Effect of bolting on root yield and qualities of autumn sugar beet cultivars

One of the significant limitations in autumn cultivation of sugar beet is bolting. To investigate the quantitative and qualitative traits of root sugar beet cultivars and their resistance to bolting, a two-year (2018-2020) experiment was conducted as a randomized complete blocks design with three replications at Varsan Agricultural Research Station of Golestan Agricultural and Natural Resources Research and Education Center, Gorgan- Iran. Treatments included commercial autumn sugar beet cultivars [five imported cultivars (Montana, Jerra-kws, Rosagold, Chemineh, and Veles) and a domestic cultivar (Sharif). There was a significant difference in bolting rates of all cultivars in both years. Veles and Sharif cultivars had the highest bolting rate (41.7% and 33.3%) in both years, respectively. The bolting rate was higher in the second than in the first year. There was a significant difference between cultivars for root yield only in 2019. The highest (85.2 t ha-1) and lowest (59.8 t ha-1) root yields were obtained from Jerra-kws Chamine cultivars. There was a significant difference between cultivars for sugar purity, sugar extraction coefficient, and molasses sugar percentage in the second year. There was no significant difference between cultivars for sugar content and harmful nitrogen in both years. The cultivars showed different reactions in terms of bolting rate and other root qualitative traits (pure sugar, extraction coefficient, sodium, potassium, and harmful nitrogen levels) in the two years.