Prediction Model of Grain Crude Protein and Amylose Content with Canopy Spectral Reflectance in Rice

Grain crude protein and amylose content are two important indexes for evaluating rice quality. The objectives of this study were to determine the relationships of grain crude protein content, amylose content to ground-based canopy hyperspectral reflectance and derivative parameters at different growth stages in rice (Oryza sativa L.) on the basis of the data from the field experiments involving two cultivars under different high-temperature stresses of booting stage in 2007 and 2008. Then the relationships of grain crude protein and amylose content to canopy reflectance of single band and all two-band combinations were analyzed. The results showed that there were significantly or very significantly correlation of grain crude protein and amylose content with canopy spectra and the first derivative at different growth stages in some wave band. The relationships of grain crude protein content, amylose content to the ratio, differential and normalized difference vegetation indices of all bands and red edge parameters were also analyzed. The fitting spectral parameter with better correlation was subsequently selected through regression analysis, DVI(810,450) was found to be the best parameter for predicting grain crude protein content (GCPC) and grain amylose content (GAC)in rice. The derived equations were tested with the observed data from the other independent experiments. The estimation precision was 0.393~0.683, estimation accuracy was 0.712~0.923, and RMSE was 8.706%~11.463%, which indicated a good fit between the predicted and observed values of grain crude protein and amylose content.