To establish the simulation model of the nutrient quality of pakchoi (Brassica chinensis), the ‘Siyueman’ was used as test strains from March 2014 to January 2015, including five sowing times. By measuring internal quality index: vitamin C, cellulose, soluble sugar and soluble protein content under different temperature and light conditions, the mathematical model of pakchoi internal quality based on light and temperature function (LTF) was established and validated by independent experimental data. The results showed that comparing with product of thermal effectiveness and photosynthetically active radiation (TEP) and growing degree days (GDD), the root mean squared error (RMSE) of prediction values on pakchoi vitamin C, cellulose, soluble sugar and soluble protein content decreased significantly. The RMSE values decreased by 81.14%, 77.46%, 77.23%, 75.53% than that of the TEP method, and 77.15%, 78.77%, 79.90%, 21.17% than that of the GDD method respectively, which indicated the prediction accuracy of the model was higher. The correlation coefficient (r) between measured data and model prediction value was more than 0.98, higher than that of RMSE method and GDD method, which indicated the simulated values were closer to measured values. This prediction model significantly improved the prediction accuracy of pakchoi, which provided a reference for crop quality simulation with resistance to weak light in greenhouse.
%U https://zgnyqx.ieda.org.cn/EN/10.3969/j.issn.1000-6362.2016.01.008