Enhancing Chrysanthemum (Dendranthema × grandiflorum) tissue culture for improved ornamental flower production: Genotypic insights and growth regulator optimization

This study addresses the need for refining in vitro regeneration protocols for chrysanthemums (D. grandiflorum), the second most prominent ornamental cut flower globally, through the strategic implementation of tissue culture techniques. The objective of the study was to evaluate the response of 4 Dendranthema genotypes (CO-1, Pink Marble, Snapper and Super White) to various plant growth regulators (PGRs) during callus culture, shoot formation, rooting and acclimatization. For this, ray floret explants were utilized and PGRs including 2,4-D, BAP, IBA, GA3, IAA and NAA were tested at different concentrations. Results revealed the superior performance of genotypes CO-1 and Super White across all stages of in vitro regeneration. Optimal conditions were identified, including a synergistic combination of 2.0 mg L-1 2,4-D and 0.100 mg L-1 BAP for callus induction, 2.0 mg L-1 BAP with 0.100 or 0.250 mg L-1 NAA for shoot formation and 1.0 mg L-1 IBA with 0.100 mg L-1 NAA for rooting. Acclimatization was successful using vermicompost + red soil + coir pith (1:1:1) as a substrate. Furthermore, tissue culture-raised chrysanthemum plants exhibited a significant increase in flower numbers upon treatment with 100 mg L-1 GA3, indicating the potential for enhanced flower quality and yield compared to conventionally grown plants. These findings provide crucial insights for optimizing large-scale chrysanthemum production and underscore the importance of tissue culture techniques in ornamental cut flower industry advancements.