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

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.