An examination of hybridization between the cattail species Typha latifolia and Typha angustifolia using random amplified polymorphic DNA and chloroplast DNA markers

Typha glauca represents a significant portion of the biomass of the wetland s surrounding the Great Lakes, USA. It is generally accepted to be a form o f hybrid between T. latifolia and T. angustifolia, which itself appears to be an exotic introduction from Europe. Based on morphological and isozyme d ata, conflicting theories have been proposed for the hybrid nature of T. gl auca: it has been described as a hybrid swarm, a distinct hybrid species an d an F-1 hybrid. Therefore, we developed random amplified polymorphic DNA ( RAPD) and chloroplast DNA markers, specific to the parental species, to ass ess hybrids. Ten RAPD primers gave 17 fragments specific to T. angustifolia and 13 fragments specific to T. latifolia. All of the interspecific hybrid s contained each of the species-specific markers, indicating an F-1 hybrid status. Furthermore, all hybrids tested contained the T. angustifolia chlor oplast haplotype, which is consistent with differential interspecific cross ing success found previously. Additional confirmation of an F-1 hybrid stat us was gained by examining seedlings from T. glauca. These progeny were exp ected to be advanced-generation hybrids, as opposed to the F-1 hybrid paren t. Analysis of the seedlings revealed segregating marker patterns consisten t with patterns observed in experimental advanced-generation hybrids, altho ugh these advanced hybrids do not appear to be a significant part of mature stands. Our data do not provide support for extensive gene now between T. latifolia and T. angustifolia. However, our results suggest that hybridizat ion between the native and introduced Typha species has impacted the native population through the spread of the F-1 hybrid, T. glauca.