桉树纸浆材生长、材性指标近交退化和杂种优势分析

以尾叶桉(Eucalyptus urophylla S.T.Blake)自交F1子代、尾叶桉株间杂交F1子代、尾叶桉自由授粉F1子代和尾×巨桉(E.urophylla×grandis)种间杂交F1子代林为试材,讨论分析了桉树生长、材性指标的近交退化和杂种优势规律性.结果如下:①尾叶桉近交退化现象呈现自交子代比自由授粉子代显著,生长性状比材质性状显著的规律性.②尾叶桉自交子代树高、胸径和材积具有显著至极显著的近交退化;生材含水率、木材基本密度和树皮厚度无近交退化.③尾叶桉自由授粉子代,树高、胸径和材积有一定程度的近交退化,但不甚显著;生材含水率、木材基本密度和树皮厚度无近交退化.④尾叶桉与巨桉种间杂交子代的树高、胸径和材积可获得显著的杂种优势,但不同杂交组合的杂种优势率大有差别;子代的生材含水率、木材基本密度和成熟材纤维长度无杂种优势;子代的树皮厚度和1% NaOH抽提物含量呈显著性降低.

Inbreeding depression and hybrid superiority in growth and wood traits of eucalypt pulp wood

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 significant 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.