Theodoros:
Dr. Ron Barnett of the Quincy Agricultural Research and Education Center is
the developer of the Florida 302 wheat. I'm sure he does not know about
DSSAT/IBSNAT coefficients for wheat, but if you approach him right, he may be
able to give you data on critical phenological dates for specific plantings
in northwest Florida, as well as point you to the right weather data sets so
you can solve them.
That's the extent to which I can help.
Good luck,
Ken Boote