The storage losses of sugar beet genotypes are closely related to damage during harvest and subsequent infestation with mould and rots. Genetic variation for storability seems to be primarily linked to textural properties of the roots such as the resistance against mechanical damage. However, no information is available about the tissue strength, tissue composition and structural organization leading to an enhanced resistance against damage and pathogen attack. Therefore, the aims of the study were the identification of genotypic differences concerning tissue strength of the beet, the relation to damage and pathogen infestation and the underlying physiological basis of tissue strength. Field trials were carried out with 6 genotypes at 2 locations in 2018. The roots were harvested in August and November. After harvest in November, a storage trial was carried out. The root strength increased from August to November. Beets with a high puncture resistance of the periderm also had a firm inner tissue. Genotypic differences in puncture resistance were not affected by the harvest time, indicating that this trait is stable throughout the growing period. A higher puncture resistance of the beet was related to a lower mould growth during storage. Genotypes with varying tissue strength also differed in fiber content (AIR), but the composition of AIR was stable over genotypes. The number of cambium rings seems not to essentially influence the tissue strength of the beet. In the further course of the project, microscopic analyzes will clarify, whether genotypic differences in tissue strength can be attributed to cell size or cell wall thickness.