Study of variation of six wood traits among Eucalyptus urophylla families

The six wood traits of 32 Eucalyputs urophylla families at 75-month-old were studied.There are obvious differences or very significant differences in all 6 wood traits among 32 families,and this verifies that through selection,the families or clones with good traits can be obtained.The wood basic density,wood moisture content,fiber width,ratio of fiber length to width are correlated with the wood growth and form-quality traits at a general level,and this shows that the 4 traits can be inherited according to Mendel's Law and selected respectively.The fiber length are correlated with tree high,diameter at breast height and individual volume at a significant level or a very significant level,and this indicates that the fiber length increases as tree age grow.The wood traits are improved along with the increase of tree age.The heritability of all wood traits are about 0.5,and this shows that all wood traits are under genetic strong control;and among the six traits,water content,basic density,bark thickness and ratio of fiber length to width have higher genetic variation coefficient(%),and this proves that Eucalyputs urophylla families have more abundant genetic variation and the genetic improvement to the families can produces higher genetic gains.The average genetic gains can reach 5.68 % ～17.66 % for wood moisture content,basic density,bark thickness and ratio of fiber length to width if the selection rate of the superior families are 25%.