Induced mutation and in vitro techniques as a method to induce salt tolerance in Basmati rice (Oryza sauva L.)

Abstract

Embryogenic callus of indica rice (Oryza sativa L.) cv. Basmati 370 induced on MS medium containing 9.05 µM 2, 4-D was irradiated at 50 Gy of gamma rays of 60 Co for creating genetic variability against salinity. Irradiated and non-irradiated calluses were screened in vitro through three consecutive proliferation phases at 4.0, 6.0, 8.0 and 10.0 d/Sm electrical conductivity of NaCl. Growth value and number of adapted mutagenized callus was more than that of non-mutagenized callus. Salinity levels beyond 6 d/Sm and 8 d/Sm were lethal to growth and adaptation of non-irradiated and irradiated callus respectively. NaCl adapted irradiated callus showed 2.0%-4.75% regeneration frequency on MS regeneration medium containing 5.37 M NAA and 9.29 µM Kinetin. Non-mutagenized salt adapted callus did not show any regeneration. From gamma ray mutagenized cultures, 2 putative lines (M 2 generation) with moderate salt tolerance were obtained at seedling stage. The results suggest that in vitro technique in connection with gamma rays may be used as a versatile approach to improve the level of salt tolerance in Basmati rice for saline environment.