Susceptibility to root tip breakage increases storage losses of sugar beet genotypes

Abstract

Good storability of sugar beet is of increasing importance, not only to reduce sugar losses, but also with regard to maintaining the processing quality. Genotypic differences are found in storage losses. However, it is not clear to which extent damage may contribute to the genotypic response. The aim of the study was to quantify the effect of root tip breakage on storage losses of different genotypes. For that purpose, in 2012 and 2013, six sugar beet genotypes were grown in field trials at two locations. After lifting roots were damaged with a cleaning device. They were stored for 8 and 12 weeks, either under controlled conditions in a climate container at constant 8°C, or under ambient temperature in an outdoor clamp. The close correlation underlines that storage losses under controlled conditions (constant temperature) can well be transferred to conditions in practice with fluctuating temperature. The strongest impact on invert sugar accumulation and sugar loss after storage resulted from storage time, followed by damage and growing environment (year × growing site). Cleaning reduced soil tare but increased root tip breakage, in particular for genotypes with low marc content. During storage, pathogen infestation and invert sugar content of the genotypes increased with root tip breakage, but the level differed between growing environments. Sugar loss was closely related to invert sugar accumulation for all treatments, genotypes and environments. Hence, it can be concluded that root tip breakage contributes considerably to storage losses of sugar beet genotypes, and evidently genotypes show a different susceptibility to root tip breakage which is related to their marc content. For long-term storage it is therefore of particular importance to avoid damage during the harvest operations and furthermore, to have genotypes with high storability and low susceptibility to damage.