Calcium chloride sprays decrease physiological disorders following long-term cold storage of apple.
Field experiments were carried out at the Horticultural Research Institute, and in five commercial apple orchards, located in southwest Finland including the Aland Islands during 1994 and 1995. The experimental cultivars were Melba, Raike, Red Atlas, Akerö, Aroma, and Lobo. The treatments were untreated control and preharvest calcium chloride (CaCl2) sprays at Ca 2.0 g/l. Fruit samples were stored for two to six months at 2-4 degrees C and 85-95% RH. The percentage of the incidence of physiological disorders of stored apples was scored. Fruit macronutrients, firmness, diameter and juice titratable acidity and percentage of soluble solids were determined. Only a few nutrient effects in the flesh of the apple cultivars were a result of CaCl2 sprayings. Preharvest CaCl2 sprays increased fruit firmness and the titratable acidity but decreased soluble solids, soluble solids/titratable acidity ratio, and the incidence of physiological storage disorders of some cultivars. When looking at the mean of all cultivars, CaCl2 sprayings increased titratable acidity and decreased soluble solids/titratable acidity ratio after four months of storage during 1995 and reduced the incidence of physiological disorders after three months of storage during 1994 and after four months of storage in 1995.