Valuing forages for genetic selection: what traits should we focus on?
D. F. Chapman A F , G. R. Edwards B , A. V. Stewart C , M. McEvoy D , M. O’Donovan D and G. C. Waghorn E
+ Author Affiliations
- Author Affiliations
A DairyNZ, c/- PO Box 85066, Lincoln University, Lincoln 7647, New Zealand.
B Faculty of Agriculture and Life Sciences, Lincoln University, PO Box 85084, Lincoln 7647, New Zealand.
C PGG Wrightsons Seeds Ltd, Kimihia Research Centre, PO Box 175, Lincoln 7640, New Zealand.
D Teagasc Animal and Grassland Research and Innovation Centre, Moorepark, Fermoy, Co. Cork, Ireland.
E DairyNZ, Private Bag 3221, Hamilton 3240, New Zealand.
F Corresponding author. Email: david.chapman@dairynz.co.nz
Animal Production Science 55(7) 869-882 https://doi.org/10.1071/AN14838
Submitted: 28 September 2014 Accepted: 19 January 2015 Published: 11 June 2015
Abstract
Failure over the past two to three decades to implement industry-led, systematic forage evaluation systems that translate forage performance data to animal production and economics means that the livestock industries are poorly positioned to judge how much economic benefit they are gaining from forage plant improvement and to propose future priorities and targets. The present paper identifies several knowledge gaps that must be filled to enable the value being delivered to pasture-based livestock industries by forage improvement to be determined, demonstrated to farmers and increased in the future. Seasonal yield, total annual yield, nutritive value and feeding value of pasture are all important traits for driving the productivity of pasture-based livestock production systems. From a farm systems perspective, persistence of the yield or quality advantage of new cultivars is also economically important. However, this is the least well defined of the productivity traits considered in the paper. Contrary to anecdotal reports, evidence indicates that the genetic potential of modern ryegrass cultivars to survive in grazed pastures is at least equivalent to that of older cultivars. Plant breeding in Europe and New Zealand has changed the seasonal yield, quality and intake potential of perennial ryegrass. On the basis of dry matter (DM) yield data from small-plot evaluation trials, the New Zealand forage value index indicates that the top-ranked perennial ryegrass cultivars offer between NZ$280 and NZ $650/ha per year potential additional operating profit to dairy businesses (depending on region), compared with a historical genetic base of cultivars that were first entered into yield testing programs between 1991 and 1996. The equivalent figure in Ireland (including nutritive value effects) is about €325/ha per year. These estimates are yet to be confirmed in animal production studies. In intensive dairy systems, current rates of genetic gain in DM yield lag well behind realised rates of gain in animal genetics and associated increases in feed demand per animal. Genetic gains in yield need to double from current rates (estimated at 0.5% per year); but, it is not known whether this is possible in an outcrossing species such as perennial ryegrass, which is normally grown in a mixture with other species, especially white clover. Improvements in DM yield in seasons where extra DM has greatest economic value in grazing systems should dominate breeding objectives, but this must now be augmented by consideration of the environmental impacts of intensive pasture-based livestock production systems and opportunities to mitigate this through germplasm selection. There is less evidence that nutritive or feeding value of ryegrass cultivars significantly limits animal production and profitability and useful improvements have already been made using tetraploids and later heading material.
Additional keywords: forage evaluation, genetic gain, grazing systems, perennial ryegrass, plant improvement, white clover.
References
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, 311–355.| Genetic improvement of forage species to reduce the environmental impact of temperate livestock grazing systems.Crossref | GoogleScholarGoogle Scholar |
Balocchi OA, Lopez IF (2009) Herbage production, nutritive value and grazing preference of diploid and tetraploid perennial ryegrass cultivars (Lolium perenne L.). Chilean Journal of Agricultural Research 69, 331–339.
| Herbage production, nutritive value and grazing preference of diploid and tetraploid perennial ryegrass cultivars (Lolium perenne L.).Crossref | GoogleScholarGoogle Scholar |
Beard KT (1987) Efficiency of index selection for dairy cattle using economic weights for major milk constituents. Australian Journal of Agricultural Research 38, 273–284.
