The Effects of Regulated Water Deficits on Pear Tree Growth, Flowering, Fruit Growth, and Yield

Abstract

Abstract Three levels of water deficit generated by 3 levels of irrigation applied at times of rapid vegetative growth and/or slow fruit growth were compared to determine their suitability for restricting vegetative growth on 5-year-old ‘Bartlett’ pear (Prunus communis L.) trees trained to a Tatura Trellis. For the period of Regulated Deficit Irrigation (RDI), the amount of water applied replaced 92%, 47%, and 23% of the evaporation calculated over the planting square (Eps). In the subsequent period of rapid fruit growth until harvest, all trees were irrigated with 150% Eps to ensure that the wetting pattern from the trickle system wetted the entire root zone. Shoot and frame growth declined in proportion to the water deficit. Fruit tended to grow more slowly on the 23% than 46% treatment during RDI, but growth on the 46% and 92% Eps treatments was similar. In the subsequent period of full irrigation, fruit growth initially was significantly faster on the RDI treatments, and the same trend was maintained for most of the remainder of fruit growth. The net result was that yield was marginally increased RDI treatments. In the subsequent season, flowering was increased on trees recieving RDI in the previous season.