Vavilov (1935) described China as the earliest and largest independent centre of origin of cultivated plants. Gansu Province occupies the geographic centre of China. With an area of 454,000 km2, latitudes ranging from 32°3′N to 42°57′N and elevations varying from 500 to 6200 m, the province has an extremely diverse climate and topography. Stretching 1653 km along the ancient Silk Road, Gansu also has a long history of agriculture (6000 years) and for centuries was exposed to dynamic cultural exchanges between the East and the West. The unique combination of these conditions allowed rapeseed to be introduced from Europe and the Middle East, to evolve over a long time of cultivation and to diversify to adapt to many types of ecological conditions and cropping systems in Gansu. Currently, rich genetic resources exist in Gansu for Brassica rapa, B. juncea, B. chinensis and Eruca sativa. Eight landraces are described to demonstrate the diversity of rapeseed genetic resources in Gansu. It is generally recognized that B. chinensis originated in China. Information provided in this paper suggests that Gansu and its adjacent regions could also be a centre of diversity for B. rapa and B. juncea.