Summary:

It is widely recognized that the conservation of the Crop Wild Relatives (CWR) in their wild habitats, where they can continue to adapt and evolve along with their natural surroundings, is fundamental to ensure the continuous supply of the novel genetic material critical for future crop improvement. The genus Beta L. (Amaranthaceae) is an important source of crops, primarily for sugar production. Within a broader research project aiming to select appropriate wild accessions and identify priority localities in which to establish genetic reserves of the wild Beta species occurring in Portugal, the aim of this study was to assess the cytogenetic diversity of wild Beta populations. For this, a large scale sampling of natural populations of B. vulgaris subsp. maritima and B. macrocarpa was performed across Portugal (including also the archipelagos of the Azores and Madeira) and genome size and ploidy level estimated using flow cytometry. The analysed populations were mostly diploid, except for one population of B. vulgaris subsp. maritima that presented both diploid and tetraploid individuals, and for two populations of B. macrocarpa where two or three cytotypes (diploids, tetraploids and/or hexaploids) were found. Leaves of both species presented variable levels of endopolyploidy. The obtained results will be discussed within the context of interspecific hybridization and cryptic diversity, and constitute significant data for the conservation of these wild Beta crop relatives.