Evaluation of genetic diversity and population structure of polygonati rhizoma germplasms: implications for better crop development and conservation of a traditional Chinese medicine

Polygonati rhizoma (PR) is an important and widely used product in Chinese traditional medicine and edible goods. The time-consuming nature of breaking dormancy in both rhizomes and seeds means that improving variety selection is limited to collection, identification, and selection of germplasms. In this study, we used two DNA-based molecular marker techniques—inter simple sequence repeat (ISSR) and start codon targeted (SCoT)—to assess the genetic diversity and population structure among PR source plants collected from 47 different regions and belonging to 12 populations (P1–P12). For molecular markers analysis, 15 ISSR and 10 SCoT markers were tested. Total number of 159 fragments (150–4000 bp) were amplified based on ISSR analysis with a range from 6 to 17 bands, 153 of them were polymorphic, ranging from 97.27 to 100%. For SCoT analysis, 164 polymorphic bands (150–5000 bp) were observed, varying from 14 to 19 bands for each primer. Nei’s genetic diversity analysis showed that the highest value was found in P11 for ISSR and P4 for SCoT markers. The highest Nei’s genetic diversity value was observed in P5 for combined markers and the low in P2. Nei’s dendrogram constructed with combined markers indicated a 75–89% of genetic similarity coefficient among populations. Population structure analysis revealed an optimum number of three groups, the same as their geographical distribution. This knowledge on PR genetic diversity can be used in future breeding programs, genetic improvement, product enhancement, and germplasms conservation.