Elevated Salinity in Irrigation Water Reduced Growth of Ricinus communis L. Cultivars

The greenhouse experiment was conducted to evaluate the salt tolerance of six castor (Ricinus communis L.) cultivars (‘Brigham’, ‘Energia’, ‘Hale’, ‘HCastor’, ‘Memphis’, and ‘Ultra dwarf’). Plants were irrigated with nutrient solution at electrical conductivity (EC) of 1.40 dS∙m^-1 or saline solution at EC of 10.0 dS∙m^-1 for 69 days. All plants irrigated with saline solution were shorter than those with nutrient solution. The reduction in height was 40%, 39%, 44%, 38%, 51%, and 50%, respectively, for ‘Memphis’, ‘Brigham’, ‘HCastor’, ‘Ultra dwarf’, ‘Energia’, and ‘Hale’, compared to their respective controls. The fruit dry weight (DW) of ‘Brigham’, ‘HCastor’, ‘Ultra dwarf’, and ‘Hale’ irrigated with saline solution was significantly reduced by 65%, 66%, 60%, and 78%, respectively. Although a reduction of 57% and 55% in the fruit DW was recorded for ‘Energia’ and ‘Memphis’, respectively, there was no significance between saline solution and nutrient solution. Total DW of the plants irrigated with saline solution decreased by 60% for ‘Memphis’ and 70% to 78% for other cultivars as compared with those irrigated with nutrient solution.  Based on the above results, ‘Memphis’ was more tolerant to salinity than other cultivars.