Characterization of Pyrus Species and Cultivars Using Gradient Polyacrylamide Gel Electrophoresis

A chemical identification procedure previously used to identify apple clones was tried with pear species and clones. Following electrophoresis, the peroxidase, esterase, and acid phosphatase isozyme patterns on anionic polyacrylamide gradient gels were determined. These patterns were found to vary with the species and clone, but not to change, within a clone during the growing season. Thus, these patterns were considered to represent genetic characteristics. The patterns were used to identify 37 selected Pyrus accessions at the National Clonal Germplasm Repository, Corvallis, Oregon. All species tested were distinguishable using this system. All the accessions of P. calleryana selected from the NCGR collection were distinct: however, one clone from outside the collection had an identical pattern to one inside the collection. Among the Chinese pear clones (complex hybrids of P. ussuriensis × P. pyrifolia) tested, three pairs of clones had the same combination. This technique appears to have the potential to readily identify pear specimens, and could be an important aid in the characterization of germplasm material.