Effect of sucrose and bencyladenine concentrations on in vitro organogenic development of chrysanthemum (Chrysanthemum morifolium)

Abstract

Background: Chrysanthemum (Chrysanthemum morifolium) is one of the most economically important ornamental species in Mexico, particularly in the State of Mexico. Optimizing in vitro propagation protocols is crucial to overcome the limitations of conventional methods and meet the demand for high-quality plants. Objective: To evaluate the effect of different concentrations of benzyladenine (BAP) and sucrose on the in vitro organogenesis of C. morifolium var. Indianapolis. Methodology: A completely randomized experimental design with a 3x3 factorial arrangement, plus a control, was established. Three concentrations of BAP (0.0, 0.5, and 1.0 mg L⁻¹) and three of sucrose (30, 45, and 60 g L⁻¹) were evaluated in an MS basal medium. The control consisted of a standardized medium with kinetin (1.0 mg L⁻¹) and sucrose (40 g L⁻¹). Variables of survival, callogenesis frequency, leaf number, main shoot length, and root length were recorded after 70 days of culture. Data were analyzed by ANOVA and Tukey's test (α = 0.05). Results: The combination of 0.5 mg L⁻¹ BAP and 30 g L⁻¹ sucrose (T4) significantly promoted survival (100%), shoot length (15.7 mm), and leaf number (6.2). The highest frequency of callogenesis (95.8%) was observed in the absence of BAP and with the maximum sucrose concentration (T3). Root development was limited across all treatments, observed in only 10% of explants, with no statistically significant differences among the treatments that induced roots. Implications: Optimizing the balance between hormonal and carbon source is fundamental to directing in vitro morphogenesis. The identified protocol (0.5 mg L⁻¹ BAP and 30 g L⁻¹ sucrose) allows for efficient direct organogenesis, which can lead to faster and more uniform clonal propagation, benefiting the productivity and competitiveness of ornamental growers. Conclusion: The concentration of 0.5 mg L⁻¹ BAP combined with 30 g L⁻¹ sucrose constitutes an optimal stimulus for direct organogenesis in C. morifolium, maximizing survival and shoot development, while high sucrose concentrations induce a stress response leading to callogenesis.