Effect of Salt Stress on Germination and Growth Parameters of Rice (Oryza sativa L.)

Abstract

The response of eight varieties of Oryza sativa L. (‘NERICA 1’, ‘NERICA 5’, ‘NERICA 12’, ‘NERICA 19’, ‘IR 29’, ‘IR 20’, ‘IWA 11’, and ‘POKKALI’, a salt tolerant check) against four salinity levels (0, 5, 10, and 15 ds m-1) were studied at germination and early growth stages. Data were analyzed using Statistical Analytical System (SAS) and means were separated by Duncan Multiple Range Test (DMRT) for Final Germination Percentage (FGP), Speed of Germination (SG), Germination Energy Percentage (GE%), shoot and root length and root and shoot dry weight. Based on dry matter yield reduction, rice varieties were classified as tolerant (T), moderately tolerant (MT), moderately susceptible (MS) or susceptible (S). Germination was not recorded at 20 ds m-1 salt concentration in all cultivars. Salinity decreased FGP, SG, GE% and led to reduction in shoot and root length and dry weight in all varieties and the magnitude of reduction increased with increasing salinity stress. Rice varieties ‘NERICA 12’, ‘IR 20’, ‘IWA 11’ and ‘NERICA 19’ showed greater salt tolerance during germination (germinated at 10 ds m-1 salinity). However, ‘NERICA 1’, ‘IR 29’, and ‘IR 20’ performed better based on dry matter yield reduction. The result suggested that ‘NERICA 1’, ‘IR 29’, and ‘IR 20’ might be used for further study of salinity effect on growth processes and physiological consequences at advanced stage of growth. The physiological responses of rice plants to salinity at various developmental stages are therefore critical for identifying salinity tolerance in the cultivars.