Genetic diversity and clonal structure of Rubia peregrina in Mediterranean vineyard and unmanaged habitats

Abstract

Summary:The genetic diversity and clonal structure of weedy and non‐weedy populations of a clonal perennial, Rubia peregrina L., were investi gated in a vineyard and in unmanaged habitats of Southern France. The overall genetic diversity of populations was evaluated on a large scale, whereas spatial distribution and clonal structure were studied on a small scale. Isozyme phenotypes were identified using electrophore‐sis of three polymorphic enzyme systems. Most isozyme phenotypes were restricted to one population. Intra‐population genetic diversity did not differ between populations, whereas clonal structure did. In the vineyard, few clones forming numerous packed ramets and with dis tinct areas were identified, whereas in the unmanaged habitats a higher number of inter mingled clones, forming few widely spaced ramets, were observed. The variability in clonal structure may be linked to different responses of clones to the contrasting environmental condi tions. These results suggest that the colonizing ability of a clonal perennial weed is not necessarily associated with low levels of genetic diversity, but may be related to the variability of the clonal structure.