Abstract: The response of 10 rice cultivars, including the salt-tolerant variety (Pokkali) and salt-susceptible variety (IR29) as controls at five salinity levels (i.e., 0, 4, 6, 8, and 10 dS·m–1) under hydroponic conditions was studied at the seedling stage in the greenhouse. The heading stage was evaluated at the salinity level of 8 dS·m–1 in a completely randomized block with 3 replications per each cultivar under non-saline and saline conditions. The results show that the growth of cultivars is retarded severely at the external salinity levels. Almost all leaves dried and died completely (score 7 and 9) at the level of 8 to 10 dS·m–1. Cultivars IR29 and OM7347 died (score 9) at 10 dS·m–1; whereas, Pokkali and IR93350 were evaluated at score 5. Salinity induces the reduction of overall agronomic parameters of cultivars, especially in dry weight relative-to-reduction over control (ROC%), salt tolerance index (STI%), pollen germination, and grain yield. Salinity-sensitive cultivars decreased their pollen viability by more than 50%, leading to a poor grain yield at a salt level of 8 dS·m–1. Tested cultivars as an initial response to salinity stress were ranked as follows: OM7347, IR87832-303-1-B, and IR29 – susceptible; OM8104, IR93340, and IR93343 – moderately tolerant, and IR86385-8D-1-2-B, IR5040, IR93350, and Pokkali – tolerant.
Keywords: heading stage, pollen germination, susceptible, seedling stage, salinity-tolerant
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