Intra-canopy variability of fruit quality in kiwifruit vines protected by anti-hail nets

In several fruit trees species, it is well known that intra-canopy variability occurs in fruit quality at harvest. This variability in fruit growth and quality has been correlated to the heterogeneous distribution of light within the canopy. Scattered light has higher penetration capacity through the canopy than direct light. The aim of the present study was to verify if intra-canopy variability can be affected by protecting the vines with an anti-hail net that increases the percent of scattered light compared to normal ambient light. Specifically, we compared vines covered with a white anti-hail net that was able to increase the percent of scattered light in the PAR range with uncovered vines. At commercial harvest, 150 fruit per treatment were harvested separately on shoots located at the proximal and the terminal part of the fruiting canes (top and bottom canopy layers, respectively). At harvest and on two dates during cold-storage (after 2 and 4 months of cold-storage), 50 fruit per treatment were sampled to measure the following qualitative parameters: flesh firmness, soluble solids content, pH, flesh color, and percent of dry matter. Most of the fruit qualitative parameters were significantly affected by cold-storage, canopy layer, and the presence of the net. During cold-storage, flesh firmness, the L* and the b* flesh color coordinates decreased, whereas soluble solids content and the a* flesh color coordinate increased. Fruit from the top canopy layer had higher soluble solids, percent dry mass, and flesh color luminosity than fruit from the bottom canopy layer. Fruit quality was significantly improved under the anti-hail net. For instance, fruits of vines under the anti-hail nets had higher percent dry matter and soluble solids content than fruits of the uncovered vines. Within-canopy variability in fruit quality was not reduced in vines protected with anti-hail nets.