Abstract
Pu'an County, located in southwestern Guizhou Province, China, is one of the original habitats for wild tea plants. It is renowned not only as the "Home of Ancient Tea Trees in China" but also as the "Core Production Area for High-Quality Early Tea in China". The wild ancient Camellia tetracocca tea trees are considered "living fossil". Understanding the genetic diversity of wild ancient C. tetracocca in Pu'an, Guizhou, is of great significance for addressing conservation concerns and mitigating genetic erosion in this endemic species. This study investigates the genetic diversity and population structure of wild ancient C. tetracocca tea plants in Pu'an County to support the development of conservation strategies. We genotyped 138 ancient wild C. tetracocca specimens using 40 intron-length polymorphism markers. A total of 180 alleles were detected, with the allele numbers per locus ranging from 2 to 10 and an average of 4.50. The number of effective alleles varied from 1.36 to 8.01, with an average of 2.86. The Shannon information index ranged from 0.28 to 2.19, with an average of 1.10. Nei's gene diversity index ranged from 0.14 to 0.88, with an average of 0.58. The polymorphic information content (PIC) varied from 0.14 to 0.85, with an average of 0.58. Our findings indicate that the genetic diversity of wild ancient C. tetracocca tea plants in Pu'an is high. Specifically, the genetic diversity in Qingshan Township surpassed that in Xindian Township. Analysis of molecular variance indicated that 91.59% of the genetic variation occurred within the subpopulations, suggesting limited differentiation. Despite their geographical separation, populations from Qingshan and Xindian showed a complex genetic relationship (FST = 0.04). STRUCTURE analysis identified three distinct genetic clusters, indicating a complex demographic history. These findings underscore the conservation significance of wild C. tetracocca populations in Pu'an and highlight the need for conservation strategies that prioritize the protection of genetically diverse subpopulations, especially in the Qingshan region.