Population structure and genetic diversity of rubber-producing dandelion (Taraxacum kok-saghyz) and other Taraxacum species

The Russian dandelion species Taraxacum kok-saghyz Rodin (TKS) is known to produce high quality natural rubber (NR) in its rootstock. Therefore, it has the potential to have a lasting impact on the NR industry. However, TKS breeding is still in its early stages. The assessment of population structure within and among diverse sets of TKS plant genetic resources will contribute to sustainable breeding progress. Furthermore, the quantification of genetic diversity within species that are closely related to TKS and comparing them to TKS will highlight the potential of interspecific hybridization breeding. Using a genotyping-by-sequencing (GBS) approach, TKS germplasm from Kazakhstan as well as European diploid and triploid Taraxacum species (referred as TO) were genotyped. By including published GBS data for germplasm collected in China, we determined the genetic differentiation. Additionally, we conducted an in-depth characterization of inter vs. intra accession diversity based on a SeqSNP approach within publicly available TKS USDA-ARS accessions. Our results revealed a low to moderate genetic differentiation and weak population structure. TO germplasm as well as Chinese collections from the literature exhibited higher genetic diversity. Furthermore, 557 species-specific markers were developed which will facilitate the study of recombination between TKS and TO genomes. This study provides comprehensive insights into the population structure and genetic diversity of TKS and wild TO plant material. These findings may ensure future breeding progress. Access to genotypic data of closely related species will facilitate to harness the chances of interspecific hybridization and introgression.