Genetic variation in Eucalyptus delegatensis.  1. Provenance variation.  I. D. Abbott and L. A. Pederick.  November 1984.  35 pp. (unpubl.)

SUMMARY

Trials have been established for the study of natural variation in Eucalyptus delegatensis R. T. Baker (alpine ash) as follows:

1. A trial with 10 provenances, mainly from the Mansfield area, established at Dowey Spur near Powelltown, Central Highlands, in 1967.
2. A trial with 14 provenances, including nine of the ten provenances in (a) above, at Sumner Spur near Powelltown, planted in 1973.
3. Two trials with 64 provenances at sites in the Mansfield area (Bindaree and Toombullup), North-eastern Victoria, and one trial with 22 provenances at a site on the Nunniong Plateau, East Gippsland, all planted in 1979. The 64 provenances were derived from systematic collections made by CSIRO from throughout the natural distribution of the species.

The most useful results have come from the two large trials near Mansfield, in which there were large and significant differences in height growth among the provenances at four years of age. The leading provenances were Royston (which was consistently the best in the Powelltown trials as well), Lake Mountain, Ada (all Central Highlands), Mt Buffalo (North-east) and Nunniong (East Gippsland), from Victoria, and Geehi, from southern New South Wales.

When the 64 provenances represented in the Mansfield trials were grouped by regions of origin, the pattern of variation became clear. The three regional groupings of Victorian provenances and those from the southern New South Wales region were of similar growth rate. They were significantly taller than those from the two northern regions (Batlow (N.S.W.) and A.C.T.) and from the Tasmanian regions, which were particularly slow-growing. The Tasmanian provenances were also distinctively different in their leaf morphology, retaining the juvenile leaf form for an indefinite number of years.

Similar results (including the high vigour of Royston) have been reported for height growth at two years of age in trials at Batlow (N.S.W.) and Rotoaira (N.Z.). In the smaller Victorian trial at Nunniong, the Gippsland provenances appear to have grown relatively faster than they did at Mansfield. The growth rate of Victorian provenances was not influenced significantly by the altitude of seed source.

Local provenances were among the higher ranked provenances in each of the three 1979 trials. Thus, on the basis of four-year height growth, the results support the practice of preference for local seed collections for regeneration purposes in Victorian forest operations. In the trials, no Victorian provenance grew poorly; thus, in practice, the use of seeds collected in other districts may not result in much diminished growth and, in fact, it may sometimes result in improved growth.

Royston (Central Highlands) appears to be a superior provenance for growth rate, with results up to 15 years of age, and its seeds could be used widely to increase forest production. Seeds for Tasmania and the northern part of the species range in the A.C.T. and adjacent N.S.W. should not be used in Victoria.