THE USE OF ISOZYMES TO IDENTIFY 60 GRAPEVINE ROOTSTOCKS (VITIS SPP)

Starch gel electrophoresis was used to produce isozyme banding patterns for the 60 grape rootstocks available from the University of California, Davis grape collections. Strips of tissue from under the bark consisting of young phloem, young xylem, and vascular cambium provided the sample material for protein extraction. Isozyme patterns were produced with the following enzyme systems: glucose phosphate isomerase (GPI), aspartate aminotransferase (AAT), phosphogluconate dehydrogenase (6-PGD), phosphoglucomutase (PGM), alcohol dehydrogenase (ADH), malate dehydrogenase (MDH), leucine amino-peptidase (LAP). The resulting patterns were consolidated and arranged in a grid designed to function as a taxonomic key. A unique isozyme profile was obtained for each rootstock. Ten unknown rootstocks were tested and their identities were determined using this system.