Interactive Effects of Gibberellic Acid and Nitrogen Fertilization on the Growth, Yield, and Quality of Sugar Beet

Two field trials were conducted during the 2014/2015 and 2015/2016 seasons at Aweesh Al-Hagar Village, center of Mansoura, Dakahlia Governorate, Egypt. A split-split-plot design with four replicates was used. The main plots assigned three nitrogen fertilizer levels, i.e., 165, 220, 275 kg/ha. sub-plots restricted to gibberellic acid (GA3) concentrations, 0, 80, 160, 240 mg/L, sub-sub received GA3 application twice, 60 120 days after planting (DAP). results showed that both root length diameter, foliage fresh weights/plant, yields/ha increased incremental level and/or concentration. Foliar N-fertilizers also significantly decreased quality parameters including sucrose total soluble solid (TSS) percentages. Early (60 DAP) had an active role on sugar beet growth, yield, compared spraying DAP. Generally, fertilizing kg N/ha or a concentration 160 mg/L DAP is recommended treatment for raising yield under ecological circumstances this research.