Gamma Irradiation and Enriched CO2 Atmosphere Storage Effects on the Light-induced Greening of Potatoes

SUMMARY – Michigan-grown Kennebec and Sebago potato tubers were exposed to gamma irradiation in the dose range of 0 to 400 Krad and subsequently stored in atmospheres containing 0.03% to 15% CO₂. Upon illumination with 3,000 lux for periods up to 20 days while maintaining the atmosphere, all tubers developed some greening. The tubers exposed to 200 and 400 Krad were inhibited from greening to the highest degree but suffered general quality loss. The levels of 10 to 20 Krad, which are suitable for the sprout inhibition of potatoes, did not cause significant inhibition of greening under any of the conditions of this experiment. Storage in enriched CO₂ atmospheres inhibited the greening to the extent of 50% at 15% CO₂, only upon prolonged illumination (12 days), while irradiation (40 Krad) was only effective after a short period (4 days) of illumination. Irradiation in the O–40 Krad range did not increase the inhibition caused by CO₂. The inhibition of potato greening by irradiation was effective through a period of 5 weeks storage in the dark prior to illumination.