In the present study, in vitro plantlet regeneration from shoot explants and callus induction in MS medium supplemented with various concentrations of auxins and cytokines are reported for Capsicum chinense Jacq. Naga Chili. Successful initiation of in vitro cultures is a crucial factor in the application of biotechnological tools.
Fig. 1: Seeds showing germination.
3.1 Micropropagation
There are several factors affecting the successful initiation cultures. In vitro regeneration of Capsicum species is reported to be difficult [13]. Successful germination of seeds
achieved in vitro. Chili plants are more likely to be contaminated by fungus [3]. In the present study, only a few percentages (6.15 %) of cultures were found contaminated. Seed germination started after 7-9 days of inoculation and 90% of germination was obtained within 18-20 days {Fig. 1}.
3.2 Multiple shoot induction
An efficient protocol for the induction of multiple shoots in vitro has developed with an average of 5.2±0.16 shoots per culture. There are reports available on multiple shoot induction in other Capsicum species using BAP and IAA, where the maximum number of shoot proliferation achieved was 4.2±0.44 per explant [14]. Multiple shoot induction occurred in high concentration of BA, either alone or with a low concentration of IAA. Out of 8 different combinations tested (Table 1), media with a composition of MS basal + 5 mgl-1 BA + 0.5 mgl-1 IAA found to be more suitable for multiple shoot regeneration in Naga Chili {Fig 2}. In this study, an average of 5.2±0.16 shoots per explant achieved which could successfully transferred to induce roots and shoot elongation. Multiple shoot formation was observed after 14 days of inoculation. These shoots were excised and subcultured in MS basal media for shoot elongation and rooting. Similar results were achieved in Capsicum chinense where MS basal medium supplemented with Thidiazuron (TDZ) and 6-benzylaminopurine (BAP) as supplements [15, 16].
Fig. 2: Multiple shoot formation.
Table 1: Mean number of shoots per different combinations of plant growth regulators.