Historical genetic responses of yield and root traits in winter wheat in the yellow-Huai-Hai River valley region of China due to modern breeding (1948-2012)

AimsThe Yellow and Huai Valleys Winter Wheat Zone (YHVWWZ) is the predominant wheat-producing region in China. This study aimed to identify genetic gains in root characteristics and grain yield of winter wheat (Triticum aestivum L.) cultivars to assist future breeding strategies.MethodsField trials were conducted in the wetter-than-average 2014-2015 and drier-than-average 2015-2016 growing seasons. Yield and related traits were measured in 17 wheat cultivars released for irrigated conditions in the YHVWWZ from 1948 to 2012.ResultsYields have increased in the 60years of breeding and selection of cultivars in this region. No change in root biomass with year of release was evident in 2014-2015, but it increased significantly in 2015-2016. The density of shallow roots (0-1m) increased significantly with year of release in both seasons, while the density of deeper roots (1-2m) decreased significantly in 2014-2015 and increased significantly in 2015-2016. Aboveground biomass increased with year of release in 2014-2015 but did not change in 2015-2016, and total biomass (root plus shoot) increased with year of release in both seasons.ConclusionsModern wheat cultivars are better adapted to different watering levels in irrigated areas than older cultivars, with more root biomass at shallow depth, higher plasticity of the root system with depth, and increased yields.