The Evaluation on the Effect of Water Stress on the Growth and Yield of Rice in Cold Area Based on RAGA-PPC Model

In order to solve the difficulty of judging the comprehensive effect of water stress on the growth and yield of rice, projection pursuit classification (PPC for short) method is presented in this paper. This method can find the best projection direction based on the sample data characteristic and judge the contribution of each evaluation index to the comprehensive evaluation target through the best projection direction. The PPC method based on real coded accelerating genetic algorithm (RAGA-PPC for short) can simplify the realizing process of PPC technology and overcome the shortcomings of calculation complexity and programming difficulty. The results show that drought in jointing stage has great effect on comprehensive growth indexes. The longer drought time at tillering stage, the worse of comprehensive growth index is. At the same time, continuous drought in rice growth duration has the most serious effect upon the physiological indexes and yield. It is reliable to apply the RAGA-PPC model to evaluate the order of comprehensive growth indexes under water stress condition. It also has great application value for establishing rice regulated deficit irrigation system.