The problems with converting Zadoks growth stages to DSSAT growth stages emerge only before anthesis, as far as I can see. After anthesis, both the Zadoks and DSSAT stages describe the various filling stages of the kernel. Before anthesis, however, the Zadoks stages track number of leaves and tillers visible in the field, whereas the DSSAT stages define basically the daylengt sensitive period. One way to relate both scales would be (see the work of e.g. Miglietta for this): - final leaf number depends on the daylength at emergence and the latitude of the location where the material was domesticated or bred; - the rate of leaf emergence is a function of the ambient temperature; - the number of spikelets per spike is related to the time between double ridge and terminal spikelet This model makes some gross assumptions, but should be helpful in converting things. Good luck, Anne Elings