Genetic diversity and chemical polymorphism of Thymus caespititius from Pico,São Jorge and Terceira islands (Azores)

Thirty-one individuals from Thymus caespititius were collected on the islands of Pico, São Jorge and Terceira (Azores) and the volatiles were isolated by distillation–extraction and analyzed by GC and GC–MS. The same plants were analyzed by RAPD using 17 arbitrary primers that generated 187 scorable polymorphic bands. The volatile composition of the individuals was in accordance with previous results obtained from the populations’ analysis, confirming that the chemical polymorphism was in some cases more evident among different plants from the same island than among those collected on different islands. RAPDs analyses using the same individuals did not show identical clustering as with the volatile oil profiles and no straight correlation among collection site, chemical analysis and molecular assessments could be found, suggesting that other molecular tools should be explored in order to fully understand the influence of both environmental and genetic factors on volatiles composition.