Chrysanthemum (Chrysanthemum morifolium L.) is an economically important ornamental crop whose improvement increasingly relies on mutation breeding and efficient in vitro propagation. The successful mutant propagation highly comes from influences of plant growth regulators, particularly benzyl amino purine (BAP), which plays a key role in shoot induction. This study aimed to determine the response of 15 M1 chrysanthemum mutants to different BAP concentrations in shoot proliferation under in vitro conditions. The experiment used a split-plot design, with BAP concentrations (0, 0.5, 1.0, 1.5, and 2.0 ppm) as main plots and 15 M1 mutants as subplots. Observed parameters included plantlet height, internode length, and the number of roots, internodes, leaves, and shoots. Data analysis used ANOVA (analysis of variance), correlation, and orthogonal polynomial regression. Flow cytometry (BD Accuri C6+) evaluated ploidy status. Results identified the number of shoots as the primary trait, with significant genotype × BAP interaction. The M4m mutant treated with 1.0 ppm BAP produced the highest average number of shoots, indicating superior responsiveness. Supporting traits also positively correlated with shoot proliferation. Ploidy analysis revealed chromosome doubling in several mutants, particularly m2p. Overall, 1.0 ppm BAP emerged as recommended for efficient in vitro propagation of chrysanthemum M1 mutants, with M4m as the most responsive genotype.
Chrysanthemum (C. morifolium L.), mutants, BAP, plantlet height, internode length, number of shoots and leaves
The chrysanthemum (C. morifolium L.) mutant plants in interaction with BAP concentrations produced the highest number of shoots in in vitro mutant propagation. Based on the results, the BAP concentrations were great recommendations for better propagation of chrysanthemum M1 mutant plants.