Effect of different irrigation managements on quantity and quality of sugar beet

Water stress is one of the main factors affecting the quantity and quality properties of sugar beet. The objective of this experiment was to study the effect of irrigation management on quality and quantity of sugar beet. The present research was conducted in Motahary Station of Sugar Beet Seed Institute, Karaj in two years, 005 and 006. The experiment was based on split plot design, in which eight irrigation regimes (non-stress, three levels of withholding irrigation at early growth stage, two levels of continuous drought stress and two levels of withholding irrigation in late season) were allocated to the main plots. Three sugar beet genotypes, 9, BPMashhad and BPKaraj, were assigned to in the sub plots. Sugar content (SC) was influenced by beet water content. In order to study the effect of irrigation managements on this trait, It is recommended to determine SC based on dry weight of roots. Sever early drought stress reduced sodium quantity as compared to the other irrigation levels. Nitrogen content was increased significantly by both levels of continuous drought as compared to the other irrigation levels. Generally, continuous drought (mild and serve) decreased alkalinity and increased the marc percentage. The maximum marc percent was observed in two levels of continuous drought. The lowest root and sugar yield were observed in two levels of continuous drought stress. White sugar yield in severe irrigation withhold in the early season was significantly higher than that of the mild stress during the season. Although, other low irrigation managements had less root yield than non-stress condition but the differences were not significant (P> 0.05). White sugar yield was decreased in two levels of continuous drought stress as compared to non-stress conditions. This important property was not affected significantly by other levels of irrigation treatment. The genotype 9 had more white sugar content and extraction coefficient of sugar, and less Na and alkalinity than the other genotypes. The interaction between genotypes and irrigation was in significant for all traits.