Research advance in yield potential and yield gap of three major cereal crops

Understanding yield potential and yield gap for major cereal crops is critical for improving crop yield and helping farmers to adopt effective cultivation strategies. Based on 64 recently published classical literatures, this review summarized research advance in yield potential and yield gap for three major cereal crops (wheat, rice and maize) grown around the world. The different methods of measurement of yield potential and yield gap were also compared. The results showed that global yield potential was 6.7 t hm^-2 for wheat, 8.1 t hm^-2 for rice and 11.2 t hm^-2 for maize, and that the average yields of farmers for wheat, rice and maize were respectively 60%, 60% and 53% of the yield potential. Furthermore, it was noted that yield estimation by crop models was one of the most effective methods of quantifying yield potential. The yield potentials based on recorded highest yield and model-estimated yield were highly reasonable. Although yield potential based on experimental yield and best farmers' yield were lower than that based on model-estimated yield, it was still important for exploring potential improvements in yield in short term. Finally, it was advanced that optimized management strategies, such as integrated soil-crop system management, were effective ways for reducing yield gap. There still existed a large potential to increase grain yield for the three major cereal crops of wheat, rice and maize. It was indicated that studies on how to close yield gap, improve grain yield and ensure food security would attract a considerable attention in the future.