Genomic Selection holds huge promise of faster value gains from genetic improvement

The Radiata Pine Breeding Company Ltd is a New Zealand company focussed on the provision of superior radiata pine germplasm to its shareholders and customers in Australasia. RPBC is embarking a development programme which can halve the traditional 25-30 year breeding and deployment cycle. The economic impact is huge as the rate of improvement in key traits, e.g. growth and wood quality, is doubled.

Genomic Selection is the key technology to enable this development. Genomic Selection is bringing step changes to animal and plant breeding because it:

  • speeds the breeding and deployment cycle by reducing the need for progeny tests
  • allows the selection and evaluation of multiple traits simultaneously
  • reduces cost and time for assessing traits that are difficult or expensive to measure
  • allows the quick introduction of new traits such as disease resistance
  • establishes a platform for introduction of other molecular technologies

The major overall gain arising from Genomic Selection is that genetically improved planting stock is deployed more rapidly in commercial forests. Unlike GE, there are no regulatory barriers to uptake.

What is Genomic Selection?

Traditionally, breeding values are calculated by observing and measuring the expressed trait in the subject tree as it is growing (phenotypic data). It can take some years before such traits can be observed or measured for. Genomic Selection, on the other hand (and this is where it can get pretty technical), involves identifying patterns of molecular markers along strands of DNA, the genetic blueprint, of trees being tested. These patterns are compared to those of a pedigree of genotypes with known phenotypic data (called a training population). This allows individuals with good genetic matches to desired traits/phenotypes to be identified. Such diagnostics can be done in the nursery when the plant is less than one year old. By contrast, to generate phenotypic data using traditional methods the plant would normally be grown to 6-8 years old.

RPBC considers that Genomic Selection is sufficiently well developed and commercially proven in many plant and animal applications to be implemented in the NZ radiata pine industry. In addition, there is a small window within which the chance of obtaining government funding is high, after which the chance of funding will be seriously diminished as new processes and priorities are introduced. Work already underway, funded mainly by Scion with some RPBC assistance, has built a robust R&D programme and created a network of international technical experts to help guide the programme.

Financial benefit

The current average wood volume removed from the national forest estate is in the order of 450 m³ per hectare. This production is based mainly on trees with GF ratings below GF19. From the early 1990s, GF19 stock was planted and this will deliver some 6-7% increase in volume growth over the next decade or so. Volume growth is expected to rise by a further 7-8% as stock with GF Plus ratings of 22/23 and above progressively entered the estate from about 2000 onwards. Without any intervention from genomics, volume increase at harvest in 2050 is estimated to be about 15% above the current level of production.

Genomic Selection, and the accompanying benefits arising from forward selection and rapid transfer of genetically improved material to germplasm producers, is anticipated to deliver commercial quantities of improved planting stock available for planting in 2022/23 with an additional 15% gain in volume being realised at harvest in 2050. This is based on a forward movement of 1½ generations in genetic improvement, together with the additional selection intensity arising from large clonal trials.

The estimation of financial benefit from Genomic Selection is made on the following assumptions:

  • a baseline of 450m³/ha for average wood removals at harvest in 2011
  • an average log value of $90/m³
  • a growing rotation of 28 years

Genomic Selection is estimated to deliver twice the amount of genetic gain per unit time.

By 2050, when the benefits of genomic selection will first be realised, there will be at least a 30% volume increase compared with current harvest. This equates to a volume increase of 135 m³, and a value increase of $12,150 per hectare. Half of these gains are contributed by genetic improvement already present in the forest estate, with the other half attributable to Genomic Selection. From that time onwards, the expectation is for gain of some 36-45m³ per hectare, and value of $3,240-$4,050, to be realised at approximately 8 -10 year intervals. Using conventional processes, similar gains will not be achieved in less than 16 years.