Physiological Changes and Evaluation of Saltol1 Introgressed Backcrossed Inbred Lines (BILs) for Early Seedling Stage Salinity Tolerance in Rice (Oryza sativa L.)

Salinity stress is a major abiotic stress to which rice is most sensitive at germination or early vegetative stages. Addressing a salinity tolerance in rice can be achieved with an effective way by employing of early seedling stage screening to narrow down a large set of germplasm with higher tolerance and key parameters can quantify tolerance level. Morpho-physiological changes were assessed for selected seven backcross inbred lines (BILs) possessing Saltol1 quantitative trait loci (QTL) of rice and their parents and checks, at early seedling stage under optimal salt concentration (120 mM NaCl). In the present study, morpho-physiological changes were assessed for selected seven backcross inbred lines (BILs) possessing Saltol1 QTL of rice and their parents and checks, at seedling stage subjected to 120 mM NaCl salt concentration. The seedling growth assessment, mineral analysis and important physiological growth characters were measured after 14 days of salt treatment to classify seven BILs into tolerant and sensitive groups. Among the screened seven ILs, IL3 showed susceptible reaction for hydroponic screening. Analysis of variance (ANOVA) revealed significant variation between improved lines, salinity treatment and their interaction for the studied traits. Salt stress affected growth parameters and important physiological traits in the studied ILs; however, the lowest reduction was observed in the tolerant groups. The tolerant group ILs also showed maintenance of low Na+, high K+ uptake and Na+/K+ ratio. The identified tolerant lines will be utilized in development of saline-tolerant heterotic hybrids and further evaluation under multi-location trial of All India Coordinated Rice Improvement Programme (AICRIP).