Silicon application to soil increases the yield and quality of table grapes (Vitis vinifera L.) grown in a Semiarid climate of Brazil

Purpose: Silicon (Si) acts to reduce biotic and abiotic stresses in plants. Herein, we aimed to assess the impact of an amorphous silica-based fertilizer (ASF) applied to soil on the yield, mineral nutrition, chlorophyll fluorescence, and postharvest quality of two cultivars of table grapes grown in a semiarid climate. Methods: The cultivars Arra 15 and BRS Vitoria were submitted to the treatments control, 175 or 350 kg ha-1 ASF. Leaf and fruit samples were collected and analyzed for Si, nutrients, and postharvest quality characteristics. Photosynthetic efficiency was assessed by measuring chlorophyll a fluorescence . Results: Both cultivars showed significant responses to Si with the ASF rates of 175 and 350 kg ha-1. The characteristics improved through ASF application compared to the control were: fruit production (6 - 22 %), bunch weight (11 %), number of berries (20 - 34 %), berry crunchiness (20 %), the content of total soluble solids (13 – 20 %), the titratable acidity (13 %), the accumulation of macro and micronutrients (12 – 45 %) and the photosynthetic efficiency (5 – 33 %). Conclusions: Soil-applied Si increases the yield and quality of grapes by improving the plant response to abiotic stresses, being such effects more significant in the dry season.