In vitro mutagenesis to improve salt tolerance in rice (Oryza sativa L.)

Abstract

Rice is the most important food crop in the world which has been severely affected with salinity. Aim of this study was to improve the salt tolerant ability of two moderately susceptible rice cultivars (White ponni and BPT-5204) using Ethyl Methane Sulfonate under in vitro condition. In this experiment salt tolerant callus were recovered in seeds treated with 0.5% EMS cultured on MS media supplemented with different concentrations of NaCl and sea water (starts with 0%, 0.5%. 1.0% and 1.5% NaCl to 10% and 25% seawater). The extant of salt tolerance was determined by callus growth parameters like callus induction frequency, relative growth rate and regeneration frequency. The reduction in growth parameters were more at 25% (v/v) sea water and 1.5% (w/v) NaCl treated media. Significant number of plants (17.23% and 22.49% plantlets respectively) was obtained in callus recovered in 3hr and 5hr EMS treated seeds cultured on 25% sea water and 1.5% NaCl treated media. Proline is an important osmaticm accumulated more under salt stress to maintain the turgor pressure and protect the plants from extreme desiccation. Under higher salt concentration BPT-5204 accumulated the higher amount of proline than white ponni. The plantlets obtained from higher concentration of salt can be transferred to field for the selection of elite lines.