The Influence of Inbreeding Depression and Hybrid Superiority on Wood Property and Tree Growth of Eucalypt

With F1 of self-pollinated Eucalyptus urophylla, F1 of inter-tree-pollinated E. urophylla, F1 of open-pollinated E. urophylla and F1 of E. urophylla×grandis as materials,inbreeding depression and hybrid superiority in growth and wood traits are analyzed and discussed. The results are as follows. ①There was a regularity for E. urophylla that F1 of self-pollinated was subjected to more intense depression than F1 of open-pollinated, and growth traits showed more signifcant depression than wood traits. ②As to F1 of self-pollinated E. urophylla, height,DBH and volume showed significant or extremely significant depression,while water content of green wood, wood density and bark thickness showed no significant depression. ③As to F1 of open-pollinated E. urophylla, height,DBH and volume showed depression to a certain degree,but not significant; Here again,water content of green wood,wood density and bark thickness showed no significant depression. ④F1 of E. urophylla×grandis showed significant hybrid superiority in height,DBH and volume,but the hybrid superiority percentage of different cross pairs varied greatly; It showed no hybrid superiority in water content of green wood,wood density and fiber length; Its bark thickness and content of 1% NaOH extractives decreased evidently.