A leaf area-based non-destructive approach to predict rice productivity

Leaf canopy dynamicsare associated with crop productivity. Frequent, non-destructive measurements of the leaf canopy using a plant canopy analyzer, followed by parameterization using a mathematical model, enabled the quantification of leaf area growth characteristics. However, an understanding of the rice (Oryza sativa L.) cultivar effect under various field conditions is limited. Therefore, this study aimed to compare leaf area growth parameters with rice productivity and analyze the cultivar differences in these relationships. In a 3-yr field experiment, six rice cultivars were grown under environments with different nutrient provisions. Two leaf area growth parameters (maximum leaf area index growth rate and maximum interception rate) were determined from the measurements obtained using a plant canopy analyzer. They were compared with five crop growth parameters for rice productivity (yield, total dry weight, crop growth rate, nitrogen uptake rate, and radiation use efficiency). A logarithmic relationship exists between leaf area growth and crop growth parameters, which varied among rice cultivars. In addition, the leaf nitrogen content at the heading stage was associated with the cultivar variations. After considering the cultivar differences, yield prediction accuracy was improved using leaf area growth parameters (from R² =.428 to R² =.752). This indicates that these parameters are considered efficient indicators of rice productivity with regard to cultivar differences and leaf nitrogen content. The evaluation method using the parameters calculated with non-destructive measurements could be a standard for crop monitoring in field experiments and will be useful for estimating crop productivity.