Effects of Plant Growth Regulators on In vitro Regeneration of Malaysian Indica rice (Oryza sativa L.) cv. MR219 by Shoot Apical Meristem

An efficient plant regeneration protocol for indica rice (Oryza sativa L.) cv. MR219 was established by means of Shoot Apical Meristem (SAM) obtained from 4-day old germinating seedlings. The effect of liquid and solid Murashige and Skoog (MS) medium towards the primary establishment of meristem tissue as well as effects of Plant Growth Regulators (PGRs) on shoots and root formation was investigated. Primary shoot induction was most effectively promoted by liquid MS medium supplemented with 0.1 mg L super(-1) Kinetin (KIN) with 83% of explant survival and 0.88 explant vigor. Overall, liquid MS medium produced significantly higher percentage of explant survival and vigor compared to solid MS medium. Best treatment for shoot multiplication was solid MS medium supplemented with a combination of 1.5 mg L super(-1) KIN and 0.05 mg L super(-1) Indole-3-Acetic Acid (IAA) with an average of 8.8 shoots, followed by solid MS medium supplemented with 1.5 mg L super(-1) KIN with an average of 7.6 shoots. However, shoots produced in MS medium supplemented with a combination of 1.5 mg L super(-1) KIN and 0.05 mg L super(-1) IAA was in concomitant with root formation. In this combination, plantlets produced had an average of 5.4 roots. Complete plantlets that were successfully transferred to soil and grown in the greenhouse were able to grow as healthy plants. This optimized protocol regenerated whole rice plantlets without any intervening callus formation. The highly efficient protocol suggested in this study can serve as an alternative to conventional propagation methods for large-scale plant regeneration throughout the year.