This release of Ensembl Plants includes the genome of Brassica rapa [1].

The Brassica include important vegetable and oilseed crops. The B. rapa varieties include Chinese cabbage, pak choi and turnip. The B. oleracea varieties include broccoli, cabbage and cauliflower. Additionally, over 10% of the world's edible vegetable oil comes from B. napus, B. rapa, B. juncea and B. carinata collectively [2].

The Brassica are a classical example of the importance of polyploidy in plant evolution, described by 'U's triangle' [3]. The three diploid species B. rapa (A genome), B. nigra (B genome) and B. oleracea (C genome) having formed the amphidiploid species, B. juncea (A and B genomes), B. napus (A and C genomes) and B. carinata (B and C genomes) by hybridization. Comparative physical mapping studies have confirmed genome triplication in a common ancestor of B. oleracea and B. rapa since its divergence from the A. thaliana lineage at least 13-17 MYA [4-5].

The BrassEnsembl site was initially developed at Rothamsted Research, working in collaboration with the EBI and other partners [6]. From release 13 of Ensembl Genomes, the EBI will be maintaining the genome browser for B. rapa in the context of Ensembl Plants.

References
[1] The genome of the mesopolyploid crop species Brassica rapa.
[2] Importance and origin. in Breeding Oilseed Brassicas.
[3] Triangle of U - Wikipedia
[4] Rates of nucleotide substitution in angiosperm mitochondrial DNA sequences and dates of divergence between Brassica and other angiosperm lineages.
[5] Comparative genomics of Brassica oleracea and Arabidopsis thaliana reveal gene loss, fragmentation, and dispersal after polyploidy.
[6] http://www.ensembl.org/info/about/credits.html.