Direct plant regeneration from leaf explants of Plumbago species and its genetic fidelity through RAPD markers

In vitro plant regeneration was achieved from leaf explants of Plumbago rosea and Plumbago zeylanica on Murashige & Skoog (1962) medium supplemented with 1.5 mg litre(-1) 6-benzylaminopurine, 0.25 mg litre(-1) indole-3-acetic acid, 50 mg litre(-1) adenine sulfate and 3% (w/v) sucrose. The shoot initials developed within 2-3 wk on the leaf margin as well as from the wounds of the leaf. High frequency shoot-bud regeneration was achieved on similar medium in subsequent subcultures. The semi-mature leaves produced more shoot-buds as compared to the younger leaves. Mature leaves did not show any response for shoot bud initiation. More than 85% of the semi-mature explants produced shoot-buds per leaf explant within 4 wk of culture. Shoots rooted easily on medium having half-strength basal Murashige & Skoog (1962) medium supplemented with 0.25 mg litre-1 indole-3-butyric acid and 2% (w/v) sucrose; 84-92% of the in vitro rooted plantlets survived in the greenhouse. The regenerated plantlets appeared morphologically similar to the mother plants. No variation was detected among the regenerated plants by the use of Randomly Amplified Polymorphic DNA (RAPD) markers. This method might be useful for assessing plant improvement programmes.