Impact of gibberellic acid on yield and quality of some sugar beet varieties

Abstract

A field experiment was conducted in Hafir Shehab El-Din (Dakhalia Governorate), Egypt (latitude of 31.5 N, and longitude of 30.32 E), and elevation of 15 m above sea level) during the 2018/2019 and 2019/2020 growing seasons, to study the impact of gibberellic acid on the yield and quality of some sugar beet varieties. A randomized complete block design (RCBD) using stripplot arrangement with four replication was used in both growing seasons, where four gibberellic acid concentrations (control= distilled water, 100 ppm, 200 ppm and 300 ppm) occupied the main plots, while the four multi-germ and mono-germ sugar beet varieties namely, Belatos, Hercule, Helsinki and Bersea, allocated in the sub-plots. The plot area was 21 m 2 (1/200 fed.) and consisted of 6 ridges, 7 m length, 0.5 m width and 0.20 m spacing between hills. Seeds were sown in the first week of October, as well as sugar beet was harvested at the age of 210 days. The soil of the experimental site was clay. All studied traits (root fresh weight, sucrose%, root yield and yield/fed.) were highly significantly affected by the two studied factors (gibberellic acid concentrations and sugar beet varieties) in both growing seasons. All studied traits were increased by increasing gibberellic acid concentration and the highest mean values were obtained by 300 ppm gibberellic acid treatment, in both growing seasons, except sucrose % was superior with 200 ppm treatment in the second growing season. The Bersea variety realized the maximum mean values for root fresh weight (kg/plant) and root yield (ton/fed.) in both growing seasons, combined with sucrose% and sugar yield (ton/fed.) in the first growing season only.