Redundancy and distinctness in flax germplasm as revealed by RAPD dissimilarity

Molecular characterization ofex situplant germplasm, although more attainable than before, has rarely been applied to a whole germplasm collection of 2000 accessions or larger. The benefits of screening large numbers of accessions have not been well recognized for germplasm management and utilization. Challenges also exist in identifying duplicated and genetically related accessions and in validating developed core subsets. Here we show how a new approach using an average marker-based dissimilarity of an accession in a collection can be applied to identify both redundancy and distinctness in a plant germplasm collection. Application of this dissimilarity measure to 2727 flax accessions genotyped by 149 randomly amplified polymorphic DNA (RAPD) markers revealed that up to 22% of accessions could be deemed to be redundant. Up to 500 of the most distinct flax accessions were identified and these can be directly screened for traits of interest to broaden the genetic base in a flax improvement programme. These results demonstrate that molecular screening of a large number of accessions with an informative diversity analysis can facilitate the management and utilization ofex situplant germplasm.