In the years 1998–2000 an investigation was carried out on ‘Jonagold’ apples harvested from 6-year old trees grafted on M.9, M.26, P 2, P 22 and P 60. In 1998 and 1999 the average calcium content in fruit was significantly higher than in 2000. The highest calcium was observed in the peel of apples, in each of the year. The effect of the rootstock on the level of calcium in the calyx, core and pedicle part of apples changed, depending on the vegetation season. In each year of the experiment the strongly dwarfing rootstock P 22 had the smallest share in the accumulation of calcium in the different parts of apples.

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