2.03 VARIETIES AND GENE EXPRESSION
Variety is a collection of stable traits, assessed primarily phenotypically (Gemet, 2023). Differences between varieties in storage losses during long-term storage are commonly observed for sugar beet, and similar to respiration, variety is a factor in the long-term post-harvest storage of sugar beet roots that interacts with many other factors. It cannot be taken as a dimension of plant health per se, only as a useful indicator of possible health status of a plant under certain conditions. This may soon change. Relatively new work from both North America and Europe has begun to study the genetic foundations of storability of sugar beet. Madritsch et al. (2020) found clear differences in gene up- and down-regulation during post-harvest storage, Karen K. Fugate et al. (2022) has linked this to respiration rates suggesting it is the transport of sucrose from vacuoles that is controlled and which in turn controls rates of respiration, and Gippert et al. (2022) linked storability to the presence of free amino acids and the down-regulation of genes involved in amino acid degradation. While this work is very exciting for the future of breeding for storage of sugar beet roots, variety is still but a (very useful) proxy for health.