Morpho-molecular assessment of local rice (Oryza sativa L.) genotypes at seedling stage for salinity tolerance

Soil salinity is considered as one of the major threats to rice production in coastal region of Bangladesh and rice plants are prone to salt stress at seedling stage. Therefore, this study was conducted to evaluate the performance of rice genotypes for salinity stress tolerance at five levels of salinity treatments i.e., control - nutrient solution without salt [EC (electrical conductivity): 0.0 dS m(-1) (deciSiemens per meter)], EC: 08 dS m(-1), EC: 10 dS m(-1), EC: 13 dS m(-1) and EC: 15 dS m-1; were used for the morphological screening at seedling stage. After initial screening of fifty-seven local rice landraces, thirty rice genotypes were selected based on their salt tolerance ability using a standard evaluation score (SES). The selected rice genotypes were further screened by morphological parameters and molecular markers. Binadhan-10 and Binadhan-17 were used as salt resistant and salt susceptible checks, respectively. The environmental effect had a weak involvement in the expression of morphological traits, which showed high heritability (in broad sense) and genetic advance as percentage of mean. Two molecular markers (RM7075 and RM10825) were used to identify the Saltol quantitative trait loci (QTL) associated with the genotypes. Based on morphological and molecular analyses, the thirty-two rice genotypes were grouped into different clusters and six genotypes (Pokkali, Holdegotal-2, Vojon, Blockkhira, Rajashail and Hatibejor) were selected as salt tolerant. The materials obtained from this study can be utilized for further breeding program and developing markers for salt tolerance in rice.