A phenomics-based dynamic model of growth and yield to simulate hundreds of maize hybrids in the diversity of European environments

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Lacube, Sébastien | Parent, Boris | Tardieu, Francois

Edité par CCSD -

National audience. Under soil water deficit, plants limit transpiration by decreasing leaf area to save water for the end of the crop cycle. A large genetic diversity is observed in maize for the processes involved in this response. We aimed to predict which combination of trait values related to leaf growth would be beneficial in the diversity of European environments. For this purpose, we have first analysed the genetic and environmental controls of leaf elongation and widening. A series of experiments revealed that leaf elongation is related to plant water status whereas leaf widening is related to the carbon available to plant. A GWAS analysis also revealed that elongation and widening depend on different alleles. This analysis resulted in a model that allows simulating leaf area in a large variety of environmental scenarios. This model resulted in estimated leaf area and yield that were close to those observed in 15 fields over Europe. The model was then used to determine ideotypes of leaf growth adapted to the different environmental scenarios. Results indicate that sensitive hybrids perform better in southern Europe under rainfed conditions while less-sensitive genotypes perform better in northern Europe or in irrigated fields. However, the best combinations of parameters determined in an unconstrained phenotypic space were not available in the observed genetic diversity. Overall, this study provides elements on where and when a combination of trait values can give a comparative advantage on yield, together with the boundary of possibilities within the current genetic diversity.

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