Seasonal variability in potential and actual yields of winter wheat in China.

• An integrated winter wheat yield evaluation based on yield variability was conducted. • Winter wheat yield potential was more stable than the actual yield. • Winter wheat yield level and yield stability showed significant improvements in China. • Some vulnerable areas in need of further attention were identified. Understanding the historical variability of winter wheat yield in China can provide insights into future wheat production security and adaptation measures. In this study, two indices, i.e., yield gap percentage (YG percentage) and yield variation difference (VD), were employed to investigate the winter wheat relatively yield level and yield variability from 1980 to 2010 in 1340 counties in China using a county-level dataset and a crop model (APSIM-Wheat). The study area was classified into four types of regions with different yield patterns: relatively high-yield level and high stability (RHY-RHS), relatively high-yield level and low stability (RHY-RLS), relatively low-yield level and high stability (RLY-RHS), and relatively low-yield level and low stability (RLY-RLS). Relatively high-yield levels in terms of YG percentage were found in the eastern parts of the Northern China Plain (NC) and the Yellow and Huai River Valleys (YH), the southern area of Xinjiang (XJ), and the northern part of the Middle and Lower Yangtze Valleys (YV), as well as a small section in the middle of Southwestern China (SW). Yield potential was more stable than the actual yield in most of the study regions, with positive VD. A decreasing trend was observed in both the YG percentage and VD over the three decades. Consequently, the county percentage of RHY-RHS and RHY-RLS increased but the percentage of RLY-RHS and RLY-RLS decreased over the three decades, indicating improved winter wheat yield level and yield stability in China, which might be attributed to the development of agricultural technology and breeding. Nonetheless, there are still some vulnerable areas in need of further attention. Western NC and southern YH are regions with a potentially stable yield in the future. Given that YH accounts for a large proportion of winter wheat production in China, further investigation should be conducted to identify the underlying causes of the low-yield level and high yield variability in YH. [ABSTRACT FROM AUTHOR]