Adapting Wheat Production to Global Warming in West Asia: Facultative Wheat Outperforms Winter and Spring Wheat at Conventional Nitrogen Levels

Global warming and weather anomalies pose significant threats to cereal production in West Asia. Winter wheat, which requires vernalization to trigger reproductive growth, is particularly vulnerable to heat, while spring wheat faces limitations due to short and hot vegetation periods. Facultative wheat, which does not require vernalization and can be planted in either fall or spring, offers potential flexibility and resilience to fluctuating temperatures. This study aimed to evaluate the development and grain yield of facultative, spring, and winter wheat varieties under different nitrogen fertilization rates in current climate conditions. Facultative wheat, grown as either facultative winter (FWW) or facultative spring (FSW), along with winter (WW) and spring wheat (SW) varieties, was cultivated over two consecutive seasons (2020-2022) at Ferdowsi University of Mashhad, Iran. Developmental stages were monitored, and grain yield, protein, and nutrient concentrations were measured at four nitrogen levels (0, 100, 200, and 300 kg N ha-1) in both shoots and grains. Crop modeling under the RCP 8.5 climate scenario supported the experiments and projections. Facultative wheat sown in autumn exhibited a shorter tillering stage and a longer early reproductive stage compared to winter wheat. While nitrogen fertilization delayed development, it significantly increased yield. Facultative wheat achieved higher grain yields at conventional nitrogen levels (100-200 kg N ha-1). Additionally, increasing nitrogen fertilization improved grain protein and nutrient concentrations (N, P, and K). Crop modeling indicated that facultative varieties sown in winter could offer greater yield stability and might benefit from a more consistent phenological development. Overall, facultative wheat performed better at conventional nitrogen levels, highlighting its potential in a changing climate in West Asia. Optimizing sowing dates and nitrogen fertilization could help mitigate some of the negative effects of rising temperatures, enhancing wheat resilience and productivity.