Soil variables and reflected light revealed the plasticity of grape and wine composition: Regulation of the flavoromics under inner row gravel covering.

Abundant gravel in vineyards bothers growers. To investigate the gravel covering inner-row effect on grapes and wines, a two-year experiment was carried out. Regional climate and vine microclimate were collected, the flavoromics of grapes and wines were determined by HPLC-MS and HS/SPME-GC-MS. Gravel covering reduced the soil moisture. Light-colored gravel covering (LGC) enhanced the reflected light by 7-16% and cluster-zone temperature by up to 2.5 °C. Dark-colored gravel covering (DGC) absorbed 13% of the solar radiation and cooled the cluster-zones. DGC promoted the accumulation of 3'4'5'-hydroxylated anthocyanins and C6/C9 compounds in grapes, while grapes of LGC were accompanied by higher flavonols. The phenolic profiles of grapes and wines among treatments were consistent. The overall aroma of grapes from LGC was lower, while DGC helped to weaken the negative effects of rapid ripening in warm vintages. Our results revealed the gravel regulate grape and wine quality through soil and cluster microclimate.