Effect of a new biostimulant made by Fabaceae tissues on ripening dynamics and must technological main parameters in Vitis vinifera cv. Ribolla Gialla

Bio stimulants are organic compounds that influence biochemical activity within the treated plant, increasing the efficiency of the whole plant or any of its parts, yet can increase the uptake of necessary nutrients. Yet, they are very safe for humans, animals, and environment; thus, their use decreases the pollution caused by chemicals. From this point of view, recently, great attention has been focused on the possibility of using natural and safe stimulants in viticulture, which is one of the most cultivated and remunerative crop worldwide. Furthermore, protein hydrolysates (PHs) bio stimulants are an important group of such products based on a mixture of peptides and amino acids, that have received increasing attention in the recent years due to their positive effects on crop performances. Hence, the aim of this work was to investigate the foliar application of a bio stimulant developed by Ilsa SPA. This product is characterized by the presence of amino acids and peptides along with the presence of triacontanol of natural origin (> 6 mg / kg), saponins and various polyphenolic compounds (tannins, flavonoids, chlorogenic; gallic and cafferico acids). All of these have a bio stimulating and antioxidant action, naturally present in the plants of the Fabaceae family and which, thanks to the enzymatic hydrolysis process, are effectively extracted and made available for the plants. Thus, it was tested in order to study its effect of on the yield components, technological maturity trend, and its effect on some must parameters interesting for winemaking. This study was conducted during the season 2021 in a private vineyard of Ribolla Gialla grapevine (Vitis vinifera, L.) grafted onto rootstock SO4, in the north-east of Italy, Friuli Venezia Giulia region. The vines were 15- year-old, cultivated at 1 x 2 m, grown in clay soil without artificial irrigation system. The trellis system adopted was a trained single Guyot. In this region, the climate is generally high rainy (about 1800 mm/year), hence for farmers and winemakers is of great interest anticipating harvest time, to avoid phytoiatric problems, especially for those variety, as Ribolla Gialla, that tend to reach the technological maturity later than other variety, without compromising any agronomic and oenological parameters. After one-studied year, the natural bio stimulant had a positive action. In fact, data showed that ripening was anticipated in the treated plants (TT), having had higher parameters at every stage than the not treated (NT). In addition, we report how the TT treatment reached a full maturity for local standards one week earlier than NT. Finally, there also was a good effect on must microbiome main components, since the Yeasts present in the must was higher in TT, meaning that the proteins in the bio stimulant promoted the growth of the microbial community of berry skin.