Response of peanut seeds to different levels of gamma radiation (60Co)

The gamma radiation from Co-60 source is widely used for sterilization aiming at preventing decomposition and toxicity from microbes in several products. The degree of radiosensitvity of a plant embryo depends on the species, the development stage during radiation, doses used and the criteria used to measure the biological effect, the germination test, being commonly used. This work aimed to study the peanut sensitivity to gamma radiation and its effects in the germination, in the vigour and seeds microflora of cultivar BRS Havana, irradiated with Co-60 source, type gammacell with rate of dosage of 12.5 kGy h(-1). The tested doses were the following: 0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 6.0, 9.0, 12.0, 15.0, 18.0, 21.0 and 24.0 kGy. With the obtained results, it was concluded that doses over 3.0 kGy damaged the seeds viability, doses over 12.0 kGy totally compromised the vigour and the peanut seed germination. Radiation over the dose of 2.0 kGy eliminated the fungus Aspergillus flavus and Aspergillus niger, and over the dose of 3.0 kGy eliminated the Aspergillus glaucus. The Penicilium spp. remained in more than 30% of seeds in all treatments with radiation, not being eliminated until doses of 24.0 kGy.