In Vitro Regeneration Technique of Papaya (Carica papaya L.) cv. Pusa Dwarf Through Shoot Tip Culture

Papaya (Carica papaya) is a polygamous plant having male, female and hermaphrodite sex forms. Male form is the least productive of them. The commercial method of propagation of papaya is seed and it is very difficult to identify the sex form at juvenile phase. Therefore, an experiment was conducted to standardize the in vitro regeneration technique in papaya through shoot tip culture for rapid multiplication of true-to-type plantlets with known sex forms. Surface sterilization of the explants with NaOCl @ 1% or HgCl2 @ 0.1% for 4 min had maximum survival rate (48.96 and 45.31%, respectively). The maximum explants establishment was obtained in MS media supplemented with 100 ppm glycine, 5 ppm casein hydrolysate and 0.05% charcoal (40.08%) followed by MS media containing 5 ppm casein hydrolysate and 0.05% charcoal (35.76%) with maximum number of shoots explants(-1) (4.00 and 3.32, respectively). Earliest shoot initiation was also observed in MS media supplemented with 100 ppm glycine, 5 ppm casein hydrolysate and 0.05% charcoal (11.20 days). Further, longest shoot was measured in MS media supplemented with BAP (3.0 mg l(-1)) and NAA (0.5 mg l(-1)) (3.25 cm). Similarly, number of leaves explants(-1) was also counted maximum in MS media fortified with BAP (2.0 mg l(-1)) and NAA (0.5 mg l(-1)) (3.10). On the other hand, number of roots per regenerated shoot and root formation per cent was recorded statistically higher in half strength MS media supplemented with 3.0 mg l(-1) IBA (1.58 and 28.47%, respectively).