Seasonal Accumulation of Calcium and Potassium in the Cortex of ‘Golden Delicious’ Apple Fruit Sprayed with 2,3,5-Triiodobenzoic Acid

The accumulation of Ca and K in the cortex of fruits of ‘Golden Delicious’ apple ( Malus domestica Borkh.) from trees sprayed with 2,3,5-triiodobenzoic acid (TIBA) was measured during 2 growing seasons. TIBA reduced the rate of Ca accumulation in treated fruits within 2 or 3 weeks of application, and the slower rate of accumulation persisted through most of the season. K accumulation in the latter part of the growing season was enhanced by TIBA. The cortex of treated fruits was lower in Ca and higher in K than that of untreated fruits at harvest. In 1 year, TIBA-treated fruit had a higher dry weight and higher N content than unsprayed fruit. Bitter pit appeared in fruit from all treated trees both years.