A fundamental question in biology is how constraints drive phenotypic changes and the diversification of life. We know little about the role of these constraints during crop domestication, nor how artificial selection can escape them. While they are considered as obstacles for the improvement of target crop traits by plant breeders, efforts to quantify them are rare. Interestingly, several generic, cross-wild species, ecophysiological and biophysical constraints have been identified in theoretical and empirical ecology, with acceleration in the last two decades with the rising of trait-based ecology.
CONSTRAINTS questions whether crop domestication has shifted ecophysiological and biophysical traits related to resource acquisition, use and partitioning, and how trade-offs between them have constrained domestication and can limit future improvements in both optimal and sub-optimal conditions.
The project is based on three objectives:
1. Revealing the existence (or lack) of generic resource-use domestication syndrome in crop species.
2. Elucidating ecophysiological and biophysical trade-offs within crop species and delineating the envelope of constraints for artificial selection.
3. Examining the shape of ecophysiological and biophysical trade-offs in crop species when grown in sub-optimal environmental conditions.
This project will be investigated within and across crop species thanks to a panel of 12 studied species (maize, sunflower, Japonica rice, sorghum, durum wheat, bread wheat, alfalfa, orchardgrass, signalgrass, pea, rapeseed, ryegrass) for which data and collections of genotypes (1,700 total) are already available, and additional high throughput phenotyping using automatons. The species have been chosen to cover a wide range of crop types: C3/C4, annual/perennial, grain vs. forage production. In addition, 400 worldwide accessions of the model species Arabidopsis thaliana will be used for a genome-wide association study (GWAS) of resource-use traits to explore the genetic determinism of biophysical and ecophysiological constraints. Collectively, we will use a multiple-tool approach by using: field measurement, high-throughput phenotyping, common-garden experiment, comparative analysis using databases, modelling, genomics.
The ground-breaking aspect of the project holds in the nature of the questions asked and in the unique opportunity to engage a translational approach from ecology to agronomy and crop science.
The objectives of this cross-disciplinary project are beyond the state-of-the-art in three disciplines: (i) beyond the trait-by-trait and constraints-blind approach in crop science and plant breeding, (ii) beyond correlative approaches in functional ecology, (iii) beyond the developmental-constraints-as-the-major-constraints-for-trait-evolution paradigm in evolutionary biology.
The identification and quantification of constraints in crop species will represent an important step towards the selection of improved cultivated species resistant to suboptimal conditions (in particular low inputs and drought).