Increasing temperature during early spring increases winter wheat grain yield by advancing phenology and mitigating...

High temperature usually reduces wheat yield, especially at critical growth stages, such as anthesis and grain filling. However, effects of increasing temperature during wintering period on winter wheat growth and development are rarely reported. Hence, this three-year field experiment evaluated how artificial warming during early spring (wintering period) affects winter wheat. The warming treatment (WT) advanced the wheat reviving, jointing, anthesis, and maturity stages, but the average temperature in each growing stage reduced, thus extending the duration of tillering, spike differentiation, and grain filling. Concurrently, the leaf area index and biomass accumulation were obviously increased. Additionally, WT showed a lower leaf senescence rate compared with that of control (CK). Also, the photosynthesis rate and SPAD of WT were increased relative to CK. WT increased superoxide dismutase and peroxidase activities, and reduced malondialdehyde content in flag leaf during the grain filling stage, suggesting WT during early spring could delay leaf senescence after anthesis, which contributed to a high filling rate and long filling duration. Correspondingly, the final spike number, kernel number, and kernel weight of WT were significantly increased compared with CK. In the three seasons, grain yield was increased by 18.2%-37.5% in WT compared with CK. Results of this study provided a new viewpoint that increasing temperature could shorten the wintering period but extend the effective growth phase, and increase grain yield in winter wheat.