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Breeding for genetic improvement of forage plants in relation to increasing animal production with reduced environmental footprint

Published online by Cambridge University Press:  01 May 2012

A. H. Kingston-Smith*
Affiliation:
IBERS, Aberystwyth University, Gogerddan Campus, Aberystwyth SY23 3EB, UK
A. H. Marshall
Affiliation:
IBERS, Aberystwyth University, Gogerddan Campus, Aberystwyth SY23 3EB, UK
J. M. Moorby
Affiliation:
IBERS, Aberystwyth University, Gogerddan Campus, Aberystwyth SY23 3EB, UK
*
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Abstract

Animal production is a fundamental component of the food supply chain, and with an increasing global population production levels are set to increase. Ruminant animals in particular are valuable in their ability to convert a fibre-rich forage diet into a high-quality protein product for human consumption, although this benefit is offset by inefficiencies in rumen fermentation that contribute to emission of significant quantities of methane and nitrogenous waste. Through co-operation between plant and animal sciences, we can identify how the nutritional requirements of ruminants can be satisfied by high-quality forages for the future. Selective forage plant breeding has supported crop improvement for nearly a century. Early plant breeding programmes were successful in terms of yield gains (4% to 5% per decade), with quality traits becoming increasingly important breeding targets (e.g. enhanced disease resistance and digestibility). Recently, demands for more sustainable production systems have required high yielding, high-quality forages that enable efficient animal production with minimal environmental impact. Achieving this involves considering the entire farm system and identifying opportunities for maximising nutrient use efficiency in both forage and animal components. Forage crops of the future must be able to utilise limited resources (water and nutrients) to maximise production on a limited land area and this may require us to consider alternative plant species to those currently in use. Furthermore, new breeding targets will be identified as the interactions between plants and the animals that consume them become better understood. This will ensure that available resources are targeted at delivering maximum benefits to the animal through enhanced transformation efficiency.

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Copyright
Copyright © The Animal Consortium 2012

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References

Abberton, MT, Marshall, AH 2005. Progress in breeding perennial clovers for temperate agriculture: centenary review. Journal of Agricultural Science 143, 117135.Google Scholar
Abberton, MT, Marshall, AH, Humphreys, MW, Macduff, JH, Collins, RP, Marley, CL 2008. Genetic improvement of forage species to reduce the environmental impact of temperate livestock grazing systems. Advances in Agronomy 98, 311355.Google Scholar
Abler, D 2004. Multifunctionality, agricultural policy, and environmental policy. Agricultural and Resource Economics Review 33, 817.Google Scholar
Alm, V, Busso, CS, Ergon, A, Rudi, H, Larsen, A, Humphreys, MW, Rognoli, OA 2011. QTL analyses and comparative genetic mapping of frost tolerance, winter survival and drought tolerance in meadow fescue (Festuca pratensis Huds.). Theoretical and Applied genetics 123, 369382.CrossRefGoogle ScholarPubMed
Barry, TN, McNabb, WC 1999. The implications of condensed tannins on the nutritive value of temperate forages fed to ruminants. British Journal of Nutrition 81, 263272.Google Scholar
