The 2018 Breeding and Deployment Strategy includes four main streams of research, each comprising discrete and related project work.

The streams concern:

  • RPBC's Breeding Objective;
  • Increasing the rate of genetic gain with genomic selection;
  • Managing genetic diversity;
  • Faster deployment of genetic gain to the production forest.

RPBC's Breeding objective

RPBC currently implements a breeding objective that includes volume, form, wood density and the modulus of elasticity (a measure of the wood's structural quality) at rotation age.

Each objective trait has a corresponding economic weight and, along with the genetic and phenotypic relationships between the objective traits and the selection traits (the traits that are measured at selection age, ~6 to 10 years), selection index coefficients for each selection trait can be derived. The selection index is used to identify parent candidates for the next round of crossing and selection.

The economic weights have been derived using a bio-economic model that projects out to sometime in the future, say 40 years. Other uncertainties inherent in the calculation of a selection index for radiata pine is the estimates of correlations between selection age traits and rotation age traits (genetic parameters). The RPBC in collaboration with the University of Canterbury and PhD candidate Arturo Bascunan are redeveloping a bio-economic model to derive breeding objectives. The main aim of this project is to use this model to identify superior trees that will still perform well at harvest age under various future economic scenarios. It will also allow us to assess the strategic importance in future of the different traits being considered currently for breeding improvement and deployment.

increasing the rate of genetic gain with genomic selection

A major research focus is on increasing the rate of genetic gain with Genomic Selection aimed at shortening the time between germplasm selection and delivery to commercial forests.

Its application will profoundly impact on driving genetic gain.

RPBC and Genomic selection

RPBC has invested heavily in developing genomic selection (GS). Its application has the potential to profoundly impact on all of the elements of the breeder's equation, and genomics will form a significant component of RPBC's future focus.

RPBC will integrate genomic selection with forward selection and regional clonal testing as the key intervention to almost double genetic gain per unit time and substantially reduce the deployment time of new, genetically-improved, planting stock in commercial forests.

WHAT is genomic selection?

Genomic Selection uses DNA markers to generate a unique DNA fingerprint for an individual, which tells us what blocks of DNA have been inherited from each of its parents.

By studying the patterns of these markers in trees that already have their traits measured (a “training population”), we start to build a picture of how these patterns could be used to make predictions in trees that haven’t yet been measured. With a good set of markers and strong prediction models between the resulting fingerprint and the traits, it’s possible to screen and select elite trees at the seedling stage, reducing the need for field testing and speeding up the delivery of gain into the next generation of trees.

With DNA fingerprints, we can also confirm the identity of clones, reveal hidden relatedness and recover (and confirm) the true pedigree of trees. Access to accurate pedigree information further increases the accuracy of prediction model and breeding value estimates, and enables a more streamlined approach to the management of inbreeding.

designer solutions for growers

The GS platform will continue to deliver additional genetic improvement for many years to come, and includes the potential opportunity to create designer solutions to optimise production across sites and traits for different market requirements.

Implementation will be via the operational programmes of the RPBC, and through the interface with seed orchards and clonal producers - the pathway to market for radiata pine germplasm.

This GS platform will provide step-change gains to industry and contribute to knowledge from other molecular technologies. Together with the Pinus radiata genome sequencing project underway at Scion, the RPBC’s genomic selection research will contribute to furthering other genetic technologies currently being researched.

For further information please contact us

managing genetic diversity

To mitigate the vulnerability of radiata pine genetic resources held in forest gene banks, a systematic conservation strategy is being developed for:

  • Provenance and progenitors for long term conservation
  • Current RPBC candidate parents
  • Future accessions under genomic breeding for long term conservation, when the RPBC breeding population is being turned-over at a much faster rate.

This requires the development of a core collection that captures the genetic diversity for conservation in various forms, such as
in situ stands, seed banks and cryo-preservation. This will require the collation and storage of eco-geographic, molecular, pedigree, genetic and phenotypic data in order to characterise, define and develop a core set. This will allow an efficient long-term genetic conservation policy for industry good that will move us away from an over-reliance on impromptu establishment of in situ forest stands.

faster deployment of genetic gain to the production forest

This research is aimed at establishing a more rapid path to the production forest (via seed or clones) of top RPBC germplasm by a strategy that makes use of somatic embryogenesis, a method for large-scale production of clonal varietals.

A nucleus of top performing parents is being selected for cross-pollination and subsequent production of SE clonal progenies. These will be cryopreserved, genotyped and clonally-tested in NZ and Australian trial sites alongside non-SE clonal progenies. This will allow extraction post-testing and faster multiplication of selected clones either for further shareholder (region-specific) testing and/or entry into seed orchards as seed parents, or as a more expeditious and direct route for deployment to the production forest as tested clones.

There is also an opportunity to make more rapid genetic gains whilst relaxing some constraints on relatedness within the nucleus compared with the wider breeding population (where it is necessary to maintain a certain population size to constrain the rate of inbreeding). SE testing will be integrated with clonal testing of the general breeding population and will use genomic selection for more informed decision making.