Determination of Optimum Lethal Dose of Ethyl Methane Sulphonate (EMS) and Its Effect on Germination Percentage and Seedling Survival in Niger (Guizotia abyssinica Cass.)
V. Prashantha *
Department of Genetics and Plant Breeding, College of Agriculture, University of Agricultural Sciences, Bangalore, Karnataka -560065, India.
S. Hemalatha *
Department of Genetics and Plant Breeding, College of Agriculture, University of Agricultural Sciences, Bangalore, Karnataka -560065, India.
K. S. Priyanka
Department of Genetics and Plant Breeding, College of Agriculture, University of Agricultural Sciences, Bangalore, Karnataka -560065, India.
N. Karthik
Department of Genetics and Plant Breeding, College of Agriculture, University of Agricultural Sciences, Bangalore, Karnataka -560065, India.
K. M. Shirisha
Department of Genetics and Plant Breeding, College of Agriculture, University of Agricultural Sciences, Bangalore, Karnataka -560065, India.
Priyanka
Department of Genetics and Plant Breeding, College of Agriculture, University of Agricultural Sciences, Bangalore, Karnataka -560065, India.
S. R. Spoorthi
Department of Genetics and Plant Breeding, College of Agriculture, University of Agricultural Sciences, Bangalore, Karnataka -560065, India.
R. Nandini
Department of Genetics and Plant Breeding, College of Agriculture, University of Agricultural Sciences, Bangalore, Karnataka -560065, India.
*Author to whom correspondence should be addressed.
Abstract
The creation and effective utilization of genetic variability are fundamental aspects of crop improvement programs. Mutation breeding is an important approach that allows the breeders to generate substantial genetic variation. Studies in several plant species have demonstrated that the effects of induced mutations differ considerably depending on the type of mutagen used and the dosage applied. Identifying the most effective mutagenic treatments is essential to obtain a higher frequency and wider spectrum of desirable mutations. The present investigation was conducted to estimate the lethal dose of the chemical mutagen EMS in niger variety JNC-6. Genetically pure seeds were treated with different doses of EMS i.e., 0.5, 0.7 and 0.9 %. Significant effects of EMS concentration on germination percentage under in-vitro and in-vivo conditions and survival percentage in in-vivo condition were observed. As the doses of the EMS applied increased, there was consequent decrease in germination and survival percentage in all the treatments compared to the unmutated control. The lowest germination (29%, 17%) was recorded at the highest EMS concentration (0.9%), whereas the highest germination (80%,79%) occurred at the lowest concentration (0.5%). At the intermediate dose (0.7%), the germination percentage was 52.20%, 51%, in-vitro and in-vivo conditions respectively. To reduce experimental losses and achieve an optimum balance between mutagenic effectiveness and plant survival, the LD₅₀ (lethal dose 50) test is performed before initiating any mutation breeding program. LD50 dose of EMS under in vitro and in vivo condition were fixed at 0.7% based on probit analysis. The frequency of morphological mutations like chlorophyll mutants, plant type mutants, and floral mutants were more in 0.7% EMS treatment compared to other treatments. After ascertaining LD50 value, mutation was induced to create variability for morphological and other desirable traits.
Keywords: Lethal dose, mutagen, EMS, germination percentage, survival percentage, niger