Identification of Raspberry Cultivars in Vivo and in Vitro Using Isoenzyme Analysis

Isoenzyme analysis of leaf tissue was used to characterize and separate 18 greenhouse-grown red raspberry ( Rubus idaeus L.) cultivars and two purple raspberry (R. × neglectus Peck) cultivars. Five enzymes were found to be useful: Phosphoglu-coisomerase (PGI), phosphoglucomutase (PGM), malate dehydrogenase (MDH), triose phosphate isomerase (TPI), and isocitrate dehydrogenase (IDH). Fourteen of the 20 cultivars were uniquely separated using these enzymes. The remaining six were assigned to three different groups. Staining for additional isoenzymes may lead to the separation of cultivars within these groups. The effect of tissue type on isoenzyme banding patterns was determined by comparing different tissues from three cultivars. No differences were noted, except in the case of the enzyme PGM, for which differences in the relative densities of the bands were seen. For PGM, the best patterns were obtained from mature tissues (leaves, stems, or petioles). Three cultivars were micro-propagated from shoot tips in vitro and were subsequently analyzed by isoenzyme staining. The culture environment was not found to have any effect on isoenzyme phenotype. This result suggests that isoenzyme analysis can be used to identify raspberry cultivars grown in vitro.