Modelling the effects of genes and QTLs on the plant sensitivity to environmental conditions

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Tardieu, Francois, F. | Parent, Boris | Welcker, Claude

Edité par CCSD -

International audience. The genetic analysis of adaptive processes, e.g. transpiration rate or growth rate, faces the problem of a high genotype×environment interaction. Modelling can greatly help this analysis, with different possible roles for models. A first purpose is to identify stable and heritable traits which account for the apparent variability of time courses under fluctuating environmental conditions. One seeks to get stable parameters calculated from time courses, for instance half times of responses, parameters of response curves or maximum rates. These traits are then used to detect QTLs or to carry out association genetics. We argue that mechanistic models are not appropriate here, first because they are based on physiological hypotheses which may or may not be compatible with the genes whose polymorphisms will be eventually be identified, second because mechanistic models use too many parameters for a genetic analysis. A second purpose is to evaluate theconsequences, atthewhole plant level, of theeffectof a QTL orof an allelic series which affects specific functions of the plant. In this case, mechanistic models are essential, over-parametrisation does not necessarily cause major problems provided that most parameters are kept common among the tested genotypes. Examples of each type of models will be discussed for their usefulness and possible drawbacks

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