鹅掌楸属种间杂种苗期生长性状的遗传变异与优良遗传型选择

Variation and Selection of Interspecific Hybrid in Liriodendron

以１个中国马褂木（Ｌｉｒｉｏｄｅｎｄｒｏｎ ｃｈｉｎｅｎｓｅ（Ｈｅｍｓｌ．） Ｓａｒｇ．）自由授粉家系为对照，对鹅掌楸属２３个种间杂种家系２ａ生苗木生长性状的研究结果表明，在苗高和地径性状上，正交、反交、回交及Ｆ１个体之间相互杂交４种交配系统之间无显著差异，但家系间在两个性状上的差异均达极显著程度（Ｐ＜０．０１）。对于苗高性状，家系平均变异系数为２９．１６％、家系内平均变幅为２．３１ｍ，在地往性状上，家系平均变异系数为３１．８７％、家系内平均变幅为２．６３ｃｍ。因此，在鹅掌楸属种间杂种优势开发中，上述４种交配系统均可采用，重点应进行家系选择和家系内选择。如果选前１０名家系，苗高和地径平均生长量可分别提高８．３０％和９．７３％。选出７株优良单株的平均苗高为３．６８ｍ，平均地径４．４ｃｍ，与杂种家系平均值相比，苗高和地径平均生长量分别可提高４５．８３％和８２．１７％。

Using one opening pollinated family of Liriodendron chinense as check, the variation of height and GLD (ground line diameter) traits among 4 matting systems and among and within 23 hybrid families in Liriodendron were studied based on the increment after the second growing season. The results revealed that the 4 matting systems of direct cross, reciprocal cross, back cross and cross among F1 individuals did not have significant difference, while the families within matting systems different significantly (P < 0. 01). The mean CV within families in height and GLD traits were 29. 16% and 31. 87%, respectively. The mean ranges within families in the two traits were 2. 31 m and 2. 63 cm, respectively. Therefore, the 4 matting systems all could be used. But for obtaining higher heterosis and gain, family selection and within family selection should be carried out. If the 10 superior families were selected, the gains in height and GLD would be 8. 30% and 9. 73%, respectively, compared with the mean of overall hybrid families. Seven superior individuals with mean height 3. 68 m and mean GLD 4. 4 cm had be selected. The gains in height and GLD were 45. 83% and 82. 17% respectively.