Chin J Plant Ecol ›› 2005, Vol. 29 ›› Issue (4): 630-635.DOI: 10.17521/cjpe.2005.0084

• Research Articles • Previous Articles     Next Articles

AN ECOLOGICAL MODEL FOR PREDICTING PROTEIN CONTENT IN RICE GRAINS

LI Wei-Guo, DAI Ting-Bo, ZHU Yan, CAO Wei-Xing()   

  1. Hi-Tech Key Laboratory of Information Agriculture, Jiangsu Province, Nanjing Agricultural University, Nanjing 210095, China
  • Received:2004-02-23 Accepted:2004-07-16 Online:2005-02-23 Published:2005-07-31
  • Contact: CAO Wei-Xing
  • About author:* E-mail: caow@njau.edu.cn

Abstract:

Grain protein content in rice (Oryza sativa) is an important indication of rice nutritional quality and is determined by both genotype and environmental factors. Much attention has been paid to the relationships between protein accumulation in rice grains and environmental factors. Modeling changes of protein content in rice under different environmental conditions is of great help for predicting rice quality and ecological zoning. In this study, Indica and Japonica rice varieties grown under different ecological environments in China (Jiangsu), Japan (Iwate, Shimane, Kyoto) and Thailand (Changmai) were grown for two years, and the relationships between grain protein content and environmental factors, including latitude (x1), altitude (x2), ecological height, latitude, altitude, (x3), and average temperature (x4), lowest temperature (x5), highest temperature (x6) and solar radiation during the grain filling period were analyzed. Environmental factor-driven equations were established for Indica rice: f (x1) =8.4E-$04x_1^2$ +0.049 05x1+0.282 1, f(x2) =2.82E-$07x_2^2$-3.8E-04x2+1.128 6, f (x3) = 9.2E-$10x_3^2$-3.1E-05x3+1.255 6, f (x4) =-0.007 $02x_4^2$+0.303 7x4-2.285, f (x5)=-0.009 $18x_5^2$+0.313 9x5-1.684 6, f (x6)= -0.006 $99x_6^2$+0.372 8x6-3.971 7; and for Japonica rice: f (x1)=-0.000 $695x_1^2$+0.038 51x1+0.466 1, f (x3)= 4.02E-$10x_3^2$-1.2E-05x3+1.090 4, f (x4)= -0.004 $16x_4^2$++0.185 9x4-1.077 4, f (x5)=-0.006 $54x_5^2$+0.228 6x5-0.996 8, f (x6)=-0.004 $12x_6^2$+0.226x6-2.099 1. By using a weighted method to modify the impacts of environmental factors on grain protein accumulation, an ecological model was developed for predicting grain protein content in Indica rice: PC=PC0×[0.138 9×f(x1)+0.152 6×f(x2)+0.187 4×f(x3)+0.180 2×f(x4)+0.168 5×f(x5)+0.173 4×f(x6)]; and PC=PC0×[0.262 3×f(x1)+0.09×f(x3)+0.202 3×f(x4) +0.246 1×f(x5)+0.198 4×f(x6)] for Japonica rice, where PC0 is the specific protein content of cultivar. The model was validated using the data sets for different years, eco-sites and varieties. The root mean square error (RMSE) was 0.27% and 0.24% for Indica rice and Japonica rice, respectively, and the RMSE was 0.25% and 0.22% for the growing areas of Indica and Japonica rice types, respectively. The results indicated that the model was accurate and applicable for predicting protein content in rice under different conditions. Yet, more experimental data in different eco-environments are required for wider testing of the present model.

Key words: Rice (Oryza sativa), Protein content, Ecological environment, Predictive model