Identification of Species-Diagnostic ISSR Markers for Six Eucalyptus Species

Eucalyptus is planted worldwide for raw material in paper and rayon industry. It is a potential out-crosser and the natural populations are highly heterogeneous displaying strong inbreeding depression. Eucalyptus hybrids have been intensively utilized for their vigor, higher wood quality and resistance to diseases. Identification of species for hybridization is predominantly based on morphological characters and is not always reliable. Hence, DNA marker based species identification and hybrid validation is an important and efficient tool in breeding programs. In the present study, attempts were made to identify species - diagnostic markers for six eucalypt species (E. camaldulensis Dehnh, E. citriodora Hook, E. grandis W. Hill ex Maiden, E. pellita F. Muell, E. tereticornis Sm and E. urophylla S.T. Blake) using ISSR-PCR fingerprints. PCR amplification using seven ISSR primers resulted in significant polymorphism among the population from different species. E. citriodora and E. tereticornis showed monomorphic frequency of maximum 37.5% and minimum 14.3% respectively. Twenty species-diagnostic markers were identified for E. camaldulensis, E. citriodora, E. grandis and E. urophylla while no marker was detected for E. pellita and E. tereticornis. A maximum of eleven and a minimum of one species-diagnostic marker were recorded for E. citriodora and E. camaldulensis respectively. Among the twenty markers, nine were present in all the individuals of a particular species.