Parameterizing patterns in wheat architecture to simulate the 3D dynamics of wheat crops

Structural 3D plant models aim at mimicking the dynamics of plant and crop structure based on experimental data. Interfaced with physical models, the 3D models can be used as tools to investigate how plant structure modulates the interaction with the environment. An example of such model is Adel wheat (Fournier et al.; 2003) which is used to analyse the consequences of architectural traits for the capture or light, pesticide, spores or the simulation of signals perceived by sensors. The purpose of this work was to revise the parametrisation of plant architecture in Adel-wheat, so as to improve the compromise between flexibility and complexity. We established parametric functions that represent the emergence, ligulation and senescence of lamina, the dynamic of active tiller population, the final dimension of all tillers organ and the final leaf number produced on each tiller. A large data base was used to define and evaluate these parametrisations, covering different densities, sowing dates, and nitrogen fertilizations and with different commercial varieties grown under field conditions. The functions were defined so that parameters are simple to interpret and easy to derive from field measurements. The new parametrisations allow for simulation of wheat crops from plant emergence to full maturity with less experimental effort, and a better agreement between simulated and measured leaf area index, than previously. Beside, this provides a view of general patterns existing in wheat architecture, which could be used in other models. Finally the work represents one step forward in the ability to characterize and represent the architectural traits for a number of genotypes and environments.