Presenting author: Guy Golan; email: golan@ipk-gatersleben.de

The genetic heritage of wheat (Triticum spp.) crops has been shaped by millions of years of pre-domestication natural selection, often driven by competition among individuals. However, agricultural production evaluates collective population performance, measured as yield per unit area, which may conflict with individual competitiveness. Active competition among crop plants uses resources that could be used for grain yield formation. Thus, yield production will benefit from less 'selfish' and more 'cooperative' resource acquisition behaviors.

Recent studies have shown a strong correlation between responses to plant density and to low light, indicating that the scarcity of light is often a limiting factor in high-density crop communities. These observations suggest that studying the basis of wheat responses to changes in the intensity and spectrum of light due to competition from neighboring plants will advance our understanding of adaptation to the high-density crop environment.

We used Recombinant Inbred Lines and backcrossed Introgression lines originating from a cross between a wild emmer genotype and an elite durum wheat cultivar to study the individual fitness of wheat grown under sunlight and simulated canopy shade and its relationships to the high-density monoculture community performance in the field. We also focused on genotype-by-environment interactions in biomass allocation among organs and identified loci underlying the investment strategies of wheat plants when facing shading by neighboring plants.

Our approach provides prospects for studying and selecting single plants under a canopy-like environment and will be useful in predicting the social behaviors of individuals in a crop community.