<![CDATA[Callus induction is influenced by growth regulators and environmental factors. This study evaluated the effect of picloram–kinetin combination and light conditions on callus formation in internode explants of Chrysanthemum morifolium ‘Puspita Nusantara’. A completely randomized block design was used with four concentrations of picloram (0–3 ppm), four concentrations of kinetin (0–3 ppm), and two light conditions (light and dark), resulting in 32 treatment combinations with three replications. Callus initiation time, percentage of callus formation, biomass, and callus morphology were observed in this study. The results showed that callus initiation time did not differ significantly among treatments. However, the interaction between picloram, kinetin, and light conditions significantly affected the percentage of callus formation, fresh weight, and dry weight. Most treatments containing picloram achieved 100% callus formation, while treatments without picloram showed a lower level of formation. The highest fresh weight was obtained in 2 ppm kinetin + 3 ppm picloram under light conditions (0.3510 ± 0.09 g), while the highest dry weight was recorded in 2 ppm kinetin + 2 ppm picloram under light conditions (0.0364 ± 0.015 g). Light conditions generally promoted greater biomass accumulation than dark conditions. All calli exhibited a compact texture, with green to yellow-green coloration under light and yellow to pale-yellow coloration under dark conditions. Overall, 2 ppm kinetin combined with 3 ppm picloram under light conditions was the most effective treatment for callus induction and biomass production. This study provides the first baseline data on callus induction in C. morifolium ‘Puspita Nusantara’, for which no previous reports are available. These findings support future callus-based propagation and secondary metabolite studies.]]>
