KOREAN JOURNAL OF HORTICULTURAL SCIENCE & TECHNOLOGY, vol.34, no.3, pp.495-509, 2016 (SCI-Expanded)
Irrigation applications (IA) and increased bud load (BL) are fundamental practices that are used to achieve optimum yields in grape production, while maintaining fruit quality parameters. Two different irrigation amounts (IA-I and IA-II) based on growth stages, in addition to a nonirrigated (rain-fed) control, along with two different BL applications [normal bud load based on traditional pruning practices (1BL) and double bud load (2BL)] were evaluated over a twoyear experiment for their effects on the biochemical composition of the berries. Berries from the rain-fed vines had higher sugar levels, whereas no significant change was detected in organic acid levels. The increased bud load (2BL) treatment yielded less sugar in the berries compared to the 1BL control in both years. The total non-colored phenolic compounds (NPC) were greater in the irrigated (especially IA-I) and 2BL treatments than in those of the rain-fed and 1BL control. However, total anthocyanin was greater in the non-irrigated and 1BL control than in the irrigated and 2BL treatments. The antioxidant contents of the berries also varied according to the treatments and years. Our results implied that implementing a higher bud load along with the IA-I irrigation application, in which irrigation applications were 50 and 75% of the cumulative evaporation from the Class A pan during berry set to veraison and veraison to harvest growth stages, respectively, can help in obtaining greater yields in high-plateau viticulture. Thus, if more buds are left on the vines, along with sufficient irrigation and rainfall, yield may increase while maintaining or increasing the biochemical composition of the berries.