Modeling bud development during the quiescent phase in red-osier dogwood ( Cornus sericea L.)

Abstract

Stages of bud development during the quiescent phase were numerically expressed by a degree growth stage (° GS) model. This phase extends from the end of rest (315° GS) to spring bud break (360° GS). This study determined temperature effects on bud development at different developmental stages during the quiescent phase. Results were used to develop a model for predicting daily bud development and spring bud break. At monthly intervals during the quiescent phase red-osier dogwood ( Cornus sericea L.) plants were exposed in growth chambers to temperatures of 5–20°C and a 12-h photoperiod. Plants were placed in a greenhouse at 20/15°C day/night temperatures and a 16-h photoperiod, and bud development evaluated on the basis of time required for terminal vegetative buds to break. Bud development increased with increasing temperatures, from 5 to 20°C, and with increasing bud development from 315 to 360° GS. In two years of study a model was developed, which used bihourly temperatures and accumulating ° GS to predict daily bud development and spring bud break within three days.