Post‐harvest physiology of tetraploid banana fruit: response to storage and ripening

SUMMARY Aspects of the post‐harvest physiology relating to storage and ripening of the fruit of tetraploid banana clones resistant to Sigatoka disease, have been compared with fruit of Valery, an important commercial triploid cultivar. Significant differences in susceptibility to low temperature injury, duration of the preclimacteric period, the texture of pulp and peel and ethylene evolution have been found between tetraploid and Valery fruit and also between tetraploid fruit of different clones. Fruit of Valery and one tetraploid clone developed serious chilling injury during storage at 12 °C whereas that of five other tetraploid clones showed only slight damage. The preclimacteric period for fruit of two tetraploid clones was 30–45% less than for Valery fruit at an equivalent stage of physical development. Pulp firmness of preclimacteric tetraploid fruit was 20–30% less than that of Valery fruit and the differences persisted through ripening. The softening response to applied ethylene was up to 15 h earlier in fruit of tetraploid clones than of Valery but respiratory patterns, colour development and starch‐to‐sugar conversion were similar. Unlike Valery fruit, ripe tetraploid fruit did not develop senescent spotting, and shelf life was terminated by rapid deterioration of peel strength to a state of severe finger drop. Temporal and quantitative differences occurred between fruit of tetraploid clones and Valery in production of ethylene and these may relate to the observed differences in control of softening in both pulp and peel.