Genetic variation in the growth of Eucalyptus regnans from an altitudinal transect of Mount Erica, Victoria.
In 1959, seed was collected from 64 trees representing 7 populations in a continuous natural forest on a 3-mile transect extending in altitude from 1200 to 3250 ft, and seedlings were raised and planted out in a uniform environment in two field trials at low altitude. Measurements and records were made during 1962-1970; certain form characters were described by a points scoring system. Significant genetic variation was detected both between and within populations: populations derived from higher altitudes showed slower growth and straighter stems; other characters (including branch angle, flowering, and survival) showed continuous (clinal) variation. At 7 years old, there was considerable height variation between but not within populations; in contrast, there was greater diameter variation within than between populations, and this variation increased with age. It is concluded that there is some scope for successful artificial selection in E. regnans, but progeny testing will probably be necessary.