# Exploring the genetic diversity of the IPK Medicago germplasm collection using GBS

## TL;DR

This study used DNA sequencing to explore the genetic diversity of 1234 Medicago plant samples, revealing important differences between wild and cultivated species.

## Contribution

The study provides one of the first genus-wide insights into the genetic relationships of both cultivated and wild Medicago species.

## Key findings

- Cultivated Medicago sativa and Medicago × varia show less genetic diversity and cluster together due to gene flow.
- Wild Medicago species display more complex and differentiated genetic structures.
- The study highlights the importance of the IPK collection for conservation and breeding strategies.

## Abstract

The genus Medicago, which includes the widely cultivated forage crop alfalfa, is of significant agricultural and ecological importance. Understanding genetic diversity in Medicago is essential for the conservation of its germplasm and its utilisation in plant breeding. This study aimed to assess the genetic diversity and population structure of the Medicago germplasm collection at the German Federal Ex situ Gene Bank.Genotyping‐by‐sequencing was used to analyse 1234 accessions of the Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), representing 40 Medicago species. After filtering, a high‐quality dataset of 23,315 single nucleotide polymorphisms (SNPs) was generated.Our analyses revealed distinct genetic clusters corresponding to Medicago species and sections, with cultivated M. sativa L. and M. × varia Martyn clustering together with less genetic diversity compared to their wild counterparts. This reflects the shared genetic composition and extensive gene flow between M. sativa and M. × varia, commonly considered a hybrid between M. sativa and M. falcata L. Wild species displayed a more complex genetic structure, with polyphyletic patterns indicating higher genetic differentiation that reflects their diverse evolutionary histories and ecological adaptations.In conclusion, the comprehensive diversity analysis of the IPK Medicago collection provides valuable insights for gene bank management, targeted conservation efforts and strategic breeding initiatives.

The genus Medicago, which includes the widely cultivated forage crop alfalfa, is of significant agricultural and ecological importance. Understanding genetic diversity in Medicago is essential for the conservation of its germplasm and its utilisation in plant breeding. This study aimed to assess the genetic diversity and population structure of the Medicago germplasm collection at the German Federal Ex situ Gene Bank.

Genotyping‐by‐sequencing was used to analyse 1234 accessions of the Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), representing 40 Medicago species. After filtering, a high‐quality dataset of 23,315 single nucleotide polymorphisms (SNPs) was generated.

Our analyses revealed distinct genetic clusters corresponding to Medicago species and sections, with cultivated M. sativa L. and M. × varia Martyn clustering together with less genetic diversity compared to their wild counterparts. This reflects the shared genetic composition and extensive gene flow between M. sativa and M. × varia, commonly considered a hybrid between M. sativa and M. falcata L. Wild species displayed a more complex genetic structure, with polyphyletic patterns indicating higher genetic differentiation that reflects their diverse evolutionary histories and ecological adaptations.

In conclusion, the comprehensive diversity analysis of the IPK Medicago collection provides valuable insights for gene bank management, targeted conservation efforts and strategic breeding initiatives.

Genotyping‐by‐sequencing of 1234 accessions from the Medicago collection of the Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) revealed broad genetic diversity across 40 species, providing one of the first genus‐wide insights into relationships between both cultivated and wild species of Medicago.