Artificial selection for grain yield has increased net CO2 exchange of the ear leaf in maize crops

Abstract Identifying the physiological traits indirectly selected during search for high-yielding maize hybrids is useful guiding further improvements. To investigate such traits, in this study we focused on critical period of kernel formation because number main yield component affected by breeding. Our results show that breeding has increased florets per ear and growth rate but not vegetative shoot rate, suggesting localised effects around ear. Consistent with possibility, net CO2 exchange leaf field-grown crops grown at high population densities. This response largely accounted light interception (which increases photosynthesis) reduced rates respiration modern compared to older ones. Modern ear-leaf area unit dry matter (specific area), which accounts respiratory load area. These observations are consistent a model where improved helps additional produced survive susceptibility stress hence produce kernels.