FROST INJURY TO FLOWER BUDS AND FLOWERS OF CHERRY VARIETIES

Cold hardiness of cherry varieties is genetically determined and varieties differ greatly. The incidence of winter injury varies between trees of a single variety (e.g. the percentage of dead flower buds on trees of 'Kecel 1' varied from 0 and 41% in 1991). Therefore, to obtain better results 10 trees per variety and 100 flower buds per tree need to be tested.

Higher rates of damage were observed in the lower part of the trees than at the top. In a frost pocket, 90% bud injury may occur in the lower parts of sweet cherry trees as a result of winter cold.

There are 3–5 primordia in flower buds of both sour and sweet cherry. In many cases not all the primordia in a flower bud suffer injury, and uninjured ones may develop fruits.

According to our results the following sour cherry varieties are frost hardy: 'Pándy meggy', 'Újfehértói fürtös', 'Cigánymeggy', 'Parasztmeggy'. In contrast, 'Érdi botermo', 'Érdi nagygyümölcsu' and 'Meteor korai' are tender varieties.