Beauchemin, KA, McGinn, SM, Martinez, TF, McAllister, TA 2007. Use of condensed tannin extract from quebracho trees to reduce methane emissions from cattle. Journal of Animal Science 85, 19901996.Google Scholar
Beha, EM, Theodorou, MK, Thomas, BJ, Kingston-Smith, AH 2002. Grass cells ingested by ruminants undergo autolysis which differs from senescence: implications for grass breeding targets and livestock production. Plant, Cell & Environment 25, 12991312.CrossRefGoogle Scholar
Broderick, GA, Walgenbach, RP, Maignan, S 2001. Production of lactating dairy cows fed alfalfa or red clover silage at equal dry matter or crude protein contents in the diet. Journal of Dairy Science 84, 17281737.Google Scholar
Bowley, SR 1997. Breeding methods for forage legumes. In Biotechnology and the improvement of forage legumes (ed. BD McKersie and DCW Brown), pp. 2542. Oxford University Press, Oxford, UK.Google Scholar
Buddle, BM, Denis, M, Attwood, GT, Altermann, E, Janssen, PH, Ronimus, RS, Pinares-Patiño, CS, Muetzel, S, Neil Wedlock, D 2011. Strategies to reduce methane emissions from farmed ruminants grazing on pasture. The Veterinary Journal 188, 1117.Google Scholar
Cahill, DJ, Schmidt, DH 2004. Use of marker assisted selection in a product development breeding program. New directions for a diverse planet. Proceedings of the 4th International Crop Science Congress, Brisbane, Australia. www.cropscience.org.au/icsc2004.Google Scholar
Carulla, JE, Kreuzer, M, Machmuller, A, Hess, HD 2005. Supplementation of Acacia mearnsii tannins decreases methanogenesis and urinary nitrogen in forage-fed sheep. Australian Journal of Agricultural Research 56, 961970.Google Scholar
Casler, MD, van Santen, E 2010. Breeding objectives in forages. In Handbook of plant breeding. Fodder crops and amenity grasses (ed. B Boller, UK Posselt and F Veronesi), Vol. 5, pp. 115136. Springer, New York.Google Scholar
Cordell, D, Drangert, J-O, White, S 2009. The story of phosphorus: global food security and food for thought. Global Environmental Change 19, 292305.Google Scholar
Department of Agriculture, Food and the Marine (DAFM) 2012. Grass and Clover Recommended List Varieties for Ireland 2012, DAFM, Dublin, Ireland.Google Scholar
Dove, H, Wood, JT, Simpson, RJ, Leury, BJ, Ciavarella, TA, Gatford, KL, Siever-Kelly, C 1999. Spray-topping annual grass pasture with glyphosate to delay loss of feeding value during summer. III. Quantitative basis of the alkane-based procedures for estimating diet selection and herbage intake by grazing sheep. Australian Journal of Agricultural Research 50, 475485.Google Scholar
Duncan, RR, Carrow, RN 1999. Turfgrass molecular genetic improvement for abiotic/edaphic stress resistance. Advances in Agronomy 67, 233305.Google Scholar
Durand, JL, Bariac, T, Ghesquiere, M, Brion, P, Richard, P, Humphreys, MW, Zwierzykowski, Z 2007. Ranking of the depth of water extraction by individual grass plants using natural 18O isotope abundance. Environmental and Experimental Botany 60, 137144.Google Scholar
Ellis, JL, Dijkstra, J, Bannink, A, Parsons, AJ, Rasmussen, S, Edwards, GR, Kebreab, E, France, J 2011. The effect of high-sugar grass on predicted nitrogen excretion and milk yield simulated using a dynamic model. Journal of Dairy Science 94, 31053118.Google Scholar
Food and Agriculture Organization (FAO) 2006. Livestock's long shadow: environmental issues and options. FAO, Rome. ftp://ftp.fao.org/docrep/fao/010/a0701e/A0701E00.pdfGoogle Scholar
FAO 2009. The State of Food and Agriculture: Livestock in the Balance. http://www.fao.org/docrep/012/i0680e/i0680e.pdf. Accessed 1 October, 2011.Google Scholar
