Deficit irrigation strategies in Vitis vinifera L. ‘Crimson Seedless’ table grape: Physiological responses, growth, yield and fruit quality

The research was conducted in Viticultural Research Institute of Manisa located in Aegean Region of Turkey during 2016 and 2017 seasons. The objective of this study was determine the effects of water stress on yield parameters, berry quality, vine growth and physiology for 6 years old ‘Crimson Seedless’ table grape variety. Three different treatments were considered; namely full irrigation (FI), deficit irrigations (DI-65 and DI-35). In FI soil water deficit in the 90 cm within the seven-day intervals was replenished to the field capacity. DI-65 and DI-35 treatments received 65 and 35% of water applied to FI. All irrigation treatments were applied by sub-surface drip irrigation system. Vine water status was monitored through midday leaf water potential while soil moisture was monitored by MobiCheck probe before the irrigations. Results showed that water deficit treatments (DI-35 and DI-65) influenced berry composition positively. At harvest, deficit irrigation treatments had higher TSS, better CIRG index and uniform coloration compared with the FI treatment. When the ?md (midday leaf water potential) values were declined by DI treatments, it was observed that gs (stomatal conductance) values were decreased and stomatal closure occurs. On the other hand, FI treatment had the highest yield value in both two seasons. Therefore, water use is so important for the purpose of obtain higher yields from field grown grapevines under Aegean Region climatic conditions. Although DI-65 treatment received nearly 35% less water compared to the FI treatment, total yield was reduced approximately 9%. Additionally, berry composition (anthocyanin content, total phenolics, flavonoids and antioxidant capacity) values and coloration were found statistically better than the FI plots. Therefore, considering water shortages in dry years deficit irrigation practices -DI-65- can be recommended. © 2020 International Society for Horticultural Science. All rights reserved.