Soft Sour Cherries—What's the Problem?

Abstract

<jats:p>Michigan growers often have severe problems with soft `Montmorency' sour cherries. Causal factors may include weather conditions, orchard practices, harvesting methods, and conditions during hold of fruits prior to processing. In this study, efforts were concentrated on orchard practices, including shading to reduce solar radiation, irrigation, nutrient level, and application of growth regulators, especially ethephon and gibberellin. Fruit firmness decreased as maturity approached, then stabilized. Significant fruit softening occurred only during mechanical harvesting. No treatments, including sprays of calcium and potassium, consistently increased firmness, but firmness was reduced in 1993 by spraying with ethephon. Firmness varied among orchards, but no “soft” fruit, as defined by industry standards, were observed in harvested fruit. Softening appeared to be caused by excessive bruising, and was always associated with mechanical damage. Advanced maturity and heavy cropping appear to predispose the cherries to greater bruise damage.</jats:p>