Plasticity in ear density drives complementarity effects and yield benefits in wheat variety mixtures

Summary

This three-year field study demonstrates that phenotypic plasticity — particularly in ear density — is the dominant mechanism driving overyielding in wheat variety mixtures, with complementarity effects accounting for most of the yield gain. The research links mixture-induced plasticity in ear density to the speed of tillering onset under shading, identifying this trait as a potential breeding target for cultivars designed for mixture systems. The findings advance understanding of the biological processes underlying intercropping benefits in cereals under field conditions.

UK applicability

The findings are likely applicable to UK wheat production, as Swiss growing conditions share temperate climate characteristics with much of the UK. The identification of tillering response to shade as a breeding criterion could inform UK wheat breeding programmes aiming to develop varieties suited to mixture-based sustainable intensification.

Key measures

Ear density, tillering onset under shade, plant height, grain yield per variety and per mixture, yield, complementarity effects, selection effects, phenotypic plasticity in response to variety mixing

Outcomes reported

The study measured trait responses and phenotypic plasticity of eight wheat varieties grown in two-way mixtures versus pure stands across three years and three field sites. Overyielding was quantified and partitioned into complementarity and selection effects, with plasticity in ear density identified as the primary driver of yield benefits.

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