The effect of regulated deficit irrigation on growth, yield, and berry quality of grapevines (cv. Sangiovese) grafted on rootstocks with different resistance to water deficit

Abstract

The aim of this work was to investigate the effect of full irrigation (FI), pre-veraison water deficit (RDI 1), or post-veraison water deficit (RDI 2) on growth, yield, and berry quality in container-grown, mature vines of cv. Sangiovese grafted onto either 1103P or SO4 rootstock over two consecutive growing seasons. Deficit irrigation regimes significantly affected vine water status of both rootstocks before and after veraison. Trunk diameter (TD) increment was markedly affected when water was restricted early, but not in the post-veraison period. Deficit irrigation from fruit set to veraison inhibited vegetative growth (TD, canopy volume, and weight of pruned wood) more than that applied from veraison to harvest. Yield was unaffected by either irrigation or rootstock in both years. Irrigation had a marked effect on berry and juice quality: the RDI 1 treatment induced the highest berry anthocyanin concentration, and the lowest titratable acidity (TA), which, instead, increased in the RDI 2 treatment. RDI treatments did not modify berry dry weight, soluble solid content, TA, anthocyanins, and epicarp total phenols in vines on both rootstocks.

Deficit irrigation differently affects aroma composition in berries of Vitis vinifera L. (cvs Sangiovese and Merlot) grafted on two rootstocks

“…Yields and berry characteristics were previously published (Palai et al 2021, Caruso et al 2022 and are reported again here to allow a better appreciation of VOC results. In brief, fruit yield per vine ranged from 1.21 kg (SO4-FI in 2018) to 2.29 kg (1103P-FI in 2019) in Sangiovese, and from 1.05 kg (SO4-RDI-1 in 2019) to 2.24 kg (SO4-RDI-2) in Merlot, but no significant differences were observed between irrigation treatments and rootstocks.…”

“…The different climatic conditions between the two growing seasons (especially mean air temperature) affected vine phenology and physiology (Palai et al 2021, Caruso et al 2022), as well as the total amount of glycosylated VOCs in berries (Figure S3, Tables 2,3). The crucial role of climatic conditions on glycosylated VOC profiles has been widely reported in previous studies (Bureau et al 2000, Song et al 2012, D'Onofrio et al 2018, Kovalenko et al 2021), but interestingly, results herein showed that the relationship between the different VOC classes that characterise berry aroma, and the effect of irrigation, remained consistent over both growing seasons.…”

“…In both cultivars, a higher concentration of most glycosylated VOC classes was measured in berries from SO4 grafted vines, especially under the RDI‐1 irrigation regime (although results were not always statistically significant), suggesting a direct effect of rootstock on the accumulation of glycosylated VOCs in berries. Plant vigour expressed as canopy volume or trunk diameter increment was greater in 1103P grafted vines relative to SO4 grafted vines (Palai et al 2021, Caruso et al 2022). In turn, vigour might have modified the leaf area to fruit mass ratio affecting accumulation of glycosylated VOCs in berries.…”

“…Full irrigation delivered 455 and 414 L/vine from fruitset to harvest in 2018 and 2019, respectively, in order to maintain the stem water potential (SWP) above −0.5 MPa. The two different RDI treatments were imposed from fruitset to veraison (RDI‐1, 37% of FI) and from veraison to harvest (RDI‐2, 49% of FI), respectively; RDI vines were fully irrigated for the remaining irrigation period (Palai et al 2021, Caruso et al 2022). The SWP was measured at 7–10 day intervals with a Scholander pressure chamber using standard protocols (Palai et al 2021).…”

“…The TSS, TA and pH were measured on 30‐berry samples from individual vines; that is the juice was extracted from each sample, TSS determined with a hand refractometer, and a 10 mL aliquot titrated with 0.1 N NaOH to an endpoint pH of 8.2 to determine TA. A TSS threshold of 22 ± 0.5°Brix was established for harvest in order to minimise the potential effects of sugar concentration on the concentration of berry VOCs; thus, the harvest date did not coincide for all irrigation treatments (Palai et al 2021, Caruso et al 2022).…”