Rootstocks are resistant to disease and drought, and they also improve the quality of grapes

Genetic research applied to vines has been working for years to find solutions to the ever-increasing problem of water scarcity, especially in some areas, and plant resistance to diseases. The guideline has always been first and foremost to maintain, and if possible, improve, the quality of the grapes; consequently, the wine that they produce. It seems that now the goal has been achieved by “M rootstocks”, selected by the research team of the University of Milan, led by professors Attilio Scienza and Lucio Brancadoro together with the sponsorship of Winegraft, the company that brings together 9 of the most important wine companies in Italy - Ferrari, Zonin, Banfi, Albino Armani, Cantina Due Palme, Claudio Quarta Vignaiolo, Angelini Wines & Estates, Nettuno Castellare (Domini di Castellare) and Cantine Settesoli - and for ten years, has sponsored the development of research on these rootstocks, multiplied and distributed exclusively by Vivai Cooperativi Rauscedo.
The latest surprising discovery regarding the Ms has revealed that they are also a vehicle to superior wine quality as well as a barrier against drought and limestone, overturning the old belief that has accompanied the spread of rootstocks since the phylloxera crisis. The discovery offers a completely new framework to fully understand the potential of the M series, which is beginning to be requested by all the major wine-growing areas in the world, a note explained. More than twenty years after carrying out experiments and microvinification in ten different production areas in Italy, from Piedmont to Sicily, the University of Milan team has demonstrated that the “4 musketeers” of the M series bring the vine to better production performance in all the different aspects that determine the quality of the grapes, and therefore of the wine: vigor and production of the vine, technological, phenolic and aromatic maturation of the grapes.
“The scope of this most recent research carried out by the University of Milan is truly revolutionary”, Marcello Lunelli, president of Winegraft commented, “because it changes the historical vision that we have always had of rootstocks. From now on, we must no longer consider them only a “barrier against” phylloxera and drought, but as an efficient biological tool “to” obtain a superior quality of the grapes and therefore of the wine”. “We have finally managed to demonstrate that even in viticulture, as has now been accredited in other areas of tree cultivation”, Attilio Scienza explained, “the rootstock is a valuable vehicle to improve the quality of production. It has taken two decades of experimenting in the field and complex microvinifications to reach this result. The reason is that objectively it is more difficult in viticulture to carry out in-depth investigations on the effect rootstock has on the quality of the grapes due to the complex interactions that are created between it, the cultivation environment and the different vines”. However, the goal has been achieved. “We have acquired a significant amount of information during this very long experimental research study”, Lucio Brancadoro emphasized, “that has given us a clearer overview of the direct effect of the choice of rootstock on the production-quality performance of the vine and grapes, referring to the quality of the wines obtained. In detail”, Brancadoro continued, “in the different grafting combinations used in various fields of comparison between M and other traditional rootstocks, among those most widespread in our Country, not only did the extreme adaptability of M to the different environments of Italian viticulture emerge, but also, by regulating the vine’s adaptive responses to various environmental conditions, M rootstocks were revealed an important driver for qualitative results. M rootstocks respond more efficiently to the increasingly extreme abiotic stresses due to climate change, allowing a more favorable ripening process of grapes, which is a premise for superior quality in oenological results”.
Winegraft explained further, “the field experiments and sensory analyses obtained on wines have demonstrated that Cabernet Sauvignon grafted on the M produced the best results in general, balanced by excellent vigor and above average sugar values. It is a high parameter that we also find in the Chardonnay, planted in comparison fields in Franciacorta and TrentoDoc, combined with higher levels of titratable acidity (specifically in malic acid) and lower pH, a determining element for quality sparkling wine production. The sensory analysis of the wines obtained from Chardonnay grafted with the M grown in Franciacorta, showed higher levels of acidity and a complex aromatic profile that enhances the notes of tropical fruit. From an olfactory point of view, these wines were more intense and, when tasted, had greater acidity, flavor, structure and persistence”. In addition to the technological parameters, the note explained, it was shown that the rootstock also highly influenced the accumulation of polyphenols during maturation, which is a determining aspect in quality of red wines. In the comparison fields combining various red vines - Nero d'Avola, Cabernet Sauvignon and Sangiovese - higher levels of total polyphenols were detected in the grapes, a more vivid shade of the coloring substances accompanied by greater accumulation and concentration, especially the non decolorizing anthocyanic fraction, which facilitates persistence of the color during wine aging. The final aspect relevant to the sensory analysis that emerged from the experiment is the aromatic composition of the grapes that M rootstocks decisively condition, because, by influencing a different response to environmental conditions, they also have direct effects on the secondary metabolism of the vine. “This aspect is currently not studied in depth as it is difficult to analyze the high number of aromatic compounds present in wines obtained from different grafting combinations”, Lucio Brancadoro explained, “in the tests we carried out on Chardonnay and Sangiovese grapes, however, beside details on increases in the individual compounds found (volatile acids, thiols, ethyl esters, phenols, norisoprenoids, and so on), in the free state or in the form of aroma precursors, we confirmed that M rootstocks are a definite driver to achieving quality in the vineyard, which is a decisive factor to obtain excellent oenological results”. The change in the viticultural perspective imposed by the results of the research carried out by the University of Milan when dealing with the choice of rootstock, is evident. “This discovery has led us to totally reconsider the approach we have always taken towards rootstocks”, Marcello Lunelli commented, “scientific proof of the importance that Ms play in determining the quality of a wine confirms the need for an accurate choice of the grafting combination that takes into account the variety and environmental characteristics, but also considered in relation to the oenological objective that we want to pursue”.