Standardization of GR₅₀ dose of gamma rays for mutation breeding experiments in safflower (Carthamus tinctorious L.)

GR₅₀ dose of gamma rays was optimized in four different genotypes of safflower. In vitro experiment during seedling stage detected very high GR₅₀ value of 579.2 Gy based on reduction of root length. Field experiments on four genotypes revealed significant difference in GR₅₀ values among safflower genotypes. The GR₅₀ values varied in between 248.7 to 374.3 Gy based on the seedling height data at 42 days after sowing. RVS 2012–13 was most sensitive to radiation, while Annegiri 1 was the tolerant.An optimal dose of 300 Gy was found suitable for large scale mutation breeding experiments in safflower.