Evaluation of effects of water stress on growing and yield of paddy based on RAGA-PPC model in cold area

In order to solve the difficulty of judging the comprehensive effects of water stress on the growing and yield of rice, projection pursuit classification (PPC for short) model was presented. It could calculate the best projection direction based on the sample data characteristics. Through the best projection direction, the contributions of each evaluation index to the comprehensive evaluation target could be judged. The PPC model based on real coded accelerating genetic algorithm (RAGA-PPC for short) can simplify the realized process of PPC model, and overcome the shortcomings of complex calculation and difficulty of programming in traditional PPC model. The results showed that comprehensive growing index was influenced greatly by drought in jointing stage. It was also worse because of the long time drought in tillering stage. At the same time, continuous drought in growth duration of rice had most serious effects on the physiological parameters and yield. It was reliable to apply the RAGA-PPC model to evaluate the order result of comprehensive growing index under water stress conditions. The model has great significance in establishing regulated deficit irrigation system of rice.