Elucidating population establishment associated with N management and cultivars for wheat production in China

Understanding population establishment associated with different cultivars and N management practices is essential to optimize populations and achieve a high yield for wheat production. A field experiment was conducted in 2012 and 2013 using five N levels and two winter wheat (Triticum aestivum L) cultivars: a low-tillering cultivar (TN) and a high-tillering cultivar (LX) in the North China Plain (NCP). The objective of this study was to evaluate grain yield and population establishment of the two cultivars in relation to the different N rates, and to determine the best N management practice and cultivar selection. Grain yield in TN was 5% higher than that of LX in 2013 (p < 0.01), but not in 2012 due to low spring temperatures and late sowing. Compared to LX, TN decreased the number of unproductive tillers in the spring while with similar productive tillers before the winter, and thus optimized population establishment and had higher yields. The optimal N rate (ONR) based on in-season root-zone N management averaged 162 kg N ha(-1), and the grain yield using ONR averaged 8.0 t ha(-1) for 2 years for both cultivars. Addition of N beyond the ONR did not increase yield, and treatments receiving 70% of the ONR had a 7.9% reduction in yield compared with the ONR treatment. The farmers' practice N rate (300 kg N ha(-1)) promoted unproductive tillers in the spring and inhibited productive tillers growth before winter, especially for the low-tillering cultivar of TN. In conclusion, selection of a low-tillering cultivar combined with optimal N management in the NCP could be a strategy useful to optimize population quantity, quality, and achieve a high yield, especially when using best crop management practices. (C) 2014 Elsevier B.V. All rights reserved.