Université de Montpellier, INRA, Montpellier SupAgro, UMR LEPSE, Montpellier, France.
Université de Montpellier, CIRAD, INRA, Montpellier SupAgro, UMR AGAP, Montpellier, France.
Plant Cell Environ. 2019 Jul;42(7):2105-2119. doi: 10.1111/pce.13539. Epub 2019 Apr 17.
Breeders select for yield, thereby indirectly selecting for traits that contribute to it. We tested if breeding has affected a range of traits involved in plant architecture and light interception, via the analysis of a panel of 60 maize hybrids released from 1950 to 2015. This was based on novel traits calculated from reconstructions derived from a phenotyping platform. The contribution of these traits to light interception was assessed in virtual field canopies composed of 3D plant reconstructions, with a model tested in a real field. Two categories of traits had different contributions to genetic progress. (a) The vertical distribution of leaf area had a high heritability and showed a marked trend over generations of selection. Leaf area tended to be located at lower positions in the canopy, thereby improving light penetration and distribution in the canopy. This potentially increased the carbon availability to ears, via the amount of light absorbed by the intermediate canopy layer. (b) Neither the horizontal distribution of leaves in the relation to plant rows nor the response of light interception to plant density showed appreciable trends with generations. Hence, among many architectural traits, the vertical distribution of leaf area was the main indirect target of selection.
选育者通过选择产量相关的特征，间接地选择了有助于提高产量的特征。我们通过分析从 1950 年到 2015 年发布的 60 个玉米杂交种的小组，来测试选育是否影响了与植物结构和光捕获相关的一系列特征。这是基于从表型平台重建中得出的新特征来计算的。利用 3D 植物重建构建的虚拟田间冠层，评估了这些特征对光捕获的贡献，并在实际田间中测试了模型。两类特征对遗传进展有不同的贡献。(a)叶面积的垂直分布具有较高的遗传力，并且在几代的选育中呈现出明显的趋势。叶片倾向于位于冠层的较低位置，从而提高了冠层中的光穿透和分布。这可能通过中间冠层吸收的光量来增加对穗的碳供应。(b)叶片在与植物行的关系中的水平分布以及光捕获对植物密度的响应都没有表现出明显的世代趋势。因此，在许多结构特征中，叶面积的垂直分布是选择的主要间接目标。
