FIGURE 3.

Illustration for the concept of (a) plant–plant interactions and (b) their consequences on crop yields of three hypothesized behaviour modes: facultative (i.e., kin‐dependent) cooperator, obligate cooperator and obligate competitor. The focal (F) plant is either grown in a mono‐culture where neighbours (N) are fully composed of relatives (kin, indicated by the blue colour), or grown in a mixed culture where neighbours (N) are composed of both relatives and strangers (non‐kin, indicated by the yellow colour). In (a), ‘+’ indicates a more cooperative trait expression and ‘−’ a more competitive one. In (b), the double‐headed arrow indicates potential variation in yields [Colour figure can be viewed at wileyonlinelibrary.com]