Prediction of chilling injury risk in 'Zesy002' kiwifruit from softening early in storage

From knowledge of kiwifruit softening, it is suggested that firmness early in storage may be indicative of the risk of chilling injury (CI) expression later in storage. Firmness early in storage integrates both the at-harvest physiology of the fruit and the subsequent temperature management. This hypothesis has been tested by measuring the firmness change up to 6 weeks into storage at 1 degrees C for Actinidia chinensis var. chinensis 'Zesy002' kiwifruit of different maturities from 10 orchards (lines) and relating this to the chilling symptoms seen after 12 and 16 weeks of storage. It is concluded that the line risk of CI may be indicated by the fruit firmness after 4-6 weeks of storage, and the within-line proportion of fruit at CI risk may be indicated by the variation in firmness of fruit after 4-6 weeks of storage, with a greater risk in fruit which are > 40 N. Individual fruit can also be identified for their risk of CI by a non-destructive firmness measurement after 6 weeks of storage. These findings suggest inventory management decisions at the line or individual fruit level may be made based on firmness data gathered early in storage.