ISHS Acta Horticulturae 368: International Symposium on Postharvest Treatment of Horticultural Crops
OCCURRENCE OF CORK SPOT (PIT) IN 'ALEXANDER LUCAS' PEARS DEPENDS ON FRUIT MINERAL ELEMENT CONTENT |
| Authors: | K. Tomala, M. Trzak |
| Abstract:
The investigations were carried out in a commercial orchard in the years 1991–1992. At harvest, sound pears and those with cork spot were collected from the same trees. Moreover, sound pears were collected from the low and upper parts of the crown of the same trees. Mineral element content was determined in each fruit separately. For chemical analysis the flesh was taken with the skin. Sound pears located in lower half of the tree crowns showed a significantly higher calcium concentration resulting in lower K:Ca ratio than those from the upper half. The pears with cork spot showed a significantly higher potassium and magnesium and significantly lower calcium content. Different contents of individual elements, like K, Ca and Mg resulted in a two times higher K:Ca and Mg:Ca ratio in affected fruits as compared with the sound ones. Multiple regression analysis of data has shown that more than 2/3 of intensity of cork spot depended on calcium and magnesium content. The fruits with cork spot exhibited a higher initial ethylene production. During storage their respiratory activity and ethylene production were more intensive and they turned yellow and overripened sooner. Calcium sprays have been effective in increasing fruit Ca and reducing cork spot and symptoms of greening during the 1993 season. This was especially true for the Wuxal Suspension Calcium. | |
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