Genetics of superoxide dismutase in apple

 Four zones of superoxide dismutase (SOD), activity were detected in apple. Genetic studies confirmed the presence of three genes Sod-1, Sod-3 and Sod-4 with three, two and two alleles respectively, including one null allele. One of these genes, Sod-1, was found to be loosely linked to Prx-2 and Prx-3. The Sod-1a allele predominated in all the three groups studied, cultivars, rootstocks and Malus species. The distinct achromatic bands produced by SOD after electrophoresis facilitate its important role with peroxidase (PRX), glutamate oxalacetate transaminase (GOT) and phosphogluconate dehydrogenase (PGD) in the discrimination of apple cultivars. Received: 22 November 1996/Accepted: 29 November 1996