通过矮化措施控制桉树砧木树体高度，再将从雷州林业局选出的6个桉树树种的31个优良无性系嫁接于矮化砧木上，然后以嫁接好的穗条作为母本进行控制授粉。结果表明：与砧木 U6的嫁接亲和性由大到小为韦塔桉 F1代杂交种＞尾叶桉＞粗皮桉＞韦塔桉＞细叶桉＞巨桉。通过人工杂交现已成功收集了17个杂交组合的种子，不同父本与同一母本的杂交组合产生的子代间在座果率、单果产种量和单果重量上均有显著差异。从座果率和单果产种量看，以 M1（E.urophylla×E. tereticornis）为母本的杂交组合表现都比较好，座果率平均为60%；韦塔桉2-1（E.wetarensis）×尾巨桉2 号（E.urophylla×E.grandis）、韦塔桉2-1（E.wetarensis）×巨桉L118（E.grandis）和尾叶桉3-5(E. Urophylla)×韦塔桉09-23A（E.wetarensis）的组合亲和性也较高，矮化园杂交育种已初见成果。%Thirty-one excellent clones belonging to six Eucalyptus tree species were selected from the forests of Leizhou Forestry Bureau, Guangdong province as the tested materials. By means of apical dominance inhibition and layering, the Eucalyptus stock-trees’ height was dwarfed, and the 31 selected clones were grafted to the dwarfed stock-trees, then the controlled pollination was conducted by using the grafted scions as the female parent. The results show that the grafted compatibility values of the 6 species with U6 as the rootstock ranked from large to small as follows: E. wetarens(F1 hybrid)> E. urophylla > E. pellita > E. wetarensis >E. tereticornis > E. grandis. Through artificial hybridization technique, the seeds of 17 hybridized combinations were successfully obtained. There were significant differences in fruit set percentage and single seed-yield and single fruit mass between the hybridized combinations of filial generations produced different male parent and same female parent. From fruit set rate and fruit seed yield, the hybridized combinations that took M1(E.urophylla×E. tereticornis)as the female parent all showed better performance than others, the mean fruit-setting rate was 60%; the grafted compatibility of E.wetarensis 2-1 × No.2(E.urophylla × E.grandis), 2-1(E.wetarensis) × L118(E.grandis)and 3-5 (E. Urophylla) ×09-23A(E.wetarensis)were relatively higher. The cross-breeding of Eucalyptus in the dwarfing garden has been some encouraging progress.
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