Increased regeneration from NaCl-tolerant callus in rice

Summary NaCl-tolerant calli were selected from two Japonica and two Indica rice (Oryza sativa L.) cultivars on basal media containing 6,000, 9,000, 12,000 or 15,000 ppm NaCl. Frequency of callus formation decreased with the increase of NaCl in the medium, especially in Indica. About half of the calli of Japonica cultivars selected on NaCl-ammended media survived 20,000 ppm NaCl but none of the Indica callus survived. In Japonica, more plants were regenerated from calli selected on all concentrations of NaCl media than from NaCl-free medium. Concentration of Cl^- in callus increased dramatically with increased NaCl content but peroxidase activity decreased.