桉树种间杂种优势和优良杂种的评选

HYBRID HETEROSIS OF EUCALYPTUS SPP.AND SELECTION

以桉树属的１９个种间杂种，４个母本天然授粉子代，１个尾对桉优良种源原种为试材，在广东省新会市大泽镇进行造林试验，２年生的调查资料分析结果如下：（１）杂种间的树高、胸径、单株村积和蓄积量生长有极显著的差异。（２）杂种间超亲优势的变异幅度较大，树高为５９．１１％～３．３８％、胸径７８．５５％～３．２０％、单株材积２１９．１０％～１３．６６％、蓄积量３３８．２３％～２５．４４４％、保存率４２．３１％～３．３３％。（３）按２０％的选择强度初步评选出４个优良的杂种，与对照种相比较，入选的杂种的平均单株材积的实际增益分别为１２２．５％、１１３．５％、８０．３％和６５．９％。

A trial was established at Xinhui city, Guangdong province with 19 interspecific hybrids of Eucalyptus spp., 4 families from natural mother trees and one super provenance of Europhylla. The analysis of investigation data indicated after planting in tWo years: (1) there were sighficant diffprenas in height, D. B. H., individual volume accumulation (IVA) and biomass among the hybrids. (2) The variance of hybrid heterotis were also sighficant, they were 59. 11%- 3. 38% hisher in height, 78. 55%-3. 20% higher in D. B. H., 219. 10%-13. 66% more in IVA, 338. 23%￣25. 444% more in biomass and 42. 31 %￣3. 33% higher in survival rate than those of their agents. (3) In case of selection rate being 20%, four hybyids had been Preliminarily determined to be superiors, which were 122. 5%, 113. 5%, 80. 3% and 65. 9% more in IVA than the control (the Provenance of E.urophylla) respectively.