Abstract:
The genetic diversity and genetic structure of
Rhododendron hemsleyanum were analyzed, and the evolutionary history of the population was discussed, so as to provide scientific basis for the protection and utilization of its germplasm resources and the reintroduction. The genetic diversity was high at the population level (
He=0.2267±0.002;
π=0.2410±0.0032).The genetic differentiation among populations was moderate (
FST=0.0626). AMOVA analysis showed that 98.42% of the total genetic variation existed within populations, and only 1.58% existed among populations. The observed heterozygosity and expected heterozygosity were 0.1636±0.0020 and 0.2267±0.0020, respectively, and the inbreeding coefficient (
FIS) was 0.2220±0.0222. All populations showed heterozygosity loss. Cluster analysis revealed that the six populations could be classified into two groups, and most individuals (98.8%) had clear pedigree. During the recent evolutionary period, the effective population size (
Ne) continued to decline until about 1000 years.
R. hemsleyanum was rich in genetic diversity in both species and population aspects, and had potential for further selection and breeding utilization. The level of genetic differentiation was medium, and the genetic variation mainly existed within the population. Due to the changes of climate and environment during the last glacial period, coupled with human activities (tourism development, infrastructure construction, etc.), the living environment gradually deteriorated, making the species face a high risk of extinction. From the perspective of conservation of this critically endangered plant, it is necessary to establish a natural conservation area for effective protection as soon as possible, and at the same time to strengthen the study of artificial breeding technology, so as to expand the population size and maintain its genetic diversity, which is of great significance to the population recovery, development and utilization of
R. hemsleyanum.