Franklinia alatamaha is a small tree in the tea family (Theaceae) that has been valued for its ornamental qualities since 1765, when it was first recorded by John and William Bartram on the Georgia Coastal Plain. The only known population of F. alatamaha became extinct in the wild by the early 1800s. However, F. alatamaha has been cultivated as an ornamental for nearly 250 years. The plants existing today are derived from seeds collected from the Georgia population by the Bartrams. To examine the genetic variation of the cultivated F. alatamaha population, leaves from live and herbarium accessions were obtained from 42 sites worldwide. Genotyping-by-sequencing (GBS) was used to determine the genetic diversity and structure of 76 F. alatamaha accessions, including a 178-year-old herbarium specimen. STRUCTURE analysis with 9604 high-quality single-nucleotide polymorphisms (SNPs) identified two subpopulations within the cultivated accessions. This result was supported by UPGMA (unweighted pair group method with arithmetic mean) and principal component analyses. F statistics indicated that there was a moderate level of genetic diversity among the cultivated accessions (F_ST = 0.09), with more genetic diversity among accessions within a subpopulation than between the two subpopulations. The inbreeding coefficient of the cultivated accessions was low (F_IS = − 0.4902), indicating that the sampled trees represent what was once a highly outcrossing population. Polymorphism was also detected by GBS analysis of 19 F. alatamaha plants grown from gamma-irradiated seeds. The genetic differentiation identified in this study may be useful for further development of new horticultural traits of F. alatamaha.

Franklinia alatamaha是茶科（Theaceae）中的一棵小树，自1765年约翰和威廉·巴特拉姆（John and William Bartram）在佐治亚州沿海平原首次记录以来，就以其观赏品质而受到重视。到1800年代初期，已知的F. alatamaha种群在野外灭绝。但是，阿拉特马哈烟草已经被作为观赏植物栽培了近250年。今天存在的植物来自Bartrams从佐治亚州种群中收集的种子。为了检查栽培的F. alatamaha种群的遗传变异，从全球42个地点获得了活和植物标本室的叶子。测序基因分型（GBS）被用来确定76种的遗传多样性和结构 F. alatamaha种质，包括一个178岁的标本室标本。使用9604个高质量单核苷酸多态性（SNP）进行结构分析，确定了栽培种中的两个亚群。该结果得到UPGMA（具有算术平均值的非加权对群方法）和主成分分析的支持。F统计表明，栽培种之间的遗传多样性水平中等（F _ST  = 0.09），一个亚群内的种质之间的遗传多样性高于两个亚群之间的种质。栽培种的近交系数低（F _IS = − 0.4902），表明采样的树木代表了曾经高度异化的种群。还通过GBS分析检测了19种由伽马射线照射的种子生长的阿拉法马烟草植物的多态性 。本研究鉴定的遗传分化可能对进一步发展F. alatamaha的园艺性状有用。