Determination of the Lethal Dose of Ethyl Methane Sulfonate (EMS) for Optimal In-vitro Mutagenesis in Banana (Musa spp. cv. Phee-gyan)

Abstract

The genetic variation in Musa (ABB group, Bluggoe subgroup) cv. ‘Phee-gyan’, a popular cultivar in Myanmar, was enhanced by in vitro application of ethyl methane sulphonate (EMS) mutagenesis to proliferated shoot tips. Shoot tips were treated with EMS at concentrations of 0%, 0.3%, 0.6%, 0.9%, 1.2%, and 1.5% across three incubation periods (30 min, 60 min, and 90 min) and cultured in five replicates using a randomized block design. The experiment was conducted at the laboratories of New Genetics (YAU) and Biotechnology Research Section (DAR) during 2023-2024. The results showed a dose-dependent decrease in survival percentage, shoot length, and fresh weight in the M1V1 generation compared to the control. The highest survival rate (91.48%) was recorded at 0.3% EMS (30 min), while the lowest survival (31.29%) occurred at 1.5% EMS (90 min). A 50% survival rate was recorded at 1.2% EMS (90 min), indicating a balance between mutation induction and plant viability. Shoot length was reduced to ~ 50% of the control at 1.2% EMS across all incubation times, while fresh weight decreased to ~ 50% of the control at 1.5% EMS (60 min and 90 min). Determining the lethal dose (LD₅₀) is essential to identify the optimum EMS concentration that maximizes mutagenesis efficiency while minimizing plant damage. Probit analysis determined LD₅₀ values based on survival percentage as 1.9% EMS (30 min and 60 min), and 1.2% EMS (90 min). For shoot length, LD₅₀ values were 1.3% EMS (30 min), and 1.1% EMS (60 min and 90 min), while for fresh weight, they were 1.9% EMS (30 min), 1.7% EMS (60 min), and 1.5% EMS (90 min). Based on these findings, 1.2% EMS (90 min) was determined to be the optimal mutagenesis condition for inducing genetic variability in banana cv. ‘Phee-gyan’. This optimized treatment could facilitate the improvement of key traits in banana breeding programs.