Description

To reach this objective we develop with a 48 month research program, through four scientific tasks (tasks 2 to 5) and one coordination and management task (task 1).

• The task 2 consists in understanding the functional relationship between WUE measured at leaf level (W_I) and tree level (W_p) with Δ¹³C and other related ecophysiological components (leaf traits, transpiration, etc..). It seeks to predict WUE at leaf and individual tree level using Δ¹³C and related traits.
• The task 3 estimates the genetic and environmental variance components of Δ¹³C and related traits and the correlations with biomass using quantitative genetic models.
• The task 4 is complementary to task 3 and seeks to understand, using association studies and fine mapping strategy, which genomic regions and which genes underlie Δ¹³C and associated traits. In task3 and task 4 the genotype by environment interaction is evaluated using appropriate field designs showing different stress levels.
• The task 5 uses tasks 2, 3 and 4 information to test selection methodologies, such as genomic selection, associating both phenotypic and genomic data. The objective is to provide new statistical models to accurately rank genotypes. WUEtree is conducted with two tree model species, the hybrid Eucalyptus urophylla x grandis and Pinus pinaster, and relies on original experimental field trials established respectively, in the Republic of the Congo and in the south west of France.

The expected results are a better understanding of the biological basis of WUE and of the genetic and environmental determinants. This new knowledge will be used for defining and selecting ideotypes presenting optimal WUE and productivity for marginal zones.