ISHS Acta Horticulturae 383: Mineral Nutrition of Deciduous Fruit Plants
DEVELOPMENT AND PREDICTION OF CALCIUM CONTENT IN APPLES |
| Author: | B. PLÍŠEK |
| Keywords: | Malus domestica, chemical analysis, fruit weight, regression |
| Abstract:
Calcium content per fruit increased in a linear correlation to growing fruit mass in the period from June to harvest time. A decrease occurred sometimes during the summer temporarily or, in the period between the last but one sampling and the final harvest. Linear regression models (Y = a + b X) expressed the development of the Ca content (Y = mg Ca per fruit, X = fruit weight in g) mostly with a sufficient significancy. Nonlinear regression models (Y = a + b/X) and multiplicative regression models (In Y = a + b In X) expressed the development of the Ca concentration (mg Ca per 100 g fresh weight). Larger fruits had higher total Ca content and lower Ca concentration during the development than smaller ones at the same time. Fruits from winter pruned trees had higher Ca content and lower Ca concentration than fruits from unpruned trees. This pruning effect continued even in the successive year. For prediction purposes four or five analyses shoud be made during the season starting at the stage of completed cell division and repeating until some 5 or 6 weeks before harvest. It is necessary to keep observing an adequate fruit size class and to predict an adequate final fruit weight. | |
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