Genetic Variation in the Spinning Gum, Eucalyptus perriniana F-Muell ex Rodway

Abstract

Two Tasmanian populations of E. perriniana were examined to determine the extent of morphological variation between two gene pools that have been isolated for perhaps thousands of years. Surprisingly few differences were noted despite small population sizes, high levels of disturbance and high levels of hybridisation with E. rodwayi. When compared to mainland E. perriniana, large genotypic differences were noted: e.g. mainland E. perriniana seeds required stratification whereas Tasmanian seeds did not. The growth rates, leaf shape and colour also differed markedly but reproductive characters did not. These differences are possibly the products of differing selective pressures associated with altitudinal differences rather than random genetic drift or introgressive hybridisation. Developmental abnormalities were noted which seem to indicate that the distinctive connate form of the juvenile leaves is under relatively simple control mechanisms.