Validation of Median Lethal Dose (LD₅₀) Estimates for EMS and SA in M₁ Populations of Mungbean (Vigna radiata L. Wilczek)

Abstract

To validate the laboratory determined LD₅₀ doses of EMS and SA, responses in two mungbean (Vigna radiata L. Wilczek) genotypes i.e., Pusa 1031 and Pusa 1431 through estimating germination % and seedling survival % under field conditions in M1 generation. A randomised block design (RBD) with two genotypes × two mutagens × three replications were used. The experiment was conducted at the Institutional farm, College of Post Graduate Studies in Agricultural Sciences, Central Agricultural University, Umiam (Meghalaya), during pre-kharif 2023. Seeds of Pusa 1031 and Pusa 1431 were treated with predetermined LD₅₀ concentrations of EMS and SA. For each genotype and mutagen combination, 375 seeds were sown to assess germination % at 10 days after sowing (DAS) and seedling survival % at 30 DAS. Observations were compared to evaluate whether the field responses matched the expected ~50% lethality threshold. Germination percentages ranged from 49.33% to 53.87%, while seedling survival % after 30 DAS varied between 46.93% to 52.00%, with Pusa 1031 exhibiting slightly greater tolerance than Pusa 1431. Both EMS and SA treatments produced values clustering around the expected 50% lethality threshold, confirming the accuracy and biological validity of the LD₅₀ doses. Graphical trends further supported the consistency of LD₅₀ induced reductions. The validated LD₅₀ doses of EMS and SA consistently produced the expected median lethality in the M₁ generation, confirming their suitability for initiating a mutation breeding programme in mungbean. These results provide a strong foundation for progressing to M₂ generation screening for beneficial mutations.