Changes in Nitrogen-Related Performance Attributes of Winter Wheat Varieties Released Between 1950 and 2020 in Dryland Region of China

In order to increase wheat yield, variety improvement plays an important role, while nitrogen (N) is a vital nutrient. The decline of water resources and the increased use of N fertilizer as a result of climate change have made it even more challenging for farmers to produce winter wheat with high yields and efficiently use water and N for sustainable agriculture. To achieve sustainable agricultural development in dry land regions of China, we need to improve yields and efficient use of N fertilizer in winter wheat. The purpose of this study is to observe the changing trends of the N application rate during the variety replacement process on winter wheat yield and NUE. In this study, a 2-year field experiment was conducted with three N application rates (0, 120, and 240 kg hm(-2)) and eight commonly grown winter wheat cultivars cultivated in the dry land areas of Guanzhong plain since the 1950 s. Two indicators of fertilizer-based N partial factor productivity (PFP) and apparent N recovery efficiency (RE), and two indicators of plant-based N use efficiency (NUTE) and N harvest index (NHI) were selected to observe the synergistic relationship between N rates and NUTE of different varieties in 2 years. The results showed that plant N accumulation (PNA), N transfer amount (NTA), N transfer efficiency (NTE), and NHI were significantly positively correlated with grain yield (r > 0.8). Nitrogen application and cultivar replacement not only increased the amount of assimilated N in grains after anthesis, but also increased the redistribution into grains. The contribution of vegetative organs to grains before anthesis ranged from 54.8 to 74.9%, which was the reason for the high N absorption efficiency and NUTE. The latest winter wheat variety of 2020 (XN20) accumulated the highest N content in all organs at flowering and maturity stages, while the oldest genotype of 1950 (BM1) accumulated minimum. The N1 and N2 treatments showed a significantly greater yield than N0. In summary, N application had a positive impact on grain yield in winter wheat, while year-to-year variability was mainly attributed to changes in variety and meteorological factors. The release of N-efficient varieties with PNA, NTA, NTE, and NHI can be selected in breeding work to increase grain yield. Under N application, PFP and RE were significantly positively correlated with yield, suggesting that these two indicators can be used as basic crop management indicators to increase yield. This provides information on effective agricultural N management measures and wheat breeding practices in the dryland regions of China.