Performance of grapevine grown on reclaimed Mediterranean karst land: Appearance and duration of high temperature events and effects of irrigation

Abstract Stony karst landscape in the Adriatic coastal area has been cultivated for centuries to grow Mediterranean crops. Shallow and less fertile soils were mostly used for rain-fed grapevine and olive production. Native grapevine cultivars are, in general, well adapted to the warm and droughty climate, but a rapid drift in weather patterns characterized mostly by long-lasting high temperature events during the growing season urges the producers to apply irrigation. This research, studying the effects of different irrigation levels on Babic grapevine performance, was carried out in two growing seasons (2015 and 2016) with contrasting weather conditions in a vineyard established on a parcel of land derived from the stony surface of a limestone plateau on the very edge of the Eastern Adriatic coast. The study evaluated the effects of different irrigation regimes based on the quantification of grapevine water use (50, 75, and 100 % of crop evapotranspiration) by measuring the total leaf area, leaf gas exchange performance, and grape yield and quality. The irrigation treatments increased the total leaf area, net photosynthetic rate, average transpiration rate, and average mesophyll CO2 concentration. The yield components and grape quality were also affected by the irrigation treatments. Positive effects of irrigation in both the experimental seasons were associated with increased yield and total soluble solids (TSS), as well as synchronized TSS and phenolic ripening. Furthermore, water stress positively affected the concentrations of anthocyanins and other polyphenols in both years of the study. In 2015, extremely high temperatures reduced the grape yield, juice yield, and anthocyanin content in grapes in non-irrigated vines as well as in all irrigation treatments. Irrigation was efficient in reducing these negative effects, except in the case of the anthocyanin content.