ELUCIDATING THE GENETIC CONTROL OF WOOD QUALITY TRAITS IN Pinus radiata

Forest Research Private Bag 3020 Rotorua New Zealand

The juvenile wood (or corewood) of radiata pine tends to have undesirable structural properties, such as high shrinkage and instability, and low stiffness. As rotation age decreases in production forests the proportion of the tree made-up of juvenile wood increases which results in lower quality and lower values wood products. These structural traits of juvenile wood are related to biochemical, cellular and anatomical properties such as low specific density, short trachied length, high microfibril angle and high grain spirality. To mitigate undesirable juvenile wood properties in future generations of plantation forests Forest Research has initiated a multidisiplinary approach that involves a combination of 1) germplasm improvement by phenotypic selection and clonal propagation, augmented by QTL discovery and marker-assisted breeding, 2) targeted gene discovery using microarray expression assays of differential and random ESTs, 3) candidate gene mapping using QTL/EST correlations, and 4) candidate gene assays in transgenic plants using early wood quality assay protocols. Progress on components of this program will be presented.