鹅掌楸不同交配组合子代遗传多样性分析

揭示不同交配类型与子代遗传多样性的关系, 对于林木杂交育种及种子园管理具有理论与实践意义。文章选取来自鹅掌楸、北美鹅掌楸及杂交鹅掌楸的16个交配亲本, 共组配14个杂交组合, 分属5种交配类型, 分别为种间杂交、种内交配、多父本混合授粉、回交、以及自交。每个交配组合随机抽取30个子代, 利用SSR分子标记检测各子代群体遗传多样性以及16个交配亲本间的遗传距离。结果表明, 总体上, 鹅掌楸交配子代群体具有较高的遗传多样性。5种交配类型子代群体中, 遗传多样性水平由高至低的趋势为: 多父本混合授粉子代、种间交配子代、杂种F1与亲本的回交子代、种内交配子代, 自交子代。子代遗传多样性与亲本间遗传距离呈显著正相关, 表明亲本间遗传距离大, 则子代遗传多样性高。相同亲本正反交子代群体的遗传多样性差别不明显。

Comparison of genetic diversity among five mating types of Liriodendron revealed by SSR markers

The exploration of relationships between mating patterns and genetic diversity of progenies has theoretical and practical significance for both interspecies hybridization breeding and seed orchard management in tree species. Sixteen plants of Liriodendron chinense, L. tulipifera, and hybrid Liriodendron were chosen as the mating parents. Fourteen combinations were obtained from 5 types of mating types including inter-species mating, intra-species mating, multi-male parent pollination, backcross and self-cross in Liriodendron. Thirty progenies from each combination together with 16 mating parents were sampled to appraise their genetic diversity and inter-parent genetic distance using 16 SSR loci. Overall, a rela-tively high level of genetic diversity was found in the progenies of the 14 mating combinations in Liriodendron. The order of genetic diversity levels among the progenies of 5 types of mating systems from high to low was multi-male parent polli-nation, inter-species, backcross, intra-species, and self-cross, respectively. A significant positive correlation was found be-tween genetic distance of the mating parents and genetic diversity of corresponding progeny, indicating that the bigger the genetic distance of mating parents, the higher the progeny genetic diversity. The level of genetic diversity of the progenies of reciprocal crosses with the same parents was almost identical.