THE RELATIVE CONTRIBUTION OF SEXUAL AND ASEXUAL REPRODUCTION TO GENETIC VARIATION IN NATURAL POPULATIONS OF THE PONDWEED POTAMOGETON PECTINATUS

Knowledge on the relative contribution of sexual vs. asexual reproduction to genetic diversity is important for understanding the population dynamics of species experiencing population decline and for establishing strategies of population restoration. Potamogeton pectinatus may simultaneously reproduce sexually and asexually and plays an important role in sustaining freshwater ecosystem; however, its populations declined dramatically in China recently. We used inter-simple sequence repeat (ISSR) markers to genotype 324 ramets of P. pectinatus from 17 extant Chinese populations. In all, 192 genets were identified. The proportion of distinguishable genets, Nei's gene diversity index, and Simpson's diversity index exhibited considerable levels of clonal and genetic diversity in P. pectinatus populations. Character compatibility analysis revealed that sexual reproduction, rather than clonal reproduction, plays a predominant role in preserving genetic variation of those populations. Seed recruitments, enhanced by habitat disturbances, might partly counteract the effects of habitat loss on genetic diversity of P. pectinatus populations.