Non-invasive techniques to estimate the influence of rootstock on leaf and berry components of Pinot blanc grapevines

Abstract

Beside the resistance against phylloxera the adaptation of rootstocks to different site properties e.g. soil pH, water availability, nutrition supply, lime content or salinity and management system of the vineyard are of major importance establishing a vineyard and balancing growth. Pinot Blanc (Vitis vinifera L.; clone Gm 2) were planted in 2003 at Geisenheim (Germany) and grafted on twenty different rootstocks. For the present study six rootstocks (125AA, 101-14/3, Richter 110, Riparia, Schwarzmann and SO4) were chosen to investigate the rootstock influence on leaf and berry components over the last three years. Therefore non-invasive techniques were used to determine the chlorophyll and nitrogen related indices in leaves and berries. The spectrometer (Multiplex®, FORCE-A) is a hand-held multi-parametric optical sensor for field and also laboratory measurements and is based on plant fluorescence. This is to distinguish from the variable chlorophyll fluorescence which is used to evaluate the photosynthetic activity of plants. During the seasons 2012 to 2014 leaves, bunches and berries were measured with Multiplex to correlate with berry ripening parameters. For seasons 2013 and 2014 no differences in total soluble solids but in yeast available nitrogen (N-OPA) were detected. The vines grafted on rootstock Riparia and Schwarzmann showed lowest nitrogen index in leaves and the lowest N-OPA values during berry ripening accordingly. This was accompanied with a lower yield over all three years. Contrary to this the highest flavonol and anthocyanin content in leaves were determined for both mentioned rootstocks. Additionally to the handheld device a poly-phenolmeter was attached to a vehicle which was used to record leaf parameters generating maps of the vineyard. This method ensures a fast determination of leaf components and may provide a decision support system adapting management practices.