[Effects of sowing method and row spacing configuration on photosynthetic matter production and yield formation of...

We explored the physiological mechanisms underlying the effects of sowing method and row spacing configuration on photosynthetic substance production and yield formation in wheat ('Jimai 22' variety) with a two-factor split-plot experiment. The main plots consisted of sowing method: wide precision sowing (K) and conventional strip sowing (T), while the subplots consisted of row spacing: 20 cm (R1), 25 cm (R2), and 30 cm (R3), resulting in six treatments. We measured flag leaf photosynthetic characteristics, senescence traits, and ¹³C assimilate accumulation and distribution under various sowing method and row spacing configurations. The results showed that KR2 treatment significantly increased SPAD values, net photosynthetic rate, transpiration rate, stomatal conduc-tance, superoxide dismutase activity, and soluble protein content in the flag leaf at 14, 21, and 28 days after flower-ing, with average increase of 23.8%, 16.3%, 16.8%, 15.6%, 14.4%, and 15.2%, respectively. It significantly reduced intercellular CO₂ concentration and malondialdehyde content by 11.9% and 12.1%, respectively. In addition, the KR2 treatment promoted the transport of ¹³C assimilates from stems and leaves to grains, and significantly increased yields by 17.5%, 10.7%, 24.9%, 10.1%, and 23.6% when compared with those in the KR1, KR3, TR1, TR2, and TR3 treatments, respectively. In summary, the 25 cm row spacing wide precision sowing method significantly improved photosynthetic characteristics of the flag leaf during the mid-to-late grain filling stage of wheat, delayed leaf senescence, and promoted allocation of photosynthetic products to grain, thereby achieving the highest yield.