Abstract

Firmness is the most relevant attribute in blueberries and softening is the main obstacle for long distant ship- ments (>45 d). The main cause of softening is dehydration, which occurs through the stem-scar and the cuticle of the fruit. The evolution of firmness during postharvest depends on the sum of the environmental conditions (E) and the agronomic managements (M) occurring along growth and development of the fruit, interacting with the genotype (G). This results in an interrelationship (G×E×M) that impacts postharvest softening, being E×M in the case of blueberries, as relevant as G. Specially, because the asynchrony in fruit set and ripening implies that any stimulus, (E or M) will have a different impact, depending on the stage of development of each fruit within the cluster. Finally, given the harvest index based on color, fruit of similar appearance may have different physio- logical maturity. All this results in a great variability of firmness within a lot, which, together with a random distribution of the berries into the clamshell (different proportion of exposed epidermis and stem-scars inside the commercial unit), would prevent firmness at harvest from being a good predictor of the final condition at destination. Considering the close association between water loss and softening in storage, and the relevance of the pedicel scar in dehydration of fruit until consumption, this article reviews the elements that support a change in the paradigm of the relevance of firmness values at harvest, both for the industry and researchers. The main argument is that by measuring the rate of dehydration, a better estimate of fruit behavior in storage could be obtained. Consequently, different patterns of water loss would be expected when fruit are exposed at various RH, assuming that the rate of dehydration at each RH would be a simplified characterization of the in-season impact of G×E×M on final postharvest condition. Over the seasons, a history of G×E×M can be constructed to make decisions, of the best destination to be reached with a required firmness, by an early estimation of the maximum potential water loss.