• Z D Miller Department of Forest Biomaterials, North Carolina State University
  • P N Peralta Department of Forest Biomaterials, North Carolina State University
  • P H Mitchell Department of Forest Biomaterials, North Carolina State University
  • S S Kelley
  • V L Chiang Department of Forestry and Environmental Resources, North Carolina State University
  • L Pearson ArborGen Inc.
  • W H Rottmann ArborGen Inc.
  • M W Cunningham ArborGen Inc.
  • I M Peszlen Department of Forest Biomaterials, North Carolina State University


Density, Specific Gravity, Quantitative Wood Anatomy, Tracheid, Modulus of Elasticity, Modulus of Rupture, Transgenic, Pinus taeda


Traditional breeding methods are often constrained by the reproductive cycles of tree species and the difficulty in achieving significant improvements to complex traits; therefore, genetic manipulation of complex traits such as wood properties has the potential to resolve those issues. The objectives of this study were to analyze MOE, MOR, and the physical and anatomical properties of 2- to 3-yr-old field-grown transgenic Pinus taeda trees modified for increased density. This investigation consisted of a total of 55 sample trees in two separate experiments. Transgenic trees from sets OX41 and OX55, modified for increased density using two variants of the same HAP5 gene, exhibited higher mechanical properties with smaller stem diameter and tracheid lumen diameter than their set of control trees. In addition, set OX55 exhibited increased cell wall thickness. In the second experiment, the transgenic group WVK249, modified for higher density using an unrelated MYB gene, exhibited similar diameter growth and increased cell wall thickness and lower lumen/cell wall ratios but no change in mechanical properties compared with its control.


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Research Contributions