PLANT DEVELOPMENT IN CROP SIMULATION-MODELS

This paper focusses on several aspects of the key role played by phasic development submodels within plant process models. Using examples of development models for wheat and soybean, it is shown that modellers cannot use developmental scales as used by agronomists or physiologists (pages 254-265, fig 1), and common ways to account for development-dependent phenomena in models (pages 256-257) (partitioning of assimilates, determination of final number of reproductive organs (figs 2 and 3), senescence) are considered. The general shape of functions used in models to describe the impact of environmental factors (pages 257-260) (temperature per se (fig 4) and through its effect on vernalisation status (fig 6), photoperiod (fig 5), water stress (fig 7)) on rates of development are examined. Some methods for estimating genetic parameters (pages 261-262) (from controlled (fig 8a) and field (fig 8b) condition experiments, through optimisation methods) are reviewed.