SCREENING OF SALT TOLERANCE POTENTIAL OF A PANEL OF VIETNAMESE RICE LANDRACES AT SEEDLING STAGE

In the present study, thirty three Vietnamese rice landraces at seedling stage were evaluated for their salt tolerance at five salinity levels of 0 mM, 100 mM, 150 mM, 200 mM, and 250 mM NaCl. Plants were grown in hydroponics with salt application at the fourth leaf stage. Salt tolerance score, survival rate and dry weights of shoot and root were measured at 7 and 14 days of stress. The results showed that increasing salinity level from 0 to 250 mM caused an obvious decrease in seedling growth of all tested Vietnamese rice landraces. At 7 days of stress, most genotypes exhibited a salt tolerance ranging from tolerant to moderately tolerant with increasing salinity. After 14 days, salt stress caused deleterious effect on almost all genotypes, especially at 200 and 250 mM, where no salt tolerant genotype were observed. At 100 mM NaCl treatment for 14 days, the lines Pokkali, G138 were noted to be the most tolerant and twenty other genotypes were ranked as moderately tolerant. At 150 mM, G138 and G45 were evaluated to be moderately tolerant as Pokkali, whereas the others were more susceptible, but less than IR29.