Identification of Apple Rootstock Cultivars by Isozyme Analysis

Abstract

Abstract Thirty-three clonal apple (Malus domestica Borkh.) rootstocks were characterized by their peroxidase, esterase, acid phosphatase, and idoleacetic acid oxidase isozyme banding patterns. Polyacrylamide disk-gel electrophoresis of shoot bark protein extracts, with a 5% to 15% acrylamide concentration gradient in the separating gel, provided adequate resolution for the anionic isozymes for all 4 enzymes, while a 5% to 20% gradient was used to separate the cationic isozymes of peroxidase and acid phosphatase. Growing conditions (greenhouse and 3 different field locations) and sample timing (February, May, August, and November) did not affect banding patterns. Virus-tested clones showed isozymic differences compared with the original contaminated material. Tissue culture propagated selections from EMLA 7 and MAC 9 stoolbeds expressed different banding patterns compared to original stocks.