Indigenous rice landraces i.e. Hori, Lombur, B-11 and Kalampazam collected from coastal areas of Bangladesh and two mutant lines viz. Lombur M4 and B11 M4 were investigated in the present study for the evaluation of their salt tolerance at seedling stage. Germination percentage and other growth parameters like root length, shoot length were assessed after two weeks of exposure to five levels of salinity namely 50 mM, 100 mM, 150 mM, 200 mM and 250 mM with control. Among the rice genotype tested, Hori, Lombur, B-11 and Kalampazam showed the improved germination percentage of 66.12%, 53.33%, 51.65% and 38.66% respectively under increasing NaCl concentrations compare to salt susceptible cheek BRRI Dhan 29 which is 23.17%. Germination percentage were obtained 88.49% and 64.98% from two mutant lines Lombur M4 and B11M4 which were found better even than the standard salt tolerant variety Pokkali is an evidence in this study. In case of shoot length, Kalampazam, Lombur M4 and B11M4 indicated less sensitivity to increasing salt stress whereas Lombur control, B-11 control and Hori showed sharp decrease. The effect of increasing salinity on root length was found insignificant. All indigenous rice genotypes showed sharp decrease in the growth parameters studied to increasing NaCl concentration though better than the salt sensitive check but the mutant lines were found resistance to the increasing salt stress in related to these characters as in Pokkali.
Keywords : Salinity Screening, NaCl, Indigenous Rice, Mutant Line, In vitro.