SUNFLO: A joint phenotyping and modelling approach to analyse and predict the differences in yield potential of sunflower genotypes

This work was focussed on improving the description of organogenesis, morphogenesis and metabolism in a biophysical plant model. A greenhouse experiment was carried out to identify and to estimate the phenotypic traits involved in plant productivity variability of 26 genotypes. The ability of the biophysical model to discriminate the genotypes was tested on previous results of a field survey focussed on evaluating their genetic progress since 1960. Plants were phenotyped on 4 areas: phenology, architecture, photosynthesis and biomass allocation. 12 traits or genotypic parameters were finally chosen to account for the phenotypic variability. A biophysical model was especially built to integrate the genotypic parameters and to evaluate their respective contribution to the variability of yield potential. A large phenotypic variability was found for each term of the energetic approach of above-ground biomass production. The biophysical model was able to account for 80 to 90% of observed variability in yield potential. This model was an interesting tool for analyzing the phenotypic variability of complex plant characteristics such as light interception efficiency. This model showed that several ways are possible to reach high yields. Unlike a classical statistic analysis, this approach allowed to highlight some efficient parameter combinations used by the most productive genotypes. The next steps will be to evaluate the genetic determinisms of the genotypic parameters and to test the reliability of the phenotyping approach.