Responses of sweet cherry trees to regulated deficit irrigation applied before and after harvesting

The current study was conducted over four years between 2016 and 2019 to determine the effects of regulated deficit irrigation (RDI) before and after harvesting of sweet cherry on yield, physiological, vegetative and fruit quality parameters. The current study used the 0900 Ziraat sweet cherry cultivar grafted onto Gisela 6 rootstock. There were six different treatments: IC, (Control) where soil moisture was kept at field capacity for each irrigation, I25, with 25% deficit irrigation of IC after harvesting, I50, with 50% deficit irrigation of IC after harvesting, I25BH, with no-deficit irrigation 30 days after full bloom and 25% deficit irrigation after this period, I50BH, with no-deficit irrigation 30 days after full bloom and 50% deficit irrigation after this period, and IFRM, with farmer's treatment of excessive irrigation (150% of ET) from colouring of fruit till harvest and 50% deficit irrigation after harvesting. When compared to IC, water saving ranged from 20.2-45.6%. The fruit yield obtained under I25 was increased by 21.8% in the last year of the current study than the yield obtained under IC treatment. Trunk and shoot growth increased for all treatments. Leaf water potential (Psi md) and stomata conductance (gsw) were affected by RDI. IFRM and I25 had a positive effect on fruit size, the same as IC. Water deficit (IBH50) applied before harvesting increased fruit flesh firmness. I25 treatment (25% water deficit after harvesting) can be applied by sweet cherry growers because it leads to high yield, better fruit quality and water saving.