Objective  To analyze genetic variation in growth traits of Tectona grandis clone and interaction between clone and site, and to select superior teak clones.

Method  Regional field tests of teak clones at two sites were carried out by using randomized complete block design.

Result  Analysis of variance results showed that tree height, DBH, individual volume of teak at 3.5 years old were all significantly different among site, clones and clone×site interaction. The variation coefficient of tree height for teak clones in Ding’an was relatively small (0.092), and the variation coefficients of DBH in Ding’an and both tree height and DBH in Jinggu were relatively large (0.118−0.167). The variation coefficients of individual volume in Ding’an and Jinggu were 0.327 and 0.305, respectively. The repeatability of tree height and DBH in Ding’an were 0.873 and 0.852, respectively. The repeatability of tree height and DBH in Jinggu were 0.851 and 0.773, respectively. The repeatability of individual volume for teak clones at 3.5 years old in Ding’an and Jinggu were 0.863 and 0.784, respectively.

Conclusion  The selected fast-growing clones for Ding’an area in Hainan were 3078-5, 7029, 7122, 7514 and 7559. The mean tree height, DBH and individual volume for the selected clones were 21.11%, 19.82% and 60.53% higher than that of the control, respectively. The superior clones of fast-growing for Jinggu area in Yunnan were 7029, Z408, 7509, 7559 and 8301. The mean tree height, DBH and individual volume for the selected clones were 31.69%, 33.66% and 128.24% higher compared with control, respectively. The genetic gain of individual volume in Ding’an and Jinggu reached 40.26% and 34.57%, respectively. The clone 7029 and 7559 were the shared superior clones in both sites.