Effect of Plant Growth Regulators and Growth Additives on the In vitro Micropropagation of Aerides odorata Var. Alba from Immature Pod Seeds

Background: The propagation of Aerides odorata through sexual means is a very slow process as its seeds lack endosperm and propagation through in vitro culture techniques from vegetative parts used as explants may results in the loss of diversity and variation in the species, therefore it is important to take the initiative for its mass propagation from seeds, followed by their subsequent establishment in its natural habitat. Methods: The investigation was conducted at Central Agriculture University, Imphal, Manipur. The seeds were inoculated on ½ MS (Murashige and Skoog) media augmented with different concentrations of BAP and coconut water to enhance seed germination. Different concentrations of NAA (2.0 mg/L) and BAP (0.1-4.0 mg/L) were added to ½ MS medium for shoot induction. The regenerated multiple shoots were then excised and single shoots were cultured individually on ½ MS media supplemented with various growth regulators viz., NAA, IBA, IAA and growth additive, banana powder (50 g/L). Result: The earliest seed initiation (25.5 days) and maximum seed germination rate (72.42%) were recorded with ½ MS media supplemented with 2.0 mg/L BAP and 15% Coconut water. Whereas, shortest duration taken for shoot initiation (17.17 days) was observed with ½ MS treated with 4.0 mg/L BAP and 2.0 mg/L NAA. Highest number of leaves (10) and highest number of shoots (6.58) were observed with ½ MS supplied with 4.0 mg/L BAP and 2.0 mg/L NAA. The treatment combinations of ½ MS supplemented with 0.5 mg/L NAA and 50 g/L Banana powder recorded the lowest number of days taken for root initiation (31.17 days), highest number of roots (5) and maximum root length (2.64 cm).