Bellon MR, Reeves J (2001) ‘Quantitative analysis of data from participatory methods in plant breeding.’ (CIMMYT: Mexico, DF)
Berry D, Buckley F (2013) EBI to fuel expansion. In ‘Irish dairying. Harvesting the potential’. Moorepark Dairying Open Day, 2013. (Eds D Berry, S Butler, P Dillon) pp. 29–33. (Teagasc, Animal & Grassland Research and Innovation Centre, Moorepark: Fermoy, Ireland)
Beukes PC, Gregorini P, Romera AJ, Woodward SL, Khaembah EN, Chapman DF, Nobilly F, Bryant RH, Edwards GR (2014) The potential of diverse pastures to reduce nitrate leaching on New Zealand dairy farms. Animal Production Science 54, 1971–1979.
| The potential of diverse pastures to reduce nitrate leaching on New Zealand dairy farms.Crossref | GoogleScholarGoogle Scholar |
Broadley MR, Bowen HC, Cotterill HL, Hammond JP, Meacham MC, Mead A, White PJ (2004) Phylogenetic variation in the shoot mineral composition of angiosperms. Journal of Experimental Botany 55, 321–336.
| Phylogenetic variation in the shoot mineral composition of angiosperms.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXms1egtA%3D%3D&md5=59bc3d5914657655a0b5a25e4dc6cd24CAS | 14739259PubMed |
Brookes IM, McRae AF, Gray DI, Cameron N (1993) Economics of milk production from perennial ryegrass cultivars with different seasonal growth patterns. In ‘Proceedings of the 17th international grassland congress’. pp. 1294–1295. (New Zealand Grassland Association: Palmerston North, New Zealand)
Bryant J, Amer P (2014) Value of genetic improvement. DairyNZ technical series issue 22, pp. 6–9. Available at www.dairynz.co.nz [Verified 1 September 2014]
Camlin MS, Stewart RH (1978) The assessment of persistence and its application to the evaluation of mid season and late perennial ryegrass cultivars. Journal of the British Grassland Society 33, 275–282.
| The assessment of persistence and its application to the evaluation of mid season and late perennial ryegrass cultivars.Crossref | GoogleScholarGoogle Scholar |
Casler MD, van Santen E (2010) Breeding objectives in forages. In ‘Fodder crops and amenity grasses’. (Eds B Oller, UK Posselt, F Veronesi) pp. 115–136. (Springer: New York)
Casler MD, Jung HG, Coblentz WK (2008) Clonal selection for lignin and etherified ferulates in three perennial grasses. Crop Science 48, 424–433.
| Clonal selection for lignin and etherified ferulates in three perennial grasses.Crossref | GoogleScholarGoogle Scholar |
Casler MD, Undersander DJ, Papadopolous YA, Bittman S, Hunt D, Mathison RD, Min DH, Robins JG, Cherney JH, Acharya SN, Belesky DP, Bowler SR, Coulman BE, Drapeau R, Ehlke NJ, Hall MH, Leep RH, Michaud R, Roswell J, Shewmaker GE, Teutsch CD, Coblentz WK (2014) Sparse-flowering orchardgrass represents an improvement in forage quality during reproductive growth. Crop Science 54, 421–429.
| Sparse-flowering orchardgrass represents an improvement in forage quality during reproductive growth.Crossref | GoogleScholarGoogle Scholar |
Chapman DF, Parsons AJ, Schwinning S (1996). Management of clover in grazed pastures: expectations, limitations and opportunities. In ‘White clover: New Zealand’s competitive edge. Agronomy Society of New Zealand special publication no. 11/Grasslands Research and Practice Series no. 6’. (Ed. DR Woodfield) pp. 55–64. (New Zealand Grassland Association and New Zealand Society of Agronomy: Palmerston North, New Zealand)
Chapman DF, Kenny SN, Lane NL (2011a) Pasture and forage crop systems for non-irrigated dairy farms in southern Australia. 3. Estimated economic value of additional home-grown feed. Agricultural Systems 104, 589–599.
| Pasture and forage crop systems for non-irrigated dairy farms in southern Australia. 3. Estimated economic value of additional home-grown feed.Crossref | GoogleScholarGoogle Scholar |
Chapman DF, Edwards GR, Nie ZN (2011b) Plant responses to climate and relationships with pasture persistence. In ‘Pasture persistence symposium. Grassland research and practice series no. 15’. (Ed. CF Mercer) pp. 99–107. (New Zealand Grassland Association: Dunedin, New Zealand)
Chapman DF, Bryant JR, McMillan WH, Khaembah EN (2012) Economic values for evaluating pasture plant traits. Proceedings of the New Zealand Grassland Association 73, 209–215.
