Evaluation of grapevine resistance to downy and powdery mildew in ‘Regent’ × ‘Bogazkere’ hybrid population segregating for resistance genes

Fruit production should be adapted to future scenarios that are frequently associated with scarce resources, especially freshwater and fertilizers. New biologically-based fruit production strategies, i.e. taking into account tree growth and water status, are required to optimize irrigation and fertilization under abiotic stress conditions. It was hypothesized that a moderate abiotic stress, here deficit irrigation with or without nitrogen deficit, in the preharvest period, could decrease postharvest losses due to diseases and pruning weights due to reduced vegetative growth, without sacrificing the yield and fruit quality. This study was conducted over two years using the same trees of ‘Moncante’ nectarine cultivar grown in a commercial orchard. Trees were assigned to three treatments: (1) full irrigation at 80% estimated crop evapotranspiration (ETc), (2) deficit irrigation, i.e. at 75% of full irrigation, and (3) deficit irrigation and deficit nitrogen, i.e. at 75% of full irrigation and 75% of usual N-fertilization adopted by the grower in this commercial orchard. Deficit irrigation alone and in combination with deficit nitrogen reduced postharvest diseases and pruning weights without significant yield losses. Our results suggest that ETc-based approaches of reduced water irrigation may be a sustainable way to decrease phytosanitary inputs and workload in the orchard while maintaining the orchard performance.