Abstract:

In this paper it is reported that the result of early selection for increasing wood density was obtained based on the genetic variation and juvenile-mature correlative analysis in new poplar clones of Populus deltoides×P.simonii. The result showed that the stage from 5th to 6th tree age is better for early selection than other tree ages; at the 5~6th tree age, the genetic gains of early selection is about 8.72%~9.71% and the annual selective efficiency about 141.30%~152.17%. The best stage selected by early selective indexes formed with two or more traits at fifth tree age. The main properties formed indexes for increasing wood density include whole average wood density (ρ_c), annual ring density (ρ_r) and earlywood density (ρ_e). Selected by the best early selective index I=2.2791 (ρ_c) +1.1088 (ρ_r) +1.1589 (ρ_e)(i=2.06) at the tree age of 5, the genetic gain of wood density was about 0.1142g/cm³ and 151.65% higher than the result selected by only direct whole average wood density at mature age of 10.

Key words: Populus deltoides×P.simonii, Wood density property, Early selection