Optimizing the harvest date for long-term storage of 'Spadona' pears (Pyrus communis L.) by prediction of the pre-climacteric minimum

- This study attempts to predict the timing of the pre-climacteric minimum (PCM).
- A model was based on fruit weight, firmness, starch degradation and seed colour.
- PCM was verified as the optimal time for harvest of 'Spadona' pears for storage.

The changes in ripening parameters of 'Spadona' pears were monitored from 95 days after full bloom (DAFB) until the end of the harvest season in 2 orchards during 3 years, in an attempt to predict the timing of the pre-climacteric minimum (PCM), as a tool for determining the optimum harvest maturity for extended controlled atmosphere (CA) storage.A model based on the pre-harvest rates of changes of fruit weight, firmness, starch degradation and seed colour was found to predict the timing of the PCM with an accuracy of 24 h of its occurrence (R2 = 0.9925). Changes in soluble solid content (SSC) and titratable acidity (TA) did not improve the model. Fruit quality assessed at removal from CA storage after 6 months, followed by 2 weeks of shelf-life at 20 °C, verified that the optimal time for harvest of 'Spadona' pears was at the PCM.