The aim of this study was to determine the effect of salinity stress and evaluate the effectiveness of seed priming in increasing salt tolerance of rice (Oryza sativa L.) accessions from Mozambique and improving their yield and grain composition. Seeds of three rice accessions (Chincherica, Gaza and IR64) were primed with solutions of 200 mM CaCl2 (?s= -1.25 MPa) and 297 mM KNO3 (?s= -1.25 MPa), for 36 h at 25 oC +2 oC, and non-primed (control). Plants were grown in a hydroponic system, in a controlled environment, under two salt treatments (60 mM NaCl and 0 mM NaCl (control)). Salinity stress decreased shoot dry mass and shoot K+/Na+ discrimination, and increased shoot Na concentration. Under 60 mM NaCl, plants of rice accession Chincherica died before the reproductive stage and there was a dramatic reduction of grain yield on the rice accessions Gaza and IR64. Salt treatment reduced grain starch concentration and increased grain protein concentration of Gaza and IR64, but did not affect grain amylose concentration. Priming treatments did not relieve the effect of salinity stress. Further studies are needed to understand the underpinning mechanisms of priming treatments (CaCl2 and KNO3) in salinity stress alleviation on rice.

Keywords: rice (Oryza sativa L.), tolerance, inorganic salts, starch, protein, amylose.