Gala apple production benefits from high shading levels and water limitation, under exclusion netting

Highlights: 40% shading maintains optimal apple tree performances; Water limitation under 40% shade is not detrimental to harvest; More shading did not remarkably affect fruit quality. Abstract The application of exclusion nets is gaining interest for apple modern production, since it can limit the use of pesticides. From the physiological point of view, information related to final fruit harvest is missing. This two-year study compared a classical anti-hail net (A, 20% shading) with an exclusion net (E, 40% shading), and their effects on Gala apple trees, under two irrigation treatments each. Physiology, production and quality parameters were tested. In both years, midday stem water potentials and leaf gas exchanges were unaffected. The higher shading properties of E created a more favourable microclimate for the trees, allowing them to improve marketable fruit weight, compared to the A net. Fruit quality was influenced by different shading and water treatments, visual red color especially in 2021; however, the other quality traits did not have similar trends over the two years. A remarkable commercial impact was gained, since higher shading provided by exclusion netting lowered water requirements. Fruit productivity was sustained or, even elevated, under water limitations when exclusion netting was used. These results are promising in the view of the increasing demand for sustainability in fruit production.