Integrative assessment of Azorean Daucus: contributions to an integrative assessment of Daucus carota subsp. azoricus Franco in the Azores.

backgroundThe Azorean carrot, Daucus carota subsp. azoricus Franco, has long been considered an endemic subspecies, yet its distinctiveness from other members of the D. carota complex remains debated. Diagnostic traits proposed by Franco (1971) are often inconsistent in the field, and molecular evidence has questioned whether the taxon represents a true native or a more recent introduction.

resultsOur integrative analyses combining molecular (ITS, COS), cytogenetic, morphological, and ecological data revealed no clear phylogenetic, morphological or cytogenetic differentiation between Azorean accessions. The convergence of umbel diameters when grown in identical environments and the variation as a continuum observed in the morphometric analyses when the subspecific identification was imposed suggests that at least some morphological variation observed in the field is environmentally induced rather than genetically fixed. Molecular analyses placed Azorean accessions within the broader D. carota complex. Nonetheless, the presence of 12 exclusive haplotypes to archipelago, of which one seems to be an ancestral haplotype, suggests long-term persistence and local diversification rather than a solely recent introduction, even in the context of centuries of reproduction with the cultivated carrot.

conclusionAzorean Daucus is best interpreted as part of the D. carota complex, showing signals of gene flow and plasticity, but the gaps in our study did not enable us to distinguish it at the subspecific level. Moreover, the lack of morphological data from islands beyond São Miguel limits broader comparisons, underscoring the need for more comprehensive morphological, genomic, and comparative sampling across Mediterranean and Macaronesian populations. Until such data are available, it is perhaps most appropriate to regard Azorean Daucus carota as a native lineage, whose precise taxonomic circumscription remains to be clarified.