Current models simulate phenologica

Current models simulate phenological development by
calculating the durations of a sequence of phenophases
between observable states of the mainstem apex (seedling
emergence, double ridges, terminal spikelet, anthesis) in
response to temperature and daylength (Slafer and Rawson,
1994). This description has only a tenuous connection to the
mechanisms of timing of apical stages. However, the
development of the apex can be better decribed as the
sequential appearance of primordia and their later differentiation
into the structures they will become. The present
model has the advantage in that it predicts the duration of
phenophases based on the number and rate of appearance
of primordia, as the timing of anthesis depends on the
number, and rate of appearance of leaves