Published online by Cambridge University Press: 25 June 2008
Germplasm accessions of wild Lactuca species are maintained worldwide in ex situ collections as gene reservoirs for quality and disease resistance traits for cultivated lettuce. Accessions of 12 Lactuca species from 6 genebanks were compared via morphological characterization and AFLP (Amplified Fragment Length Polymorphism)-based profiling to estimate the extent of duplication. A method of assessing redundancy within very similar, but not identical accessions, is proposed, based on 352 polymorphic AFLP products. Seven duplication groups showed a high level of AFLP similarity, and one pair of Lactuca saligna accessions displayed identical AFLP profiles. In several cases, the morphological assessment indicated that a taxonomic reclassification of accessions was necessary. Candidate duplicates were identified using population parameters and inter- and intra-accession variability. The implications of these findings on the conservation of wild species are discussed.