1Genetics Section, Department of Plant Sciences, Texas A&M University, College Station, Texas, 77843, U.S.A.
2Department of Genetics and Plant Breeding, College of Agriculture, A.P.A.U., Rajendranagar, Hyderabad 500 030
Mutagenic effectiveness and efficiency of hydrazine (HZ) and ethyl mcthanesul phonate(EMS) were studied with a local sorghum variety of Texas, TX-414, based on M1 seedling injury, sterility and chlorophyll and morphological mutations in the M2 generation, HZ was found to be highly efficient mutagen based on low seedling injury and seed sterility, in the M1 generation, than that of EMS. HZ induced a broader spectrum of chlorophyll and morphological mutations in the M2 generation compared to EMS. The 0.015 M concentration was the most efficient mutagenic treatment for both HZ and EMS, when M1 seedling injury and M2 mutation frequency was considered. Relative toxicity, uptake of the mutagen by the seeds and mutagen concentration seem to be important factors to be considered in the use of chemical mutagens for mutation breeding programmes. Recent advances in sorghum improvement are mainly due to spontaneous mutations followed by selection and hybridization. Induced mutagenesis as a tool for amending and rectifying the characters has made only a beginning in sorghum. The basic information on mutagenic sensitivity, effectiveness and efficiency of the mutagens, methods of handling the material and treatment procedures required to maximize the induction of mutations is essential for successful mutation breeding programme in sorghum. With this view, the present study was undertaken to assess the relative mutagenecity of hydrazine, a structural isomer of nucleic acid thymidine and ethyl methanesulphonate, an alkylating agent, by measuring their effect on various M1 biological characters and chlorophyll and morphological mutations in M2 generation of grain sorghum.
