Colleagues: In the subroutine NFACTO of CERES-Wheat, there is an algorithm
for the calculation of a modified Zadoks scale (ZSTAGE) based on the 1-5
development scale (XSTAGE) used in CERES Wheat. (By modified, I mean that
values are calculated in 0-9 range rather than in the 0-99 range, as in the
original Zadoks scale.) The value of the ZSTAGE is used to calculate TCNP,
the critical N concentration. My concern is about the values of the Zadoks
scale used to develop this algorithm. For example, an  XSTAGE of 1 goes
from emergence to terminal spikelet initiation. What are the corresponding
values of the Zadoks scale? Emergence is at 1 (10). The value for terminal
spikelet initiation from the algorithm is 2 (20) which corresponds to the
beginning of tillering from the Zadoks scale. Does terminal spikelet
initiation occur at the beginning of tillering or later on just before stem
elongation (jointing, at a Zadoks scale of 3(30))? Similar comments can be
made about the other beginning and ending values of the other Zadoks scale.
Thanks for your help.
        Albert Weiss