The Surface Wax of Several Grapes in Japan

Abstract

The amounts of the surface wax and its major component, the hard wax, of ‘Delaware’grapes increased rapidly until 30 days after full bloom and made little change thereafter to the harvest time. On the contrary, the soft wax kept almost a constant level in the early stage of berry growth and increased steadily in the late stage. Further, with the advance of berry growth, a distinct change occurred in the composition of long-chain alcohols, the main components of the soft wax. These seasonal trends in the hard and soft waxes were similarly observed in both gibberellic acid (GA)-treated (seedless) and untreated (seeded) berries.The accumulation of surface wax was inhibited in‘Delaware’when the postbloom GA application was late for the recommended time, 10 days after full bloom.The amount of the surface wax was compared at maturity among 5 leading cultivars in Japan.‘Delaware’, regardless of GA treatment, was highest in the amount of total and hard waxes, followed by‘Muscat Bailey A’, ‘Campbell Early’, ‘Kyoho’and‘Muscat of Alexandria’, in this order. In the amount of soft wax, however, ‘Campbell Early’was highest, followed by‘Kyoho’, GA-treated‘Delaware’, ‘Muscat of Bailey A’, GA-untreated‘Delaware’and‘Muscat of Alexandria’, in this order.