A new framework for modelling seed germination and seedling tillering of
winter wheat in the field
AbstractSeed germination is regulated by multiple environmental cues and
understanding their relationships is critical to planning seed drilling
and subsequent seedling management. We develop a new framework by
viewing the metabolic reactions associated with seed germination as a
moving event in a physiological dimension to simulate seed germination.
Fluctuations in environmental cues and genetic heterogeneity of seed lot
make the metabolic reactions in each seed uncertain, and we use an
average germination rate to describe the average metabolic reactions and
a dispersion coefficient to describe the genetic heterogeneity. We apply
the model to winter wheat seeds drilled at different dates in plots
under different soil water contents and prove that the model accurately
reproduces the time course of germination in all treatments. We found
the average germination rate increases nonlinearly with temperature in
the base-suboptimal temperature range, and there is an optimal soil
water content where the germination rate peaks due to soil anaerobicity.
Our model can be fitted to field data using temperature and soil water
content to describe the trade-off impact of soil water on soil
anaerobicity and imbibition, whereas the difficulty of obtaining
accurate water potential and oxygen measurements makes this difficult
with the hydrothermal time models.