Induced variability and assessment of mutagenic effectiveness and efficiency in sorghum genotypes [Sorghum bicolor (L.) Moench]

Abstract

Purpose

Sorghum is an important cereal crop, cultivated for food, fodder and biofuel. Mutation breeding techniques are used to create genetic variability for qualitative and quantitative traits in crop plants. The purpose of this study was to create induced variability and estimate mutagenic effectiveness and efficiency of physical and chemical mutagens in two sorghum cultivars.

Materials and methods

Gamma rays (100, 200, 300 and 400 Gy, Co⁶⁰ source, Bhabha Atomic Research Center, Mumbai, India), ethyl methane sulfonate (0.1%, 0.2%, 0.3%, and 0.4% EMS, Sigma-Aldrich, Bangalore, India) and their combinations were used to mutagenize 296B (rainy season) and Parbhani moti (post-rainy) cultivars. Morphological and yield traits were analyzed for enhanced variability in qualitative and quantitative traits across M₂ and M₃ generations.

Results

Based on the mutagenic sensitivity, lethal dose at 50% survivability (LD₅₀) for both the genotypes was found to be 269–281 Gy in case of gamma rays and 0.32–0.33% for EMS. Based on reduced germination and survivability, mutagenic sensitivity was dose dependent and genotype independent. High frequency of chlorophyll mutations (albino, xantha, viridis, variegated and chlorina) was linearly correlated with dose in both the genotypes. Among the favorable mutants, dwarf and brown midrib were isolated from Parbhani moti population, which could be used in the cross breeding programs. A combined treatment, 100 Gy + 0.1% EMS showed high mutagenic effectiveness and efficiency. Enhanced genetic variation for quantitative traits as measured by wide range values and coefficient of variation was attributed to the effect of physical and chemical mutagens. Early flowering and high grain yield (24–49% increase over control) mutants were identified in M₂ and validated in M₃ generation in both genotypes.

Conclusions

This study has revealed wide genetic variability and better effectiveness and efficiency of the physical (300 Gy) and chemical mutagens (0.2%) and their combination (200 Gy + 0.2%) across two sorghum genotypes. Significant correlations identified between quantitative traits will help in better selection in the segregating generations.

Keywords:

• EMS
• gamma rays
• genetic variability
• induced mutations
• mutagenic efficiency

Acknowledgements

The authors are thankful to Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Centre, Mumbai, India for Gamma ray irradiation of sorghum seeds.

Disclosure statement

Authors declare no potential conflict of interest.

Additional information

Funding

The authors are thankful to BRNS for providing financial support to conduct this experiment.

Notes on contributors

H. V. Kalpande

Dr. H. V. Kalpande is currently working as head of the Department of Agriculture Botany, VNMKV, Parbhani, India. He has been involved in the Sorghum Breeding for yield and quality improvement in collaborations with national institutes and ICRISAT. He has published more than 70 research articles in peer reviewed journals.

S. M. Surashe

Dr. S. M. Surashe received his Ph.D. in Genetics and Plant Breeding from VNMKV, Parbhani, India. He has been involved in the collaborative mutation research project on Sorghum and published 10 research papers.

Ashok Badigannavar

Dr. Ashok Badigannavar has been working as scientific officer at Bhabha Atomic Research Centre (BARC). He graduated in the field of Genetics and Plant Breeding and currently working on the development of sorghum varieties with improved grain yield and seed quality traits using conventional and mutation breeding techniques.

Ambika More

Dr. Ambika More is working as an Assistant Professor at the Department of Agriculture Botany, VNMKV, Parbhani, India. She has served for 12 years in the genetic improvement of sorghum using traditional and mutation breeding tools. She has participated in the national/international collaborative projects and published more than 40 research papers.

T. R. Ganapathi

Dr. T. R. Ganapathi is heading the Nuclear Agriculture Division of Bhabha Atomic Research Centre (BARC). He has been working on micro propagation and genetic transformation in Banana. Dr. Ganapathi has published more than 170 research publications and a fellow of Maharashtra Academy of Science.