Vol. 10, Issue 11 (2021)

Author(s):
M Durga Devi, C Subesh Ranjith Kumar, J Rajangam, S Santha and C Sankar

Abstract:
The study was carried out to determine the optimum dose of gamma radiation and Ethyl Methane Sulphonate (EMS) for effective mutation breeding program in acid lime var. PKM 1. Acid lime seeds were mutated by using physical mutagen i.e., gamma rays (⁶⁰Co source) at five different doses (5Gy, 10Gy, 15Gy, 20Gy and 25Gy) at IGARI, Kalpakkam, Chennai. For chemical mutagenesis, different concentrations of EMS @ 0.2%, 0.4%, 0.6%, 0.8% and 1.0% was used. The survival rate, growth potential, morphological and other physiological parameters were evaluated during the study period. Result showed that using linear regression model, The LD₅₀ doses for gamma ray and EMS were observed at 7.66Gy and 0.33% respectively, and predicted as 10Gy and 0.4%EMS.Chimeral effect viz., minor leaf variations were observed in treated seedlings such as leaf shape, leaf length and serration and to be observed for stability. Maximum variability in seedling height, internodal length and thornless characters were observed in seeds treated with 10 Gy and 25Gy dose of gamma radiation. Mutagenic treatment significantly decreased the shoot length, leaf area, fresh weight, dry weight, and relative water content and chlorophyll content but increased root length with increasing the dose of mutagens. From the results it is observed that the variation increases with increase in the dose/concentration of the mutagens. The result of the study empharized the determination of absorbtion dose as 10Gy, 0.4% EMS respectively and produced promising variation the thornless, internodal length which has a promising impact in understanding the variation in further generation.