CALCIUM ACCUMULATION IN DELICIOUS APPLE FRUIT

Seasonal patterns of fruit growth and calcium (Ca) accumulation in 'Delicious' apple fruit were observed over four years and four growing regions. Although temperature and precipitation varied greatly, fruit consistently accumulated Ca in a quadratic fashion, with maximum uptake occurring early in the season. Little Ca accumulated in fruit during the three weeks prior to harvest. Under some conditions, fruit appeared to lose Ca during this time. Loss of fruit Ca was not closely associated with precipitation. Calcium uptake was greatest during periods of high evaporative demand.