Genotyping-by-Sequencing data of weedy and domesticated Brassica rapa L.

The study of domestication contributes to our knowledge of evolution and
crop genetic resources. Human selection has shaped wild Brassica rapa into
diverse turnip, leafy, and oilseed crops. Despite its worldwide economic
importance and potential as a model for understanding diversification
under domestication, insights into the number of domestication events and
initial crop(s) domesticated in B. rapa have been limited due to a lack of
clarity about the wild or feral status of conspecific non-crop relatives.
To address this gap and reconstruct the domestication history of B. rapa,
we analyzed 68,468 genotyping-by-sequencing-derived SNPs for 416 samples
in the largest diversity panel of domesticated and weedy B. rapa to date.
To further understand the center of origin, we modeled the potential range
of wild B. rapa during the mid-Holocene. Our analyses of genetic diversity
across B. rapa morphotypes suggest that non-crop samples from the
Caucasus, Siberia, and Italy may be truly wild, while those occurring in
the Americas and much of Europe are feral. Clustering, tree-based
analyses, and parameterized demographic inference further indicate that
turnips were likely the first crop type domesticated, from which leafy
types in East Asia and Europe were selected from distinct lineages. These
findings clarify the domestication history and nature of wild crop genetic
resources for B. rapa, which provides the first step toward investigating
cases of possible parallel selection, the domestication and feralization
syndrome, and novel germplasm for Brassica crop improvement.