Nano-calcium and its potential to improve ‘Red Delicious’ apple fruit characteristics

Abstract

This study evaluated the effects of preharvest nano-calcium fertilization on quantitative and qualitative characteristics of apple (Malus domestica Borkh. ‘Red Delicious’) fruit. From 70 days after full bloom to 30 days before commercial maturity, calcium chloride (0, 1.5, and 2.0%) and nano-calcium (0, 1.5, and 2.0%) solutions were sprayed on apple trees. This was performed five times during the growing season at 2-week intervals. Fruit weight, density, length (L), diameter (D), and L/D were evaluated at harvest. Additionally, several quality characteristics were measured: fruit firmness, total soluble solids (TSS), titratable acidity (TA), total phenolic content (TPC), total antioxidant activity (TAA), total anthocyanins content, starch content, fiber content, total sugars, and calcium content. The effects of nano-calcium treatment on fruit quality and quantity were more significant than that of conventional calcium chloride. The greatest improvements were obtained using 2.0% nano-calcium. TA, TPC, TAA, fiber, and starch content were significantly increased under the nano-calcium treatment. Compared to the control, TSS, total sugars, and anthocyanin content decreased under the calcium chloride and nano- calcium treatment. Our results support the use of nano-calcium as a promising fertilizer for improving the overall characteristics of apple fruit.