Use of Isozyme Techniques to Identify Peach x ‘Nonpareil’ Almond Hybrids

Two isozyme systems, phosphoglucomutase (PGM) and 6-phosphogluconate dehydrogenase (PGD), were identified that permit the early verification of peach x almond hybrids as opposed to plants resulting from accidental self-pollination. Nondestructive samples for analysis can be taken from cotyledons or primary leaves. Isozymes of PGM-2, PGD-1, and PGD-2 were found to be monomorphic in the peach [ Prunus persica (L.) Batsch] cultivars studied. P. amygdalus Batsch ‘Nonpareil’ was found to be heterozygous at the PGM-2 banding region, bearing the peach allele and a slower migrating allele. This locus allows verification of 50% of the hybrids. ‘Nonpareil’ was homozygous for alleles contrasting to peach at the PGD-1 and PGD-2 banding regions, allowing the unequivocal verification of all hybrids.