Strategy and techniques for mapping horticultural genomes

HRI has adopted the strategy of establishing reference populations for genome mapping of horticultural species. In the case ofBrassica oleracea, doubled haploid families have been generated from crosses between subspecies. These lines can be maintained indefinitely by selfing, allowing accumulation of large amounts of data on defined genotypes (using molecular markers) which are then linked with replicated phenotypic assessment In the case of apple, reference progeny segregating for a large number of genes have been established and replicated by grafting for distribution to different regions of Europe. For both species, data are organised in relational databases, allowing full analysis of any relationships which might exist. Methods are being developed to optimise the process of identifying informative molecular markers, with particular emphasis on markers which can be used for a wide range of species.