Photosynthesis driven crop growth models for greenhouse cultivation; advances and bottlenecks.

In recent years considerable progress has been made in modelling growth of green-house crops. Nevertheless, the share of research in this field compared to crop modelling in general is only a few percent. Yet, crop growth models have a great potential for greenhouse production systems, because they are characterised by a high degree of complexity, intensity and diversity. Therefore it is important that crop growth models find a wider application in research and in practice. To achieve a wider use of crop growth models in the field of greenhouse production, there is a strong need for co-operation among researchers in agriculture in general and in greenhouse horticulture in particular. Progress has been observed in the dynamic modelling of dry matter distribution, in crop photosynthesis and in the evaluation of respiration. Furthermore, the necessary validation of models and sub-models is in progress, while model applications begin to emerge. There is a clear tendency towards a more professional attitude of modelling research and related to this, the concentration of modelling activities in specialised teams, with better tools and working methods. To stimulate use of models in research and in practice with respect to protected cultivation, quality, standardisation, portability and flexibility of models remain a matter of concern