Synergy between breeding for yield in winter wheat and high-input agriculture in North-West China

Abstract

The aims of this paper were to explore the response of winter wheat grain yield and its components to supply of resources (nutrients, water), and how this response changed with varieties selected for yield in north-west China between 1970s and 2010s. Three varieties representing the decades 1980, 2000, and 2010 in season 2013–14, and five varieties representing the decades from 1970 to 2010 in season 2014-15 were combined factorially with 11 input levels (9 nutrient treatments under irrigation and 2 nutrient treatments in rainfed condition), returning a range of environmental mean yield from 1.1 to 7.3 t ha⁻¹ Yield ranged from 0.9 t ha⁻¹ for the oldest variety under rainfed conditions and low input of nutrients to 8.3 t ha⁻¹ for the newest variety under irrigation and high supply of nutrients, biomass ranged from 2.3 to 18.2 t ha⁻¹ , and harvest index ranged from 0.33 to 0.49. The interactions between varieties and supply of resources were analysed from the perspective of phenotypic plasticity, quantified as the unitless slope of linear models relating the trait for each variety and the environmental mean of the trait. Plasticity of yield and plasticity of grain number increased with year of cultivar release, reflecting the enhanced ability of newer varieties to capture the benefits of higher inputs. Plasticity of harvest index declined with year of release, highlighting the stability of harvest index of newer varieties compared to their older counterparts. Our study demonstrates the synergy between breeding and agronomy whereby selection for yield has improved the ability of winter wheat to capture the benefits of higher inputs that has been a major feature of Chinese agriculture over the last six decades.