Variation in the chloroplast genome of 44 accessions representing 14 Eucalyptus L'Hér. species from the series Viminales (sensu Pryor and Johnson 1971) was investigated. Southern analysis of the chloroplast genomes restricted with 12 enzymes revealed 20 restriction-site polymorphisms of which 7 were autapomorphic to individual trees. The 13 informative restriction-site polymorphisms were distributed between individuals of different species, but none was species-specific. Fourteen chloroplast haplotypes were identified for south-eastern Australian individuals. In endemic Tasmanian species, five haplotypes were identified. Chloroplast haplotypes appear to have a mosaic distribution in south-eastern Australia, more closely associated with geographical regions than with morphological species boundaries. The biogeographic distribution of chloroplast haplotypes may be explained by a combination of interspecific hybridisation and introgression, and convergent evolution. The lack of species-specificity of cpDNA variation indicates that, although cpDNA is not appropriate for species-level phylogeny analysis in the series Viminales, it may provide useful information in studies of biogeography and gene flow in Eucalyptus.

Parental and consensus maps were constructed in an F2 inter-provenance cross of Eucalyptus globulus, using amplified fragment length polymorphism (AFLP) and microsatellite (or simple sequence repeats [SSR]) markers. The female map had 12 linkage groups and 118 markers, comprising 33 SSR and 85 AFLP loci. The male map had 14 linkage groups and 130 markers comprising 36 SSR and 94 AFLP loci. The integrated map featured 10 linkage groups and 165 markers, including 33 SSR and 132 AFLP loci, a small 11th group was identified in the male parent. Moderate segregation distortion was detected, concentrated in gender specific groups. The strongest distortion was detected in the female parent for which causal mechanisms are discussed. The inclusion of SSR markers previously mapped in several different eucalypt species within the subgenus Symphyomyrtus (E. globulus, E. camaldulensis, and predominantly E. grandis and E. urophylla), allowed comparison of linkage groups across species and demonstrated that linkage orders previously reported in E. globulus, E. grandis and E. urophylla were largely conserved.

Fragmentation of lignotubers and the consequent problems in genotype identification make demographic studies of mallee eucalypts unreliable. DNA fingerprinting using Random Amplification of Polymorphic DNA (RAPD) markers was employed to determine if a hybrid copse between Eucalyptus risdonii and E. amygdalina was clonal. Based on lignotuber morphology this copse appeared to be composed of approximately 20 separate individuals. No variation in RAPD genotype was observed for 67 bands scored from nine primers among the 20 individuals. In contrast, variation was observed between individuals sampled from outside the copse (average 28.6 band differences between any two individuals) and within full sibling families (average 12.9 band differences between individuals). On this basis the copse was considered to be clonal (one genet), originating from lignotuber fragmentation, and measured 5.5 × 3.5 m. The rate of radial expansion in 15-year-old seedling and lignotuber cohorts was measured and used to estimate the age of the hybrid copse. The hybrid genet appeared to be at least 900 years old. While such estimates must be viewed with caution they strongly support the suggestion that mallee eucalypts may attain ages far in excess of single-stemmed eucalypts.

PI 345635 est controll6e par un seul gdne rdcessif (tan tan) ayanr des effets pi€io-tropiques sur la pigmentation de la plante ainsi que sur I'6paisseur des t6guments. L'h6ritabilit6 de la teneur en ranins est de 66,4 + 4,4vo, bas6e sur la m6thode d'analyse des composantes de la variance. La sdlection pour une teneur en tanins plus ou moins 6lev6e devrait 6tre efficace.