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Effect of the concentration of mineral constituents in apples on their postharvest quality and storage performance. I. Relations between the mineral composition of apples and their susceptibility to physiological disorders

Jan Ben

Department of Pomology
Faculty of Horticulture, Agricultural University
29 Listopada 54, 31-425 Kraków, Poland

The relation between the concentration of mineral constituents in Jonagold apples and their susceptibility to bitter pit and internal breakdown was investigated in 3-year experiments. Samples of apples for analysis were taken 2 or 3 weeks before the due time of fruit harvest in 11 orchards lying in the provinces of Cracow and Nowy Sącz, the content of N, P, K, Ca and Mg being determined in them. At the due time of harvest 50-60 kg of apples from each orchard were taken for storage. After the storage period the susceptibility of the apples to physiological disorders was determined.

When the K/Ca ratio ranged from 24-27 the percentage of apples affected by bitter pit was 5.1-3.8. With the K/Ca ratio increasing to 39 the susceptibility of the apples to bitter pit reached 11.2%.

The internal breakdown of apples was determined to an almost equal degree by Ca concentration in the fruit, the N/Ca ratio increasing from 11 to 19, and that of P/Ca from 2.2 to 3.0.

Ben J., 1997. Effect of the concentration of mineral constituents in apples on their postharvest quality and storage performance. I. Relations between the mineral composition of apples and their susceptibility to physiological disorders. Folia Horticulturae 9/1: 43-50.