Study on morphological and genetic diversity of Rehmannia glutinosa cultivated in Japan

It is said that Rehmannia glutinosa is grouped into two types, Akaya and Kaikei, in Japan. However, previous reports of genetic analysis of R. glutinosa in commercial products suggest the existence of varieties other than these two, and therefore, it is inappropriate to simply classify them into these two varieties. In this study, we clarified the diversity of R. glutinosa cultivated in Japan on the basis of morphological observation and genetic analysis. We conducted principal component analysis (PCA) of R. glutinosa morphology, including leaf surface color, leaf undersurface anthocyanin coloration, root shape, and the ratio of string root. We also performed (1) sequence-related amplified polymorphism (SRAP) analysis and (2) polymorphism analysis of the TEOSINTE BRANCHED1, CYCLOIDEA, and PCF (TCP) gene region. We were able to separate Akaya type from Kaikei type, and to divide Kaikei type into three small groups. These two gene analysis methods were also useful in estimating the patrilineal and matrilineal strains of a hybrid origin. Our findings revealed that Akaya type and Kaikei type can be distinguished on the basis of morphological and genetic analyses, and that Kaikei type cultivated in Japan exhibited morphological and genetic diversity.