Rootstock-scion interactions: nutrient uptake efficiency, water status, and canopy development

Abstract

The performance of the cultivars Chardonnay, Merlot, Pinot gris and Pinot noir grafted onto nine rootstocks or on their own roots was evaluated over a three year period. A split block factorial design was used to compare the effect of the rootstocks Riparia Gloire de Montpellier (RGM), 101-14 MGt, 3309C, 110R, 5BB, 420A MGt, Gravesac, SO4, 44-53M, or ungrafted vines on the scion canopy development, stem water potential, leaf chlorophyll content and macro and micro-nutrient content at bloom and véraison. The range in petiole K and Mg was wider than in Ca levels. Overall, Merlot had the highest leaf chlorophyll content, petiole P, K, and Ca and the lowest Mg at bloom and véraison. The opposite was true for both Pinot cultivars. Merlot also had higher B, Cu, Na, and Zn levels than the other cultivars. Ungrafted vines had the highest chlorophyll content and with the exception of B, Mn, and Mo, had if not the highest, among the highest levels of petiole nutrients at either sampling timing. Vines grafted to 44-53M had low chlorophyll content and low levels of Mg, P, Fe, and Cu but displayed high levels of B and K. Vines on Gravesac and 3309C had low levels of chlorophyll and Fe. Interactions between scion and rootstock were found on petiole K, and Ca at bloom and K, Mg and B at véraison. Rootstocks imparting high vigour, such as 420A and 5BB, showed high levels of leaf chlorophyll, bloom and véraison P and Mg and véraison Ca and Mn. Boron was highest for vines grafted to 44-53M, 3309C, and 110R. 110R conferred high vigour to Merlot and Chardonnay and moderate vigour to Pinot noir. 3309C devigourated Pinot noir but imparted moderate vigour to the other cultivars. 420A imparted high vigour to Chardonnay and Pinot gris and moderate vigour to Merlot and Pinot noir. Gravesac and SO4 imparted high vigour to Pinot gris and moderate vigour to the other three cultivars. Across all varieties, RGM, 44-53M and 101-14MGt imparted low to moderate vigour but showed high sensitivity to drought. Despite the large canopy, vines grafted to 5BB showed the highest drought tolerance. It is apparent that the scion is able to influence rootstock nutrient uptake efficiency and this is reflected in different expressions of conferred vigour.