Variation in leaf characteristics among provenances of Eucalyptus camaldulensis Dehn. grown in Zambia

Abstract

Eight morphological characters of leaves were examined in 2-year-old trees of 25 provenances of Eucalyptus camaldulensis Dehn, grown in a replicated trial in Zambia. Provenances differed significantly in leaf length and width, base angle, and oil gland density but significant effects were attributed to trees within provenances. Leaf curvature also varied between provenances, trees, and branches. The tip angle and the number of veins did not vary significantly. Leaf length and oil gland density were related to maximum temperature at seed source rather than to latitude but the reverse occurred for leaf width. Significant amounts of variation were explained by a linear combination of temperature and latitude but not by longitude, altitude, or rainfall. Information on seven traits was combined in principal component analysis in which the first component (a measure of leaf shape) accounted for 36% of total observed variation while the second (weighted largely on leaf length) accounted for 26%.

Mapping of both univariate and multivariate results indicated that there are two major ecotypes and gave some evidence of clinal and ecotypic variation within them. The conclusions support those of other workers both in natural populations in Australia and in exotic populations elsewhere.