Modeling Temperature Requirements for Rest Development in Cornus sericea1

Abstract

Temperature requirements for rest development were determined and used in developing an empirical model for predicting rest development in terminal vegetative buds of Cornus sericea L. Vegetatively mature plants were exposed to 5° to 20°C under a 12-hr photoperiod (SD) in growth chambers, and depth of rest was measured by days to terminal bud break at 20°/15° (day/night) under a 16-hour photoperiod (LD). Rest development proceeded only after vegetative maturity was attained. Time from vegetative maturity to maximum rest decreased with decreasing temperature. Rate of rest development at all temperatures varied and was dependent on growth stage. The annual growth cycle and rest development were described and quantified by a degree growth stage (°GS) model. Using temperature and accumulating °GS, the model predicted maximum rest within 2 days in both years.