Abstract

Genetic variation was observed among a series of Eucalyptus viminalis populations whose habitats range from wet to dry climates and from relatively fertile to infertile soils.

. In comparison with populations from low-rainfall areas, two high-rainfall populations showed rapid germination and fast early seedling growth, the latter being correlated with large seed weight. Older seedlings were capable of continuing fast growth in response to high nutrient levels, and the root/shoot ratios of 6-month-old seedlings were significantly lower than those of seedlings from low-rainfall areas.

Populations from within the low-rainfall areas showed some differences in germination, root lengths and growth rates and these appear to be related to site fertility and soil water-holding capacity. Relatively slow growth, even in response to increased nutrient supply, was observed in a population naturally occurring on a granite soil of fair fertility but poor water-holding capacity.

Low-rainfall populations also showed a greater lignotuber development than high-rainfall populations and the growth of the lignotuber was not markedly affected by nutrient supply.