The present study aimed to optimize the in vitro direct shoot organogenesis system for propagation, in vitro flowering, and genetic fidelity analysis of micropropagated clones of Ceropegia lawii. The efficiency of various plant growth regulator treatments was evaluated during various regeneration stages. Direct shoot organogenesis cultures were established through stem nodal buds on Murashige and Skoog (MS) medium supplemented by 6-benzylaminopurine (BAP, 0.5 mg/l). Maximum frequency of shoot induction and multiplication (98.5%) with 14 ± 0.5 shoots per explant was attained through the augmentation of BAP (2.0 mg/l) in the MS medium. In vitro-derived shoots were rooted optimum (89.62%) with 6.9 ± 0.1 numbers of roots while transferring to a half-strength MS medium supplied with indole-3-butyric acid (1.5 mg/l). A maximum number of flowers (5.6 ± 0.1) with 91.33% induction frequency were reported when microshoots were transferred to the MS medium formulated with BAP (2.0 mg/l) in combination with sucrose (175 mM). Tissue culture-derived plantlets were adapted best in a mixture of sterile soil, sand, and coco peat (1:2:1) with 88% of survival rate. Inter-simple sequence repeat analysis of regenerated plantlets revealed 99.33% genetic integrity of in vitro regenerated clones when compared with the donor plant. The findings of the present study reveals that the direct shoot organogenesis approach produces a large number of genetically stable plantlets of C. lawii which helps in its conservation and fulfills further industrial necessities.
Key words: Ceropegia lawii, Direct shoot organogenesis, In vitro flowering, ISSR analysis, Acclimatization, Endangered, Endemic, Medicinal plant, Molecular markers
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