# Towards Stewardship of Wild Species and Their Domesticated Counterparts: A Case Study in Northern Wild Rice (Zizania palustris L.)

## TL;DR

This study explores the genetic differences between wild and cultivated Northern Wild Rice, revealing limited gene flow and insights into their population structure and management history.

## Contribution

The study provides new insights into the genetic diversity and population structure of wild and cultivated Northern Wild Rice using genome-wide SNP data.

## Key findings

- Wild Northern Wild Rice populations cluster primarily by geographical location.
- Cultivated populations are genetically distinct from wild ones, indicating limited gene flow.
- Genome-wide scans suggest strong selection pressure in cultivated Northern Wild Rice for irrigated paddy traits.

## Abstract

Northern Wild Rice (NWR;
Zizania palustris
L.) is an aquatic, annual grass with significant ecological, cultural, and economic importance to the Great Lakes region of North America. In this study, we assembled and genotyped a diverse collection of 839 NWR individuals using genotyping‐by‐sequencing (GBS) and obtained 5955 single‐nucleotide polymorphisms (SNPs). This collection consisted of samples from 12 wild NWR populations collected across Minnesota and Western Wisconsin, some of which were collected over two time points; a representative collection of cultivated NWR varieties and breeding populations; and a
Zizania aquatica
outgroup. Using these data, we characterized the genetic diversity, relatedness, and population structure of this broad collection of NWR genotypes. We found that wild populations of NWR clustered primarily by their geographical location, with some clustering patterns likely influenced by historical ecosystem management. Cultivated populations were genetically distinct from wild populations, suggesting limited gene flow between the semi‐domesticated crop and its wild counterparts. The first genome‐wide scans of putative selection events in cultivated NWR suggest that the crop is undergoing heavy selection pressure for traits conducive to irrigated paddy conditions. Overall, this study presents a large set of SNP markers for use in NWR genetic studies and provides new insights into the gene flow, history, and complexity of wild and cultivated populations of NWR.

Analysis of Northern Wild Rice (
Zizania palustris
) wild and domesticated populations reveal little to no gene flow between the two as well as insights into the historical management of wild populations.