Elimination of the UV com-ponent from sunlight markedly reduced the coloration and the anthocyanin content in the skin of ‘Hakuho’ peach fruit. Kliewer (1977) reported that the anthocyanin formation in grape berries was markedly inhibited when the berries were exposed to 37/32 °C, day/night under high solar irradiation. In this experiment, however, the production of anthocyanin under the polyethylene film, compared with the UV-proof film showed that temperature stress was not a key factor affecting the response as both treatments had elevated temperatures. On the other hand, the artificial irradiation by UV fluorescent light increased anthocyanin content in whole fruit and skin discs.