Comparative analysis of performance and stability among composite cross populations, variety mixtures and pure lines of winter wheat in organic and conventional cropping systems

•Wheat composite cross populations (CCPs), mixtures and monocultures were trialled.•Increasing plant diversity in the field raised wheat yield by 2–4% over monocultures.•Yield superiority values were better in the diverse population than in monocultures.•Competitiveness was higher in CCPs than in mixtures.•However, yields and yield stability were similar in CCPs and mixtures.