GENETIC IMPROVEMENT OF EUCALYPTS IN NEW ZEALAND

Tree breeding, integrated with an active programme of species and provenance testing, is being conducted in Eucalyptus botryoides, E. saligna, E. regnans, E. delegatensis, E. fastigata, E. obliqua, and E. nitens. The programmes involve provenance trials and family tests to give a broad base of genetic variability of the different species, and to form genetically improved local seed sources. Several other species are being tested on a small scale. Selection criteria vary somewhat among the 7 main species, but fast growth, good stem form and branching characteristics, and useful wood are needed in all species. Genetic variation of practical significance has been found in the tolerance of E. regnans and E. fastigata to frost. Considerable emphasis is being placed on searching for strains of E. nitens which are less palatable to the Eucalyptus tortoise beetle, Paropsis charybdis. The breeding method used entails selecting the best trees in the most promising provenances, followed by intermating among these to produce the improved seed via seed stands, seedling seed orchards, clonal seed orchards, and progeny-tested seed trees