Effects of four irrigation regimes on yield, fruit quality, plant water status, and water productivity in a furrow-irrigated red raspberry orchard.

Due to drought intensification in Mediterranean-type climates, raspberry growers need to implement irrigation scheduling to save water without decreases in yield and fruit quality. A study was performed to evaluate the effects of four irrigation levels on yield (Y), fruit number (FM2), fruit weight (FW), water productivity (WP), fruit quality (titratable acidity (TA), soluble solids (SS), weight to volume ratio (WV)), midday stem water potential (Ψ stem), and water stress integral (WSI) in a furrow-irrigated red raspberry (Rubus ideaus L. 'Heritage') orchard. An experimental plot was established within a commercial raspberry orchard located in the Colbún valley, Maule Region, Chile, during the 2012/13 and 2013/14 growing seasons. The irrigation treatments were 125 (T 1, farmer irrigation management), 100 (T 2), 75 (T 3) and 50% (T 4) of crop evapotranspiration (ETc). The results showed significant differences among treatments for Y and FM2, with the highest and lowest values observed under the T 3 and T 1 treatments, respectively. The T 4 treatment had the highest values of WSI and WP compared to the other treatments. The effects of irrigation levels were not significant for SS and WV, but the lowest TA was observed under the T 1 treatment. Results suggested that water application based on the 75% of ETc associated with Ψ stem > −1.0 MPa was the most appropriate irrigation strategy for the furrow-irrigated red raspberry orchard because it had the highest Y (9.25 kg m−2) and saved water by 20–28% compared to the 125% and 100% ETc treatments. • Over- and under irrigation reduced significantly yield in a furrow-irrigated red raspberry orchard. • Raspberry plants irrigated at 75% of actual evapotranspiration (ETc) had the highest yield and water productivity. • Raspberry plants irrigated at 75% of ETc had midday stem water potential (Ψ stem) > −1.0 MPa. • Ψ stem values and 75% of ETc seem to be an appropriate irrigation management strategy in furrow-irrigated raspberry orchards. [ABSTRACT FROM AUTHOR]