On-the-go sensing of grape berry anthocyanins during commercial harvest: development and prospects

Background and Aims: The development and adoption of Precision Viticulture approaches to grape and wine production have been hindered by the lack of a commercially available sensor for on-the-go sensing of fruit quality during harvest. In this work, we sought to deploy the Multiplex (R), a fluorescence-based non-contact hand-held optical sensor on a harvester, for on-the-go sensing of berry anthocyanins during the South Australian vintage of 2010. Methods and Results: Measurements made of anthocyanin concentrations in the laboratory using the Multiplex showed high correlation (R-2 > 0.9) with those made on the same grapes using the standard spectrophotogrametric method. When used in hand-held mode in the field, data collected using Multiplex demonstrated a similar spatial structure to that observed in other data layers (remotely sensed vigour, yield, elevation). Similarly, when deployed on a harvester as an on-the-go sensor, data obtained using Multiplex exhibited the expected spatial structure. Conclusions: Meaningful measurement of grape berry anthocyanins on-the-go during harvest is feasible using Multiplex. Significance of the Study: This is the first time that berry colour has been sensed on-the-go during harvest. The work therefore paves the way for a greater focus on attributes of fruit quality in the delineation of vineyard management zones and implementation of Precision Viticulture.