EVALUATION OF FROST RISK IN APPLE BY MODELING CHANGES IN CRITICAL TEMPERATURES WITH PHENOLOGY
Frost damage is a major concern in fruit-producing regions. Quantitative assessment of the risk of frost damage is important in selecting orchard sites and in the installation and operation of frost control tools. The risk depends mainly on frost hardiness and minimum temperature. We constructed a model of spring phenology from bud break to petal fall of Fuji apple, analyzing the effect of chilling and forcing temperatures on bud development. By curve-fitting the relationship between growing degree-hours (GDH) and critical temperatures of the buds, we expressed the changes in frost hardiness with development as a function of predicted GDH. We investigated the springtime changes in frost hardiness (Tc) and daily minimum air temperature (Tm) during 1977-2009. Taking into account the difference between plant and air temperatures and the local diversity in Tm, we predicted that frost events would occur on days when Tm-Tc<3°C. The predictions agreed well with observations: the lower the value, the severer the frost damage. These models of spring phenology and frost hardiness will be useful not only for assessing the present risk of frost damage from historical temperature records, but also for predicting the future risk from simulated temperatures.
Asakura, T., Sugiura, H., Sakamoto , D., Sugiura, T. and Gemma, H. (2011). EVALUATION OF FROST RISK IN APPLE BY MODELING CHANGES IN CRITICAL TEMPERATURES WITH PHENOLOGY. Acta Hortic. 919, 65-70
Malus ×domestica, phenology model, frost hardiness, bud break, leaf unfolding, full bloom