The effect of gamma radiation from Cobalt- 60 source on the seed germination of maize (Zea mays)

This experiment was conducted as a factorial experiment in a completely randomized design with three replications, to investigate the effect of Gamma rays on germination of maize (Zea mays</em>) using the Cobalt-60 radiation therapy apparatus. The first factor consisted of 4 maize genotypes (AR64, Dehgan 400, Fajr 260 and 704) and the second factor was gamma-ray dose in eight levels (0, 50, 100, 150, 200, 300, 400 and 500 Gy). In this study, traits such as root length, stem length, coleoptile length, root number, vigor index, mean germination time and germination percentage were evaluated. The results showed that the differences between genotypes for all traits, the difference between gamma-ray levels and the interaction between genotype and gamma-ray doses factor were significant for all traits except for germination percentage. Genotype 704 with the highest mean of 92.5% and genotypes of Dehgan 400 and Fajr 260 had the lowest germination percentage. Regarding the different reaction of the cultivars to gamma-ray doses, the appropriate dose for RA64 is 100-150 Gy, for Dehgan 400 is 150 Gy, for Fajr 260 is 100 Gy and 704 is 50 Gy. However, doses higher than the values indicated for each of the cultivars had a negative effect on maize seed germination characteristics and growth.