Salicylic Acid Reduces Wheat Yield Loss Caused by High Temperature Stress by Enhancing the Photosynthetic Performance of the Flag Leaves

High temperature stress during grain filling substantially decreases wheat productivity; thus, to ensure food security, heat tolerance in must be developed. It remains unclear whether exogenous salicylic acid (SA) can induce high temperatures at the grain-filling stage. In this study, a two-year pot culture experiment using cultivar ‘Yangmai 18’ was conducted from 2018 2020. The plants were pre-sprayed with SA heading stage (SAH), anthesis (SAA), 5 days after (DAA; SA5), and 10 DAA (SA10). After that, subjected (G) simulated passive warming method period between 15 19 DAA. results showed compared normal control group (NN), significantly reduced yield photosynthetic capacity of wheat. application different stages loss damage caused by stress; effectiveness treatments descending order SAAG > SA5G SA10G SAHG. Exogenous treatment increased amount proportion dry matter distributed stem sheaths leaves grains, decreased rachises glumes maturity stage, thereby reducing under stress. leaf area, stomatal density, chlorophyll content, soluble protein maximum photochemical efficiency (Fv/Fm), actual (?PSII), activity sucrose phosphate synthase (SPS) flag improving performance summary, restored injured post-anthesis stress, which effectively alleviated inhibition growth ultimately loss. Spraying had greatest effect abating