Abstract Detail

Crops and Wild Relatives

McAlvay, Alex [1], Ragsdale, Aaron [2], Qi, Xinshuai [3], Bird, Kevin [4], Velasco, Pablo [5], Pires, Joseph Chris [6], Emshwiller, Eve [7].

Domestication and ferality of Brassica rapa (pak choi, napa cabbage, oilseeds, and turnips) clarified through Genotyping-By-Sequencing.

The study of domestication and wild forms of crop species enhances our knowledge of artificial selection and crop genetic resources. Crops in the genus Brassica present a powerful model to understand domestication due to dramatic morphological differentiation of crops and availability of extensive genomic tools. Human selection has shaped Brassica rapa into diverse leafy (e.g., pak choi, napa cabbage, rapini), oilseed (e.g., sarsons, turnip rape), and turnip crops. Despite the global economic importance of B. rapa crops, the nature of weedy forms, center(s) of domestication, and origins of morphotypes are unclear, jeopardizing the ongoing resilience of B. rapa crops. To address this knowledge gap, we used genomic data from genotyping-by-sequencing to investigate genetic diversity, structure, and demography in the largest diversity panel of B. rapa crops and weeds to date. We also constructed a species distribution model for wild B. rapa during the mid-Holocene, when domestication is thought to have occurred. Weedy samples from the Caucasus had the highest nucleotide diversity and emerged as sister to all other B. rapa samples in our tree-based analyses, suggesting that spontaneously occurring B. rapa in the Caucasus are truly wild. Weedy samples from Europe and the Americas had lower diversity and were affiliated with European turnip crops suggesting a feral origin. Clustering and tree-based analyses suggested that turnips were the first crop type domesticated, with subsequent parallel selection for leafy and oilseed types in East Asia and Europe. These findings clarify the domestication history of B. rapa and the nature of spontaneous populations, which will help conserve crop wild relatives and support future studies of the complex process of domestication.

1 - 20 N Franklin St., Madison, WI, 53703, United States
2 - McGill University, 3640 rue University, Montréal, QC, H3A 1B1, Canada
3 - University Of Arizona, 2929 E 6th Street Apt 210, Tucson, AZ, 85716.0, United States
4 - Michigan State University, Horticulture, 1066 Bogue St., East Lansing, MI, 48824, United States
5 - Misión Biológica de Galicia, Carballeira, 8. Salcedo, Pontevedra, Galicia, 36143, Spain
6 - 371 Bond Life Sciences Center, 1201 Rollins Street, Columbia, MO, 65211, United States
7 - UW-Madison, Botany Dept, 321 Birge Hall, 430 Lincoln Drive, Madison, WI, 53706, United States

Keywords:
domestication
Crop wild relatives
Brassica
feral.

Presentation Type: Oral Paper
Session: 9, Crops and Wild Relatives
Location: 109/Mayo Civic Center
Date: Monday, July 23rd, 2018
Time: 2:30 PM
Number: 9005
Abstract ID:537
Candidate for Awards:None