桉树种间杂交可配性及可利用组合分析

Cross Compatibility of Interspecific Hybrid Combinations of Eucalyptus and Analyses of Existing Hybrid Combinations

为明晰桉树各树种间杂交可行性,确定适合国内使用的桉树杂交亲本和杂交组合,本研究基于我国已有的桉树树种特性,在保证其他条件一致的情况下,4 a间通过在华南地区对选定的母本和父本进行人工控制授粉,持续跟踪坐果情况并收获果实,使用一般线性模型、相关分析等方法分析各树种间、各父母本间、各组合间杂交可行性和成功率。本研究共进行杂交控制授粉701个组合,参与杂交的母本有6个树种,父本有10个树种,共授粉花蕾26018朵,其中收到果实的组合占53.50%,杂交成功率是22.70%;年份间的杂交成功率差异显著;母本间的杂交成功率差异极显著,杂交成功率与授粉的花蕾数不全为正相关,相关系数在0.4~0.8之间。细叶桉、尾叶桉、韦塔桉为母本的杂交成功率较高,其中细叶桉达到35.99%,按杂交成功率划分可将各母本归为2个子集;父本方面,巨桉杂交成功率达到38.86%,其次是粗皮桉,横脉组做父本杂交成功率较高;不同组之间,横脉组内杂交成功率较高,窿缘组内杂交成功率低,与亲缘关系不成正比,横脉组与窿缘组之间杂交成功率高。尾叶桉、细叶桉是优良母本,巨桉、粗皮桉是优良父本。细叶桉×巨桉、细叶桉×尾叶桉等组合可重点用于台风区,尾叶桉×粗皮桉、尾叶桉×巨桉等组合可重点用于非台风区。

This study aimed to clarify affinities among various species of Eucalyptus and determine their suitability for use as hybrid parents for domestic use in China.Based on genetic relationships between various Eucalyptus species and the characteristics of each species,we carried out controlled pollinations among selected parents in South China over a 4 year period.From these pollinations,seed conditions and harvested seed numbers were assessed to enable analyses of inter-species,inter-parent and other cross combinations using general linear models and related analyses.A total of 701 combinations of controlled pollinations were carried out in this study with 6 female parent species and 10 male parent species.From these pollinations,seeds were obtained from 53.50%of the flowers pollinated with an overall hybridization success rate of 22.70%.Analysis based on the combinations of received seeds showed significant differences in the hybridization success rate among years and among female parents.Even so,hybridization success rate was not positively related to the number of flowers pollinated with correlation coefficients varying between 0.4 and 0.8,The hybridization success rate was higher when Eucalyptus tereticornis,Eucalyptus urophylla and/or Eucalyptus wetarensis were used as female parents,with E.tereticornis providing the highest success rate at 35.99%.Based on hybridization success rates,female parents can be classified into 2 subsets.When used as male parents,the hybridization success rate of Eucalyptus grandis was highest at 38.86%,with Eucalyptus pellita second highest.Species from Section Transversaria generally had a higher success rate as male parents than species from other Sections.When hybridization success was examined on the basis of section,the hybridization success rate of species from Section Transversaria was higher than for species from Section Exsertaria but not proportional to the closeness of the genetic relationships among the species being hybridized.Even so,the overall hybridization success rate of species from both Section Transversaria and Section Exsertaria was relatively high with E.urophylla and E.tereticornis proving good as female parents.Meanwhile,E.grandis,E.pellita proved good as male parents.Other studies have shown that E.tereticornis×E.grandis and E.tereticornis×E.urophylla can be used in typhoon susceptible areas,while E.urophylla×E.pellita and E.urophylla×E.grandis can be used in regions not overly susceptible to typhoons.