Foley, JA, DeFries, R, Asner, GP, Barford, C, Bonan, G, Carpenter, SR, Chapin, FS, Coe, MT, Daily, GC, Gibbs, HK, Helkowski, JH, Holloway, T, Howard, EA, Kucharik, CJ, Monfreda, C, Patz, JA, Prentice, IC, Ramankutty, N, Snyder, PK 2005. Global consequences of land use. Science 309, 570574.Google Scholar
Foresight 2011. The future of food and farming: challenges and choices for global sustainability. Foresight/Government Office for Science, UK. http://www.ukcds.org.uk/_assets/file/publications/future-of-food-and-farming-report.pdf. Accessed 1 October, 2011.Google Scholar
Gatford, KL, Simpson, RJ, Siever-Kelly, C, Leury, BJ, Dove, H, Ciavarella, TA 1999. Spray-topping annual grass pasture with glyphosate to delay loss of feeding value during summer. I. Effects on pasture yield and nutritive value. Australian Journal of Agricultural Research 50, 453464.Google Scholar
Gerdemann, C, Eicken, C, Krebs, B 2002. The crystal structure of catechol oxidases: New insight into the function of type-3 copper proteins. Accounts of Chemical Research 35, 183191.Google Scholar
Hall, MB, Huntington, GB 2008. Nutrient synchrony: sound in theory, elusive in practice. Journal of Animal Science 86, E287E292.Google Scholar
Helgadóttir, Á, Connolly, J, Collins, RP, Fothergill, M, Kreuzer, M, Lüscher, A, Porqueddu, C, Sebastià, MT, Wachendorf, M, Brophy, C, Finn, J, Kirwan, L, Nyfeler, D 2008. The benefits of sward diversity for cultivated grasslands. Grassland Science in Europe 13, 3951.Google Scholar
Henry, RJ 2001. Plant genotyping – the DNA fingerprinting of plants. CABI Publishing, Wallingford, UK.Google Scholar
Hess, HD, Kreuzer, M, Diaz, TE, Lascano, CE, Carulla, JE, Soliva, CR, Machmuller, A 2003. Saponin rich tropical fruits affect fermentation and methanogenesis in faunated and defaunated rumen fluid. Animal Feed Science and Technology 109, 7994.Google Scholar
Hess, M, Sczyrba, A, Egan, R, Kim, TW, Chokhawala, H, Schroth, G, Luo, SJ, Clark, DS, Chen, F, Zhang, T, Mackie, RI, Pennacchio, LA, Tringe, SG, Visel, A, Woyke, T, Wang, Z, Rubin, EM 2011. Metagenomic discovery of biomass-degrading genes and genomes from cow rumen. Science 331, 463467.Google Scholar
Hoekstra, NJ, Schulte, RPO, Struik, PC, Lantinga, EA 2007. Pathways to improving the N efficiency of grazing bovines. European Journal of Agronomy 26, 363374.Google Scholar
Holden, LA, Muller, LD, Varga, GA, Hillard, PJ 1994. Ruminal digestion and duodenal nutrient flows in dairy cows consuming grass as pasture, hay, or silage. Journal of Dairy Science 77, 30343042.Google Scholar
Hörtensteiner, S 2009. Stay-green regulates chlorophyll and chlorophyll-binding protein degradation during senescence. Trends in Plant Science 14, 155162.Google Scholar
Humphreys, MW, Marshall, A, Collins, R, Abberton, M 2011. Exploiting genetic and phenotypic plant diversity in grasslands. In Grassland productivity and ecosystem services (ed. G Lemaire, J Hodgson and A Chabbi), pp. 148157. CAB International, Wallingford, UK.Google Scholar
Humphreys, MW, Yadav, RS, Cairns, AJ, Turner, LB, Humphreys, J, Skot, L 2006. A changing climate for grassland research. New Phytologist 169, 926.Google Scholar
Johnson, RR 1976. Influence of carbohydrate solubility on non-protein nitrogen utilization in the ruminant. Journal of Animal Science 43, 184191.Google Scholar
Jones, BA, Hatfield, RD, Muck, RE 1995a. Screening legume forages for soluble phenols, polyphenol oxidase and extract browning. Journal of the Science of Food and Agriculture 67, 109112.Google Scholar
Jones, BA, Muck, RE, Hatfield, RD 1995b. Red clover extracts inhibit legume proteolysis. Journal of the Science of Food and Agriculture 67, 329333.Google Scholar
Kearsey, MJ, Farquhar, AGL 1998. QTL analysis in plants; where are we now? Heredity 80, 137142.Google Scholar
