Effect of bolting on the yield and quality of two sugarbeet cultivars in autumn sowing area in Dezful region of Iran

The objective of this experiment was to evaluate technological properties of two sugar beet cultivars (HI1059 and Palma) under conditions of bolted and non-bolted plants. The experimental design was randomized complete block design (RCBD) with four replications and was carried outat Safiabad Research Center, Dezful, Iran, in 2011-2012 growing seasons. At harvest, bolted and non-bolted plants of each plot were separated. Sugar content, concentration of impurities (potassium, sodium and amino-nitrogen), molasses sugar, root yield, sugar yield, cutting resistance of rootand vascular tissue to parenchyma tissue ratio traits were measured using standard methods. In general, mean bolting (%) in HI1059 and Palma cultivars were 33% and 51, respectively. Analysis of variance showed that the experimental treatments effect for yield and quality traits of sugar beet was not significant. Results of group comparison between bolted and non-boltedplants in both varieties showed that sugar content reduced from 16.1 to 15.6% on HI1059 variety and from 16.4 to 15.9% in Palma cultivar, respectively, due to bolting. Despite the slight decrease in root yield (5%), and sugar yield (7%) in bolted plants, these reductions were not significant. Similarly, despite a slight increase in concentration of impurities, molasses sugar, energy for cutting root andvascular tissue to parenchyma tissue ratio in bolted plants, differences were not-significant. Although bolting appeared about one month before harvesting in the two sugar beet cultivars, but it had no significant effect on yield and quality of sugar beet. However, bolting causes some disturbs sugar beet harvesting and creates physical and chemical problems in the process of sugar extraction in the factory. Further research of variety trails over growing seasons may provide more knowledge regarding theeffect of bolting on yield and technical quality of sugar beet.