Chapman DF, Lee JM, Waghorn GC (2014a) The interaction between plant physiology and pasture feeding value. Crop & Pasture Science 65, 721–734.
| The interaction between plant physiology and pasture feeding value.Crossref | GoogleScholarGoogle Scholar |
Chapman DF, Edwards GR, Pinxterhuis JB (2014b) Plants for dairy grazing systems operating under nitrate leaching limits. Proceedings of the New Zealand Society of Animal Production 74, 86–93.
Chaves B, De Vliegher A, Van Waes J, Carlier L, Marynissen B (2009) Change in agronomic performance of Lolium perenne and Lolium multiflorum varieties in the past 40 years based on data from Belgian VCU trials. Plant Breeding 128, 680–690.
| Change in agronomic performance of Lolium perenne and Lolium multiflorum varieties in the past 40 years based on data from Belgian VCU trials.Crossref | GoogleScholarGoogle Scholar |
Cheeke PR (1998) ‘Natural toxicants in feeds, forages and poisonous plants.’ (Interstate Publishers: Danville, IL)
Clark DA (2011) Changes in pastoral farming practices and pasture persistence: a review. In ‘Pasture persistence symposium. Grassland research and practice series no. 15’. (Ed. CF Mercer) pp. 7–13. (New Zealand Grassland Association: Dunedin, New Zealand)
Clark DA, Penno JW, Neil PG (1997) Nutritional merits and problems of pasture. In ‘Milk composition, production and biotechnology’. (Eds RAS Welch, DJW Burns, SR Davis, AI Popay, CG Prosser) pp. 397–418. (CAB International: Wallingford, UK)
Conaghan P, Casler MD (2011) A theoretical and practical analysis of the optimum breeding system for perennial ryegrass. Irish Journal of Agricultural and Food Research 50, 47–63.
Conaghan P, Casler MD, McGilloway DA, O’Kiely P, Dowely LJ (2008) Genotype × environment interactions for herbage yield of perennial ryegrass sward plots in Ireland. Grass and Forage Science 63, 107–120.
| Genotype × environment interactions for herbage yield of perennial ryegrass sward plots in Ireland.Crossref | GoogleScholarGoogle Scholar |
Corkill L (1958) Presidential address. Proceedings of the New Zealand Grassland Association 20, 1–10.
Cosgrove GP, Pacheco D, Burke JL, Death AF, Hickey MJ, Lane G (2007) Effects of water soluble carbohydrate in forage on aspects of nitrogen partitioning in cows. In ‘Meeting the challenges for pasture-based dairying. Proceedings of the 3rd Australasian dairy science symposium’. (Eds DF Chapman, DA Clark, KL Macmillan, DP Nation) pp. 350–358. (National Dairy Alliance: Melbourne)
Crush JR, Waller JE, Care DA (2005) Root distribution and nitrate interception in eleven temperate forage grasses. Grass and Forage Science 60, 385–392.
| Root distribution and nitrate interception in eleven temperate forage grasses.Crossref | GoogleScholarGoogle Scholar |
Crush JR, Easton HS, Waller JE (2006a) Genetic variation in perennial ryegrass for root profile characteristics. In ‘Breeding for success: diversity in action. Proceedings of the 13th Australasian plant breeding conference’, Christchurch, New Zealand, 18–21 April 2006. (Ed. CF Mercer) pp. 63–65. (New Zealand Grassland Association: Dunedin, New Zealand)
Crush JR, Woodward SL, Eerens JPJ, Macdonald KA (2006b) Growth and milksolids production in pastures of older and more recent ryegrass and white clover cultivars under dairy grazing. New Zealand Journal of Agricultural Research 49, 119–135.
