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

Abstract

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.