Effects of low energy (160 keV) X-ray on microbial inactivation, sprouting inhibition and genetic variation in potato

The effects of low energy X-ray irradiation on microbial inactivation, sprouting inhibition and genetic variation were surveyed. There was an inverse correlation between the exposure dose in range of 0 Gy-5000 Gy and the survival rate of microorganisms. The dose of 1000 Gy seemed to be suitable for inactivation of microorganisms because the respective survival rate is relatively low (0.59%). Dose rate of 13.87 Gy/min was the most appro-priate to inactivate the microorganisms, with the survival rate of 0.37%. Applying the irradiation dose of 1000 Gy and dose rate of 13.87 Gy/min, there was a significant sprouting inhibition of irradiated potatoes compared to the control for six months storage. The effect of irradiation dose (100-1200 Gy) and dose rate (8.63-19.62 Gy/ min) on genetic variation of the irradiated samples was assessed by DNA fingerprints induced from using three molecular techniques including Random Amplified Polymorphic DNA (RAPD), Start Codon Targeted Poly-morphism (SCoT) and CAAT box - derived polymorphism (CBDP). At the irradiation dose of 1000 Gy and dose rate of 13.87 Gy/min, the level of genetic variation was relatively low (4.85%). Thus, this treatment is a suitable condition of irradiation for potato treatment with the purpose of preservation.