Abstract
In addition to the ontogenetic transition to sexual reproduction, most plants show change in their vegetative phenotype. Vegetative changes are particularly evident in the genus Eucalyptus where many tree species are heteroblastic, exhibiting a marked difference in leaf anatomy and morphology between juvenile and adult leaves. This change can be associated with important differences in leaf physiology and pest resistance and is believed to be of adaptive significance. Studies have shown that both vegetative and reproductive phase change are under strong quantitative genetic control and the onset of sexual reproduction appears to be genetically independent of vegetative phase change. While the molecular genetic control of vegetative and reproductive phase change is being examined in annual model species, there is little knowledge of the genetic control of these processes in trees. We will use a large E. globulus F2 progeny (500+ individuals) grown at two sites to identify QTL for vegetative and reproductive phase change. The F2 was derived from crossing normal E. globulus parents with those from a dwarf ecotype of E. globulus exhibiting precocious vegetative phase change and precocious flowering. High stringency marker ordering mapped over 800 DArT and microsatellite markers onto the expected 11 linkage groups. This E. globulus linkage map will be invaluable in establishing the conservation of gene order (synteny) between E. globulus and E. grandis. This is important because we need to establish synteny between these genomes since E. globulus is being sequenced using Next Generation sequencing with the E. grandis sequence as a framework.