title: Radiation capture and conversion efficiencies ofMiscanthus sacchariflorus,M. sinensisand their naturally occurring hybridM. ×giganteus.
abstract: Miscanthusis 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 hybridMiscanthus×giganteusis 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. sacchariflorusandMiscanthus×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 ofMiscanthuswas 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 inkor 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%. InM. ×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 hybridM. × giganteusare 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.
authors.affiliation: Institute of Biological, Environmental and Rural Sciences (IBERS) Aberystwyth University Gogerddan Aberystwyth, Ceredigion SY23 3EE UK.
authors.forename: Christopher Lyndon
authors.initials: CL
authors.lastname: Davey
authors.affiliation: Institute of Biological, Environmental and Rural Sciences (IBERS) Aberystwyth University Gogerddan Aberystwyth, Ceredigion SY23 3EE UK.
authors.forename: Laurence Edmund
authors.initials: LE
authors.lastname: Jones
authors.affiliation: Institute of Biological, Environmental and Rural Sciences (IBERS) Aberystwyth University Gogerddan Aberystwyth, Ceredigion SY23 3EE UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Squance
authors.affiliation: Institute of Biological, Environmental and Rural Sciences (IBERS) Aberystwyth University Gogerddan Aberystwyth, Ceredigion SY23 3EE UK.
authors.forename: Sarah Jane
authors.initials: SJ
authors.lastname: Purdy
authors.affiliation: Institute of Biological, Environmental and Rural Sciences (IBERS) Aberystwyth University Gogerddan Aberystwyth, Ceredigion SY23 3EE UK.
authors.forename: Anne Louise
authors.initials: AL
authors.lastname: Maddison
authors.affiliation: Rothamsted Research Harpenden, Hertfordshire AL5 2JQ UK.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Cunniff
authors.affiliation: Institute of Biological, Environmental and Rural Sciences (IBERS) Aberystwyth University Gogerddan Aberystwyth, Ceredigion SY23 3EE UK.
authors.forename: Iain
authors.initials: I
authors.lastname: Donnison
authors.affiliation: Institute of Biological, Environmental and Rural Sciences (IBERS) Aberystwyth University Gogerddan Aberystwyth, Ceredigion SY23 3EE UK.
authors.forename: John
authors.initials: J
authors.lastname: Clifton-Brown
keywords: Miscanthus; diversity; extinction coefficient; radiation‐use efficiency; sensitivity analysis; yield