In vitro screening for salt tolerance in Rice (Oryza sativa)

An experiment was conducted to study the performance of rice genotypes for salt tolerance under in vitro condition. Seven genotypes include salt tolerant (Pokkali, CSR 10, TRY 1 and TRY2), moderately tolerant to salt (White Ponni and BPT 5204) and susceptible (IR 29) were used for this study through embryo culture technique. Callus was initiated in MS medium + 2 mgl-1 2,4D + 0.5 mgl-1 Kin and different concentration of Nacl viz., 50mM, 100mM and 150mM were added with the medium to create salt stress. Statistical analysis revealed that all the genotypes and treatments and their interaction effect were significantly different from each other. Among the seven genotypes studied Pokkali was significantly superior for callus induction with 62 % followed by CSR 10, TRY(R) 2 and TRY1 with 58 %, 54.5 % and 53 % respectively. Pokkali registered the highest level of callus development (35%) even at high level of Nacl stress (150mM) followed by TRY 2 (25%) and CSR 10 (24%). When the callus for these genotypes were transferred to regeneration media in the same level of Nacl stress (50mm, 100mM and 150mM) highest level of regeneration of green islets was realized in Pokkali (37.5 %) followed by CSR 10 (31 %) and TRY (R)2 (25 %). From these observation, it was concluded that somaclones obtained form the varieties of Pokkali, CSR 10 and TRY(R) 2 could be evaluated further in the natural field condition to develop a high yielding salt tolerant varieties or could be used as a donor for the development of salt tolerant varieties. This in vitro screening technique with different concentration of Nacl stress could also be used as a goof screening technique for salt tolerances rather than the field screening because of less time, little space and less labour and the results also very accurate than the field screening.