To study the effect of salinity and Zn levels on growth, yield, and nutrient composition of rice (Oryza sativa L.), an experiment was conducted at IRRI with three levels of salinity (ECe 2.5, 5.6, and 8.7) and three levels of Zn (0, 10, and 20 mg Zn/kg soil), and two rices (salt-tolerant experimental line IR10198-66-2 and salt-sensitive variety IR28). Salinity decreased plant height; yield-contributing characters; and shoot, straw, and grain yields in IR28. In contrast, salinity up to ECe 5.6 did not affect these plant parameters in experimental line IR10198-66-2 but at ECe 8.7, it decreased the panicle weight and shoot, straw, and grain yields. The application of Zn at rates as high as 10 mg/kg soil increased the height and improved the yield-contributing characters and the shoot, straw, and grain yields in IR28; it has no effect in IR10198-66-2. In general, the shoot, straw, and grain yields were higher in IR10198-66-2 than in IR28.
Salinity increased the concentrations of N, Na, Mg, and Cu and decreased the concentration of K in shoot and straw of IR28. However, in IR10198-66-2, salinity did not affect the concentrations of K, Na, and Mn, but at its highest level (ECe 8.7) increased those of N and Cu. In grains, salinity increased the concentrations of Na, Fe, and Zn; decreased those of P and Mn; and did not affect those of N, K, Ca, Mg, and Cu in both varieties. The application of Zn at rates up to 10 mg Zn/kg soil reduced the concentration of Na and increased that of K in IR28 but had no effect on the concentration of Na and K in IR10198-66-2. In both varieties, Zn application reduced the concentrations of P, Ca, Mg, and Fe and increased those of Zn and Mn. IR10198-66-2 had lower concentrations of Na, Ca, Mn, Fe, Zn, and Cu and higher concentrations of K and Mg than IR28.