IUFRO Breeding theory and progeny testing

Clonal forestry is becoming a very important activity in breeding and deployment of many commercial forestry species. Because it is a relatively new practice, several aspects need to be understood and solved. Genetic testing of clones is one area for which guidelines are lacking for adequate characteristics of clonal field trials. The overall goal of this study was to identify ‘optimal’ or ‘near optimal’ experimental designs for the prediction of clonal values and estimation of genetic parameters in order to achieve maximum genetic gains from clonal testing. In this study, simulations of single-site trials with sets of unrelated clones ‘planted’ in environments with different patterns of variability were generated and studied.

For the last four years the Southern Tree Breeding Association (STBA) of Australia has been using the TREEPLAN® system for an integrated genetic evaluation of all of the current and ancestral trees in its national breeding populations of Eucalyptus globulus and Pinus radiata. These evaluations have involved the simultaneous multivariate prediction of breeding values for each species of over 150,000 genotypes from 3 to 4 generations of breeding for more than 10 traits. The models used include all relevant design features and weight each trial by its heritability. Age to age, site to site and inter-trait correlations are all used and are incorporated in the trait definitions. These large multi-variate runs represent the most comprehensive breeding value calculations for tree breeding, but they run in less than 10 minutes on a standard computer. They are only possible because of an integrated data management system, some sophisticated programming from the Animal Genetics and Breeding Unit (AGBU) of the University of New England (Drs Bruce Tier and Richard Kerr), and some approaches to combining information across sites with heterogenous variances contributed by the Cooperative Research Centre for Sustainable Production Forestry (me and Dr Luis Apiolaza). TREEPLAN® is based on the BREEDPLAN® software that routinely predicts genetic values for 23 additive and 3 maternal traits in breeding populations of 1.2 million animals, so it is very efficient.