Comparison of isoenzymes in Prunus avium separated by two different electrophoretic techniques

Isoenzyme variation for seven systems revealed by two different electrophoretic procedures was compared in Prunus avium. Fourteen cultivars and 14 wild selections were analysed for acid phosphatase (ACP), isocitrate dehydrogenase (IDH), leucine aminopeptidase (LAP), malate dehydrogenase (MDH), phosphoglucomutase (PGM), shikimate dehydrogenase (SKD) and superoxide dismutase (SOD). Extracts were separated by isoelectric focusing (IEF) and by polyacrylamide gel electrophoresis (PAGE). For the eight loci that had been described previously in these enzyme systems on the basis of IEF analysis, we compared the variation revealed with IEF and PAGE. Similar variation was revealed for Acp‐1 and Pgm‐1, and the alleles revealed by PAGE could be identified directly with those reported for IEF. For Lap‐1, Mdh‐1 and Skd‐1, variation was seen with IEF but not with PAGE. For Mdh‐2, PAGE revealed additional variation not revealed by IEF. For Idh‐1, different patterns of variation were revealed by PAGE and IEF, and both procedures would be needed to genotype cherry accessions. We were unable to detect variation corresponding to that reported previously for Sod‐1 with either technique. The implications of these findings for allele labelling, for studies of genetic diversity and for linkage analysis are discussed.