Comparison of genetic diversity in four Typha species (Poales, Typhaceae) from China

Life history traits play an important role in the level and distribution of genetic diversity, and comparing closely related species with similar life histories can provide insight into the determinants of genetic variation in plant populations. In this study, we used variations of one chloroplast DNA fragment, one nuclear gene, and six microsatellites to compare the levels and distributions of genetic diversity in four widespread Typha species from China. Surveys were conducted on 898 individuals from 120 sites. The individuals of all four species formed monophyletic clades and distinct genetic clusters, suggesting no hybridization between T. angustifolia and T. latifolia in China. The levels of cpDNA nucleotide diversity followed the order T. latifolia > T. laxmannii > T. angustifolia > T. orientalis, whereas the genetic diversity in nDNA and nSSR of T. laxmannii and T. angustifolia was higher than that of T. latifolia. In T. angustifolia, T. laxmannii, and T. orientalis, more than half of genetic variation occurred within populations, and in T. latifolia, most of genetic variation occurred among populations. The variation in the levels and distributions of genetic diversity among the four species can be attributed to differences in inflorescence characteristics which either limit or enhanced outcrossing rates.