Modeling and Visualization of Rice Panicle Morphology.

Modeling and visualization of panicle growth and architecture in rice (Oryza sative L.) is useful for constructing virtual and digital rice growth system. The objectives of this study were to develop a process-based morphological model for rice panicle and realize a visualization of panicle growth on rice plant. Based on the time-course observations on morphological properties of panicles on main stem and tillers of rice plant in four experiments involving different cultivars, nitrogen rates, water regimes, a dynamic simulation model was developed to virtually represent morphological formation of rice panicle by coupling with our rice growth model (RiceGrow). The length of central rachis, primary branches and secondary branches of rice panicle were quantified in thermal time as modified by plant nitrogen and water status. Numbers of primary and secondary branches were determined by lengths of central rachis and primary branches, respectively. Spikelet numbers on branches were estimated by branch length and total number of spikelets. By integrating the morphological model and topological structure of rice panicle, a parameter-based geometrical model of rice panicle was established for visualization with the help of 3D geometric technology. The whole model included 3 submodels: central panicle axis curve submodel, primary and secondary branch geometry submodel, and spikelet geometry submodel. Quadratic Bezier curve was introduced to describe central panicle rachis curve, while Cylinder and Ellipsoid were used to simulate branches and grains. Finally, growth process of 3D morphological structure of rice panicle was realized on the computer using the platform of VC++.net and OpenGL. The results of this study will help lead to further visualization of whole rice plant.