# Scaling up orphan crop research: genebank genetics highlight geographic structure in cultivated cowpea from 10 617 global accessions

## TL;DR

This study analyzes the genetic diversity of cowpea using 10,617 global samples, revealing distinct genetic groups and highlighting untapped resources for crop improvement.

## Contribution

The largest genetic diversity analysis of cowpea to date, revealing global genetic structure and duplication patterns across genebanks.

## Key findings

- Nine distinct genetic groups with geographic associations were identified, reflecting dispersal history and regional adaptation.
- Redundancy across genebank collections suggests a need for better curation and integration of cowpea germplasm.
- Sub-Saharan African landraces do not capture all global genetic diversity, indicating untapped resources elsewhere.

## Abstract

Vigna unguiculata (L.) Walp. is a dryland legume crop, providing essential food and nutritional security for millions of people across the semi‐arid tropics, in Africa, Asia and Latin America. However, as a typical ‘orphan crop’, cowpea has long remained underrepresented in global genomic research to support crop improvement. Here, we conducted the largest genetic diversity analysis of cowpea to date, comprising 10 617 accessions sourced from seven international collections. Using genotyping‐by‐sequencing, we characterised the global patterns of genetic diversity, assessed redundancy within and across collections, and examined the geographic structure of the cowpea global allele pool. Our results revealed nine distinct genetic groups with clear geographic associations and fine‐scale population differentiation, reflecting dispersal history, regional adaptation and the influence of modern breeding. Duplication across collections was detected, highlighting the need for improved curation and integration of germplasm resources. Landraces from sub‐Saharan Africa do not fully capture the genetic diversity present in several other geographic regions, indicating the existence of abundant and untapped genetic resources worldwide. These findings not only provide insights into the genetic structure and evolutionary history of cowpea but also offer a valuable foundation for harnessing global germplasm diversity to enhance breeding potential and accelerate crop improvement.

Cowpea genetic diversity assessments have focused on African germplasm with limited exploration of cowpea germplasm from multiple genebanks and origins. This cowpea collection revealed that cowpea's dispersal history throughout the globe is synonymous with its genetic structure, highlighting opportunities to enhance crop improvement by utilising untapped worldwide genetic resources.