Kingston-Smith, AH, Theodorou, MK 2000. Post ingestion metabolism of forage in the rumen. New Phytologist 148, 3755.Google Scholar
Kingston-Smith, AH, Thomas, HM 2003. Strategies of plant breeding for improved rumen function. Annals of Applied Biology 142, 1324.Google Scholar
Kingston-Smith, AH, Bollard, AL, Humphreys, MO, Theodorou, MK 2002. An assessment of the ability of the stay-green phenotype in Lolium species to provide an improved protein source for ruminants. Annals of Botany 89, 731740.Google Scholar
Kingston-Smith, AH, Bollard, AL, Armstead, I, Thomas, BJ, Theodorou, MK 2003a. Proteolysis and programmed cell death in clover leaves is induced by grazing. Protoplasma 220, 119129.Google Scholar
Kingston-Smith, AH, Bollard, AL, Thomas, BJ, Brooks, AE, Theodorou, MK 2003b. Nutrient availability during the early stages of colonization of fresh forage by rumen micro-organisms. New Phytologist 158, 119130.Google Scholar
Kingston-Smith, AH, Merry, RJ, Leemans, DK, Thomas, H, Theodorou, MK 2005. Evidence in support of a role for plant-mediated proteolysis in the rumens of grazing animals. British Journal of Nutrition 93, 7379.Google Scholar
Kriss, M 1930. Quantitative relations of the dry matter of the food consumed, the heat production, and gaseous outgo and the insensible loss in body weight of cattle. Journal of Agricultural Research 40, 283295.Google Scholar
Lee, MRF, Olmos Colmenero, JDJ, Winters, AL, Scollan, ND, Minchin, FR 2006. Polyphenol oxidase activity in grass and its effect on plant-mediated lipolysis and proteolysis of Dactylis glomerata (cocksfoot) in a simulated rumen environment. Journal of the Science of Food and Agriculture 86, 15031511.Google Scholar
Lee, MRF, Jones, EL, Moorby, JM, Humphreys, MO, Theodorou, MK, MacRae, JC, Scollan, ND 2001. Production responses from lambs grazed on Lolium perenne selected for an elevated water-soluble carbohydrate concentration. Animal Research 50, 441449.Google Scholar
Lee, MRF, Harris, LJ, Moorby, JM, Humphreys, MO, Theodorou, MK, MacRae, JC, Scollan, ND 2002. Rumen metabolism and nitrogen flow to the small intestine in steers offered Lolium perenne containing different levels of water-soluble carbohydrate. Animal Science 74, 587596.Google Scholar
Leury, BJ, Siever-Kelly, C, Gatford, KL, Simpson, RJ, Dove, H 1999. Spray-topping annual grass pasture with glyphosate to delay loss of feeding value during summer. IV. Diet composition, herbage intake, and performance in grazing sheep. Australian Journal of Agricultural Research 50, 487495.CrossRefGoogle Scholar
Liu, Z, Lane, GPF, Davies, WP 2008. Establishment and production of common sainfoin (Onobrychis viciifolia Scop) in the UK. 1. Effects of sowing date and autumn management on establishment and yield. Grass and Forage Science 63, 234241.Google Scholar
Macheix, JJ, Sapis, JC, Fleurit, A 1991. Phenolic compounds and polyphenol oxidase in relation to browning grapes and wines. CRC Reviews of Food Science 30, 441486.Google Scholar
MacRae, JC, Campbell, DR, Eadie, J 1975. Changes in the biochemical composition of herbage upon freezing and thawing. The Journal of Agricultural Science 84, 125131.Google Scholar
Marley, CL, Fychan, R, Jones, R 2006. Yield, persistency and chemical composition of Lotus species and varieties (birdsfoot trefoil and greater birdsfoot trefoil) when harvested for silage in the UK. Grass and Forage Science 61, 134145.Google Scholar
Marley, CL, Fychan, R, Fraser, MD, Winters, A, Jones, R 2003. Effect of sowing ratio and stage of maturity at harvest on yield, persistency and chemical composition of fresh and ensiled red clover/lucerne bi-crops. Grass and Forage Science 58, 397406.Google Scholar
