Dear Frits
Besides the recorded phenology stages in field, I calculated
that dimensionless DVS used by Wagenningen group, through
accumulated temperature devision to the whole needed to a
special stage.
but the problem is still on, It seems to me that to have a
comparision of simulated phenology with observation, one has
to have an anatomical recording phenology sampling.
Terminal spikelet is not a sort of  shape that we walk in the
field and say we are at this stage or not, but it is more easy
to find that how many true leaves we have on a plant scale.
 
I wonder if anybody else faced such a problem and found a way?
Regards
Mohammad