Snowdon, RodStich, BenjaminFlüß, Helge ChristianHelge ChristianFlüß2026-01-222026-01-222025978-3-95547-159-0https://jlupub.ub.uni-giessen.de/handle/jlupub/21255https://doi.org/10.22029/jlupub-20600The global supply of natural rubber is critically dependent on a single species, Hevea brasili-ensis, leaving it vulnerable to disease and economic pressures. This dissertation addresses the urgent need for alternative rubber sources by focusing on the genetic improvement of Rus-sian Dandelion (Taraxacum kok-saghyz, TKS), a promising temperate-climate resource crop. The primary goal was to develop genomic tools to accelerate the breeding of high-yielding TKS varieties. To achieve this, the study first assessed the genetic landscape of TKS and related species. Using Amplified Fragment Length Polymorphism (AFLP) markers, the research confirmed that TKS is genetically distinct from related species like the common dandelion, while also revealing low to moderate genetic diversity within existing breeding germplasm. This highlights a need to strategically incorporate new genetic material to ensure long-term breeding success. A biparental F1 mapping population was created by crossing high and low rubber-producing parent plants. Extensive multi-year field trials across three different locations revealed signifi-cant phenotypic variation for rubber content, ranging from 0.1 % to 24 %. A high broad-sense heritability (𝐻2) of 0.656 was calculated for this trait, indicating strong genetic control and a high potential for improvement through selective breeding. The core of the project involved creating the first high-resolution genetic maps for TKS using Genotyping-by-Sequencing (GBS). This resulted in two detailed parental maps. Each resolved into eight linkage groups corresponding to the haploid chromosome number of TKS. These maps served as the foundation for quantitative trait loci (QTL) analysis to identify genomic regions controlling rubber production. The analysis successfully identified three major, statistically significant QTL associated with rubber content. Two QTL were located on the maternal map and one on the paternal map, with individual loci explaining between 9.1 % and 15.4 % of the phenotypic variance. By aligning these genetic findings with the TKS physical genome, the study confirmed a previously re-ported major QTL region on chromosome A1 and discovered a novel major QTL on chromo-some A7. In conclusion, this research provides a vital genomic toolkit for TKS improvement. The high-resolution maps and identified QTL for rubber content are foundational resources for modern breeding. The SNP markers linked to these QTL can now be used to develop tools for marker-assisted selection (MAS), enabling breeders to identify superior plants at an early stage, thereby accelerating the development of commercially viable TKS cultivars and helping to se-cure a sustainable future for natural rubber.enAttribution 4.0 Internationalddc:630