Testing a model of early season temperature effects on apple fruit growth.

摘要

A growth model describing early-season temperature impacts on the final size of 'Harrold Red Delicious' apple fruits, developed using data from controlled environment studies, was tested using independent field data. The model simulates changing developmental temperature responses by transfer of tissue between two conceptual compartments with different growth dynamics and temperature sensitivity. Growth within the first compartment contributes to setting a potential size, which is used to reflect early-season temperature differences. The model fitted the original data well. The model was re-parameterized to use daily temperature means, and used to predict diameter of 'Royal Gala' apples growing in Hawke's Bay, a major production region on the eastcoast of the North Island, New Zealand. The change of cultivar was required by lack of suitable field data for 'Delicious'. This also meant that re-estimation of a selection of model parameters using a subset of the data was required. Parameter selection schemes were based on two different transferability hypotheses. The re-fitted model described seasonal differences in Hawke's Bay satisfactorily but overpredicted size in Canterbury on the east coast of the South Island. The results suggest that the model is adequate for analysis of seasonal temperature effects on fruit size, and for coarse-scale analysis of regional climatic effects. It has been recently implemented within the CLIMPACTS software suite (IGCI, University of Waikato) to assess the impact of global climate change scenarios on apple fruit production.