油松种子发芽率和苗木高生长的近交效应

The Effectof Inbreeding on the Germination of Seedsand the Incrementof Seedlings of Pinustabulaeformis

在油松种子园中对 6个无亲缘关系的无性系进行双列杂交 ,包括自交。同时取亲本的自由授粉种子作为对照。在它们的子代林中 ,取一个全同胞家系和一个自由授粉家系 ,各选 4～ 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 ,油松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)的增加而增大 ;同异交相比 ,自交、回交和全同胞交配组合的种子发芽率分别平均降低 88%、42 %和 2 0 % ,苗木平均高度分别下降2 7%、17%和 13% ;不同个体之间近交衰退程度存在明显差异。

Intercross and selfing within 6clones without genetic relationship was made in seed orchard of Pinus tabulaef ormis.The seeds from free pollination of them were taken as controls.In the F1 stands,4～ 6florescent individuals were se- lected from a full sib genealogy and a free pollination genealogy.Tests of inbreeding selfing,backcross,and cross among full sibs and cross were conducted respectively. The result showed that,due to inbreeding,the germination percentage of seeds and height increment of seedlings of Pinus tabulaef ormiswere decreased and the larger the inbreeding coefficient,the larger the inbreeding depression was.In comparison with seeds from cross,the germination percentage of seeds from selfing,back- cross,and cross among full sibs decreased to88% ,42 % and2 0 % respectively,and the height increment of seedlings decreased to 2 7% ,1 7% and 1 3 % respectively. The result also showed that,among the individuals,there was obvious difference in degrees of the inbreeding deprssion.