A search for diagnostic AFLP markers in Cichorium species with emphasis on endive and chicory cultivar groups

The genus Cichorium consists of two widely cultivated species C. intybus (chicory) and C. endivia (endive) and four wild species, C. bottae, C. spinosum, C. calvum, and C. pumilum. A multivariate and an UPGMA (unweighted pair group method average) analysis based on AFLP (amplified fragment length polymorphism) markers were used to establish the genetic relationships among the species and cultivar groups of C. intybus and C. endivia. At the species level, the results correspond with previously obtained phylogenetic relationships in that C. bottae is the most divergent species, and C. intybus and C. spinosum, as well as C. endivia, C. pumilum, and C. calvum formed clusters. Based on the congruence between phylogenetic and genetic analyses, unique markers were expected for all species, however, hardly any specific marker was found except for C. bottae. The analysis of cultivar groups of C. intybus resembled the species analysis in two respects: (i) grouping of cultivars according to cultivar groups, and (ii) lack of markers unique to cultivar groups. In contrast to C. intybus, the cultivar series of C. endivia do not form distinct groups, which would reflect that crosses have been made among the various cultivar groups. The relationships among Cichorium species and cultivars will be useful for setting up a core collection of Cichorium, and stress the importance of inclusion of the wild species in the collection.