In vitro screening of several potato genotypes (29 cultivars and lines) to salinity stress was conducted. Single
node explants were evaluated on the basis of their growth, microtuberization and biochemical analysis under different
concentrations of salt (NaCl) stress. In most cases, increasing NaCl in the tissue culture medium resulted in reduction in
plantlet growth, rooting and microtuberization potential in varying degrees, depending on the cultivar. Some genotypes
such as Oceania, 97f-267 and Picasso produced higher number of microtuber under 150 mM NaCl than control.
Generally, 97f-267, Oceania and Universa genotypes were ranked among salt tolerant, while Nicola, Safran, Diamant
were ranked as moderate and Elodi, Triomph, Marabel, Bolista and 99-981 were ranked as salt sensitive based on
morphological characters. Photosynthetic pigments decreased under salt stress, however, Universa and Safran
maintained higher chlorophyll content under salt conditions (100 mM NaCl) comparing with control (0.0 mM NaCl)
plantlets. Also, Universa and Safran accumulated more proline and free amino acids under stress treatment comparing
with control, than other tested genotypes. The activities of antioxidant enzymes were different among potato genotypes.
In this respect, Universa and Safran had higher catalase (CAT) activity under salt stress (100 mM NaCl) than control
treatment (0.0 mM NaCl), however, superoxide dismutase (SOD) activity was not good indicator for salinity tolerance
in the tested potato genotypes.