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IGER INNOVATIONS 2007 Asian elephant grass (Miscanthus) for bioenergy John Clifton-Brown and John Valentine Why Miscanthus? 24 Crop specifications 24 Germplasm for breeding 26 Energy crops: a real land use option 27

Asianelephantgrass (Miscanthus)for bioenergy€¦ · Miscanthus genotypes as a basis for crossing Fig. 3. Japanese Miscanthus sacchariflorus in full flower in November2006.Photo:JCB

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Page 1: Asianelephantgrass (Miscanthus)for bioenergy€¦ · Miscanthus genotypes as a basis for crossing Fig. 3. Japanese Miscanthus sacchariflorus in full flower in November2006.Photo:JCB

IGER INNOVATIONS 2007

Asian elephant grass(Miscanthus) forb ioenergy

John Cli f ton-Brown and John Valent ine

Why Miscanthus? 24

Crop specifications 24

Germplasm for breeding 26

Energy crops: a real land use option 27

Page 2: Asianelephantgrass (Miscanthus)for bioenergy€¦ · Miscanthus genotypes as a basis for crossing Fig. 3. Japanese Miscanthus sacchariflorus in full flower in November2006.Photo:JCB

A s i a n e l e p h a n t g r a s s ( M i s c a n t h u s )f o r b i o e n e r g y

IGER INNOVATIONS 2007

24

John Cli f ton-Brown and John Valent ine

iomass crops are becoming increasinglyimportant as concerns grow about climate changeand the need to replace carbon dioxide-producingfossil fuels – oil, coal and gas – with carbon-neutralrenewable sources of energy.

Why Miscanthus?To succeed in this role, a crop has to grow rapidlyand yield a reliable, regular harvest. A primecandidate for the UK is Miscanthus, or Asianelephant grass, a perennial species that producesover 3 metres of bamboo-like stems in a year. Morethan 30 field trials distributed across Europe sincethe early 1990’s have confirmed the potential of thishighly impressive grass originating from East Asia.Data from these trials have shown that Miscanthus xgiganteus yields reach a peak 2 to 4 years followingestablishment, depending on the site’s environmentalconditions. Though few of the trials have yet beenmonitored for long enough to determine true long-term yield persistence under European conditions(>10 years), stands of M. sacchariflorus in China,which are cut annually, have remained productive for30 years since the establishment of a celluloseindustry. Stands of Miscanthus sinensis in Japanhave long been harvested for forage and forthatching and this still continues up to the presentday.

B

Crop specificationsMiscanthus species are perennial rhizomatousgrasses with C4 type photosynthesis. C4 species arecapable of higher rates of photosynthesis, and useless nitrogen and water than the more common C3temperate species. Consequently, Miscanthusspecies require very low levels of supplementaryinputs and typically have higher energy output :input ratios than most other candidate energy crops.Current estimates of these energy ratios for

Fig. 1.M. floridulus growing at 2100m in Taiwan. Plant collectors:Dr Yu-Chung Chiang (Pintung University) and JCB. Photo: Dr LinHuang (IGER)

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Page 3: Asianelephantgrass (Miscanthus)for bioenergy€¦ · Miscanthus genotypes as a basis for crossing Fig. 3. Japanese Miscanthus sacchariflorus in full flower in November2006.Photo:JCB

Miscanthus range between 22 and 50 as delivered tothe power station gate, depending on assumptionsused in the life cycle analysis of the crop. In practicalterms, basic calculations show that a crop yield 12tDM ha-1 would have the energy equivalent of 30 to35 barrels of oil per hectare. Under this analysis,when crude oil prices are above about $60 per barrel,then energy crops are economically viable forfarmers to grow once the utilisation chain is put inplace.

