EXPERIMENTAL DETERMINATION OF THE GROULT REDUCTION DOSE (GR₅₀) AND THE LETHAL DOSE (LD₅₀) FOR SOYBEANS IRRADIATED BY GAMMA RAYS

ABSTRACT

The degree of radiosensitivity depends mostly on the species, the stage of the embryo at irradiation, the doses employed and the criteria used to measure the effect. One of the most common criteria to evaluate radiosensitivity in seeds is to measure the average plant height at a determined time after germination. The radiation dose value that causes a 50% growth reduction of a population is called GR₅₀. The goal of this research was to study soybean radiosensitivity from a quantitative point of view. Soybena seeds from Instituto Agronômico, Campinas, SP, were irradiated in a ⁶⁰Co gamma source type 220 excell from MDS Nordion with dose rate of 1.48 kGy / h in CENA. Applied doses in kGy unit was follows: 0.0, 0.10, 0.20, 0.30, 0.40 and 0.50. It was concluded that the GR₅₀ of soybeans is 0.30 ± 0.04 kGy. It was not possible to determine the LD₅₀ for the dose range employed in this experiment.

KEY WORDS
Soya; food irradiation; radiosensitivity; radiation; biological effects; gamma rays