Calibration of the maize yg2 assay using gamma radiation and ethylmethanesulfonate

Michael J. Plewa, Patrick A. Dowd, Elizabeth D. Wagner

Research output: Contribution to journalArticlepeer-review


A standard protocol for the yellow‐green‐2 (yg2) forward mutation assay in Zea mays is proposed. A detailed calibration of the assay using 137Cs gamma rays and ethylmethanesulfonate (EMS) was conducted. Gamma ray‐induced mutant sectors in leaves 4 and 5 exhibited one‐hit kinetics. The radiation doses ranged from 25 to 500 rads. The mean induced mutation rate per rad of gamma radiation was 4.54 × 10−6. This value was constant for the primordial cells of leaves 4 or 5. The induction of forward mutation by EMS also exhibited one‐hit kinetics in the concentration range 0.25–20 mM (0.33–23.54 μmol EMS/kernel). The mean induced mutation rate per mM EMS was 1.79 × 10−4, and the mean induced mutation rate per μmol of EMS per kernel was 1.52 × 10−4. Using the induced mutation rates for gamma radiation and EMS, the rad equivalent was calculated. One rad of gamma radiation is equivalent to the exposure of a 2.53 × 10−5 M EMS solution or to 2.99 × 10−8 mol of EMS per kernel.

Original languageEnglish (US)
Pages (from-to)781-795
Number of pages15
JournalEnvironmental Mutagenesis
Issue number6
StatePublished - 1984


  • Zea mays
  • ethylmethanesulfonate
  • forward mutation
  • gamma radiation
  • rad equivalent
  • yg2

ASJC Scopus subject areas

  • Genetics
  • Health, Toxicology and Mutagenesis


Dive into the research topics of 'Calibration of the maize yg2 assay using gamma radiation and ethylmethanesulfonate'. Together they form a unique fingerprint.

Cite this