Phenotype and ploidy evaluation of colchicine-induced Echeveria ‘Peerless’

Objective: The study was conducted to evaluate the phenotype and ploidy level of colchicine-induced Echeveria ‘Peerless’. Methods: Leaf cuttings of Echeveria ‘Peerless’ were treated with different concentrations of colchicine (0.2%, 0.4%, 0.6%, 0.8%, and 1.0%) for different durations (3, 6, 9, and 12 h). The survival and mutation rates following various treatments were determined, and the phenotypic characteristics were evaluated 12 months after the treatment. Putative succulent plants were subjected to stomatal evaluation and flow cytometry to confirm the ploidy level. Results: Colchicine treatment produced more compact mutant plants with thicker and shorter leaves with a redder tone. In addition, colchicine-induced mutant plants showed obviously broader leaf apices than control plants. Treatment with 0.2–0.6% colchicine for 3–12 h achieved a survival rate of over 50% while producing the required effects. Moreover, treatment with 0.2–0.6% colchicine for 3–12 h or with 0.8% colchicine for 3–9 h successfully produced diploid–tetraploid mixoploids, which explains the altered phenotype, increased stomatal size, and decreased stomatal density of the succulents. Conclusions: This study established an effective method to induce polyploidy in Echeveria ‘Peerless’, which can be used to create novel genetic sources for developing and breeding new cultivars.