New insights gained from collections of wild Lactuca relatives in the gene bank of the Institute of Evolution, University of Haifa

The Institute of Evolution's (IoE's) Wild Lettuce Gene Bank (WLGB), established in the mid 1990s, contains new and extensive collections of five wild Lactuca relatives (WLRs) originating from Israel and Armenia: L. serriola, L. aculeata, L. georgica, L. altaica, and L. saligna. The objectives of the WLGB relate to the identification, collection, distribution, conservation, and characterization of the population genetic structure of these unique germplasms for crop improvement. Comprehensive studies are ongoing to determine the taxonomic position and crossing potential of the critical mass of collected species with domesticated lettuce, L. sativa, based on: (i) select morphological and phenological characteristics; (ii) molecular data; (iii) downy mildew resistance and (iv) variation in biologically active secondary metabolite content. In this review we present an overview of our key findings and highlight the advances in knowledge on these themes. Our germplasm collections and novel results, obtained by detailed, large-scale screening of natural populations and individuals for genetic variation, will considerably advance crop breeding research and practices. In addition, we critically summarize the recent literature and findings relating to three additional WLRs: L. dregeana, L. scarioloides, and L. azerbaijanica. The main long-term purpose of our research is to facilitate broadening of the genetic variation of domesticated lettuce by using new and adaptive germplasm in interspecific hybridization of lettuce.