DISSERTATION RESEARCH: Weedy Brassica rapa in Mexico: a unique study system to investigate potential ongoing "redomestication" of a feral crop

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

This project investigates the domestication of an important food source, weedy field mustard (Brassica rapa L.). Understanding the transition from wild to domesticated plants provides both important knowledge for crop improvement and a unique opportunity to study evolutionary change because domestication often involves selection for preferred traits. Most humans rely on crops that were domesticated from wild plants thousands of years ago, which makes it a challenge to determine the dual roles of humans and environment in domestication. Examples of people domesticating plants today may provide insights into this process. The researchers will study an ongoing relationship between seven Mexican cultural groups and weedy field mustard to get at the ecological and cultural aspects of domestication. Field mustard was domesticated in Europe and Asia and selected for many diverse forms, such as turnips, bok choi, and Chinese cabbage. It is unclear which domesticated or weedy forms were introduced to Mexico and what region they were introduced from. This project integrates information from genetic data, physical measurements, chemistry, and interviews with farmers, to study an ongoing domestication process. In addition, the project will include the training of undergraduate and graduate students, and contribute to our understanding of crop domestication, food security, and control of an invasive species. Weedy Brassica rapa provides a powerful study system to elucidate plant ferality and domestication. The availability of extensive genomic tools and the plant's short life cycle facilitate the use of inferentially powerful techniques to clarify the nature of local adaptation and artificial selection of invasive field mustard across a country-wide transect of Mexico. The research involves the novel application of RNA-sequencing, reciprocal transplant experiments, glucosinolate chemistry, and semi-structured and structure interviews, to study ongoing domestication of an important food source. Data will quantify the genetic structure and introduction history of B. rapa in Mexico, local uses and management practices of field mustard by different ethnic groups, and how different management regimes drive local population adaptation of the plant.