Abscisic acid preharvest application alleviates chilling injury in oranges during cold storage

Orange fruit are sensitive to develop chilling injury (CI) during postharvest storage. Symptoms are brown depressed areas in the flavedo that coalesce with time causing severe economic losses. Abscisic acid (ABA) is applied during preharvest in different crops to promote cold tolerance but its effect in citrus fruit remains unknown. The objective of this work was to study the effect of preharvest application of ABA in alleviating CI during cold storage (1.0 +/- 0.5 degrees C). ABA at 500 mg.L-1 was applied at three different maturity stages of 'W. Navel', 'Valencia' and 'Salustiana' oranges. ABA reduced incidence and severity of CI in the three orange cultivars. This positive effect was cultivar-dependent, being more pronounced in 'W. Navel' and 'Valencia' compared to 'Salustiana'. 'Salustiana' presented the highest CI incidence (>80% of the fruit with symptoms after 9 weeks of storage) and ABA applications only delayed its appearance. CI incidence was reduced up to 61% in 'W. Navel' and 74% in 'Valencia' compared to untreated fruit, concomitantly to severity. Evaluation of fruit quality revealed that ABA application does not affect fruit colour firmness or maturity index. Preharvest applications of ABA in oranges alleviate CI during postharvest cold storage without affecting fruit quality.

Automated summary

This study investigated the effect of preharvest application of abscisic acid (ABA) on alleviating chilling injury (CI) during cold storage of citrus fruit. The results demonstrated that ABA reduced the incidence and severity of CI in different citrus cultivars, without affecting fruit quality.