The use of genomic information for tree selection has the potential to identify more accurately individual trees carrying favorable genes and at earlier stages of their development than we had ever done before. This innovation, known as genomic selection, is possible as soon as trees are big enough to provide the small amount of tissue (for example, a leave or a needle) that is required for DNA analyses. Young plants can be selected for their future performance or by their resistance or tolerance to environmental stresses at the nursery, well before their evident characteristics (definite phenotypes) are available in the field. It is thought the technique will be revolutionary for forest trees.
The most revolutionary benefit comes from the shortening of the generally long time required to assess phenotypically a candidate to selection, usually 10 to 15 years in the best of the cases and dependent on the species. Making things faster is not just a question of return of investment; early evaluation brings promptness and flexibility when facing challenging demands, especially those associated to the suitability of existing varieties to global change. One good example in B4EST is that of selecting Ash trees that are tolerant to a rapidly expanding wave of a destructive fungus.
B4EST has made a strategic choice of the most economically, ecologically and socially important tree species in Europe for innovative breeding, covering a wide range of current and potential habitats, industrial uses and societal values, with three broadleaf (hardwood) and four conifer (softwood) species. Some are the object of advanced breeding programs (Norway spruce, Scots pine, maritime pine and poplar), and are therefore the ideal candidates to adopt further breeding innovations. Some represent highly productive non-native species of great potential in Europe (Eucalyptus), while others species like Stone pines provide sustainable high value non-wood products or are highly threatened like Ash. These species can also be considered as pioneer models for all 48 forest tree species listed in EU directives regulating forest reproductive material trade.
Genomic selection requires screening genomes with thousands of genetic markers. Such tools are typically expensive to develop for a single partner, or for a single species, unless high demands can be guaranteed over a long period. B4EST represents the ideal framework to gather partners and species to a level of demand that opens up the door to extremely competitive rates, within the consortium and for external partners.
B4EST is developing three genotyping arrays, highly miniaturized devises able to screen up to 50,000 markers each, for six of the species lacking such resources (Norway spruce, Scots pine, maritime pine, stone pine, ash and poplar). They will be available in September 2019. It will also develop genomic selection at an operational level on all the above species (including Eucalyptus), in different contexts and for different objectives. By doing so, new statistical tools able to handle massive data will be tested over relevant collections of more than 2,000 individuals per species, paving the way for further implementations in other species in the future.
This article explains research that will take place in B4EST Work Package 3 which is led by Dr Leopoldo Sanchez Rodriguez, INRA (Orleans).