NZDFI Tree Breeding Programme

Breeding Strategy

Farm foresters have been planting trials and small blocks of a myriad of durable species for many years. These will produce sawlogs of variable wood quality. We know that the underlying cause of variable wood quality is genetic. However, these existing trees are a very narrow genetic resource that severally limits screening to remove undesirable features.

Therefore, the establishment of a wide genetic resource for tree improvement is the primary strategy of the NZDFI. Therefore we plan to establish large base breeding populations of up to five selected eucalypts that produce durable timber (Class 1 and 2 Australian Standard, AS5606-2005) and show the potential for excellent survival and growth on the drylands (<1000 mm/yr rain) of Gisborne to Canterbury. These breeding populations will allow evaluation of between and within family variation at an early age (3-4 yr) so as to select the best families and individuals for fast growth, good form and early heartwood formation. Using rapid early screening techniques we plan to have improved germplasm available by 2014. Subsequently, we plan to screen for elite timber properties (high durability, intense colour, reduced checking and growth stresses).

Each species will be planted at three sites across the NZDFI regions to expose trees to different growing conditions.  The NZDFI have selected sites to cover a range of abiotic (cold, drought, soils etc) and biotic (pests, diseases) stress factors likely to be found in the drier parts of these regions. These diverse sites de-risks the project against the unknown relative contributions of genetic and environmental effects on disease, growth and early heartwood formation and ensures that a broad-based elite selection is possible by testing the species across a range of environments and providing comparative data for screening individual families.

We have chosen multiple species for a number of reasons.

• Diversification reduces risk.
• Individual species are site specific, having evolved in niche environments in Australia. A selection of species is required to cover the diversity of NZ dryland sites.
• Out crossing of species will create elite hybrids that capture the best traits of each species and extend the range of sites able to successfully grow durable eucalypts.
• Only scattered natural populations remain in Australia and we will archive and undertake innovative research techniques to genetically improve these species.

A distinctive feature of the NZDFI tree breeding programme is the very early and intensive selection for roundwood followed by selection for traits needed for producing high value sawlogs.  Large breeding populations are planned therefore, to capture a broad range of genetic diversity from which to select for the key traits of fast growth, good form, early heartwood formation and ability to coppice for vegetative propagation.

This early screening will be at age 3-5 dependent on site productivity and aim to select trees to produce seed that will grow into uniform trees suited for use as durable posts. This will provide growers greater certainty of crop value at 8 years.

Our second screening (8-10 years hence) will be for traits critical to timber – colour, collapse, growth stresses, ease of drying, shrinkage and stability.

Conceptually, the breeding programme could stop at stage one (durable poles) and still be successful. In addition, the breeding programme is planned to provide the potential to follow overseas initiatives in developing inter-specific hybrids. Thus the breeding strategy is based on establishing these species in pairs, because inter-species breeding is possible within sub-species.

Breeding Population Establishment

Breeding populations are planned for E. bosistoana and E argophloia; E. camaldulensis and E. quadrangulata; and E. macrorhyncha and E. globoidea. NZDFI is committed to this strategy so as to improve growth, form and productivity by capturing hybrid vigour and broaden the diversity of sites durable species can be grown. It may also reduce the potential impact of diseases and pests while offering the prospect to greatly improve the aesthetics and properties of the timber.

In spring 2009 and 2010 the first breeding populations of E. bosistoana were planted..

E argophloia, E. globoidea  and E. quadrangulata, are planned for planting in spring 2011 as well as an additional class 1 durable species, E. tricarpa. Seedlings for planting breeding populations are being grown by Morgans Road Nursery in Marlborough under contract to the Marlborough Research Centre.

With our SFF grant, there is funding to establish breeding populations for three additional species with a total of up to 60,000 trees at possibly nine separate sites across the Hawkes Bay, Wairarapa, Marlborough and Canterbury regions.

Landowner Consultation & Support:

NZDFI have been generously offered many sites by landowners keen to provide land for durable eucalypt research plantings. From those that are offered, it has been possible to select a wide range of sites that are planned for planting with breeding populations in 2011.

There has been consultation with the landowners on the NZDFI forestry rights agreement required between the landowner and Marlborough Research Centre Trust. The contribution of every site planted by NZDFI is valued as an ‘in kind contribution’ based on a fair market annual rental and recorded as an in kind contribution to the project.

Landowners involved are interested in trees and ensure that their site is fenced and kept stock free.

Breeding Population Site Requirements

• Good access by SH or local road within 1 hour drive on main centre.
• Located on property with good all weather internal farm road or track access.
• Site needs to be already fenced or easily fenced off by the landowner.
• Flat to easy to moderate slopes with uniform land surface.
• Slopes either north, east or west facing.
• Rainfall around 1000mm or less.