Reproductive resilience but not root architecture underpin yield improvement in maize (Zea maysL.)

Plants capture soil resources to produce the grains required to feed a growing population. Because plants capture water and nutrients through roots, it was proposed that changes in root systems architecture (RSA) underpin the three-fold increase in maize grain yield over the last century 1,2,3,4 . Within this framework, improvements in reproductive resilience due to selection are caused by increased water capture 1 . Here we show that both root architecture and yield have changed with decades of maize breeding, but not the water capture. Consistent with Darwinian agriculture 5 theory, improved reproductive resilience 6,7 enabled farmers increase the number of plants per unit land 8,9,10 , capture soil resources, and produced more dry matter and grain. Throughout the last century, selection operated to adapt roots to crowding, enabling reallocation of C from large root systems to the growing ear and the small roots of plants cultivated in high plant populations in modern agriculture.