CLONAL DIVERSITY IN A RHODODENDRON FERRUGINEUM L. (ERICACEAE) POPULATION INFERRED FROM AFLP MARKERS

In the European Alps, Rhonodendron ferrugineum can constitute dense po pulations with almost 100% of cover. The developmental pattern by laye ring and the resulting complexity of population structure make it diff icult to identify distinct clones even by excavation. Therefore genoty pic structure of a R. ferrugineum population, in the French Alps, was inferred from AFLP markers. In a first step, we analysed 400 samples u sing AFLP profiles generated by one selective primer pair. Seventeen b ands out of 25 were polymorphic (68%). We identified a total of 32 mul tilocus genotypes. In a second step, the 32 genotypes were verified by applying two additional primer pairs to the two most distant samples from each genotype. The mean similarity (proportion of band sharing) b etween pairs of clones was 0.85 (range from 0.52 to 0.94). The spatial distribution of clones showed that vegetative spreading mainly occurr ed down a slope. Based on an annual shoot mean growth of 2.6 cm/year a nd the size of the widest clone, we estimated the age of the oldest in dividual to be at least 300 years. A single genotype can occupy a larg e surface and sometimes form a dense patch, suggesting that this speci es adopts a phalanx growth form with limited intermingling of some gen ets.