Balanced below- and aboveground growth improved yield and water productivity by cultivar renewal for winter wheat

The improvement in yield was mainly attributed to the maintenance of higher photosynthetic capacity during the reproductive growth stage and greater above-ground biomass accumulation. These improvements were larger under wet conditions than that under dry conditions, indicating that the yield potential was increased by cultivar renewal. Traits related to yield and WP improvements included the increased harvest index and reduced root: shoot ratio.

New cultivars reduced the redundancy in root proliferation in the topsoil layer, which did not compromise the efficient utilization of soil moisture but reduced the metabolic input in root growth. Balanced above- and belowground growth resulted in a significant improvement in root efficiency at grain yield level up to 40% from the cultivars released in the 1970s to those recently released. The results from this study indicated that the improved efficiency in both the above- and below-parts played important roles in enhancing crop production and resource use efficiency.