Calcium Levels of ‘Golden Delicious’ Apples as Influenced by Calcium Sprays, 2,3,5-triiodobenzoic Acid, and Other Plant Growth Regulator Sprays1

Abstract

Abstract When ‘Golden Delicious’ apple fruit ( Malus domestica Borkh.) Ca concentration was depressed by 2,3,5-triiodobenzoic acid (TIBA), 3 sprays of Ca(NO 3 ) 2 increased fruit Ca concentration and visibly reduced fruit pitting and internal breakdown. TIBA application at intervals from full bloom stopped Ca accumulation in the skin, but not in the flesh. Consequently, it appears that Ca moves into the flesh for a longer period after bloom, but at a slower rate than it does into the skin. TIBA was the only one of several growth regulators used that reduced fruit Ca concentration. Although within a given year Ca was associated with pitting, low-Ca fruit did not pit every year. Apparently, low Ca predisposes fruit to pitting, but pit development is associated with unknown factors.