Marshall, AH, Williams, TA, Abberton, MT, Michaelson-Yeates, TPT, Olyott, P, Powell, HG 2004. Forage quality of white clover (Trifolium repens L.), Caucasian clover (T. ambiguum M. Bieb.) hybrids and their grass companion when grown over three harvest years. Grass and Forage Science 59, 9199.Google Scholar
Marshall, AH, Bryant, D, Latypova, GA, Hauck, B, Olyott, P, Morris, P, Robbins, MP 2008. A high throughput method for the quantification of proanthocyanidins in forage crops and its application in assessing variation in condensed tannin content in breeding programmes for Lotus corniculatus and L. uliginosus. Journal of Agricultural and Food Chemistry 56, 974981.Google Scholar
Martinez, MV, Whitaker, JR 1995. The biochemistry and control of enzymatic browning. Trends in Food Science & Technology 6, 195200.Google Scholar
McCouch, SR, Doerge, RW 1995. QTL mapping in rice. Trends in Genetics 11, 482487.Google Scholar
McSweeney, CS, Palmer, B, McNeill, DM, Krause, DO 2001. Microbial interactions with tannins: nutritional consequences for ruminants. Animal Feed Science and Technology 91, 8393.Google Scholar
Merry, RJ, Lee, MRF, Davies, DR, Dewhurst, RJ, Moorby, JM, Scollan, ND, Theodorou, MK 2006. Effects of high-sugar ryegrass silage and mixtures with red clover silage on ruminant digestion. 1. In vitro and in vivo studies of nitrogen utilization. Journal of Animal Science 84, 30493060.Google Scholar
Miller, LA, Moorby, JM, Davies, DR, Humphreys, MO, Scollan, ND, MacRae, JC, Theodorou, MK 2001. Increased concentration of water-soluble carbohydrate in perennial ryegrass (Lolium perenne L.): milk production from late-lactation dairy cows. Grass and Forage Science 56, 383394.Google Scholar
Min, BR, Attwood, GT, McNabb, WC, Molan, AL, Barry, TN 2005. The effect of condensed tannins from Lotus corniculatus on the proteolytic activities and growth of rumen bacteria. Animal Feed Science and Technology 121, 4558.Google Scholar
Mohan, M, Nair, S, Bhagwat, A, Krishna, TG, Yano, M, Bhatia, CR, Sasaki, T 1997. Genome mapping, molecular markers and marker-assisted selection in crop plants. Molecular Breeding 3, 87103.Google Scholar
Moorby, JM, Evans, RT, Scollan, ND, MacRae, JC, Theodorou, MK 2006. Increased concentration of water-soluble carbohydrate in perennial ryegrass (Lolium perenne L.). Evaluation in dairy cows in early lactation. Grass and Forage Science 61, 5259.Google Scholar
Moorby, JM, Kingston-Smith, AH, Abberton, MT, Humphreys, MO, Theodorou, MK 2009. Improvement of forages to increase the efficiency of nitrogen and energy use by ruminants. In Recent Advances in Animal Nutrition (ed. PC Garnsworthy and J Wiseman), pp. 3965. Nottingham University Press, UK.Google Scholar
Moose, SP, Mumm, RH 2008. Molecular plant breeding as the foundation for 21st century crop improvement. Plant Physiology 147, 969977.Google Scholar
Neményi, M, Mesterházi, , Pecze, Z, Stépán, Z 2003. The role of GIS and GPS in precision farming. Computers and Electronics in Agriculture 40, 4555.Google Scholar
Oenema, O, Velthof, GL, Yamulki, S, Jarvis, SC 1997. Nitrous oxide emissions from grazed grassland. Soil Use and Management 13, 288295.Google Scholar
Parsons, AJ, Edwards, GR, Newton, PCD, Chapman, DF, Caradus, JR, Rasmussen, S, Rowarth, JS 2011a. Past lessons and future prospects: plant breeding for yield and persistence in cool-temperature grasses. Grass and Forage Science 66, 153172.Google Scholar
Parsons, AJ, Rowarth, JS, Rasmussen, S 2011b. High-sugar grasses. CAB Reviews: perspectives in agriculture, veterinary science, nutrition and natural resources 6, 112.Google Scholar
Parveen, I, Threadgill, MD, Moorby, JM, Winters, A 2010. Oxidative phenols in forage crops containing polyphenol oxidase enzymes. Journal of Agricultural and Food Chemistry 58, 13711382.CrossRefGoogle ScholarPubMed
