Manntschke Annette, Hempel Lina, Temme Andries, Reumann Marcin, Chen Tsu-Wei
Group of Intensive Plant Food Systems, Albrecht Daniel Thaer-Institute, Faculty of Life Sciences, Humboldt Universität zu Berlin, Berlin, Germany.
Plant Breeding, Wageningen University & Research, Wageningen, Netherlands.
Front Plant Sci. 2025 Mar 19;16:1490483. doi: 10.3389/fpls.2025.1490483. eCollection 2025.
Breeders work to adapt winter wheat genotypes for high planting densities to pursue sustainable intensification and maximize canopy productivity. Although the effects of plant-plant competition at high planting density have been extensively reported, the quantitative relationship between competitiveness and plant performance remains unclear. In this study, we introduced a shoot competitiveness index (SCI) to quantify the competitiveness of genotypes and examined the dynamics of nine competitiveness-related traits in 200 winter wheat genotypes grown in heterogeneous canopies at two planting densities. Higher planting densities increased shoot length but reduced biomass, tiller numbers, and leaf mass per area (LMA), with trait plasticity showing at least 41% variation between genotypes. Surprisingly, genotypes with higher LMA at low density exhibited greater decreases under high density, challenging expectations from game theory. Regression analysis identified tiller number, LMA, and shoot length as key traits influencing performance under high density. Contrary to our hypothesis, early competitiveness did not guarantee sustained performance, revealing the dynamic nature of plant-plant competition. Our evaluation of breeding progress across the panel revealed a declining trend in SCI (R² = 0.61), aligning with the breeding objective of reducing plant height to reduce individual competitiveness and increase the plant-plant cooperation. The absence of historical trends in functional traits and their plasticities, such as tiller number and LMA, suggests their potential for designing ideal trait-plasticity for plant-plant cooperation and further crop improvement.
育种者致力于培育适合高密度种植的冬小麦基因型，以实现可持续集约化并最大化冠层生产力。尽管关于高密度种植下植株间竞争的影响已有大量报道，但竞争力与植株表现之间的定量关系仍不明确。在本研究中，我们引入了地上部竞争力指数（SCI）来量化基因型的竞争力，并研究了200个冬小麦基因型在两种种植密度的异质冠层中生长时九个与竞争力相关性状的动态变化。较高的种植密度增加了地上部长度，但降低了生物量、分蘖数和单位面积叶质量（LMA），性状可塑性在基因型间显示出至少41%的变异。令人惊讶的是，低密度下具有较高LMA的基因型在高密度下表现出更大的下降，这与博弈论的预期相悖。回归分析确定分蘖数、LMA和地上部长度是影响高密度下表现的关键性状。与我们的假设相反，早期竞争力并不能保证持续的表现，这揭示了植株间竞争的动态性质。我们对整个群体育种进展的评估显示SCI呈下降趋势（R² = 0.61），这与降低株高以减少个体竞争力并增加植株间协作的育种目标一致。功能性状及其可塑性，如分蘖数和LMA，缺乏历史趋势，表明它们在设计理想的植株间协作性状可塑性和进一步改良作物方面具有潜力。
