Modeling bud break phenology in 'Chardonnay' grapevine using the chill overlap model framework
Bud break time in grapevines (Vitis vinifera) defines growth cycle onset, and is strongly sensitive to temperature. Delays during this stage can have impacts on the whole growth cycle, making it a key phenological stage. Changing temperatures, due to climate change, make the need for accurate models to predict phenological patterns increasingly relevant, potentially affecting vineyard management, establishment and adaptability. Chardonnay bud break data from Californian and Spanish wine regions were used to estimate chilling requirements, and the compensatory relationship of overlapping chill and heat phases during specific temperature accumulation periods. Considerable variation in day of the year observation data, and diversification of climates across locations, enhanced the performance reliability of the model, leading to more accurate predictions over different climates. Preliminary evaluation of the model yielded acceptable model performance. However, variation due to the use of different criteria to define phenological stages, differences in microclimatic conditions, clonal variability among vineyards and vineyard management practices may be important factors to be considered for further increasing model accuracy. The chill-overlap model provided a framework for predicting bud-break in grapes but there is a necessity for deeper analyses in order to develop a more robust global model.
Prats-Llinàs, M.T., Pope, K.S., DeJong, T.M. and Marsal, J. (2018). Modeling bud break phenology in 'Chardonnay' grapevine using the chill overlap model framework. Acta Hortic. 1229, 157-162
chill requirement, heat requirement, chill portions, heat units, endodormancy, ecodormancy