Peyraud, JL, Astigarraga, L 1998. Review of the effect of nitrogen fertilisation on the chemical composition, intake, digestion and nutritive value of fresh herbage: consequences on animal nutrition and N balance. Animal Feed Science and Technology 72, 235259.Google Scholar
Plaxton, WC 2004. Plant response to stress: biochemical adaptations to phosphate deficiency. In Encyclopedia of plant and crop science (ed. R Goodman), pp. 976980. Marcel Dekker, NY, USA.CrossRefGoogle Scholar
Potter, P, Ramankutty, N, Bennett, EM, Donner, SD 2010. Characterizing the spatial patterns of global fertilizer application and manure production. Earth Interactions 14, 122.Google Scholar
Ramírez-Restrepo, CA, Barry, TN 2005. Alternative temperate forages containing secondary compounds for improving sustainable productivity in grazing ruminants. Animal Feed Science and Technology 120, 179201.Google Scholar
Roldán-Ruiz, I, Kölliker, R 2010. Marker-assisted selection in forage crops and turf: a review. In Sustainable use of genetic diversity in forage and turf breeding (ed. C Huygue), pp. 383390. Springer, London, UK.Google Scholar
Ronald, P 2011. Plant genetics, sustainable agriculture and global food security. Genetics 188, 1120.Google Scholar
Schulze, J, Adgo, E, Merbach, W 1999. Carbon costs associated with N2 fixation in Vicia faba L. and Pisum sativum L. over a 14-day period. Plant Biology 1, 625631.Google Scholar
Shortle, JS, Ribaudo, M, Horan, RD, Blandford, D 2012. Reforming agricultural nonpoint pollution policy in an increasingly budget-constrained environment. Environmental Science & Technology 46, 13161325.Google Scholar
Skøt, L, Humphreys, J, Humphreys, MO, Thorogood, D, Gallagher, J, Sanderson, R, Armstead, IP, Thomas, ID 2007. Association of candidate genes with flowering time and water-soluble carbohydrate content in Lolium perenne (L). Genetics 177, 535547.Google Scholar
Spangenberg, G, Kalla, R, Lidgett, A, Sawbridge, T, Ong, EK, John, U 2001. Breeding forage plants in the genome era. Proceedings of the 2nd International Symposium, Molecular Breeding of Forage Crops, Lorne and Hamilton, pp. 139. Victoria, Australia.Google Scholar
Stevens, CE, Hume, ID 1998. Contributions of microbes in vertebrate gastrointestinal tract to production and conservation of nutrients. Physiological Reviews 78, 393427.Google Scholar
Stewart, A, Hayes, R 2011. Ryegrass breeding – balancing trait priorities. Irish Journal of Agricultural and Food research 50, 3146.Google Scholar
Sullivan, ML, Hatfield, RD 2006. Polyphenol oxidase and o-diphenols inhibit postharvest proteolysis in red clover and alfalfa. Crop Science 46, 662670.Google Scholar
Taweel, HZ, Tas, BM, Smit, HJ, Elgersma, A, Dijkstra, J, Tamminga, S 2005. Effects of feeding perennial ryegrass with an elevated concentration of water-soluble carbohydrates on intake, rumen function and performance of dairy cows. Animal Feed Science and Technology 121, 243256.Google Scholar
Tas, BM, Taweel, HZ, Smit, HJ, Elgersma, A, Dijkstra, J, Tamminga, S 2006a. Effects of perennial ryegrass cultivars on milk yield and nitrogen utilization in grazing dairy cows. Journal of Dairy Science 89, 34943500.Google Scholar
Tas, BM, Taweel, HZ, Smit, HJ, Elgersma, A, Dijkstra, J, Tamminga, S 2006b. Utilisation of N in perennial ryegrass cultivars by stall-fed lactating dairy cows. Livestock Science 100, 159168.Google Scholar
Thomas, H, Smart, CM 1993. Crops that stay green. Annals of Applied Biology 123, 193219.Google Scholar
Thomas, H, Evans, C, Thomas, HM, Humphreys, MW, Morgan, G, Hauck, B, Donnison, I 1997. Introgression, tagging and expression of a leaf senescence gene in Festulolium. New Phytologist 137, 2934.CrossRefGoogle Scholar
