WHAT IF THERE WERE A “UNIVERSAL GRAFTHOLDER" TO PROTECT AGAINST THERMAL CLIMATE CHANGE AND DISEASE? THIS IS THE GOAL OF THE INTER-UNIVERSITY AND MADE IN ITALY "AGER" SERRES PROJECT, EXPLAINED BY THE CO-ORDINATOR, ATTILIO SCIENZA

A radical change in viticulture, which had been the same for at least a thousand years, came with the phylloxera insect. It was A ruthless insect, native to North America that arrived in Europe in the second half of the nineteenth century, attacked the roots of European vines, leading quickly to the death of almost all the wine heritage of the continent, that had been cultivated up to then, not grafted.
The phylloxera disaster imposed a definitive change to the European wine industry, and the introduction of American vines (immune to phylloxera) as grafts, from Cabernet Sauvignon to Sangiovese, marked the end of the autonomous existence of European vines. Yet another epoch making revolution could take place from the vine roots in European viticulture and beyond.
Attilio Scienza, Professor of Viticulture at the University of Milan and coordinator of the "Ager Serres" project (http://users.unimi.it/serres/dca---unito-.html), which involves also the University of Turin, the University Cattolica of Piacenza and the Research Centre for Viticulture of Conegliano Veneto: "This is a three year project which, thanks to modern molecular biology, will provide useful information of the so-called molecular markers of rootstocks and accelerate the results of grafts, greatly shorten reproduction and also progressively collect in a single , universal graft holder, elements capable of protecting against various environmental and chemical stress, which the vine root apparatus is subject to”.
Studies on graftholders have unfortunately been mostly neglected, but are instead extremely important as "the brain of a vine, where all the adjustments of its overall physiological functioning take place”, notes Scienza, “is the root system. In this sense, our project is unique to the world because we are the only ones that have turned our attention to this part of the "mysterious" vine, first of all because it is located in a non-visible part”.
After European wine was almost completely devastated by phylloxera, the solution of grafting the fruit became the only way to try to keep the European wine industry alive. An incredible job on the vine root apparatus was carried out within a few years, roughly from the end of the 19th century to the beginning of the 20th. But, “the most serious disaster was resolved through the introduction of graftholders in viticulture”, continued Scienza, “and European vineyards had practically resolved the greatest danger, except for a few crossbreeds, Paulsen, Ruggeri and Richter, which led to the application of graftholders, for example, more resistant to drought. Research on this essential element of the vine was interrupted, to resume, but only sporadically, in the 1950s in Bordeaux, with the new graftholders, Fercal and Gravesac”. The shock generated by the phylloxera insect created a wealth of knowledge about roots and graftholders, at least several hundred, with different characteristics and behavior but that still cannot be adequately exploited, “since there are four rootstocks, 5bb, SO4, 140 Ruggeri and 110 Paulsen, which form 90% of the world's most widely used ones”, Scienza explained, “creating a shortage of options that does not help an even more important qualitative development”.
Meanwhile, viticulture has conquered other areas of production, from Australia to Chile, which bring out new issues for rootstock, since the land in those areas is often different from European land as far as chemical composition and climate interaction are concerned. And climatic changes have dramatically brought out even more critical issues: first of all, drought resistance of graft holders. And this is why the "Ager Serres" project began and is endorsing four new "M series” rootstocks, thanks to modern techniques of molecular biology, particularly suitable for water stress.
“The project is not limited just to this issue”, says Professor Scienza, “because research includes the aim to find molecular markers, i.e., traces of DNA responsible for resistance and tolerance to various critical environmental and chemical issues, drought, salinity of the soil and so on, identifying those most suitable for propagation in a much shorter time frame than those permitted by traditional breeding techniques. These”, continues Scienza, “will allow a pattern of genetic improvement of the "pyramid" of rootstocks, and the ultimate goal will be to put into one individual, all the elements of environmental and chemical resistance, using several parents for crossings, each of whom possess a particular factor of resistance. This will eventually create”, concludes Scienza, “ a "universal graftholder," i.e., a sole individual capable of resisting all the critical chemical properties of soils and climatic conditions - first of all, drought”.