Vine Water Relations and Quality of ‘Muscat of Alexandria’ Table Grapes Subjected to Partial Root-zone Drying and Regulated Deficit Irrigation

Abstract

The effects of several irrigation strategies on vine water relations and the quality of table grapes, Vitis vinifera L. 'Muscat of Alexandria', were evaluated from veraison to harvest. The treatments included: (1) standard practice irrigation (control): re-irrigation when the soil moisture tension reached 15 kPa; (2) regulated deficit irrigation (RDI): re-irrigation 4 to 7 days after reaching a soil moisture tension of 15 kPa; (3) fixed partial rootzone drying (FPRD): one half of the root system was re-irrigated when the soil moisture tension reached 15 kPa; and (4) alternate partial root-zone drying (APRD): one half of the root system was re-irrigated when the soil moisture tension reached 15 kPa, and every week the irrigated half was switched. Treatments were continued for 7 weeks until harvest. During the experiment, RDI vines received 58% less irrigation water than the controls, while 33% less irrigation water was applied to FPRD and APRD vines. The results showed that only RDI vines had a significantly lower midday stem water potential compared with the control. Vines of FPRD and APRD treatments had the highest efficiency of water use (photosynthetic rate/stomatal conductance). At harvest, RDI fruit had markedly higher TSS, sugars, and amino acids, a similar acidity, and lower firmness and smaller size compared with the control. FPRD and APRD fruits had slightly higher TSS, sugars, and amino acids, a similar firmness and size, and lower acidity compared with the control. Aroma concentrations were high in RDI and FPRD fruits.

Effects of Pre-Harvest Deficit and Excess Irrigation Water on Vine Water Relations, Productivity and Quality of Crimson Seedless Table Grapes

“…Titratable acidity (TA) percent decreased with decreasing irrigating level and was significantly lowest in berries of 80 % ETc irrigated vines (0.37 & 0.34 % in 2011 & 2012, respectively) as compared with control (0.72 & 0.64 % in 2011 & 2012, respectively) and all other treatments. These results are consistent with reports of El-Ansary et al (2005) and El-Ansary and Okamoto (2007Okamoto ( & 2008. TSS to Acid ratio (Table 3) was significantly highest in berries of 80 % ETc irrigated vines (50.54 & 55.57 in 2011 & 2012, respectively), followed by 90 % ETc irrigated vines (31.06 & 29.35 in 2011 & 2012, respectively) and control vines (23.89 & 27.13 in 2011 & 2012, respectively), and was lowest in berries of excess irrigated vines.…”

“…Number of bunches per vine was adjusted in all experimental vines when berries reached 8 mm in diameter to approximately 42 bunch per vine. Starting at bud break, a weekly fertigation of a complete liquid fertilizer containing 60 ppm N was implemented, and its level was reduced to one third at beginning of veraison (El-Ansary and Okamoto, 2007). Each vine was irrigated by two drip irrigation lines having 0.5 m spaced drippers (4 liters per hour water discharge per dripper).…”

Fruit quality and volatile fraction of ‘Pink Lady’ apple trees in response to rootstock vigor and partial rootzone drying

“…In a subsequent study, DI increased volatile concentration only after apple ripening or cold storage and not at harvest 26. In grapes, both DI and fixed PRD, but not alternated PRD, tend to increase fruit aroma concentrations 27. This inconsistency could be due to different degrees of water stress developed, as demonstrated in grapes where aroma is enhanced by mild stress but inhibited by severe stress 28.…”

Impact of Water Deficit during Fruit Development on Quality and Yield of Young Table Grape Cultivars

“…Only a few studies have focused on the comparison of yield and quality of different table grape cultivars exposed to water deficits [22], especially on young vines. Most studies have investigated the performance of a single cultivar [9,10,27,28] most of which to our knowledge are not cultivated in Germany currently. Therefore, the aim of our experiment was to evaluate the effect of water deficit treatment on quality and yield of four 3-year old, own rooted and potted table grape cultivars already grown in Germany and to evaluate their suitability for a potential cultivation under foreseen water limiting conditions due to climate change.…”