Tree Improvement (Genetics)

Considerable effort is being spent by governments to encourage farm forestry as a legitimate land use in low rainfall areas and on soils that are unsuitable for traditional commercial species. For these efforts to be successful, it is imperative that those promoting farm forestry have confidence that the species being recommended are appropriate. There is therefore a need for genetic material suitable for low rainfall areas and specific soil types.

 

There are a range of species that have different requirements and different potential end uses. The Australian Low Rainfall Tree Improvement Group (ALRTIG) is important in its role in selecting and producing improved seed from seed orchards through partners in this program. PIRSA Forestry is a partner to this important group and a number of growers have progeny trials and seed orchards for genetic tree improvement of trees that are suitable for low rainfall areas and specific soil types.

Eucalypts

There are a number of eucalypt species that are being selected for, improved and improved seed grown in orchards. Through PIRSA Forestry’s partnership in ALRTIG we are responsible for a number of progeny trials and seed orchards. The species include:

  • Eucalyptus cladocalyx (sugar gum)
  • Eucalyptus occidentalis (swamp yate)
  • Corymbia maculata (spotted gum)
  • Corymbia variegata (spotted gum)

 

Measurements of progeny trials of E. occidentalis, E. cladocalyx and the Corymbia species have recently been assessed for growth, form and branching characteristics. PIRSA Forestry manages an ALRTIG E. cladocalyx seed orchard that has had its first seed collection in 2006.

 

Other species that are trialed for suitability in the low rainfall and specific soil types include:

  • Casuarina glauca (swamp sheoak)
  • C. obesa (swamp bulloke)
  • Cupressus macrocarpa (Monterey cypress)
  • C. lusitanica (Mexican cypress)
  • Chamaecyparis nootkatensis x Cupressus macrocarpa (Leyland cypress) 
  • E. globulus (Tasmanian blue gum)
  • E. grandis (flooded gum)
  • E. largiflorens (black box) 
  • E. robusta (swamp mahogany)
  • E. saligna (Sydney blue gum)
  • E. viminalis (manna gum)

 

PIRSA Forestry has also been involved in Saltgrow trials looking at eucalyptus hybrids. These hybrids have been developed for better salt tolerance and timber properties. Eucalyptus hybrids have also been popular overseas and imported seedlings and clones have been trialed. The hybrids include:

  • E. camaldulensis x grandis
  • E. camaldulensis x globulus

Pinus species

There are a number of pine species that grow in low rainfall regions. These are being tested for their suitability to the low rainfall area of the Upper South East. A number have been established to evaluate the growth and form of the pine species listed below. Comparisons between some species, provenances and families within species are also being undertaken to determine the most suitable for the region. Trials have been established in conjunction with ALRTIG with P. pinaster.

 

The species being trialed are listed below. Species with different provenances are listed with the provenance in brackets.

  • Pinus brutia
  • P. canariensis
  • P. eldarica
  • P. nigra
  • P. pinaster
  • P. radiata
  • P. radiata var. binata (Guadalupe)
  • P. radiata var. binata (Cedros)
  • P. roxburghii

 

In 1997 a trial was set up to evaluate different provenances of Pinus radiata var. binata in low-rainfall areas. At this early stage the provenance Guadalupe is performing well at all sites, with the provenance Cedros also performing well in places.

 

For further information please contact PIRSA Forestry

 

 

Last Revised January 2007