show Abstracthide AbstractReference genome assembly for Brassica rapa subsp. trilocularis R-o-18, an inbred line of the mustard crop yellow sarson. The genome assembly includes pseudochromosome molecules that have been anchored an oriented with respect to the linkage groups A01-A10 of B. rapa. This was achieved by allele matching of >12,000 genome by sequencing markers that segregated in a recombinant inbred line population generated from an F1 of R-o-18 x Chiifu-401-2 (B. rapa subsp. pekinensis) The genome has been aligned with that of Z1 (subsp. trilocularis) and Chiifu (subsp. pekinensis). The R-o-18 inbred line has been used as a model for a range of genetic, functional genomics and related studies. This includes the RevGen EMS TILLING population (Stephenson et al. (2010) https://doi.org/10.1186/1471-2229-10-62) and a DNA hypomethylated population (Amoah et al. (2012) DOI: 10.1186/1471- 2229-12-193). The availability of this genome aligned with the initial reference Chiifu Chinese Cabbage genome (Wang et al. (2011) doi: 10.1038/ng.919 ) with an associated RIL population allows detailed analysis of collinearity and functional alleles affecting post-domestication evolution of crop types. R-o-18 has phenotypic characteristics of short generation time, no vernalisation requirement, self-compatibility, non-branching habit, yellow seed coat, high seed seed erucic acid and high seed glucosinolate content.