Kin recognition, multilevel selection and altruism in crop sustainability

Summary Intraspecific competition among crop plants is undesirable. Less competitive crops are predicted to increase yield and decrease the need for added resources. Wild plants demonstrate the ability to recognize kin and potentially help their relatives by reducing their competitive behaviours, a form of altruism. Altruism can also evolve through multilevel selection. Are these processes relevant to sustainable agriculture? Crops do grow predictably with kin. However, their evolution is more strongly dictated by artificial selection (crop breeding), which incorporates individual and group selection, making multilevel selection more relevant than kin selection in favouring altruism. While current crop breeding protocols attempt to target the reduction of competitive traits, early mass selection may have the opposite effect. We predict that kin recognition itself is not relevant to crops, because of the consistently high relatedness within crop stands. Nonetheless, crops have shown cultivar and kin recognition. We argue that these responses cannot be assumed to demonstrate altruism, as current breeding practices offer little opportunity for kin selection. Synthesis. There is the opportunity to favour altruism through artificial breeding. Here we suggest how crop breeding protocols could be changed to favour cooperation by increasing group selection during early breeding.