Genetic structure of island populations of wild cardoon [Cynara cardunculus L. var. sylvestris (Lamk) Fiori] detected by AFLPs and SSRs

Wild cardoon [Cynara cardunculus L var. sylvestris (Lamk) Fiori] is a non-domesticated robust perennial plant characterized by a rosette of large spiny leaves and branched flowering stems. It is native to the Mediterranean basin where it grows in a variety of habitats, from mesic riparian sites to xeric rocky slopes. Wild cardoon is potentially exploitable for the production of lignocellulosic biomass, oil from seeds, and biopharmaceuticals, such as caffeoylquinic acids (cynarine) and luteolin from leaves, and inulin from roots. The genetic variation present at microsatellite (SSR) and amplified fragment length polymorphism (AFLP) loci has been assessed in seven Italian populations of wild cardoon, collected from Sicily and Sardinia. Thirty individuals, randomly sampled from each population were genotyped at five SSR loci and fingerprinted using seven AFLP primer combinations. Genetic distance estimates both within and between populations were consistent between the two marker systems. As a result of the geographical isolation, the Sardinian and Sicilian populations were clearly differentiated, forming two distinct gene-pools. Most of the genetic variation was partitioned within rather than between populations. The genetic distribution will allow the design of rational sampling strategies to capture the genotypic range present.