Biodiv Sci ›› 2019, Vol. 27 ›› Issue (4): 355-365.

• Original Papers: Plant Diversity •

### Genetic diversity and population structure of Populus yunnanensis

Zhang Yahong1,Jia Huixia1,Wang Zhibin2,Sun Pei1,Cao Demei1,Hu Jianjun1,*()

1. 1 State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091
2 Zhangjiakou Jinshatan Forest Farm, Huaian, Hebei 076150
• Received:2019-01-21 Accepted:2019-04-18 Online:2019-04-20 Published:2019-06-05
• Contact: Hu Jianjun

Abstract:

Populus yunnanensis is an endemic tree species to Southwestern China. It is a typical southern Populus species that is fast-growing species with easy to clone propagules and is highly adaptable. It is important to research the genetic diversity and population structure of P. yunnanensis for the collection, preservation and utilization of the germplasm resources. In this study, 64 individuals were collected from six populations, spaning the main distribution areas of P. yunnanensis, including Zhaotong (ZT), Huize (HZ), Songming (SM), Eryuan (EY), Lashihai (LS) and Sichuan Meigu (MG). A total of 34 pairs of SSR primers and three pairs of cpDNA primers were used to determine out the genetic diversity and genetic structure. A total of 154 alleles were detected by SSR primers in P. yunnanensis. The average number of alleles was 4.529. The observed heterozygosity (Ho) and expected heterozygosity (He) were 0.552 and 0.472, respectively. And the average genetic differentiation coefficient (Fst) was 0.238. The average polymorphism information content (PIC) was 0.421 and the gene flow (Nm) was 0.806. The results of the DAPC, PCoA and UPGMA analyses showed that the six populations can be divided into three sub-categories: Group І included ZT, HZ and four individuals of SM. Group II included EY, LS and the six remaining individuals of SM; and group III included MG; SM population include mixed genetic components from І and ІІ. A total of 35 variable sites were detected in the three cpDNA combinations, forming 13 haplotypes. Among them, haplotype H5 was the most widely distributed in the population, while the remaining ones were of private haplotypes. Analysis of molecular variance (AMOVA) showed that genetic variation within the population was greater than between populations. The study clarifies that P. yunnanensis has geographical distribution characteristics and is suited to in situ conservation. As ZT population has the highest genetic diversity and contains seven chloroplast haplotypes, it should be given protection priority.