Eco-geographical distribution of Lactuca aculeata natural populations in northeastern Israel

The wild lettuce, Lactuca aculeata Boiss. et Ky., is closely related and fully interfertile with cultivated lettuce, Lactuca sativa L. Altogether, 155 accessions of this wild species, which is rare conserved within the world's germplasm collections, were collected from 12 localities throughout northeastern Israel. Ten of these localities represent different sites across the Golan Heights, while two, high-density populations were suprisingly found at the Hula Plain (first report of this species in this region). Lactuca aculeata was recorded at various elevations (222-968 m a. s. l.) and habitats. The taxonomic status of 30 L. aculeata accessions was morphologically validated during ex situ seed regeneration of 31 random accessions representing all 12 localities. Characterization of 12 traits showed that the Israeli populations of L. aculeata do not exhibit broad morphological variability, but more great levels of variation were obtained for developmental traits. Relatively little variability was observed in the morphology of cauline leaves or in the distribution of anthocyanin pigmentation in bracteae. In two cases, L. aculeata plants lacked trichomes in the inflorescence, a typical feature in the majority of plants. These unique collections of wild lettuce may carry novel sources of genetic variation for a wide range of traits and, thus, should be of interest for careful evaluation and exploitation in lettuce breeding.