Clonal selection in a globe artichoke landrace: characterization of superior germplasm to improve cultivation in Mediterranean environments

The morphological (using International Union for the Protection of New Varieties of Plants (UPOV) descriptors) and field performance of five clones selected from the globe artichoke landrace Spinoso di Palermo were determined over two seasons, and their amplified fragment length polymorphism (AFLP) profiles detected using seven primer combinations (PCs). The number of heads produced averaged 13·8 per plant (equivalent to a fresh weight yield of 2·1 kg/plant), but two of the clones produced 15·6 heads per plant (2·4 kg/plant). Three clones produced noticeably larger second-order heads (mean of 156 g), and so were considered to be suitable for the production of desirable heads over a prolonged harvesting period. Head yield and the number of heads per plant were associated with a moderate level of broad sense heritability (0·29–0·46), implying that these traits could be viewed as primary selection criteria. From the list of 51 UPOV descriptors, 18 varied among the five clones, but variation at just six, simply scored, descriptors was sufficient to discriminate completely between the examined clones. Full discrimination was also achieved by applying only three of the seven selected AFLP PCs. According to the AFLP profiles, two of the clones were highly similar. The similarity matrices calculated from the UPOV descriptors and the AFLP profiles were highly correlated with one another. The data are optimistic and indicate that the performance of Spinoso di Palermo could be much improved via clonal selection.