Modeling morphological dynamics and color characteristics of rice panicle

This paper was to develop the models for predicting the dynamics of panicle geometric morphology, panicle and branch curves and panicle color, and to visualize rice panicle in three dimensions (3D). Based on three experiments with different rice (Oryza sativa L.) cultivars, the time-course data were collected on the panicle geometric morphology, (including the number of branches and spikelets, the lengths of panicle and branches, and the diameter of panicle axis), the spatial coordinates of panicle axis and branches, and the RGB (red, green and blue) values of panicle color in rice. The dynamics of rice panicle morphology, panicle and branch curves, and RGB values of panicle color with thermal time (TT) were then characterized and simulated. The derived models were further used to visualize rice panicle in 3D. The results indicated that some appropriate functions (quadratic, logistic, exponential and Gaussian) could be chosen to describe the dynamics of the panicle geometric morphology and the RGB values of panicle color with time (growing process) and space (distributions of panicle organs) during panicle development. Combining the above models with the topological structure of rice panicle, rice panicle was visualized with Microsoft.Net and OpenGL (a graphics library). Validation of the models with the independent data indicated that all relative root mean square errors (RRMSEs) between the measured and simulated values were below 20%. Comparison of virtual and real panicles at different development stages showed that the virtual rice panicles were quite similar to real panicles. Overall, the present study could effectively simulate the dynamic changes of 3D morphology and color characteristics of rice panicle, and would provide a key technological support for fulfilling visualization of the whole rice plant.