In vitro Salt and Drought Tolerance of Manfalouty and Nab El-Gamal Pomegranate Cultivars

Pomegranate is a major fruit crop recommended for new reclaimed soils in Egypt. Stress tolerance to salinity and drought predominant in there soils initiated goals of this investigation. Shoots produced from micropropagation of two main pomegranate cultivars; Manfalouty and Nab El-Gamal on woody plant medium (WPM) supplemented with mg/l 5.0 GA3, 0.02 IBA and 0.1 BA at establishment stage and 1.0 mg/l BA at multiplication stage were cultured on WPM containing 0.0, 4.0, 6.0 and 8.0 g/l NaCl in vitro salt tolerance. For in vitro drought tolerance, WPM medium was tested at full strength supplemented with polyethylene glycol (PEG) at zero, 5 and 10%. All studied characteristics of both cultivars negatively responded to the increasing of NaCl concentration. Survival percentage, plantlet height, average leaves number, average number of nodes, average internode length and fresh and dry weight significantly decreased using 6.0 and 8.0 g/l NaCl compared to control. Additionally, the two cultivars treated with 4.0 and 6.0 g/l NaCl had significantly lower contents of nitrogen, phosphorus, potassium, calcium and magnesium % and higher sodium % compared to control. The highest value of sodium % and the least values of other elements were obtained by 6.0 g/l NaCl. Moreover, same characteristics also significantly decreased by increasing the concentration of PEG from zero to 5 and 10%. Manfalouty plantlet had slightly (insignificant) higher values of these characteristics compared to Nab El-Gamal one. N, Ca and Mg content in Manfalouty and Nab El-Gamal plantlet significantly decreased by increasing PEG concentration. K content took the contrary trend and slightly increased (insignificant). The highest contents of P and Na in both cultivars were recorded using 5% PEG compared to control and 10% PEG