The high yield level sugar beet has reached in the past years might have altered the morphology of the storage root. The
study thus aimed at analyzing storage root diameter and length in relation to yield under various environmental
conditions. For that purpose, data of various field and pot experiments were included covering a broad range of storage
root diameters and yield levels of sugar beet. It turned out that there was a close relationship between storage root
diameter and root yield, which was not affected by different environmental conditions (site, year). Furthermore, breeding
progress had obviously not changed this relation, as it was not affected by varieties. Results from pot experiments
could well be compared with field trial data. In field trials, storage root length did not exceed 25 cm independent of
yield level, whereas in pot experiments plants formed longer storage roots with higher yield levels. It is discussed that
increasing penetration resistance in soil could limit the further expansion of the storage root diameter. A more aboveground
growth of the storage root with increasing yield level, however, will make yield estimates based on root diameter
more difficult.