1978 Volume 13 Issue 1-2 Pages 10-13
It has been stated that the partial browning often occur around the vascular bundle of potato tubers(Danshaku Variety) when gamma-irradiation is done soon after harvest for sprout inhibition.
The object of this study was to determine the browning tendency by gamma-irradiation on the six varietiesof potatoes grown in the spring and the autumn. Potato tubers of six common Japanese varieties, Danshaku, May Queen, Unzen, Tachibana, Nourin 1, and Oojiro used for the examination. The latter four varieties have resting period, and usually used as double cropping potatoes in Japan.
The potatoes of spring cropping were planted on Mar. 5 and harvested on June 5. The potatoes of autumn cropping were planted on Sept. 8 and harvested on Dec. 12. At two, four and eight weeks after harvest a sample was exposed to 15 kilorads of 60Co gammarays at a dose rate of 30 kilorads per hour. On the tenth day in the case of spring cropping and on the twenty fifth day in the case of autumn cropping after last irradiation, these samples were cut through base end to examine the browning of vascular bundle of tubers.
The browning was not observed entirely in all varieties of.autumn cropping potatoes. However in the case of spring cropping potatoes, the apparent browning was observed in Danshaku and Oojiro irradiated at two and four weeks after harvest. The browning tendency of irradiated spring cropping potatoes are summarized in Table 1.
Whether the browning occur around the vascular bundle by gamma-irradiation or not, seems to have relation to the variety and the maturing stage of potatoes.
