Preveraison Water Deficit Accelerates Berry Color Change in Merlot Grapevines

Abstract

Abstract:In red varieties, berry color change from green to red is one of the first events associated with ripening and is often used as an indicator of veraison by viticulturists. Water deficit can accelerate ripening and increase pigment accumulation in the berry skin. The impact of water deficit on the timing and progression of berry color change in the vineyard has been largely overlooked. Here we present three years of observations (2011 to 2013) on the progression of color change in Merlot vines subjected to water deficit (WD) or irrigation (C) regimes. Water deficit did not affect the date at which berries started changing color in 2011 and 2012, but pigmentation began three days earlier in WD than in C vines in 2013. Water deficit accelerated pigmentation in all three years and WD berries completed color change five days earlier than C berries on average.

Water Deficits Do Not Improve Fruit Quality in Grapevine Red Blotch Virus-Infected Grapevines (Vitis vinifera L.)

“…In 2017, average preveraison Ψ stem ≈ -0.68 MPa across treatments, yet foliar symptoms were first observed approximately two weeks preveraison (25 July); while in 2018, average preveraison Ψ stem ≈ -1.12 MPa across treatments, and symptoms were observed approximately at veraison (5 August). Since the appearance of foliar symptoms of GRBD are dependent on vine phenology ( Blanco-Ulate et al, 2017 ), and preveraison water deficits have been shown to accelerate coloration of berries at veraison ( Castellarin et al, 2007 ; Herrera and Castellarin, 2016 ), this result suggests that the onset of foliar symptoms is dependent on factors other than water status such as carbohydrate/nutrient status and/or solar radiation. Although vine nutrient status was not monitored in this study, it should be noted that 2018 was characterized by wildfire smoke that significantly reduced solar radiation during the preveraison period that could have delayed the onset of symptoms in that year.…”

“…Irrigation management is arguably the most effective tool for controlling all aspects of vine growth and development ( Williams and Matthews, 1990 ). While moderate water deficits can advance ripening and improve fruit quality ( Matthews and Anderson, 1988 ; Castellarin et al, 2007 ; Herrera and Castellarin, 2016 ), severe water deficits can reduce vegetative growth, photosynthesis, and yield ( Williams et al, 2010a ; Williams et al, 2010b ; Williams, 2012 ). The onset of ripening in grape involves a transition from xylem to phloem water transport into berries ( Greenspan et al, 1994 ), thus the advancement of ripening due to water deficits may also interact with present GRBV infection given its putative limitation to the phloem ( Sudarshana et al, 2015 ).…”

Multi-Omics and Integrated Network Analyses Reveal New Insights into the Systems Relationships between Metabolites, Structural Genes, and Transcriptional Regulators in Developing Grape Berries (Vitis vinifera L.) Exposed to Water Deficit

“…The involvement of multiple stress regulons ( Nakashima et al, 2014 ) might be critical to orchestrate the balance between stress-responsive regulation and the berry ripening program. These examples suggest that increased osmotic stress signals induced by water deficit may further fine-tune the ripening program through regulating multiple interacting TFs, possibly accelerating ripening ( Castellarin et al, 2007b ; Herrera and Castellarin, 2016 ). Further supporting this, several TF ‘switch’ genes that may be master regulators of berry ripening, such as VviMYBA1-2 , VviNAC1/VviNAC33-47-71 , and VviLBD15-18-38 ( Palumbo et al, 2014 ), are induced under water deficit from the onset of ripening onward.…”

Postveraison Deficit Irrigation Effects on Fruit Quality and Yield of “Flame Seedless” Table Grape Cultivated under Greenhouse and Net

“…RDI during ripening has shown promising results, enhancing red skin color in several wine and table grape cultivars [22,24,31,32]. In fact, previous results in experiments carried out by us on "Crimson Seedless" (a midseason cultivar) in the same location showed earlier and more intense acquisition of red color in the skin of the berries leading to higher commercial yield, without negative effects on berry size or production [23].…”

“…As stated before, better results were obtained by our team on "Crimson Seedless" (with longer periods of RDI). Several authors have also documented color improvement in wine and table grape cultivars in response to DI [22,24,31,33].…”