Abstract:

The difference of wood tissue proportion of eucalyptus clones was studied to improve the efficiency of genetic improvement of wood properties. 11 clones from Guangxi Province were chosen as sampling materials, the vessel proportion, axial parenchyma proportion, ray proportion, fiber proportion were measured by biological anatomy methods. The results show that there are significant differences in the vessel proportion, axial parenchyma proportion, ray proportion, and fiber proportion among the clones. The vessel proportion increases with the increase of tree age and then decreases slightly at the 5^th year. The axial parenchyma proportion decreases rapidly at first, rises rapidly after the 7^th year, and then decreases again. The ray proportion increases annually and the fiber proportion decreases with the increase of tree age. The vessel proportion, axial parenchyma proportion, and ray proportion are well fitted by polynomial equation (R²=0.8655, 0.7263, 0.6130). The fiber proportion is well fitted by logarithmic equation and power equation (R²=0.8172, 0.8154). The tissue proportion of eucalyptus clones is under strong genetic control, and the repeatability of each index is above 0.90. It is feasible to carry out genetic improvement of clone tissue proportion.

Key words: eucalyptus clones, tissue proportion, clone variation, radial variation, genetic parameter