Abstract

                                Mutagenic effectiveness and efficiency of Gamma ray was studied in two genotypes of Kodomillet (Paspalum scrobiculatum L.) viz., CO 3 and TNAU 51. Seeds of the two genotypes were subjected to gamma irradiation at a dose of 400, 500, 600, 700 and 800 Gray .The mortality percentage, lethality and injury in M1 seedlings were found to have linear relationship with the dose of gamma rays. Considering the mortality and mutation frequencies, the dose 500 Gray was found to be highly efficient. Chlorophyll mutants like Albino, Xantha, Chlorina, Striata and Viridis were found to occur in varying proportions in the M 2 generation. The occurrence of more than one type of chlorophyll mutants in the same dose might be due to simultaneous mutations in more than one locus. The mutagenic effectiveness and efficiency were calculated based on biological damage. Both mutagenic effectiveness and efficiency reduced with the increase in dose of irradiation. In the present investigation, 400 Gray dose was observed to be highly efficient in terms of survival reduction for CO3 while for TNAU 51, 800 Gray dose was observed to be highly efficient. With reference to height reduction, 800 Gray dose recorded maximum efficiency. The 800 Gray dose was found to be highly effective for inducing mutation in both the genotypes. But, for optimum recovery of viable mutants, 500 Gray dose was found to be effective dose in kodomillet.

Key words : Kodomillet, Gamma Rays, Mutation, Effectiveness, Efficiency