FROM TRAIT TO GENOME: CHARACTERISING BRASSICA DIVERSITY

¹ Horticulture Research International, Wellesbourne, Warwick, CV35 9EF, UK

Modern crop varieties generally comprise a narrow genepool, despite the existence of extensive allelic variation within germplasm collections. In order to provide tools that will broaden the genetic diversity available for future crop improvement, it is important to understand the relative contribution of specific alleles to desirable traits. For Brassica crops there is an increasing amount of information available at the genetic and genomic level. For B. oleracea we have characterised a wide range of quantitative trait loci (QTL) using reference doubled haploid (DH) populations and saturated linkage maps. In order to understand such traits in the context of natural variation, we are developing Diversity Fixed Foundation Sets (DFFS). The DFFS are collections of genetically fixed lines that represent a snapshot of diversity within the relevant genepool. Extending the development of these structured core collections for other Brassica species will facilitate representative surveys and compilation of data for comparative studies. To underpin UK oilseed rape crop improvement, we are initiating development of B. napus DFFS within the Defra OREGIN project , and hope that this will catalyse establishment of an international reference set. For each DFFS we are ensuring that allelic variation is 'fixed', preferably through use of doubled haploid lines, or alternatively by inbreeding. This allows a wide range of phenotypic and genotypic studies to be carried out on replicated plants over many years. Seed, DNA, genotype and phenotype information will be secured long-term and be available in the public domain to encourage widespread use.