Genome‐wide comparative diversity uncovers population structure, global distribution, and targets of selection in hexaploid oat

Here, we performed comprehensive genomic analyses aimed at elucidating the population structure, worldwide phylogeography, and breeding selection in cultivated oat. We utilized 73 261 single-nucleotide polymorphisms from a diverse collection of 920 oat accessions, encompassing 487 landraces and 433 modern cultivars. Through an examination of spatial and genetic patterns, we identified six genetic groups among landraces. Geographical isolation, founder effects, and chromosomal structural variations were responsible for the observed genetic structure. Phylogeographic reconstruction traced modern cultivars primarily back to the European gene pool, while highlighting the genetic distinctiveness of the East Asian hulless oats and Mediterranean landraces, which represent underutilized reservoirs of diversity. A comparative scan for selection signatures across major breeding regions demonstrated that modern breeding efforts have tapped into only a fraction of the diversity present in landraces, revealing both shared and region-specific selection targets. This study provides a comprehensive variation map and offers insights into the distribution of genetic diversity in oats. The findings emphasize the importance of leveraging landrace germplasm, particularly from East Asian and Mediterranean origins, to broaden the genetic base of modern oats and guide the development of cultivars with enhanced yield and adaptability.