Late sowing mitigates winter wheat yield loss under seasonal warming by enhancing photothermal efficiency

Abstract

Adjusting sowing dates is a promising strategy for adapting crops to climate change. However, the interactive effects of sowing date and seasonal warming on winter wheat ( Triticum aestivum L.) yield in the North China Plain remain unclear. We investigated whether delayed sowing mitigated yield losses under future warming. A 2‐year field experiment (2020–2022) with three sowing dates (early, normal, and late) and three temperature regimes (CK: control, WS: winter–spring warming, and FF: flowering–filling warming) was conducted. Results showed a significant interaction between warming and sowing date. Ambient temperature and WS reduced yield under early sowing, with yields of 8139.09 kg hm ⁻² and 6124.02 kg hm ⁻² , respectively, below those of late sowing at the same temperature by ≥11.33%. However, there were no significant yield differences between early and late sowing under FF. Late sowing yielded well under all warming scenarios because of improved photosynthesis resulting from relatively high chlorophyll content (SPAD values) during grain filling. Multivariate analyses identified dry matter transfer volume of vegetative organs after anthesis (DMA) and photosynthetically active radiation (PAR) interception as key yield determinants. Structural equation modeling further revealed that PAR exerted the strongest direct positive effect on yield (path coefficient = 0.86, p  < 0.001). We conclude that delayed sowing mitigated warming‐induced yield loss mainly by enhancing post‐flowering PAR interception, which increased DMA and the number of fertile spikelets. This study clarifies the physiological mechanism and provides a basis for optimizing wheat cultivation in the North China Plain under climate change.