Miscanthus is a rhizomatous C4 grass of great interest as a biofuel crop because it has the potential to produce high yields over a wide geographical area with low agricultural inputs on marginal land less suitable for food production. At the moment, a clonal interspecific hybrid Miscanthus × giganteus is the most widely cultivated and studied in Europe and the United States, but breeding programmes are developing newer more productive varieties. Here, we quantified the physiological processes relating to whole season yield in a replicated plot trial in Wales, UK. Light capture and conversion efficiency were parameterized for four carefully selected genotypes (M. sinensis, M. sacchariflorus and Miscanthus × giganteus). Differences in the canopy architecture in mature stands as measured by the extinction coefficient (k) were small (0.55–0.65). Sensitivity analysis on a mathematical model of Miscanthus was performed to quantify the accumulative intercepted photosynthetically active radiation (iPAR) in the growing season using (i) k, (ii) variation in the thermal responses of leaf expansion rate, (iii) base temperature for degree days and (iv) date start of canopy expansion. A 10% increase in k or leaf area per degree day both had a minimal effect on iPAR (3%). Decreasing base temperature from 10 to 9 °C gave an 8% increase in iPAR. If the starting date for canopy expansion was the same as shoot emergence date, then the iPAR increases by 12.5%. In M. × giganteus, the whole season above ground and total (including below ground) radiation‐use efficiency (RUE) ranged from 45% to 37% higher than the noninterspecific hybrid genotypes. The greater yields in the interspecific hybrid M. × giganteus are explained by the higher RUE and not by differences in iPAR or partitioning effects. Studying the mechanisms underlying this complex trait could have wide benefits for both fuel and food production.

中文翻译：

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Miscanthus sacchariflorus、M. sinensis 及其天然杂种 M. × giganteus 的辐射捕获和转换效率。

芒草是一种根状茎 C4 草，作为生物燃料作物非常受关注，因为它有可能在不适合粮食生产的边缘土地上以低农业投入在广阔的地理区域内产生高产量。目前，克隆种间杂种Miscanthus  ×  giganteus是欧洲和美国种植和研究最广泛的品种，但育种计划正在开发更新的、产量更高的品种。在这里，我们在英国威尔士的重复小区试验中量化了与整个季节产量相关的生理过程。对四种精心挑选的基因型（M. sinensis、M. sacchariflorus和Miscanthus ）的光捕获和转换效率进行了参数化。 × 巨人）。由消光系数 ( k )衡量的成熟林分树冠结构的差异很小 (0.55-0.65)。对芒草的数学模型进行了敏感性分析，以使用 (i) k，(ii) 叶片膨胀率热响应的变化，(iii) 基础温度来量化生长季节中累积截获的光合有效辐射 (iPAR)。度数和 (iv) 冠层扩展的开始日期。k增加 10%或每度日叶面积对 iPAR 的影响最小 (3%)。将基础温度从 10 °C 降低到 9 °C，iPAR 增加了 8%。如果冠层扩展的开始日期与芽出现日期相同，则 iPAR 增加 12.5%。在M。×  giganteus，整个季节的地上和总（包括地下）辐射利用效率（RUE）比非种间杂种基因型高 45% 到 37%。种间杂种M. × giganteus的更高产量是由较高的 RUE 而非 iPAR 或分配效应的差异来解释的。研究这种复杂特征背后的机制可能对燃料和粮食生产都有广泛的好处。