USING A FLUORESCENCE PROXIMAL SENSOR TO STUDY SPATIAL VARIABILITY OF GRAPE PHENOLS IN A TEMPRANILLO VINEYARD

The phenol content of berries is a very important parameter to define grape and wine quality. The aim of this work was to study the spatial variability of grape phenols in a vineyard using a new proximal fluorescence sensor. A regular sampling grid of 67 blocks was built in a 2.2 ha Tempranillo (Vitis vinifera L.) vineyard. The phenol content of grapes was assessed using a portable fluorescence sensor, called Multiplex™, in three clusters of three vines per block at two different timing (veraison and harvest). Omnidirectional semivariograms were built for three Multiplex™ parameters (ANTH_RG, FERARI and FLAV) which are related to anthocyanins and flavonols content in grapes. Kriged maps were obtained for each parameter at veraison and harvest. All parameters showed a stronger spatial dependence at veraison and a larger range at harvest. These results suggest that a portable proximal sensor can be used to assess the spatial variability of grape phenols in a vineyard and for mapping winegrape composition attributes.