Prediction of Developmental Changes due to Climate Change in ‘Delaware’ Grapes in Osaka, Japan, based on Simulated Data

We predicted developmental changes (endodormancy breaking, budding, and full-flowering) in ‘Delaware’ grapes induced by climate change in Osaka Prefecture, Japan, to consider adaptation measures. Endodormancy breaking (the day when the accumulation of chilling hours below 7.2°C reached 600 h; DCH600), budding, and full-flowering dates were estimated using models based on air temperature. A projected air temperature dataset until 2100 with 1 km resolution for two emission scenarios of Representative Concentration Pathways (RCP2.6, low; RCP8.5, high) was applied to these models. DCH600 was delayed by 19 (RCP2.6) and 21 (RCP8.5) days in 2041/2042-2050/2051, whereas in 2091/2092-2099/2100, it was projected to be 21 (RCP2.6) and 48 (RCP8.5) days later than that in 1981/1982-1990/1991. Conversely, the budding date was earlier by 6 (RCP2.6) and 7 (RCP8.5) days in 2041-2050 than in 1981-1990. The full-flowering date was earlier by 9 (RCP2.6) and 12 (RCP8.5) days in 2041-2050 than in 1981-1990. Based on these prediction results, it may be possible to sustain ‘Delaware’ grape production until 2050 through advanced cultivation management. However, after 2050 under RCP8.5, delayed DCH600 and inadequate chilling are predicted, necessitating a change in cropping type or conversion to other fruit trees.