Mineral nutrition and internal defects in vapour heat treated mango fruit

Abstract

Optimum fruit quality is crucial for export. For ‘Calypso™’ mango fruit, vapour heat treatment (VHT) is an important postharvest measure for fruit fly control. However, this phytosanitary treatment has been associated with expression of physiological disorders in the fruit. Among other determinants, fruit robustness and postharvest quality is linked to preharvest mineral nutrition. Notably, fruit nitrogen (N) to calcium (Ca) and potassium (K) to Ca balance is related to fruit robustness and innate capacity to tolerate postharvest stresses. A multi-year N and Ca field trial was established in a commercial orchard. ‘Calypso™’ fruit at commercial maturity (Avg. 14.43% dry matter) were subject to VHT vs. no VHT treatment. During shelf-life assessment at 20°C, VHT fruit exhibited shorter shelf-life (15.3 d) than non-VHT control fruit (20.6 d). Three distinct internal disorders were observed in afflicted fruit at eating ripe: flesh cavity (FC), flesh cavity with white patches (FCWP), and ricyness (R). FC was evident in both VHT and non-VHT fruit. FCWP and R appeared only in VHT fruit. FCWP severity was correlated with mesocarp N: Ca (r=0.46) and (K+Mg): Ca (r=0.44) ratio. Farm information management systems (FMIS) encompassing nutrient application and on-farm practices could inform predictive modelling for the incidence and severity of FCWP in ‘Calypso™’ mango subject to VHT.