Exploring the diversity of three Northern Atlantic sea beet populations

Sea beet [<i>Beta vulgaris</i> ssp. <i>maritima</i> (L.) Arcang.] populations exhibit high genetic diversity and possess valuable traits that could enhance resilience, disease resistance, and tolerance to abiotic stress. In contrast, the genetic variation in the sugar beet breeding gene pool is limited. Our objectives were to examine sea beet population diversity using high-density marker data and substantial sample sizes within a population simultaneously. Their genetic diversity and population structure were investigated to evaluate their potential for direct mapping of traits with association mapping. Within this study, a total of 1,363 genotypes across three Northern Atlantic sea beet populations from Denmark, France, and Ireland were analyzed using 16,201 SNP markers. The findings reveal genetic variation among the populations, with the Irish population exhibiting the highest genetic diversity and pronounced population structure. The Danish population showed low genetic diversity and minimal population structure, while the French population displayed intermediate levels of both, genetic diversity and population structure. Based on its high genetic diversity, the Irish population appears to have the most potential for use to directly map traits by association mapping, provided that the challenges posed by the severe population structure can be adequately addressed within analysis.