Morphological and Molecular Screening of Rice (Oryza sativa L) for Salinity Tolerance at Seedling Stage - Abstract
Saline agriculture encourages the use of salt-tolerant rice to maintain rice productivity, which is one of the solutions to the saline soil problem. In this study, the screening of salinity tolerance at the seedling stage of rice genotypes was carried out on the basis of morphological and molecular characterization. 21 rice genotypes along with the tolerant check (Pokkali), were screened using Peter nutrient solution with salinized (6 dSm-1 NaCl), and non-salinized (control) conditions. For phenotypic observation, four parameters such as shoot length, root length, shoot fresh weight and root fresh weight were used for salinized and non-salinized conditions in hydroponic system. The International Rice Research Institute’s modified standard evaluation score (SES) was used to assess the visual symptoms of salt toxicity. A wide range of salt injury was observed in response to 10 days of salt stress, resulting in a range of salt tolerance scores from 3 to 9. Based on the SES scores, percent reduction and stress tolerance index at 6 dSm-1, 8 genotypes were screened as tolerant, 10 genotypes as moderately tolerant and 3 genotypes as susceptible. Twelve SSR markers linked to salt-tolerance QTL were used to evaluate the salinity of genotypes. Across all loci, a total of 31 alleles were observed. Four markers (RM336, RM7075, RM10793 and RM3412b), could differentiate genotypes based on their PIC value and MI index. Only the PSBK rice genotype was genetically related to Pokkali, according to cluster analysis and haplotype analysis. After phenotypic and molecular assessment, 6 genotypes were identified as tolerant, 11 genotypes as moderately tolerant and 5 genotypes as susceptible.