Genetic diversity and population structure of Opisthopappus longilobus and Opisthopappus taihangensis (Asteraceae) in China determined using sequence related amplified polymorphism markers

The genetic diversity and structure of four Opisthopappus longilobus and nine Opisthopappus taihangensis populations from Mts. Taihang were analyzed using SRAP markers. The results showed that O. longilobus (PPB = 95.16%, H = 0.349, I = 0.517) and O. taihangensis populations (PPB = 94.58%, H = 0.332, I = 0.504) had high genetic diversity. The genetic diversity within populations varied according to two species. Low genetic differentiation was detected among O. longilobus (ΦST = 0.105) and O. taihangensis (ΦST = 0.188) populations, respectively. Significantly genetic variation was found between O. longilobus and O. taihangensis (ΦST = 0.232). The dendrogram generated from pairwise genetic distance among all populations showed two distinct clusters, each corresponding to one species. A Mantel test revealed insignificant positive correlation between genetic distances and geographic distances (rO. longilobus = 0.3021; rO. taihangensis = 0.3658; P > 0.05). Those results indicated that self-compatibility, effective gene flow, biological traits, and historical factors may be the main factors causing geographical differentiation in the structure of O. longilobus and O. taihangensis populations.