Tilman, D, Cassman, KG, Matson, PA, Naylor, R, Polasky, S 2002. Agricultural sustainability and intensive production practices. Nature 418, 671677.Google Scholar
Turner, LB, Cairns, AJ, Armstead, IP, Ashton, J, Skot, K, Whittaker, D, Humphreys, MO 2006. Dissecting the regulation of fructan metabolism in perennial ryegrass (Lolium perenne) with quantitative trait locus mapping. New Phytologist 169, 4557.Google Scholar
Turner, LB, Cairns, AJ, Armstead, IP, Thomas, H, Humphreys, MW, Humphreys, MO 2008. Does fructan have a functional role in physiological traits? Investigation by quantitative trait locus mapping. New Phytologist 179, 765775.Google Scholar
Van Nevel, CJ, Demeyer, DI 1996. Control of rumen methanogenesis. Environmental Monitoring and Assessment 42, 7397.Google Scholar
Vicentini, F, Hortensteiner, S, Schellenberg, M, Thomas, H, Matile, P 1995. Chlorophyll breakdown in senescent leaves: identification of the biochemical lesion in a stay-green genotype of Festuca pratensis Huds. New Phytologist 129, 247252.Google Scholar
Wachendorf, C, Lampe, C, Taube, F, Dittert, K 2008. Nitrous oxide emissions and dynamics of soil nitrogen under N-15-labeled cow urine and dung patches on a sandy grassland soil. Journal of Plant Nutrition and Soil Science-Zeitschrift Fur Pflanzenernahrung Und Bodenkunde 171, 171180.CrossRefGoogle Scholar
Wilkins, PW, Humphreys, MO 2003. Progress in breeding perennial forage grasses for temperate agriculture. Journal of Agricultural Science 140, 129150.Google Scholar
Wilkins, PW, Lovatt, JA 2003. Progress in improving the ratio of water-soluble carbohydrate to crude protein in perennial ryegrass. Aspects of Applied Biology 70, 3136.Google Scholar
Wilkins, PW, Lovatt, JA 2007. AberMagic – diploid intermediate heading ‘high sugar grass’. UK National List 2007. Department for Environment, Food and Rural Affairs, Cambridge.Google Scholar
Wilkins, PW, Lovatt, JA 2011. Gain in dry matter yield and herbage quality from breeding perennial ryegrass. Irish Journal of Agricultural and Food Research 50, 2330.Google Scholar
Wilkins, PW, Lovatt, JA, Hayes, RC 2007. Effect of a stay-green locus on the dry matter yield, nitrogen yield and shoot density of perennial ryegrass. Grass and Forage Science 62, 453458.Google Scholar
Winters, A, Minchin, F 2002. The effect of PPO on the protein content of ensiled red clover. In Proceedings of the 13th International Silage Conference SAC, 11–13 September 2002 (ed. LM Gechie and C Thomas), pp. 84–85. Auchincruive, Ayr, Scotland.Google Scholar
Winters, AL, Minchin, FR, Merry, RJ, Morris, P 2003. Comparison of polyphenol oxidase activity in red clover and perennial ryegrass. In Crop quality: its role in sustainable livestock production (ed. MT Abberton, M Andrews, L Skøt and MK Theodorou), pp. 121128. The Association of Applied Biologists, Warwick, Manchester, UK.Google Scholar
Woledge, J, Pearse, PJ 1985. The effect of nitrogenous fertilizer on the photosynthesis of leaves of a ryegrass sward. Grass and Forage Science 40, 305309.CrossRefGoogle Scholar
Vergé, XPC, Worth, DE, Desjardins, RL, McConkey, BG, Dyer, JA 2012. LCA of animal production. In Green technologies in food production and processing (ed. IJ Boye and Y Arcand), pp. 83113. Springer, US.Google Scholar
Xu, Y, Crouch, JH 2008. Marker-assisted selection in plant breeding: from publication to practice. Crop Science 48, 391407.Google Scholar
Zhu, W-Y, Kingston-Smith, AH, Davies, DR, Troncoso, D, Merry, RJ, Pichard, G, Thomas, H, Theodorou, MK 1999. Evidence of a role for plant proteases in the degradation of herbage proteins in the rumen of grazing cattle. Journal of Dairy Science 82, 26512658.CrossRefGoogle ScholarPubMed