|Authors: ||J. Joubert, P.J.C. Stassen, J. Wooldridge|
|Keywords: ||Malus × domestica, calcium, fruit quality, K/Ca ratio, magnesium, nitrogen, potassium, vigour|
The effects of six rootstocks, M.9 (Cepiland), CG.222, M.7A, CG.707, M.793 and CG.239 on macro element concentrations in ‘Reinders Golden Delicious’ apple fruit and leaves were studied over two consecutive seasons: 2004-06. Mineral analyses were performed on fruit and leaf samples collected at harvest in mid-February.
Average yields were greater and average fruit masses were slightly lower in 2005/06 than in the previous season.
In the fruit, nitrogen tended to be high in CG.239, relative to all other rootstocks.
Similarly, phosphorus was higher in CG.707 and CG.239, relative to M.9. High fruit potassium (K) concentrations were observed in CG.707, whereas magnesium tended to be low in CG.222. These tendencies were consistent in both seasons.
Fruit calcium (Ca) concentration and total fruit Ca content in M.793 and M.7Awere higher than in other rootstocks in 2004/05, but did not differ significantly in 2005/06. Both fruit Ca concentration and fruit Ca content were marginally higher, on average, in 2004/05 than in 2005/06. Fruit K/Ca ratios also showed rootstock-induced differences in 2004/05, when ratios decreased in the sequence: CG.707, CG.239 > CG.222 > M.7A, but not in 2005/06. The average K/Ca ratio was higher in 2005/06 than in the previous season.
Rootstock had no effect on fruit mass in 2004/05, but fruit mass from CG.239 significantly exceeded that from M.7A and M.9 in 2005/06. The effects of rootstock on leaf element composition were generally not significant.
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