Abstract: High temperature is one of the common agricultural meteorological disasters, affecting the growth and development of crops. In order to study the effect of high temperature at the seedling stage on the phenology of strawberry in greenhouses, the strawberry variety " Benihoppe " was taken as the experimental material, and different high temperatures (32℃/22℃, 35℃/25℃, 38℃/28℃, and 41℃/31℃) and different stress days (2d, 5d, 8d and 11d) were performed on the strawberry seedlings in greenhouses in 2018 and 2019, and then transplanted to Venlo glass greenhouse for normal cultivation experiment. The data of 2018 quantitatively were used to analyze the effects of high temperature and stress days on the phenology of strawberries in greenhouses, and constructed three models for the effects of high temperature on the growth period of strawberries, including the PDT model, the TEP model, and the GDD model. The experimental data in 2019 were fitted to verify the established model. The results showed that mild (32°C for 2 to 11 days) and moderate high temperature (35°C for 2 to 8 days) at the seedling stage helped strawberries to early entry to the flowering stage, fruit setting stage and picking period, while severe (38°C for 2 to 5 days) and very severe (38°C 8 to 11 days and 41°C for 2 to 11 days) high temperature delayed the time for strawberries to enter the phenology mentioned above. Compared with the TEP model and GDD model, the high temperature impact model based on the PDT was more accurate and had the smallest error. The coefficient of determination(R2) between the simulated values and the measured values of flowering stage, fruit setting stage and harvesting stage were 0.84, 0.82 and 0.97, respectively, the root mean square error(RMSE) were 1.39d, 1.50d and 1.56d, respectively, the relative error(RE) were 2.27%, 2.23% and 1.57%, respectively. Therefore, in the greenhouse strawberry planting process, it is recommended to use the PDT model to predict the start and end times of the strawberry flowering stage, fruit setting stage and harvesting stage.

Key words: Strawberry, High temperature at seedling stage, Physiological development time, Product of thermal effectiveness and PAR, Growing degree days, Phenology simulation