INHERITANCE OF 6-PHOSPHOGLUCONATE DEHYDROGENASE AND ESTERASE ISOENZYMES IN APPLE

Three apple progenies from controlled crosses (‘Elstar’ x Malus scheideckeri ‘Hillieri’, ‘Elstar’ x M. purpurea ‘Aldenhamensis’ and ‘Jonagold’ x ‘Hillieri’) were analysed by polyacrylamide gel electrophoresis. The inheritance of 6-phosphogluconate dehydrogenase (6-PGD) and esterase (EST) enzymes, extracted from vegetative buds, was studied. Three alleles were determined for 6-Pgd-1 and three alleles for 6-Pgd-2. In addition to earlier reported zones of the 6-PGD enzyme, a new polymorphic zone of enzyme activity, 6-PGD-III, was identified. Two phenotypic forms were found, one with 3 bands and one with 5 bands. Six loci were determined for EST: Est-I (two alleles), Est-2 (two alleles), Est-3 (two alleles), new locus Est-3' (monomorphic), Est-4 (two alleles), and new locus Est-5 (two alleles). The chi square test showed that the isoenzymes were inherited in accordance with expected ratios.