Preliminary evaluation of the transpiration response of young actinidia fruit to the weather

The relationship between fruit transpiration in Actinidia deliciosa and the principle weather variables was examined to determine the predominant drivers of fruit transpiration during early fruit development. On days 23 and 62 after full bloom detached fruits were mounted adjacent to a weather station and weighed hourly over 24-h periods. Radiation, air temperature, humidity and windspeed were recorded. Fruit transpiration and weather data were analysed using classical regression procedures. Air temperature and relative humidity were the variables most closely correlated (R2>0.84). Accumulation in the fruit of the phloem-immobile mineral calcium occurs predominantly during this early-season period so this result for fruit transpiration may indicate the weather patterns associated with enhanced fruit calcium accumulation.