连续3年对中山杉302(Taxodium ‘Zhongshansha302’)回交一代(Backcrossed F1,简称为BCF1)〔中山杉302(T. ‘Zhongshansha302’)×墨杉(T. mucronutum Tenore)〕的13个无性系的苗期生长量(株高和地径)、标准木的地上部分生物量和分枝结构进行了测定,结果表明:BCF1102、BCF1118、BCF161和BCF1149的生长量和地上部分生物量明显高于亲本中山杉302,可以作为优选出的4个具有潜在推广价值的新无性系:其中BCF1102、BCF1118和BCF1613个无性系树干生物量占地上部分总生物量的比例均大于50%,也高于其他无性系,而树枝生物量比例较低,可以作为速生用材类型,BCF1149树叶生物量占地上部分总生物量的比重高达45%,可以作为速生观赏类型。运用通径分析方法对标准木的分枝结构与树高生长量的关系进行了分析,结果表明分枝数量是树高生长的首要决定因素,这4个速生无性系单株分枝数量高于其他类型。盐碱地造林结果表明:在pH8.5的滨海轻盐上,除BCF161的生长量受到一定抑制外,其他3个无性系BCF1102、BCF1118和BCF1149的生长量仍高于亲本中山杉302。运用RAPD分子标记鉴定了这4个优良无性系的遗传身份。

Growth rate ( height and root diameter ) and biomass above-ground as well as twig structure of the first backcrossed generations of ( BCF1 ) Taxodium `Zhongshansha 302' ×T .mucronatum Tenore were monitored during continued three years. The results showed that the average growths of height and biomass above ground of BCF1102, BCF1 118, BCF161 and BCF1 149 were significantly higher than mother plant T. `Zhongshansha 302' . Among the four, BCF1 102, BCF1118 and BCF1 61 might be used as the type of fast growing timber forest with their higher percentage ( >50% ) of trunk biomass and lower twig biomass to total biomass above-ground, BCF1149 might be used as the type of fast-growing ornamental forest with its higher leaf biomass. The relationships between twig structure and tree height were concluded by path analysis, it showed that twig number was a determinative factor to the growth of height, twig numbers of the 4 merit clones were more than that of other clones. Experiments in saline-alkali soil ( pH 8. 5) indicated that the growth rates of BCF1102, BCF1 118 and BCF1 149 were superior to T . `Zhongshansha 302' except the growth of BCF1 61 were inhibited partly. Genetic properties of the 4 selected clones were verified by RAPD markers.