LD₅₀ determination and phenotypic evaluation of three Echeveria varieties induced by chemical mutagens

Objective: The study aims to determine the Lethal Dose 50 (LD₅₀) of Echeveria varieties as induced by chemical mutagens. Methods: Three cultivated varieties from Echeveria species, namely ‘Brave,’ ‘Viyant,’ and ‘Snow bunny,’ were induced with chemical mutagens: colchicine, ethyl methanesulfonate (EMS), methyl methanesulfonate (MMS), and sodium azide (NaN₃). Each mutagen was diluted to different concentrations: colchicine (0.2%, 0.4%, 0.6%, 0.8%, 1.0%), NaN₃ (0.02%, 0.04%, 0.06%, 0.08%, 0.1%), EMS, and MMS (0.1%, 0.2%, 0.3%, 0.4%, 0.5%). Soaking durations for each concentration level were 3, 6, 9, and 12 h. The survival rate and phenotypic data for mutated plants per variety in response to chemical mutagens were collected. Results: The LD₅₀ evaluation revealed maximum concentration and treatment duration vary per varieties. Regardless of varieties, EMS-treated leaf cuttings had the highest survival rate. However, upon phenotypic evaluation, the results revealed that mutagenic plants were only taken from those treated with colchicine. Conclusion: The use of colchicine to produce mutated succulents should be further investigated at the molecular level. The results of the study are highly beneficial for mutation breeding programs for other succulent varieties or other related crops.