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Deployment of genetic gain in Radiata pine plantations

The GF Plus™ genetic rating system was first introduced in 1998. We can now look back at the level of genetic improvement deployed in the forests planted since then. The information described in this article is mainly sourced from the recent Radiata Pine Breeding Company (RPBC) report “RPBC Genetic Improvement Monitoring Process Report (Project 19) Jun-15”.

The total ortets in the RPBC germplasm archive was just over 1,000 in 1998. This has grown to over 4,000 in 2015. Many of the RPBC 2nd generation selections have been incorporated into the production population and used in seed orchards to produce control pollinated (CP) seeds. The average proportion of CP/clonal treestocks planted in NZ since 2001 was around 64% (range 50% to 74%). Treestocks grown from GF19 open pollinated (OP) seed takes up about 36% of the market on average (range 20% to 40%) and its market share has been eroded since the introduction of stand-select seed in 2010.

benefits of genetic gain in Radiata pine

Types of treestock sold in New Zealand since 2001

The GF Plus™ certification scheme provides the genetic ranking of five key traits in Radiata pine – growth, straightness, branching habit, Dothistroma resistance and wood density. A sixth trait, the core-wood stiffness (PME), has been added to the new 2015 GF Plus™ values but it was not included in the analysis. The average GF Plus™ ratings for commercial CP seedlots certified each year from 2001 to 2014 showed a definitive positive gain in most key traits except the straightness trait, which remained pretty much the same. The argument is that you can’t make a straight tree straighter.

The biggest genetic gains in the Radiata pine deployment population since 2001 are Dothistroma resistance and wood density. The commercial CP seedlots deployed in 2014 have gained an average of nearly three GF Plus™ points on Dothistroma resistance and over six points in wood density since 2001. The gap between the top 10% and the average GF Plus™ values shown in the graphs below indicate that the genetic quality for each trait still varies considerably among commercial seedlots. Hence not all not all equally rated seedlots are the same!

Genetic gain in Radiata pine through breeding, though incremental, is definitely happening and genetic improvement is being deployed via the trees we plant each year. Planting trees with the best, and appropriately chosen genetics, is the easiest thing we can do to improve the future value of our forests.

wood density improvement in Radiata pine breeding

dothistroma resistance improvement in Radiata pine breeding

Genetic gain of Wood Density and Dothistroma resistance traits in the GF Plus™ certified commercial CP seedlots between 2001 and 2014 based on their 2015 GF Plus™ values. Note the difference between "average" values and "top 10%". Which seedlot would you rather have?