Genetic relationships among Rehmannia glutinosa cultivars and varieties

Many cultivars of Rehmannia glutinosa are grown in China for medicinal uses, but detailed agronomic and morphological descriptions are available for only a few. Knowledge of genetic relationships among most of the cultivars is also scanty and poorly documented. Here, cultivars, varieties and some sexually produced seeds of R. GLUTINOSA were raised in the field and studied for morphological diversity including shape, color, edges of leaves, color of anther, cornal and root, as well as yield of the medicinal part of the roots. Random amplified polymorphism DNA (RAPD) and amplified fragment length polymorphism (AFLP) were used to determine genetic relationships and ribosome DNA internal transcribed spacer (ITS) sequences were used for analyzing sequence variations and phylogenetic history. The 118 and 1019 polymorphic markers produced by 10 RAPD and 8 AFLP primers discriminated cultivars and varieties satisfactorily. Sixty-eight accessions were clustered in three main groups at 0.69 similarity levels by unweighted pair-group method arithmetic average (UPGMA) cluster analysis using RAPD in combination with AFLP markers. The average polymorphism information content (PIC) and Shannon index were 0.438 and 2.19 in RAPD and 0.476 and 26.68 in AFLP primers, respectively. This indicates that AFLP markers would be more efficient than RAPD for screening large numbers of R. GLUTINOSA accessions. The analysis of ITS sequences indicated that ITS1 - 5.8S-ITS2 of R. GLUTINOSA was informative in its 611 - 614-bp-long sequence and had 106 variable sites. Phylogenetic trees generated based on ITS sequences as well as the dendrogram obtained from two molecular markers identified four accessions: BY3, BY5, BY6 and Wildness6, with great genetic divergence.