Effects of gamma irradiation on onion sprouting. I.--Influence of dose rate and post-harvest period of treatment.

Onions of "Dorata di Parma" variety were exposed to 10 Krads of Co60 gamma irradiation in 5, 10, 20, 40, and 80 minutes in December, 1975 and then stored in the cold storage (10 +/- 1 degree C; R.H. 65-70%) and at the room temperature (15-20 degrees C; R.H. 40-70%) for 3 months, to study the influence of dose-rate and post-harvest period of treatment. Average number of buds sprouted in each onion bulb under cold storage condition ranged from 2-3, while this number was found to increase to 3-4 under ambient storage conditions. Although no effect of either irradiation or dose rate was observed when onions were irradiated after the break of their dormancy, however, a significant slowing down effect of irradiation could be observed as far as the rate of growth of sprouts was concerned. Weight loss was also reduced significantly in the irradiated onions as compared with controls.