Rapid in vitro mass multiplication of orchids Aerides maculosa Lindl. and Rhynchostylis retusa (L.) Bl. from immature seeds

The callus embryoid plant regeneration was developed using immature seeds of Aerides maculosa Lindl. and Rhynchostylis retusa (L.) Bl. Immature capsules of 5-10 wk after pollination (A. maculosa) and 10-20 wk after pollination (R. retusa) were used for callus induction. In both the species, best response of callus induction was observed on Vacin and Went (VW) medium supplemented with 15% coconut water (CW, v/v). In A. maculosa, maximum number of protocorm-like bodies (PLBs; 13.93 per callus) was noted on VW medium supplemented with BA (1 mg L super(-1))+NAA (1 mg L super(-1)) + 15% CW. While in R. retusa, maximum number of PLBs (15.83 per callus) was noted in Murashige and skoog (MS) medium supplemented with BA (1 mg L super(-1))+NAA (1 mg L super(-1))+15% CW. In vitro regenerated plantlets of both the species were acclimatized to green house conditions. The highest survival rate of plantlets (60%) was noted in the combination of charcoal pieces, brick pieces (1:1) and coconut husk.