Characterisation and lethal dose determination of EMS induced mutation in Gallong jhum rice (Oryza sativa L.)

Abstract

Chemical mutagenesis has been used to increase genetic diversity in crop plants. Among the chemical mutagens, Ethyl Methane Sulphonate (EMS) is stated to be the most effective and strong mutagen causing a high frequency of nucleotide substitution, as found in different genomes. Determination of mutagenic sensitivity is an important step in the mutation breeding program as it differs with species and varieties. Therefore, an attempt was made in the study to determine the lethal dose (LD50) of EMS for Gallong jhum rice. A detailed phenotyping was performed after treating the rice with six different EMS concentrations (0%, 0.4%, 0.5%, 0.6%, 0.8%, 1.0% and 1.5%). Phenotypic and biochemical parameters on the M1 generation were measured to determine EMS sensitivity for the Gallong rice. The results show that as the concentration of EMS increased, there was a decrease in germination, seedling height, root length, and emergence under field conditions compared to the control in the M1 generation. The result showed that 0.8% concentration of EMS induced mutation at saturated level in the rice seeds, while 1 to 1.5% concentrations of EMS were detrimental for the growth and development. The results concluded that 0.8% EMS concentration as LD50 could be used in rice mutational programs.