Rootstock and irrigation induced different response in berry aromatic characteristics in ‘Merlot’ and ‘Sangiovese’ grapevines
Giacomo Palai is a PhD student at the Department of Agriculture, Food and Environment of the University of Pisa, Italy. He is supervised by Dr. Giovanni Caruso and Prof. Claudio D’Onofrio. His research focuses on the sustainable management of water resources in viticulture, with the objective to increase fruit quality. To achieve this aim, he has conducted a study on the effect of different deficit irrigation strategies and cultivar-rootstock combinations in grapes. He is researching berry aroma profile in fully productive ‘Sangiovese’ and ‘Merlot’ grapevines grafted on 1103 Paulsen and SO4 rootstocks during two consecutive seasons. ‘Merlot’ and ‘Sangiovese’ are two important international red grapevine cultivars and were grafted onto two rootstocks with a different response to the water deficit. Cultivar-rootstock combinations were subjected to water stress from fruit set through veraison (pre-veraison), and from veraison through harvest (post-veraison), whereas they were fully irrigated for the rest of the irrigation period. Control grapevines were fully-irrigated throughout the entire season. The results showed a higher concentration of volatile organic compounds (VOCs) on ‘Merlot’ berries contrasted with ‘Sangiovese’ berries. The two cultivars were different in their berry aromatic profile, characterized by monoterpenes, C13-norisporenoids and benzene derivatives in ‘Sangiovese’, and phenols, vanillins and benezene derivatives in ‘Merlot’. The total VOCs and the typical aroma classes that characterize the cultivars were increased under pre-veraison water stress treatment, probably triggering the biosynthetic pathways of VOCs. Furthermore, ‘Merlot’ and ‘Sangiovese’ showed a different response towards the water stress magnitude imposed on pre-veraison treatment, providing an indication to manage vines’ water status and irrigation in a specific way depending on the cultivar. On the contrary, post-veraison deficit irrigation treatment was detrimental or irrelevant on VOCs accumulation, affecting the main biosynthetic pathways in a critical phase. The rootstocks affected berry VOCs concentration especially under pre-veraison water deficit. In particular, SO4 grafted grapevine showed higher VOCs amounts with respect to 1103 Paulsen, magnifying the irrigation effect and the typical cultivar-related berry flavour characteristics. These results suggest that deficit irrigation represents a useful tool to enhance grape berry aroma. The rootstock-scion combination can significantly magnify or reduce this effect.
Giacomo Palai won the ISHS Young Minds Award for the best oral presentation at the XII International Symposium on Integrating Canopy, Rootstock and Environmental Physiology in Orchard Systems, which was held virtually in USA in July 2021.
Giacomo Palai, Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124, Pisa, e-mail: firstname.lastname@example.org
The article is available in Chronica Horticulturae