Effects of bud load and regulated deficit irrigation on Italia and Hamburg mi̇sketi̇ table grape cultivars grown in the Pozanti conditions

In this study, the effects of two Regulated Deficit Irrigation practices (RDI-1 and RDI-2) and bud load treatments on yield and quality of Italia and Hamburg Misketi table grape varieties were studied. It has been carried out for two years in Cukurova University Pozantı Agricultural Research Center (POZMER) during the periods of 2012-2013 and 2013-2014. The midday leaf water potential thresholds were used for irrigation timing, and those values were set as -10 bars until flowering, -13 bar between fruit set-veraison and veraison-ripening periods, and -12 bar after harvest for both RDI treatments. Water volumes applied in irrigations to the RDI-1 plots were 50% and 75% of the cumulative evaporation from the Class A Pan between the growth stages berry setting-veraison and veraison-ripening, respectively, while those portions for the RDI-2 treatment was vice versa. Both RDI treatments and the non-irrigated treatment have been examined for two bud-loads based on mean shoot weight; 1) Normal bud-load (20 buds for the first 500 g shoot weight and then 10 buds for each additional 500g) 2)Increased bud-load (double amount of the traditional bud load). Irrigation and higher bud load treatments slightly increased grape yield in both years depending on the varieties. The cluster and berry weight were also slightly higher in irrigated vines. Soil water content values were all revealed increases in both RDI treatments. Key Words: Viticulture, Regulated deficit irrigation, bud load, quality, leaf water potential