Miscanthus species are typically diploid ortetraploid. Hybrids between species with differentploidy levels result in the highly productive triploidhybrids such as M. x giganteus. Since these are

IGER INNOVATIONS 2007

25

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sterile, these must be propagated vegetatively. In theUK, rhizome propagation has been the preferredroute for commercial exploitation. Areas set to M. xgiganteus in the UK have reached over 10,000hectares in 2007 and there is a continuous expansionas more development companies are established.Projections of yield with a proprietary model(MISCAMOD) for EU countries, assuming a 10%agricultural land take for energy crops, show that theUK could produce up to 7% of its electrical powerfrom Miscanthus sources. In some EU regions withsuitable growing conditions, energy derived fromMiscanthus biomass could exceed the currentrenewable energy source (RES) targets set by the EUby up to five-fold.

Fig. 2. M. sinensis growing on volcanic islands in Japan. Photo: JCB

Page 4: Asianelephantgrass (Miscanthus)for bioenergy€¦ · Miscanthus genotypes as a basis for crossing Fig. 3. Japanese Miscanthus sacchariflorus in full flower in November2006.Photo:JCB

IGER INNOVATIONS 2007

26

Traditionally, biomass has had a niche role inproviding ‘base load’ for both the heat and electricitymarkets since it can provide non-intermittentrenewable power. In recent years, however, newmarket opportunities are opening up as policyfavours the production of renewable transport fuels.The bioethanol industry in the USA has now begunto influence maize corn prices. Maize is an annualand we believe that Miscanthus as a perennial cropwould have considerable advantages. Analyses atIGER indicate that Miscanthus has a chemical

composition suitable for conversion to ethanol withappropriate enzymes. Second generation fuels suchas bio-butanol are also under consideration.

Germplasm for breedingAs existing varieties have not been bred specificallyfor high yields, we know that we can make majorgains in Miscanthus productivity throughscientifically-based plant breeding. The key toestablishing a successful breeding programme is awide genetic base. To this end, the UK Departmentfor Environment, Food and Rural Affairs (Defra)funded a collecting trip to seek out new specimenssuitable for incorporation into IGER’s breedingprogramme. Planning the trip in conjunction withcounterparts in Asia took months, but was helpedenormously by the presence at IGER of Dr LinHuang, from Taiwan, who is a biological data analystat the Institute. Lin Huang also joined the expedition,which took place in October 2006, as interpreter andrecorder.

Field selected genotypes and populations withagronomically promising characteristics werecollected in duplicate so that each partner institutecould plant a reference collection. Furthermore,agreements were negotiated to enable IGER to sharecommercial benefits with each country. Both of theseactions form an important part of the rules set by theUN in their protocols for the Convention onBiological Diversity (CBD). Collected samples arecurrently held in strict quarantine and are subject tostringent treatments to clean up material before it canbe released from quarantine.

Work will now begin on characterising the newMiscanthus genotypes as a basis for crossing

Fig. 3. Japanese Miscanthus sacchariflorus in full flower inNovember 2006. Photo: JCB

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Page 5: Asianelephantgrass (Miscanthus)for bioenergy€¦ · Miscanthus genotypes as a basis for crossing Fig. 3. Japanese Miscanthus sacchariflorus in full flower in November2006.Photo:JCB

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[email protected]@bbsrc.ac.uk

programmes aiming to produce varieties suitable forconditions in the UK. Armed with this new materialfrom Asia, we aim to increase yield and improveother traits associated with chemical composition,while retaining tolerance to stresses such as long drysummers. By increasing genetic diversity, breedingof improved varieties will also reduce geneticvulnerability of Miscanthus spp. to offer protectionagainst unexpected pests and diseases.

Energy crops: a real land use optionIn contrast to arable crops such as wheat which havealso been proposed as energy crops, Miscanthus has

lower fertiliser requirements, no annual ploughing(only once at establishment), positive effects onbiodiversity and, therefore, a less adverseenvironmental impact. Biomass crops are beginningto make a significant impact on the UK agriculturalsector, and the new breeding programme looks set tosecure the future of Asian elephant grass as an optionfor farmers.

Note: The IGER genetic improvement programme isfunded by Defra.

Fig. 4. Miscanthus trial at Aberystwyth - Summer 2006.