Wheat genetic improvement affects the fate of 15N fertilizer, improving nitrogen uptake and utilization

Abstract

Context

Excessive fertilization increases production costs and contributes to environmental pollution, threatening agricultural sustainability. The efficiency with which wheat accumulates fertilizer nitrogen (N) directly affects economic returns and overall nitrogen use efficiency (NUE). Genetic improvement is a key strategy for enhancing NUE in wheat.

Objective and methods

This study examined eight widely cultivated wheat varieties released between 1948 and 2015 in the Huang-Huai-Hai region, using ¹⁵N stable isotopes to assess N uptake and utilization from fertilizer and soil indigenous N sources.

Results

Genetic improvement has significantly enhanced wheat NUE, primarily by increasing N accumulation and transport capacity. Notably, wheat breeding has led to higher pre-anthesis N accumulation, while post-anthesis N accumulation has remained largely unchanged. Modern wheat varieties exhibit greater absorption of both fertilizer N and soil indigenous N. Additionally, the proportion of fertilizer-derived ¹⁵N retained in wheat has increased, with a strong positive correlation observed between the ¹⁵N uptake and root traits such as root length, weight, and surface area in the topsoil (0–20 cm). Genetic advancements have also improved post-anthesis N translocation, leading to higher translocation rates and a greater contribution of N to grain formation. Both fertilizer and soil indigenous N translocation increased as the variety release year progressed. At the end of the growing season, wheat absorbed 21.5–28.8 % of fertilizer N, with 35.4–49.8 % remaining in the soil and 25.6–30.6 % lost through leaching. Genetic improvement has enhanced wheat’s capacity to absorb fertilizer-derived ¹⁵N, increasing ¹⁵N nitrogen recovery efficiency and reducing the amount of residual ¹⁵N fertilizer in the soil, with no significant change in ¹⁵N fertilizer nitrogen loss.

Conclusions

These findings support the development of climate-smart, sustainable agricultural systems by integrating genetic improvement and refined N management strategies. Future wheat breeding programs should prioritize root system optimization to enhance fertilizer N uptake and minimize residual soil N.