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<p>Row spacing configurations consistently alter the asymmetric competition between the main stem and tillers in wheat, which significantly impacts grain yield. However, the physiological mechanisms that enable wheat to cope with intraspecific competition and build resilience in growth are not fully explored. We conducted two-year field experiments on wheat with conventional uniform row-spacing (CS) and four-to-one narrow-wide strip (FS) sowing under seeding rates of 93.8 (D1), 187.5 (D2) and 281.3 kg ha<sup>−</sup> <sup>1</sup> (D3). Tiller growth, dry matter and nitrogen accumulations, and photosynthetic traits were investigated. The result showed that tiller number per plant decreased and tiller mortality rate increased with increasing seeding rates. The FS planting led to a 24.1–89.9% higher dry matter ratio between the main stem and tillers compared to the CS planting. This, along with greater variability of plant height, suggested stronger intraspecific competition, which increased the tiller mortality rate by 13.3–58.3% under D1 and D2 rates. However, both sowing patterns exhibited a similar and high tiller mortality rate under D3 across years. The FS planting reduced leaf area index by 21.3–43.5% across seeding rates. Furthermore, decrease in population size in the FS planting reduced competition between individuals after anthesis, which exhibited a robust resilience in post-anthesis dry matter accumulation. This was corroborated by the findings that the FS narrow-wide planting increased inter-row CO<sub>2</sub> concentrations by 22.2 to 28.8 μmol mol<sup>−1</sup> at 15 days after anthesis compared to the CS planting. Consequently, the net photosynthetic rate of flag leaves increased markedly by 34.6–46.4% at 15 DAA, along with a notable increase of 16.3% in apparent quantum efficiency, 35.2% in maximum photosynthetic rate, 21.0% in maximum carboxylation rates, and 21.2% in maximum electron transport rates. Despite suffering from pre-anthesis intraspecific competition, the FS planting achieved a yield comparable to that of the CS planting. Overall, these findings reveal the physiological basis of the post-anthesis growth resilience from intraspecific competition in strip-planted wheat by enhancing photosynthetic efficiency.</p>

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Harnessing Intraspecific Dynamics in Strip-Planted Wheat: The Dual Role of Competition in Tiller Mortality and Post-Anthesis Growth

  • 期刊论文

  • 发表日期：

    2025年12月5日

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  • Yu Liu,
  • Yonghua Li,
  • Shuhui Song,
  • Xiaojie Feng,
  • Zhanhong Hao,
  • Songlin Ye,
  • Xinsheng Niu,
  • Guohua Mi,
  • Peng Ning

摘要

Row spacing configurations consistently alter the asymmetric competition between the main stem and tillers in wheat, which significantly impacts grain yield. However, the physiological mechanisms that enable wheat to cope with intraspecific competition and build resilience in growth are not fully explored. We conducted two-year field experiments on wheat with conventional uniform row-spacing (CS) and four-to-one narrow-wide strip (FS) sowing under seeding rates of 93.8 (D1), 187.5 (D2) and 281.3 kg ha− 1 (D3). Tiller growth, dry matter and nitrogen accumulations, and photosynthetic traits were investigated. The result showed that tiller number per plant decreased and tiller mortality rate increased with increasing seeding rates. The FS planting led to a 24.1–89.9% higher dry matter ratio between the main stem and tillers compared to the CS planting. This, along with greater variability of plant height, suggested stronger intraspecific competition, which increased the tiller mortality rate by 13.3–58.3% under D1 and D2 rates. However, both sowing patterns exhibited a similar and high tiller mortality rate under D3 across years. The FS planting reduced leaf area index by 21.3–43.5% across seeding rates. Furthermore, decrease in population size in the FS planting reduced competition between individuals after anthesis, which exhibited a robust resilience in post-anthesis dry matter accumulation. This was corroborated by the findings that the FS narrow-wide planting increased inter-row CO2 concentrations by 22.2 to 28.8 μmol mol−1 at 15 days after anthesis compared to the CS planting. Consequently, the net photosynthetic rate of flag leaves increased markedly by 34.6–46.4% at 15 DAA, along with a notable increase of 16.3% in apparent quantum efficiency, 35.2% in maximum photosynthetic rate, 21.0% in maximum carboxylation rates, and 21.2% in maximum electron transport rates. Despite suffering from pre-anthesis intraspecific competition, the FS planting achieved a yield comparable to that of the CS planting. Overall, these findings reveal the physiological basis of the post-anthesis growth resilience from intraspecific competition in strip-planted wheat by enhancing photosynthetic efficiency.