Fingerprinting Apple Cultivars by Electrophoretic Isozyme Banding Patterns

Anionic electrophoretic isozyme patterns of peroxidase, esterase and acid phosphatase and cationic peroxidase isozyme patterns from shoot bark protein extracts were used to identify clonal apple scion cultivars. Each of the 21 cultivars included in this study developed a unique combination of isozyme patterns which allowed it to be distinguished from the others. Sports within cultivars exhibited identical patterns of enzymes, with the exception of ‘Wijcik’, a natural compact mutant of ‘McIntosh’ which could be distinguished from the latter, although it was indistinguishable from the cultivar ‘Spartan’. Isozyme patterns remained constant when samples were taken from wood of different ages, at several times of the year and with trees growing in different locations and on different rootstocks.