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

Abstract

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.