A New Breeding Strategy for Pinus radiata in New Zealand and New South Wales

A new breeding strategy is presented for the Radiata Pine Breeding Company, a New Zealand based research consortium, that drives the breeding program for Pinus radiata for both the New Zealand and New South Wales based Australian forest plantation industry. The new strategy builds on the existing base for P. radiata, and on the last strategy review in 2000. The new strategy comprises a large open-pollinated (OP) Main Population (MP) with 500 female parents and two sublines (250 female parents per subline). The MP will be tested using alpha designs, single-tree plots and incomplete blocks to maximise efficiency. Each subline will be tested on four sites, geographically distant from the other subline. The MP will be managed in discrete generations. Selection of the next generation will be using a combination of backward and forward selection, but the strict control of inbreeding with identified lineage will rely on the development of parental reconstruction for OP progeny. There are alternatives to this, however, such as estimating the group coancestry and accepting some additional increase in inbreeding. This is a new and significant departure from previous breeding strategies for P. radiata in New Zealand. There will also be a single, small Elite Population (EP), tested 50% as progeny and 50% as clones. Twenty four parents will be tested each year as clones and 24 as seedling progeny with some overlap between the two. It is expected that the clonal population will capture the greatest gains in traits with low heritabilities, and the half-sib progeny will capture the greatest gains in traits with high heritabilities. The two sublines will be maintained in the EP, and breeding will be managed as a rolling front with trials established every year, while trials of the MP will be established every 10 years.