Eco-geographical distribution of lactuca saligna natural populations in israel

Crops can be drastically improved by effective utilization of the immense variation in genetic resources for resistance to abiotic and biotic stresses possessed by natural populations of wild relatives. To protect Israel's and the world's lettuce crop, samples of seeds from 562 plants that morphologically seemed to be the wild species Lactuca saligna L. (least lettuce, willow-leaf lettuce) were collected from 41 localities, representing different climatic and edaphic environments throughout Israel. Searching and collecting trips were conducted in September-October of 2004-2006. L. saligna was recorded throughout Israel except for desert areas (e.g., Negev and Judean deserts) and extreme environmental/soil conditions (Dead Sea area). L. saligna was recorded at various altitudes (10 to 1277 m asl) and different habitats and soil types. In all, the taxonomic status of 214 of the accessions was morphologically validated as L. saligna during multiplication of 220 accessions in the greenhouse. In rosette formation and leaf morphology, different morphotypes of L. saligna were distinguished in the territory of Israel. Individual populations varied in size and morphological uniformity/heterogeneity. Natural infection by diseases was not recorded in collected populations of L. saligna. We believe that the unique collection of this wild lettuce could carry previously unknown morphological and genetic variation, including resistance against pathogens and pests, hence could be suitable for further detailed research and exploitation in lettuce breeding.