Adaptation of sugarcane plants to saline soil

•Genetic variation in salt tolerance was found within sugarcane.•The salt-tolerant cultivar maintained biomass, leaf area and photosynthesis at 160 mM NaCl.•The salt-sensitive cultivar suffered at 80 mM NaCl.•The salt-tolerant cultivar excluded Na+ from roots and leaves.•Proline increased with increasing salinity but glycine betaine did not.