Materials and methods
2.1. Plant material and explant sterilization
The plant material was collected from the East-Coast of South India which includes the coastal Puducherry and Tamil Nadu. The survey was conducted to select the superior and healthy plant material from January to June, 2013. The fresh shoots of the P. foetida were collected from different places and brought to the laboratory. Some plants were maintained in the greenhouse to get better and healthy shoots. Nodal shoot segments with one to two nodes (2–3 cm long) were used as explants for the establishment of cultures. Explants were trea- ted with 0.1% (w/v) Bavistin (a systemic fungicide; BASF India Ltd., India) for 5 min. Surface sterilization was carried out with 0.1% (w/v) HgCl2 (disinfectant, Hi-Media, India) for 5 min under aseptic conditions in laminar air flow cabinet (Technico Systems, Chennai). These were finally rinsed 5–6 times with sterile distilled water.