Coumarin Content, Morphological Variation, and Molecular Phylogenetics of Melilotus.

and are widely used in forage production and herbal medicine due to the biological activity of their coumarins, which have many biological and pharmacological activities, including anti-HIV and anti-tumor effects. To comprehensively evaluate and coumarin content (Cou), morphological variation, and molecular phylogeny, we examined the Cou, five morphological traits and the molecular characterization based on the L-F spacer and internal transcribed spacer (ITS) regions of 93 accessions. Significant ( < 0.05) variation was observed in the Cou and all five morphological traits in both species. Analysis of population differentiation (Pst) of the phenotypic traits showed that powdery mildew resistance (PMR) had the greatest Pst, meaning that this trait demonstrated the largest genetic differentiation among the accessions. The Pst values of dry matter yield (DMY) and Cou were relatively high. Biplot analysis identified accessions with higher DMY and higher and lower Cou. Analysis of molecular sequence variation identified seven haplotypes of the L-F spacer and 13 haplotypes of the ITS region. Based on haplotype and sequence analyses, the genetic variation of was higher than that of Additionally, ITS sequence analysis showed that the variation among accessions was larger than that among species across three geographical areas: Asia, Europe, and North America. Similarly, variation among accessions for both the L-F and ITS sequences were larger than the differences between the geographical areas. Our results indicate that there has been considerable gene flow between the two species. Our characterization of Cou and the morphological and genetic variations of these two species may provide useful insights into germplasm improvement to enhance DMY and Cou.