Selecting for cooperative crops to develop sustainable agriculture – SCOOP

In agriculture, intraspecific competition is undesirable, since it drives the evolution of traits toward phenotypic values lowering group performance. Plant height is a well-documented example: tall plants win access to light over shorter plants by diverting resources to vegetative structures, which leads to a negative correlation between height and seed production of the group. This motivated breeding for shorter plants during the Green Revolution. Agriculture is nowadays challenged by the need to ensure crop production while limiting environmental costs. Density is known to strongly affect competition for resources, and is a main limiting factor for crop yields. Breeding for cooperative phenotypes that do not invest resources in competitive interactions at high planting density could help sparing natural land from conversion to agriculture. Still, apart from height for plants competing for light, we know very little about the traits that affect the outcome of competition, the phenotypes that make a plant cooperative on such traits, and which breeding strategies can promote cooperative phenotypes.
The kin selection theory formalized by the evolutionary biologist W. Hamilton, has been very successful in explaining the evolution of cooperative phenotypes, which have a beneficial effect on group performance, including altruistic phenotypes whereby the individual pays a cost on its own performance. The weak competitor crop ideotype targeted by breeders during the Green Revolution can thus be viewed as a cooperative plant in the kin selection theory, shorts plants being altruistic. Interestingly, the kin selection theory has been poorly mobilized in agriculture.
In SCOOP, we ask whether breeding for cooperative crops can help designing more sustainable agrosystems with high productivity by taking an integrative approach linking evolutionary biology and functional ecology. The consortium comprises four partners (AGAP, CEFE, ISEM, BPMP) with scientists from CNRS, INRA and Montpellier SupAgro. Our model system includes the cultivated durum wheat Triticum turgidum L. subsp. durum, its wild form Triticum turgidum ssp. dicoccoides and its first domesticated form Triticum turgidum ssp. dicoccum. Durum wheat is a major source of staple food, mostly used for the production of pasta and semolina. In France, it is the fourth most important crop production.
In this project, we will address three main questions: (1) Which phenotypes and alleles are cooperative at high planting density? (2) Has cooperation evolved during domestication and breeding? (3) Which breeding schemes can select for cooperation?
SCOOP is organized into three work packages. In WP1, we will identify alleles and phenotypes on above- and belowground traits, which are cooperative in high-density plots, using a combination of experiments in the field and in controlled conditions. In WP2, we will test whether human selection has selected for more cooperative alleles and phenotypes during the evolutionary history of durum wheat. To do so, we will assess whether there has been a temporal shift in the frequency of cooperative alleles and in the mean phenotypic value of traits studied in WP1 among the three subspecies of Triticum turgidum. In WP3, we will assess the relevance of different selection schemes for promoting plant cooperation, by combining theoretical work and experimental evolution.
This project will help addressing fundamental questions in evolutionary biology and ecology, as well as pressing issues in agriculture. Indeed, SCOOP will contribute to improved comprehension of the evolution of traits driving plant-plant interactions in cultivated species. SCOOP will also have major implications for the design of novel and easy to implement breeding strategies needed for the development of sustainable agriculture.