Phenological response of spring wheat to timing of photoperiod perception: The effect of sowing depth on final leaf number in spring wheat

• Non-constant rate of development in germinated wheat (Triticum aestivum) seeds prior to Pp perception observed.
• Two mechanisms are proposed to explain this unexpected results.
• We built on the molecular-phenological framework of Brown et al. (2013) and propose a mechanism based on vernalisation genes Vrn1, Vrn2, and Vrn3.

Wheat phenological modelling literature suggests final leaf number (FLN) targets of wheat (Triticum aestivum) will be set only once daylight is perceived and will be based upon environmental and cultivar-specific genetics at that time. Development is thought to proceed relative to thermal time regardless of light perception prior to emergence. Modelled predictions of final leaf number (FLN) and thence anthesis are based on this mechanism. Results did not support this hypothesis, and we suggest and alternative hypothesis based on molecular interactions between vernalization genes Vrn1, Vrn2 and Vrn3.