In vitro plantlet regeneration from cotyledon segments of Capsicum chinense Jacq. cv. Naga King Chili, and determination of capsaicin content in fruits of in vitro propagated plants by High Performance Liquid Chromatography

• We report an in vitro plantlet regeneration system from cotyledon segments.
• Highest number of multiple shoots was obtained from rosette-like structures.
• Putrescence and thidiazuron mediated direct multiple shoot induction obtained.
• Fruits of in vivo and in vitro propagated plants were found equally pungent.

An in vitro plantlet regeneration system has been developed from cotyledon segments of Capsicum chinense Jacq. cv. Naga King Chili, a very pungent chili species of India. Rosette-like structures (RLS) were induced on the explants which on transfer to medium containing indole-3-acetic acid (IAA) resulted in multiple shoots in course of time. Agar-based Murashige and Skoog (MS) medium fortified with 18.16 μM thidiazuron (TDZ) was found to be the most suitable medium for RLS induction and shoot formation. Maximum number of multiple shoots (9.5 ± 0.39) and roots (8.6 ± 0.50), and root length (2.4 ± 0.02 cm) were obtained from rosette-like structures in medium containing 5.70 μM IAA. Combined effect of putrescine (Put) (5.6 μM) and TDZ (4.54 μM) mediated direct multiple shoot (5.8 ± 0.44) induction. The in vitro rooted plantlets were transferred to glass house for hardening and acclimatization, wherein 90% survival was recorded. The hardened plantlets, thus developed were established in soil and bore normal fruits after 4 months of transfer. The capsaicin content in matured fruits of in vitro propagated plants was found to be 0.05236 g/g d wt (837,760 Scoville Heat Units, SHU), where as in vivo raised plantlets yielded 0.0545 g/g d wt (872,000 SHU) respectively.