PROGNOSING STORAGE ABILITY OF 'GLOSTER' APPLES

Authors:	K. Tomala, M. Trzak, J. Kobylinska
Abstract: Fruitlets, leaf and fruit samples from 17 commercial apple orchards in Central Poland were analysed in the years 1991 and 1992. Besides, in one orchard, apple trees were sprayed with Phosyn products (containing B, Zn, Mg, Ca or Ca and P) in 1992. Immediately after fruit harvest, internal ethylene concentration, starch index, flesh firmness and soluble solids were determined. After 6 months in cold storage, fruit quality was evaluated with special reference to the incidence of bitter pit. Correlation coefficients between the percentage of fruits affected by bitter pit and the content of particular mineral elements and their ratios in fruits, fruitlets and leaves were calculated. The frequency of bitter pit was always correlated with K, Mn and Ca content and K:Ca ratio, irrespective of the organ analysed. It indicates that, for prognosis of apple storage ability, fruitlet or leaf analysis for mineral nutrients may be as effective as fruit analysis. Phosyn products increased Ca concentration in fruit tissue and decreased the percentage of apples with bitter pit. Apples obtained from terminal flowers had a significantly higher Ca concentration than those from lateral flowers.
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