杉木种子发芽率和苗木高生长的近交效应

THE EFFECT OF INBREEDING ON SEED GERMINATION AND SEEDLING HEIGHT GROWTH OF CHINESE FIR

在杉木种子园中对6个无亲缘关系的无性系进行了双列杂交,包括自交。同时取亲本的自由授扮种子作为对照。在他们的子代林中,取一个全同胞家系和一个自由授粉家系,各选4至6株开花植株连同它们的亲本,分别进行自交、回交、同胞内交配和异交测定。结果表明,杉木近交使得种子发芽率和苗木高生长量大幅度下降。近交衰退随着近交系数(F)的增加而加大。同异交相比,自交、回交和全同胞交配、半同胞交配组合的种子发芽率分别平均降低约88％、42％和20％,苗木平均高度分别下降27％、17％和13％左右。结果也显示,在不同个体之间近交衰退程度存在明显差异。

Six unrelated clones of Chinese fir in a seed orchard were mated using full dialel mating pattern with selfing and open-pollination. Seeds were collected from each parent, testings were also established. And then, in this progeny test plantation, the 4-6 flowered trees in one full-sib family and one open-pollinated family were chosen to be mated in involving self-, back-, within sib- and outcrossing. Three groups of experiments indicated that inbreeding resulted in much reduction both in seed germination and seedling height growth. The inbreeding depression has increased with the increase of inbreeding coefficients, Comparing with outcrossing, the percentages of seed germination of selfing, backcrossing and full-sib-mating, half-sib-mating have been reduced by about 88 %, 42 % and 20 %, and those of seedling height growth reduced by about 27%, 17% and 13% respectively. There were significant differences in inbreeding depression between the families or mating parents.