Long-term storability of different sugarbeet genotypes – Results of a joint IIRB study

Abstract

In 2008/09 and 2009/10, storage trials with 12 sugarbeet genotypes were carried out under different conditions in six countries. The genotypes were grown in strips and harvested in September/November either by machine (using good agricultural practice) or by hand. Samples were then stored either in nets incorporated in clamps or in separate nets/bags or containers inside a barn or climate room. All samples were weighed and analyzed before and after storage for sugar (by polarimetry), potassium, sodium, amino nitrogen, total soluble nitrogen, sucrose, glucose, fructose, raffinose, betaine and glutamine content. After storage the samples were also examined visually. Differences between the genotypes were observed for root tip breakage, sprouting, moulds and rot, although these differences were not unambiguous in all experiments and varied between the observations in the different countries. The sugar losses ranged from 0 to 66% of the initial amount and seemed to be related to various biotic and abiotic factors. Root damage by machine harvest and storage temperature were dominant factors in relation to the sugar losses. Genotypes also showed significant differences in sugar losses, but a strong interaction with year and site existed. Correlations could be found between sugar losses and initial sugar content (r = –0.66), initial betaine content (r = –0.62) and root tip breakage (r = +0.66) and after storage, moulds (r = +0.87), rot (r = +0.88) and invert sugars (r = +0.89). Chemical analyses showed differences between the genotypes for the decrease in beet quality after storage, not only by a reduction in sugar content but also by an increase in invert sugar and soluble nitrogen.