# Genetic Diversity of Sweetpotato (Ipomoea batatas (L.) Lam.) from Portugal, Mozambique and Timor-Leste

## TL;DR

This study examines the genetic diversity of sweetpotato in Portugal, Mozambique, and Timor-Leste, revealing distinct genetic backgrounds despite shared history.

## Contribution

The study provides new insights into the genetic structure of sweetpotato populations from historically connected regions using SSR markers.

## Key findings

- SSR analysis revealed high polymorphism and substantial genetic variability in sweetpotato accessions.
- Population structure analysis grouped on-farm accessions into two clusters and genebank samples into three distinct clusters.
- Azorean landraces were genetically distant from other samples, and Mozambican landraces formed three genetic clusters.

## Abstract

Historically, Portugal played a role in the global diffusion of sweetpotato (Ipomoea batatas). Although, at present, the crop holds limited importance on the Portuguese mainland, it is still highly relevant in the Azores and Madeira archipelagos and in the Portuguese ex-colonies Mozambique and Timor-Leste. Using SSR markers, we assessed the genetic diversity of sweetpotato germplasm from a broad range of geographic regions from the three abovementioned countries, as well as the genetic diversity and identity of sweetpotato accessions held at “Banco de Germoplasma de Moçambique—IIAM”. The relationships and the genetic structures among sweetpotato accessions were also determined. The SSR analysis revealed high polymorphism and numerous alleles per locus, highlighting substantial genetic variability. Population structure analysis grouped on-farm accessions into two clusters, while the genebank samples formed three distinct clusters. Principal coordinate analysis based on the Bruvo distance supported these findings. The Azorean landraces were the most distant from all the other samples. Within the germplasm bank, Mozambican landraces were divided into three genetic clusters, reflecting diverse origins. Our results suggest that, despite shared historical ties, sweetpotato from Portugal, Mozambique and Timor-Leste do not share a common genetic background.

Portugal contributed to the global diffusion of sweetpotato (Ipomoea batatas L. Lam.). Although it is of minor importance on the Portuguese mainland, it is one of the most common crops in the Azores and Madeira archipelagos and is highly relevant in the Portuguese ex-colonies Mozambique and Timor-Leste. We analyzed the genetic diversity and population structure of sweetpotato from these five geographic provenances using twelve nuclear simple sequence repeat (SSR) markers. We studied 45 accessions, 15 of which were collected from farmers’ fields in these five regions and 30 of which are held at “Banco de Germoplasma de Moçambique”. The SSR markers showed a high level of polymorphism and a high number of alleles per locus. Population structure analyses using Bayesian clustering (STRUCTURE) grouped accessions from farmers’ fields into two groups and divided samples of “Banco de Germoplasma de Moçambique” into three groups. A principal coordinate analysis (PCoA), based on the Bruvo distance, supported the population structure analysis. Concerning the genebank accessions, the two analyses indicated three clusters, all of them containing Mozambican landraces. From our results, it may be concluded that sweetpotato populations from the three countries do not share a common genetic background, despite the shared history of the countries.