Abstract
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.
Highlights
IntroductionMiscanthus is a rhizomatous C4 grass of interest as a potential biofuel crop (Visser & Pignatelli, 2001; Hastings et al, 2009a; Somerville et al, 2010; Zub & Brancourt-Hulmel, 2010)
Miscanthus is a rhizomatous C4 grass of interest as a potential biofuel crop (Visser & Pignatelli, 2001; Hastings et al, 2009a; Somerville et al, 2010; Zub & Brancourt-Hulmel, 2010). This is because it has the potential to produce high yields (Clifton-Brown et al, 2001) over a wide geographical area with low agricultural inputs (Beale & Long, 1997; Zub & Brancourt-Hulmel, 2010) and can be grown on marginal land not cultivated for food production
Canopy architecture is crucial to intercepting light and producing yield
Summary
Miscanthus is a rhizomatous C4 grass of interest as a potential biofuel crop (Visser & Pignatelli, 2001; Hastings et al, 2009a; Somerville et al, 2010; Zub & Brancourt-Hulmel, 2010) This is because it has the potential to produce high yields (Clifton-Brown et al, 2001) over a wide geographical area with low agricultural inputs (Beale & Long, 1997; Zub & Brancourt-Hulmel, 2010) and can be grown on marginal land not cultivated for food production. M. 9 giganteus is a naturally occurring hybrid of M. sinensis and M. sacchar- To address both these issues, a physiologically based model of yield is needed which can be parameterized for different genotypes. Genetic segregation and recombination during breeding would be expected to produce further variation especially in a genetically diverse and nondomesticated plant like Miscanthus (Hartl & Clark, 2007)
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