Abstract: Tomato is one of the most important vegetables grown in China and around the world. In the facility production of tomato, not only the genetic characteristics of varieties and the management of water and fertilizer, but also the meteorological conditions such as temperature and light are important factors affecting the high yield and quality growth and development of tomato. In the actual production, the favorable meteorological conditions are often obtained by adjusting the temperature and light, so as to achieve the purpose of efficient production. Based on the clock model, this study attributed the influencing factors of each development stage to the air temperature and sunshine hours in the greenhouse, summarized the temperature of three basis points in each development stage of tomato, and constructed the development process simulation model of "Rijk Zwaan882" and "Provence" two common greenhouse tomato varieties in the north of China. The experiment was conducted in solar greenhouse (116.97°E, 39.43°N, altitude 8m) of Tianjin Agricultural Science and Technology Innovation Base from 2013 to 2015. According to the characteristics of light and temperature response of tomato growth and development in solar greenhouse, the different development stages and development phases of tomato were characterized by the mathematical index expression in clock model, and the development stage of tomato was indexed. Then, the model parameters of each development stage were solved, and the initial values of the model parameters, such as the basic development coefficient, the genetic parameters of temperature response characteristics and the genetic parameters of light response characteristics, were obtained, and the model was statistically tested and adjusted. The error between the simulated value and the measured value was minimized, and the final value of the model parameters was obtained. A simulation model of tomato development periods in greenhouse were established based on the clock model. The results showed that, firstly, the regression estimated root mean square error (RMSE) between the simulated values and the actual observed values in the five tomato development stages of the model were 8.3, 14.4, 16.3, 23.7 and 28.1 days, respectively. The standard root mean square error (NRMSE) of regression estimation were 20.78%, 20.18%, 20.21%, 17.35% and 14.86%, respectively, indicating that the simulation effect of this model was good. Secondly, the clock model simulation results was compared with the method of growing degree days (GDD) model simulation results. the RMSE of the tomato in each development stage of the clock model of the simulated values and the measured values was in 8.3−28.1 days, NRMSE was in 14.86%−20.78%, and the RMSE of the tomato in each development stage of GDD model of the simulated values and measured values was in 5.9−33.1 days, NRMSE was in 15.09%−34.38%. It was showed that the clock model could accurately predict development of greenhouse tomato development periods. In general, it was helpful to provide guidance for greenhouse tomato planting users to determine planting time, marketing time, management and control, so as to improve the economic benefits of tomato planting.

Key words: Greenhouse, Tomato, The clock model, Development periods simulation