants have to compete with weeds. The
productivity drops even more if disease breaks out, as all the plants in the
field have the same genetic traits (or lack of traits).
> How does this drive for genetic turnover affect the prospects
> of the perennial cropping systems being touted by some as the future of
> agriculture ?
Most of the plants or animals in "perennial" cropping systems will - over
time - segregate themselves into separate, more-or-less pure, genetic lines.
Over time, the hybrid vigor will be lost. There are fewer hybrids in
perennial crops than in artificially-induced annual crops.
The issue is whether we humans want artificial, monogenic crops with
lots of yield but requiring considerable human intervention; or do we
want less artificial, polygenic crops with lower yields and less
> Do the benefits out weigh the flaws ?
I don't have the answer to that. The question goes beyond genetics,
agriculture, and economics. It stabs at the heart of our present and
Fayetteville, Arkansas USA