| Growth and milksolids production in pastures of older and more recent ryegrass and white clover cultivars under dairy grazing.Crossref | GoogleScholarGoogle Scholar |
Di H, Cameron KC (2002) Nitrate leaching in temperate agroecosystems: sources, factors and mitigating strategies. Nutrient Cycling in Agroecosystems 64, 237–256.
| Nitrate leaching in temperate agroecosystems: sources, factors and mitigating strategies.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38Xptl2quro%3D&md5=9523d18190d97ca5e52de035e3ea6b47CAS |
Dillon P, Roche JR, Shalloo L, Horan B (2005) Optimising financial return from grazing in temperate pastures. In ‘Utilisation of grazed grass in temperate animal systems’. (Ed. JJ Murphy) pp. 131–147. (Wageningen Academic Publishers: Wageningen, The Netherlands)
Doyle CJ, Elliott JG (1983) Putting an economic value on increases in grass production. Grass and Forage Science 38, 169–177.
| Putting an economic value on increases in grass production.Crossref | GoogleScholarGoogle Scholar |
Doyle PT, Kelly KB (1998) The Victorian dairy industry: improving performance. In ‘Agronomy: growing a greener future’. (Eds DL Michalk, JE Pratley) pp. 119–127. (Australian Society of Agronomy Inc.: Wagga Wagga, NSW)
Easton HS, Baird DB, Cameron NE, Kerr GA, Norriss M, Stewart AV (2001) Perennial ryegrass cultivars: herbage yield in multi-site plot trials. Proceedings of the New Zealand Grassland Association 63, 183–188.
Easton HS, Stewart AV, Kerr GA (2011) Ryegrass in pastures: breeding for reslience. In ‘Pasture persistence symposium. Grassland research and practice series no. 15’. (Ed. CF Mercer) pp. 139–147. (New Zealand Grassland Association: Dunedin, New Zealand)
Edwards GR, Chapman DF (2011) Plant responses to defoliation and relationships with pasture persistence. In ‘Pasture persistence symposium. Grassland research and practice series no. 15’. (Ed. CF Mercer) pp. 39–46. (New Zealand Grassland Association: Dunedin, New Zealand)
Edwards GR, Parsons AJ, Rasmussen S (2007) High sugar grasses for dairy systems. Proceedings of the New Zealand Grassland Association 69, 161–172.
Faville MJ, Richardson K, Gagic M, Mace W, Sun XZ, Harrison S, Knapp K, Jahufer MZZ, Palanisamy R, Pirlo S, Johnson R, Rasmussen S, Bryan G (2010) Genetic improvement of fibre traits in perennial ryegrass. Proceedings of the New Zealand Grassland Association 72, 71–78.
Gastal F, Durand J-L (2000) Effects of nitrogen and water supply on N and C fluxes and partitioning in defoliated swards. In ‘Grassland ecophysiology and grazing behaviour’. (Eds G Lemaire, J Hodgson, A de Moraes, C Nabinger, PC de F Carvahlo) pp. 15–29. (CAB International: Wallingford, UK)
Glassey CB (2011) Summer pasture yield variation in a central Waikato location from 1979–2010: implications for pasture persistence. In ‘Pasture persistence symposium. Grassland research and practice series no. 15’. (Ed. CF Mercer) pp. 15–20. (New Zealand Grassland Association: Dunedin, New Zealand)
Gowen N, O’Donovan M, Casey I, Rath M, Delaby L, Stakelum G (2003) The effect of grass cultivars differing in heading date and ploidy on the performance and dry matter intake of spring calving dairy cows at pasture. Animal Research 52, 321–336.
| The effect of grass cultivars differing in heading date and ploidy on the performance and dry matter intake of spring calving dairy cows at pasture.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3sXot1Cms7k%3D&md5=201f57ba52f85332d0b0f3ae71bfb5c3CAS |
Hageman I, Lantinga WEA, Schlerpers H, Neuteboom JH (1993) Herbage intake, digestibility characteristics and milk production of a diploid and two tetraploid cultivars of perennial ryegrass. In ‘Proceedings of the 17th international grassland congress’. pp. 459–460. (New Zealand Grassland Association: Palmerston North, New Zealand)
Hodgson J (1990) Plants for grazing systems. Proceedings of the New Zealand Society of Animal Production 50, 29–34.
