Stability of genetic effects across clonal and seedling populations of Eucalyptus globulus with common parentage

Eucalyptus globulus is widely planted in temperate regions of the world for pulpwood production and there are breeding programs in many countries. While breeding and deployment programs in Australia mainly use seedlings, in countries such as Chile, Portugal and Spain, a combination of seedlings and clones are used for genetic testing and plantation establishment. In the present study, we compared clones and seedlings produced from the same twenty open-pollinated families of the Jeeralang provenance of E. globulus, and randomised within the same field trial established in NW Tasmania. We specifically aimed to test whether mean performance, variance components, genetic parameters and breeding values estimated from the two propagule types were comparable. We studied the susceptibility of the juvenile foliage to leaf disease caused by Teratosphaeria nubilosa, the height at which the transition to the adult foliage occurred, as well as growth at selection and harvest ages. While the clones exhibited less disease damage, switched to the adult foliage at a slightly lower height and had less height and diameter growth than the seedlings, no significant differences in estimates of additive genetic variances and narrow-sense heritabilities between the two propagule types were detected. The additive genetic correlations estimated between the clonal and seedling populations did not differ significantly from one. The propagule type also had little effect on estimates of genetic correlations between traits. Thus, our results argue that while differences in trait means need to be taken into account, the propagation method is unlikely to affect the genetic architecture and predictions of breeding value in this species.