Non destructive in vineyard grape selection by a fluorescence sensor for differential wine making

The use of a non-destructive fluorescence sensor (Multiplex® - Force-A, Orsay, France) allowed for the selection of grapes with higher and lower phenolic (anthocyanins, anth) and soluble solids (ss) content directly on the vines. The mapping of the anth index (ANTH_RG) and the chlorophyll index (CHL) was performed, just before harvest, at the Fattoria di Magliano (South Tuscany, Italy) in September 2013, on grape bunches of Sangiovese and Merlot cvs. Optical measurements of Sangiovese in a single vineyard and of Merlot in two different areas were performed manually, using a 15×15 m grid. The ANTH_RG and CHL showed high spatial variability. Based on this, once calibrated against wet chemistry of berry samplings, two areas with the lowest and highest anth and ss level were identified in the vineyards by segmentation according to the median values. The obtained maps can be used to perform a selective harvest for the production of wines with differentiated quality and market values.