Breeding plan for the development of Douglas-fir (Pseudotsuga menziesii var. menziesii) in New Zealand
By Mari Suontama, Charlie Low, Heidi Dungey, June 2016.
Download SWP-T003 (pdf)
Douglas-fir is renowned for its stiff wood and is one of the finest structural timbers in the world. Eighty per cent out of 105,000 hectares planted Douglas-fir in New Zealand is grown in the South Island. Under the changing climate scenarios, breeding for wood production and resilient forests becomes increasingly important in order to boost the interest in growing this species in New Zealand. Since the current breeding plan for Douglas-fir is out-dated, a requirement to update breeding objectives along with selection criteria and operational actions in the breeding programme has been required and is reported here.
Generous genetic resources of Douglas-fir exist in New Zealand ensuring excellent prospects for the future development. Breeding objectives have targeted improved growth and form, and wood stiffness.
New objectives have been defined via the Specialty Wood Products Douglas-fir breeding workshop held in June 2016 for growth and form, wood quality, i.e. stiffness and resistance to Swiss Needle Cast (SNC). The target for growth was a 35 year rotation length and yield of 600 m3 TRV (total recoverable volume) per ha including 20 m3 per ha MAI (mean annual increment). Form is an essential selection criteria and the target should be retained at the level of that for tree material at the 1996 progeny trials. The breeding plan will target maintenance of wood stiffness at a minimum level of 8 GPa. SNC is the major limiting factor for growing Douglas-fir more widely in the Central North Island. Consequently, needle retention indicating resistance to SNC is included in the overall objective as a secondary trait and the long-term target was set to needle retention of 3 years.
The current breeding programme is in its second generation and the breeding strategy is to proceed using open-pollinated seed with forwards selection. To mitigate possible effects of genotype by environment interaction (G x E) on genetic gains, a consideration of different breeding zones-seed orchards-deployment areas across New Zealand was endorsed.
Through researching the implementation of new breeding technologies (genomics) and planning of efficient strategy to test tree material, this breeding plan update aims to deliver 30% faster growing, straight, healthy trees with stiff wood for Douglas-fir in New Zealand by 2025.
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