Abstract:In order to select excellent strains of Eucalyptus grandis, the growth traits, quality traits and crown width of 173 families from 11 provenances at 53-month-old grown in alpestrine of south Yunnan were analyzed. The results showed that there were significant differences in growth traits, quality traits and crown width among provenances and families. The phenotypic and genetic variation coefficients of DBH, H, V, stem form, branch and crown width were 26.90%~28.84%, 23.84%~25.28%, 62.34~67.55, 13.04%~25.62%, 13.04%~25.41% and 35.07~39.93, respectively. The provenance heritabilities were ranged from 0.94 to 0.96 and the family heritabilities were ranged from 0.88 to 0.95. The correlation analysis showed that there were significant positive correlations between DBH with H, V, stem form and crown width, also between H with other traits. The correlation coefficient between stem form and branch were 0.70, while that between crown width with stem form and branch were -0.03. The genetic gain of V was the biggest among all traits, and it was 66.11% by 5% selection rate. The change trend of genetic gain in H, DBH, stem form and branch were similar under different selection rate whereas the rank of their genetic gain was different. The 17 families were selected under 10% selection rate by comprehensive index selection, which derived from No. 1 (Copperlode, QLD), No. 4 (Koombooloomba, QLD), No. 6 (Copperlode Falls Dam, QLD), No. 7 (Bambaroo, QLD), No. 9 (Tianma, Dongxi, Fujian), and No. 11 (Leshan, Sichuan) provenances. The provenances of No. 2 (Ravenshoe, QLD) and No. 8 (Tully Gorge National Park, QLD) grow slowly. The best six families were No. 289, No. 283, No. 2, No. 42, No. 121 and No. 82, derived from six selected provenances, indicating that the selected families not only had good growth and branch traits but also had rich genetic diversity.
