Distribution and abundance of Beta patula Aiton and other crop wild relatives of cultivated beets on Madeira

In the Archipelago of Madeira four crop wild relatives of beets are native: Beta patula, Beta vulgaris subsp. maritima, Patellifolia procumbens, and Patellifolia patellaris. All species are valuable genetic resources for the sugar beet breeding. Only in the very eastern part of the Madeira Island on the islet Ilhéu do Desembarcadouro and Ilhéu Chão the endemic species Beta patula can be found. On both islets the plant number of this very rare species, and of the two widely distributed species B. vulgaris subsp. maritima and P. procumbens was established and the habitat described. The results of the species census are presented. The establishment of a genetic reserve for Beta patula is suggested in this paper with the objective to protect this species more effectively.