Effect of Growing Media and Nutrition on Establishment of Vanda coerulea Plantlets during Hardening

Vanda Coerulea is an endangered orchid species and also possesses high market value. Apart from in vitro multiplication techniques, there is a need for proper hardening management for in vitro derived plantlets. So, the present study was carried out to identify the best potting mixture along with best nutritional composition for establishment of plantlets. Well grown six months old in vitro grown plantlets with well-developed roots were selected for the study. Plantlets were removed from the culture medium and washed gently under running tap water, and the media traces from the roots were removed. Plantlets were then treated with Bavistin (0.1%) solution for 2 minutes and transferred to the potting medium. Five different compositions of sterilized potting medium viz. leaf mould, coco-chips, brick chips, sphagnum moss, and cocopeat were taken. Each composition of medium was formulated in 1:1:1 ratio comprising three media in one formulation. Spraying of four different compositions of inorganic nutrients NPK (0:0:0; 10:10:10; 20:20:20 and 30:30:30) were done in weekly interval @ 0.1%. It was observed that the highest average survival rate of plantlets (58.33 %,), highest plant height (6.85cm) and maximum number of leaves (6.33) were found in media comprising of leaf mould + sphagnum moss + brick chips. Similarly, NPK 20:20:20 shows better in terms of survival percentage of plantlets (41.66 %,), highest plant height (6.76cm) and maximum number of leaves (6.33). The interaction effect of leaf mould + sphagnum moss + brick chips with weekly spraying of NPK 20:20:20 shows better result in terms of survival percentage of plantlets (91.66 %,), plant height (8.40 cm) and number of leaves (7.33). These combinations of media and nutrition can be used for establishment and development of plantlets at hardening.