-----. In other words,
>the "superior" strains will have 10% (or 5% or 7% or
>whatever) more of whatever nutrients it naturally
>possessed. That part is pretty easy - basic selective
>breeding for highest nutient content.

!0 % of what?
i can't follow you very well , if we have more of all the nutrients, the
food is becoming more dense, concentrated , or does it include more water
too ? In that case i see that  moderns vegetables and fruits are much
"bigger than their wild couterpart..
In the case  they  will be richer in nutrients for the same weight, it just
don't fit with my observation that  wild foods are allways denser than their
domestics outcomes. They are always in my experience more satisfying and
nourishing than  their  inflated offsprings.
what you are saying suggest that it is possible to improve upon nature . In
nature 's balance everything is always at its fullest potential, in human
made unbalance we got richer element at the detriment of something else.
 this something else is often recognised later on and   is seen as a new
problem that render the intervention of humans even more necessary to fix
it)
It  will be way more "intelligent " to not disturb in the 1st place ( by
using the word intelligent,  i take advantage to throw an additional
comment to the thread about the so called higher  technological intelligence
of Japaneses who are in fact in a bigger environmental mess than other
occidental countries)
that 's the illusion  we are in , we are living in a century of seeming
abondance of food and yet most of the peoples in the world are starving for
real nutrients  (occidentals rich people included)
I let scientists to their follies and go back to my garden... Where the
plants grow from their own accord and joyously  reproduce themselves on
their own. HOpe i can save enough  real seeds to help us to awaken from this
dream of improvement upon nature.
jean-claude