Modelling Gene-Trait-Crop Relationships: Past Experiences and Future Prospects

Classical crop models have long been established to understand crop responses to environmental factors, by integrating quantitative functional relationships for various physiological processes. In view of the potential added value of robust crop modelling to classical quantitative genetics, model-input parameters or traits are increasingly considered to represent 'genetic coefficients'. A number of case studies, in which the effects of quantitative trait loci or genes have been incorporated into existing ecophysiological models to replace model-input traits, have shown promise of using models in analyzing genotype-phenotype relationships of more complex crop traits. Studies of functional genomics will increasingly enable the elucidation of the molecular genetic basis of these model-input traits. To fulfil the great expectations from this integrated modelling, crop models should be upgraded based on understandings at lower organizational levels. The recently proposed 'crop systems biology', which combines modern genomics, traditional physiology and biochemistry, and advanced modelling, is believed ultimately to realize the expected roles of in silico modelling in narrowing genotype-phenotype gaps. We will summarise recent research activities and express our opinions on perspectives for modelling genotype-by-environment interactions at crop level.