Genetic analysis of shrinkage of new triploid clones of Populus tomentosa

The wood samples of 9 triploid clones of Populus tomentosa were cut from 9-year-old clonal stand. The oven-dried and air-dried samples were used to study their genetic variation in shrinkage. The results indicated that there were significant differences between clones and all the coefficients of shrinkage that were found to be under strong genetic control. The vertical variation pattern within tree of shrinkage was downward with the tree height. The clonal repeatability^s in shinkage of oven-dried and air-dried timber in volume, radial and tangential direction were respectively 0.89, 0.95, 0.84, 0.67, 0.84 and 0.68.