USE OF ISOENZYME ANALYSIS TO CHARACTERIZE RASPBERRY CULTIVARS AND DETECT CULTIVAR MISLABELING

Isoenzyme staining was used to characterize 55 of 78 raspberry cultivars (Rubus idaeus L., R. x neglectus Peck, and R. occidentalis L.). Six enzymes were needed to achieve this characterization: isocitrate dehydrogenase, malate dehydrogenase, phosphoglucoisomerase, phosphoglucomutase, shikimic acid dehydrogenase, and triose phosphate isomerase. The 23 cultivars that were not uniquely characterized were grouped into eight groups of two and two groups of three and four. Two of these groups comprised black raspberry cultivars, all of which were similar isozymically. Isoenzymes could not distinguish between the cultivar Willamette and a spine-free mutant of the cultivar. Analysis of cultivars obtained from several sources revealed that raspberry cultivar mislabeling exists but is not very prevalent. Regular isoenzyme analysis of raspberry cultivars held by germplasm repositories, certified and other propagators, and breeders is both feasible and advisable for early detection of cultivar mislabeling.