Einfluss von Genotyp, Erntetechnik und Erntebedingungen auf die Entstehung von Lagerfäule und die Invertzucker-akkumulation während der Langzeitlagerung von Zuckerrüben

Since 2013, the glucose content of all beet samples from beet reception and field trials is routinely analyzed in The Netherlands using a biosensor which is integrated into the automatic beet laboratory system. The invert sugar content is subsequently calculated from the glucose content using a linear conversion factor. This additional information helps to identify beet deliveries with a questionable beet quality at an early stage and provides valuable information on various agronomic factors that increase invert sugar accumulation in the beet. Based on results obtained during the past years, different factors are highlighted that affect the invert sugar content in the beet. Among these factors, beet deterioration following frost damage and the presence of root rot due to infestation by pests and diseases have shown to increase the invert sugar content dramatically. In addition, unfavorable storage conditions and bad harvesting quality had a substantial impact on invert sugar accumulation. Growth conditions and beet variety also influenced the invert sugar content markedly, although to a much lesser extent. Using the obtained data, the most important control measures that enable growers to prevent undesired invert sugar formation and consequent sugar losses in their beet are discussed.

Effect of agronomic factors on invert sugar accumulation in sugar beet

Leijdekkers¹

2016

Zuckerrübenlagerung – vom Mikrobiom zum Transkriptom

Liebe¹,

Varrelmann²

2018

Durch die zunehmende Verlängerung der Verarbeitungskampagne haben sowohl die Bedeutung der Zuckerrüben-lagerung in Feldrandmieten wie auch die dabei auftretenden Zuckerverluste zugenommen. Während der Lagerung wird die Zuckerrübe von Mikroorganismen besiedelt, die Lagerfäulen hervorrufen. Es wird vermutet, dass der dadurch entstehende Zuckerverlust auf die Aktivität von pflanzlichen und mikrobiellen Saccharose abbauenden Enzymen zurückzuführen ist, jedoch fehlte bisher der experimentelle Nachweis. Ziel der Untersuchungen war es daher, die Gen-expression dieser Enzyme in der Interaktion zwischen der Zuckerrübe und dem Lagerfäuleerreger Fusarium graminearum zu analysieren, um Rückschlüsse auf ihre Aktivität zu ziehen. Mit Hilfe des Verfahrens der real-time PCR (qPCR) konnte die Expression der pflanzlichen und mikrobiellen Gene nachgewiesen werden, wobei das Expressionsniveau eine starke Variabilität in Abhängigkeit vom untersuchten Gewebe (nekrotisch, Übergang, gesund) und der Inkubationsdauer (7, 14, 21 und 28 Tage) aufwies. Tendenziell zeigten die mikrobiellen Gene eher eine reduzierte Expression während der Fäulnisausprägung, wohingegen die pflanzlichen Gene zum Teil eine starke Expression aufwiesen. Die Ergebnisse demonstrieren erstmalig, dass die Ausbildung von Lagerfäulen zu einer starken Induktion pflanzlicher und mikrobieller Saccharose abbauender Enzyme führt. Dies verdeutlicht die zentrale Bedeutung mikrobiell induzierter Zuckerverluste für die Zuckerrübenlagerung.

Importance of harvesting system and variety for storage losses of sugar beet

Hoffmann¹,

Engelhardt²,

Gallmeier³

et al. 2018

Damage resulting from harvest operations increases the storage losses of sugar beet. Because of different equipment, the kind and extent of damage may differ between harvesting systems. The objective of the study was to analyze (I) the impact of different harvesting systems and cleaning intensities on damages of sugar beet, and furthermore, (II) the effect of these damages on storage losses. In 2015 and 2016 at four sites, two sugar beet varieties were harvested with two six-row harvesters (axial rollers versus turbines for cleaning) using three cleaning intensities with three replicates in tracks of 200m length. Roots were stored in a climate container at 9°C for 5 and 12 weeks. The results show that the diameter of root tip breakage and surface damage increased with cleaning intensity. Marked differences occurred among varieties and sites. The factor analysis indicates that the extent of damage (root tip breakage, surface damage) had a considerable impact on the infestation with mold and rots, the accumulation of invert sugar and sugar losses after storage. However, the higher root tip breakage of beets harvested by harvester2 was accompanied by lower sugar losses than in harvester1 after 12weeks storage, in particular with the aggressive cleaning intensity. The marked impact of the cleaning intensity emphasizes the importance of the operator and of the optimal setting of the harvester for a good harvest quality and thus storability of sugar beet.