Improving Root Quality and Yield of Sugar Beet by Nano-silicon and Tebuconazole Under Limited Irrigation

Recently, nano-fertilizers and triazoles have been employed in agriculture as a new strategy to reduce the unfavorable effects of water stress. Thus, this study aimed to assay the role of nano-silicon and tebuconazole on sugar yield and root impurities under normal and drought stress conditions. The experiment was performed as a split-plot factorial experiment based on a randomized complete block design with three replications during two consecutive seasons (2016 and 2017). The treatments which included three levels of irrigation regime were carried out as the main plot including 100%, 75%, and 50% sugar beet evapotranspiration (ETs), and factorial combination of tebuconazole (0 mg L−1 and 25 mg L−1) and nano-silicon (0 mM, 1 mM, and 2 mM) were implemented as a subplot. Severe water deficiency had deleterious effects on yield, root quality, and physiological traits. However, under severe water stress, nano-silicon at 1 mM significantly decreased root α-amino nitrogen and sodium contents by 32% and 43% in 2016 and 25% and 37% in 2017, respectively, compared to the control treatment. In contrast, nano-silicon and tebuconazole significantly increased leaf relative water content, root calcium content, and sugar yield. In general, under severe water stress conditions, the significant effects of nano-silicon on sugar yield are due exclusively to improved root quality traits (especially α-amino nitrogen and sodium contents). Besides, the findings provide data that nano-silicon and tebuconazole might have a high potential for profitable sugar production under water stress.