Crop legacies as genetic targets for sustainable farming systems

Food production must rise while its environmental footprint falls, an imperative sharpened by pressure to use fewer external inputs. Meeting this challenge requires gains from aspects that crop breeding has so far overlooked. One such source is the soil, because every crop transforms the environment in which it grows, shaping the conditions experienced by the next crop. We propose that these legacy effects, expressed through altered soil nutrients, water, structure and microbial communities, could offer new breeding targets. Many traits that modulate these effects vary within major crop species, and this variation is heritable and therefore selectable. We advocate breeding for farming systems to exploit this untapped genetic dimension. We outline the mechanisms underpinning this relationship, the frameworks needed to quantify it and the practical challenges of integrating legacy-aware selection into breeding pipelines. Every crop leaves a legacy, and understanding this provides a pathway to a more sustainable agricultural future.