Evaluation of the yield and nitrogen use efficiency of the dominant maize hybrids grown in North and Northeast China

Breeding high-yielding and nutrient-efficient cultivars is one strategy to simultaneously resolve the problems of food security, resource shortage, and environmental pollution. However, the potential increased yield and reduction in fertilizer input achievable by using high-yielding and nutrient-efficient cultivars is unclear. In the present study, we evaluated the yield and nitrogen use efficiency （NUE） of 40 commercial maize hybrids at five locations in North and Northeast China in 2008 and 2009. The effect of interaction between genotype and nitrogen （N） input on maize yield was significant when the yield reduc- tion under low-N treatment was 25%-60%. Based on the average yields achieved with high or low N application, the tested cultivars were classified into four types based on their NUE： efficient-efficient （EE） were efficient under both low and high N inputs, high-N efficient （HNE） under only high N input, low-N efficient （LNE） under only low N input, and noneffi- cient-nonefficient under neither low nor high N inputs. Under high N application, EE and HNE cultivars could potentially in- crease maize yield by 8%-10% and reduce N input by 16%-21%. Under low N application, LNE cultivars could potentially increase maize yield by 12%. We concluded that breeding for N-efficient cultivars is a feasible strategy to increase maize yield and/or reduce N input.