Blanc Emmanuelle, Barbillon Pierre, Fournier Christian, Lecarpentier Christophe, Pradal Christophe, Enjalbert Jérôme
Université Paris-Saclay, INRAE, CNRS, AgroParisTech, GQE-Le Moulon, Gif-sur-Yvette, France.
Université Paris-Saclay, AgroParisTech, INRAE, UMR MIA-Paris, 75005, Paris, France.
Front Plant Sci. 2021 Sep 29;12:734056. doi: 10.3389/fpls.2021.734056. eCollection 2021.
Increasing the cultivated diversity has been identified as a major leverage for the agroecological transition as it can help improve the resilience of low input cropping systems. For wheat, which is the most cultivated crop worldwide in terms of harvested area, the use of cultivar mixtures is spreading in several countries, but studies have seldom focused on establishing mixing rules based on plant architecture. Yet, the aerial architecture of plants and the overall canopy structure are critical for field performance as they greatly influence light interception, plant interactions and yield. The very high number of trait combinations in wheat mixtures makes it difficult to conduct experimentations on this issue, which is why a modeling approach appears to be an appropriate solution. In this study, we used WALTer, a functional structural plant model (FSPM), to simulate wheat cultivar mixtures and try to better understand how differences between cultivars in key traits of the aerial architecture influence mixture performance. We simulated balanced binary mixtures of cultivars differing for different critical plant traits: final height, leaf dimensions, leaf insertion angle and tillering capability. Our study highlights the impact of the leaf dimensions and the tillering capability on the performance of the simulated mixtures, which suggests that traits impacting the plants' leaf area index (LAI) have more influence on the performance of the stand than traits impacting the arrangement of the leaves. Our results show that the performance of mixtures is very variable depending on the values of the explored architectural traits. In particular, the best performances were achieved by mixing cultivars with different leaf dimensions and different tillering capability, which is in agreement with numerous studies linking the diversity of functional traits in plant communities to their productivity. However, some of the worst performances were also achieved by mixing varieties differing in their aerial architecture, which suggests that diversity is not a sufficient criterion to design efficient mixtures. Overall, these results highlight the importance of simulation-based explorations for establishing assembly rules to design efficient mixtures.
增加种植多样性已被视为农业生态转型的一项主要手段，因为它有助于提高低投入种植系统的恢复力。就收获面积而言，小麦是全球种植最广泛的作物，在一些国家，品种混合种植的方式正在推广，但此前的研究很少聚焦于基于植株架构制定混合规则。然而，植株的地上架构和整体冠层结构对田间表现至关重要，因为它们极大地影响着光照截获、植株间相互作用和产量。小麦混合物中存在大量的性状组合，这使得针对此问题进行实验变得困难，这就是为什么建模方法似乎是一个合适的解决方案。在本研究中，我们使用了功能-结构植物模型（FSPM）WALTer来模拟小麦品种混合物，并试图更好地理解地上架构关键性状的品种差异如何影响混合物表现。我们模拟了在不同关键植株性状上存在差异的品种的平衡二元混合物：最终株高、叶片尺寸、叶片着生角度和分蘖能力。我们的研究突出了叶片尺寸和分蘖能力对模拟混合物表现的影响，这表明影响植株叶面积指数（LAI）的性状对群体表现的影响大于影响叶片排列的性状。我们的结果表明，混合物的表现会因所探究的架构性状值的不同而有很大差异。特别是，通过混合具有不同叶片尺寸和不同分蘖能力的品种可实现最佳表现，这与众多将植物群落功能性状多样性与其生产力联系起来的研究结果一致。然而，混合地上架构不同的品种也会导致一些最差的表现，这表明多样性并非设计高效混合物的充分标准。总体而言，这些结果凸显了基于模拟探索来制定组装规则以设计高效混合物的重要性。
