Effect of pre-harvest calcium sprays on storage quality and shelf life of apple

Abstract:

Post-harvest specialists working in apple supply chains have long argued that nothing replaces the value of calcium nutrition established in the orchard: no after-harvest treatment, no matter how sophisticated, fully compensates for a deficiency at fruit-set. This research tested that proposition by applying pre-harvest foliar calcium chloride sprays at four concentrations (0, 0.5, 1.0, and 1.5%) to Royal Delicious apple trees in the central Chilean valley during the 2023 season. Sprays were applied at 20, 40, and 60 days after fruit-set, and fruits were harvested at commercial maturity in March 2023. Storage quality was evaluated over 12 weeks at 0–1 °C and 90–95% relative humidity. The 1.5% calcium treatment retained 56 N firmness at week 12, against 31 N for the untreated control, and reduced cumulative weight loss from 8.4% to 3.2%. Bitter-pit incidence dropped from 14.8% in controls to 3.1% in the 1.5% regime, and total soluble solids were preserved within the marketable range throughout storage. Vitamin C retention improved proportionally with calcium dose. The data support routine adoption of pre-harvest calcium programmes in Chilean apple orchards targeting extended storage markets.