Resistance of Iranian rice (Oryza sativa L.) genotypes to NaCl stress

Rice (Oryza sativa L.) is the most important food for half of the world's population. Rice is sensitive to salinity, which is one of the important stresses to limit rice growth and yield in Asia. In order to evaluate the effects of salinity stress on rice vegetative and agronomic characters an experiment was conducted using forty genotypes. The genotypes were tested at 4 salinity levels (0; 6; 8; 12 ds m-1), in factorial arrangement based on a complete randomized block design with 3 replications in greenhouse at the University of Agricultural Science and Natural Resources, Sari, Iran, 2008. The vegetative growth of rice cultivars was reduced under salt stress. Effect of salinity, genotypes and their interaction were significant on all measured traits including, number of tillers, plant height, shoot and root length, shoot and root and leaf dry weight and biomass. By increasing the level of salinity, biomasses of genotypes were reduced. In 12 ds m-1 salinity treatment, biomass in Sahel, Neda, Nemat, IR229, IR28, line 5, line 7 and line 19 was less than IR29 (sensitive check), but biomass in Shastak mohammadi, Fajr, line 109 was more than Pokkali (tolerant check) at the same salinity level. Grouping genotypes was performed by the Ward cluster analysis method and two clusters were identified. Genotypes such as Shastak mohamaddi, Hasani, Gerdeh, Tarom, Deilamani, Anbarbo, Nok siyah, Dom siyah, IR229, Lines 3, 7,19, 39, 75, 76, 83, 109, 126, MTM2, Sang tarom, F114, Musa tarom, Fajr, Dasht, Khazar and Ghasrodashti were located in same cluster as the tolerant group and other genotypes were grouped as the susceptible group.