EVALUATION FOR SALT STRESS TOLERANCE IN TWO STRAWBERRY CULTIVARS

Salt stress conditions have been found to destroy the vital physiological process in plant where slower cell division and cell enlargement or both and limit mineral nutrient uptake with clearly nutritional imbalance. A greenhouse pot experiment was carried out at Agricultural Research Station, Mu’tah University, Jordan to evaluate growth responses and mineral composition of two strawberry cultivars to salt stress by different NaCl levels. Six NaCl levels (0, 25, 50, 75, 100 and 150 mM) and two strawberry cultivars, Camarosa and Albino, were used. Nutrient elements were added at the 0.5-strength Hoagland nutrient concentration. Distilled water supplemented with half strength Hoagland solution was used as control. Number of leaves and runners of both strawberry cultivars were significantly reduced by increasing NaCl level. Growth parameters (shoot, root and total dry weights and root: Shoot ratios) were significantly reduced with each increase in salinity level. Camarosa had higher value for all these parameters compared with Albino. Leaf chlorophyll content of both strawberry cultivars was significantly decreased when 25 mM NaCl or higher was applied. Regardless of NaCl level, Camarosa cultivar had significantly higher chlorophyll content compared with Albino. Elevated salinity level significantly increased leaf proline content of both cultivars. Albino leaves accumulated higher proline compared with Camarosa at salinized and non-salinized treatments. Both strawberry cultivars had significantly higher leaf and root Na and Cl contents under salinized conditions compared with non-salinized conditions. Each increase in NaCl level resulted in an increase in leaf and root Na and Cl contents of both cultivars. On contrast, leaf K content was decreased with salinity, root content of this mineral was significantly increased with salinity. It could be recommended to avoid growing ’Camarosa’ and ’Albino’ strawberry using irrigation water of 25 mM NaCl or more.