The performance of spring wheat cultivar mixtures under conventional and organic management in Western Canada

Wheat (Triticum aestivum L.) cultivar mixtures may stabilize yield across environments, control air-borne diseases, and manage pest populations in both conventional and organically managed systems. The objective of this study was to evaluate agronomic and end-use quality characteristics of wheat cultivar mixtures. Five Canada Western Red Spring wheat cultivars ('Go Early', 'Carberry', 'Glenn', 'CDC Titanium', and 'Lillian') differing in agronomic and quality traits were selected to compose 20 possible two-way and three-way combinations. Field experiments were conducted in four conventional and two organic environments in Alberta and Saskatchewan, Canada in 2016 and 2017. Wheat cultivar mixtures out-yielded their mid-component averages in both conventional and organic environments. Averaged across locations, two mixtures, Glenn-Lillian and Go Early-Glenn-Lillian, significantly out-yielded their mid-components. The overall yield increase ranged from 3.3 to 14.1%, with a mean of 0.18 Mg ha(-1) over different environments. Grain yield was negatively correlated with protein content (r = -.53) and falling number was negatively correlated with sedimentation volume (r = -.66) in conventional systems. Protein content was positively correlated with falling number in both conventional (r = .60) and organic (r = .40) systems. Days to maturity was positively correlated with yield (r = .40) and sedimentation volume (r = .40), but negatively correlated with falling number (r = -.80) in organic system. Sole cultivars were more stable under conventional, and mixtures were more stable under organic management. Our results suggest that wheat cultivar mixtures may provide yield advantage under abiotic stresses in conventional, whereas superior yield and grain quality in organic management.