Studying the Changes of Accumulation some Mineral and Organic Osmoregulator Compounds in Different Sugar Beet (Beta vulgaris L.) Cultivars under Salinity Stress

This experiment was performed to study osmoregulators in sugar beet under salinity stress, and determine the best method for screening of tolerant and susceptible cultivars, in the greenhouse of Shahid Chamran University of Ahvaz during 2009-2010 growing season. Three sugar beet cultivars (BR1, Jolgeh & Rassoul) were grown under three salinity levels including control (Zero), 100 and 200 mM NaCl using factorial experiment based on randomized complete block design with three replicates. The results showed that by increasing salinity, root and shoot dry weight and leaf area decreased significantly (P≤0.01). As salinity increased, leaf relative water content (RWC) and potassium amount decreased. While characters such as relative membrane permeability (RMP), sodium content, proline, and total soluble sugar increased in leaves of all three cultivars. Evaluation of tolerance and susceptibility of cultivars based on stress susceptibility index (SSI) showed that, in 200 mM sodium chloride treatment, cultivars; Rassoul, BR1 and Jolgeh were tolerant, semi-tolerant, and susceptible, respectively. With regard to results the correlation of traits showed that, root dry weight had highest correlation with SSI under salinity stress conditions, so root dry weight could be used as an appropriate criterion for selection of tolerant cultivars at seedling stage.