Hume DE, Sewell JC (2014) Agronomic advantages conferred by endophyte infection of perennial ryegrass (Lolium perenne L.) and tall fescue (Festuca arundinaceae Schreb.) in Australia. Crop & Pasture Science 65, 747–757.
| Agronomic advantages conferred by endophyte infection of perennial ryegrass (Lolium perenne L.) and tall fescue (Festuca arundinaceae Schreb.) in Australia.Crossref | GoogleScholarGoogle Scholar |
Humphreys MO (1989) Water-soluble carbohydrates in perennial ryegrass breeding. I. Genetic differences among cultivars and hybrid progeny sown as spaced plants. Grass and Forage Science 44, 231–236.
| Water-soluble carbohydrates in perennial ryegrass breeding. I. Genetic differences among cultivars and hybrid progeny sown as spaced plants.Crossref | GoogleScholarGoogle Scholar |
Jafari A, Connolly V, Walsh EJ (2003) Genetic analysis of yield and quality in full-sib families of perennial ryegrass (Lolium perenne L.) under two cutting managements. Irish Journal of Agricultural and Food Research 42, 275–292.
Kelly S, Smith E, Brazendale R (2011) Pasture renewal in the Waikato and Bay of Plenty regions: an overview of farmer practice, experience and attitudes. In ‘Pasture persistence symposium. Grassland research and practice series no. 15’. (Ed. CF Mercer) pp. 21–24. (New Zealand Grassland Association: Dunedin, New Zealand)
Kingston-Smith AH, Marshall AH, Moorby JM (2013) Breeding for genetic improvement of forage plants in relation to increasing animal production with reduced environmental footprint. Animal 7, 79–88.
| Breeding for genetic improvement of forage plants in relation to increasing animal production with reduced environmental footprint.Crossref | GoogleScholarGoogle Scholar | 22717231PubMed |
Lancashire JA, Ulyatt MJ (1975) Live-weight gains of sheep grazing ryegrass pastures with different cellulose contents. New Zealand Journal of Agricultural Research 18, 97–100.
| Live-weight gains of sheep grazing ryegrass pastures with different cellulose contents.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaE2MXkslOgu7s%3D&md5=573204fa53ef5b536fc451b268de1191CAS |
Lee MRF, Merry RJ, Davies DR, Moorby JM, Humphreys MO, Theodorou MK, MacRae JC, Scollan ND (2003) Effect of increasing availability of water-soluble carbohydrates on in vitro rumen fermentation. Animal Feed Science and Technology 104, 59–70.
| Effect of increasing availability of water-soluble carbohydrates on in vitro rumen fermentation.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3sXht1Ghtbs%3D&md5=750b8c3944632c4071254695742fb4efCAS |
Lee JM, Matthew C, Thom ER, Chapman DF (2012) Perennial ryegrass breeding in New Zealand: a dairy industry perspective. Crop & Pasture Science 63, 107–127.
| Perennial ryegrass breeding in New Zealand: a dairy industry perspective.Crossref | GoogleScholarGoogle Scholar |
Lilburne L, Webb T, Ford R, Bidwell V (2010) Estimating nitrate-nitrogen leaching losses under rural land uses in Canterbury. Report no. R10/127. Environment Canterbury Regional Council, Christchurch, New Zealand.
Litherland AJ, Lambert MG (2007) Factors affecting the quality of pastures and supplements produced on farms. In ‘Pasture and supplements for grazing animals’. Occasional publication no 14. (Eds, PV Rattray, IM Brookes, AM Nicol) pp. 81–96. (New Zealand Society of Animal Production: Hamilton, New Zealand)
Macdonald KA, Verkerk GA, Thorrold BS, Pryce JE, Penno JW, McNaughton LR, Burton LJ, Lancaster JAS, Williamson JH (2008) A comparison of three strains of Holstein-Friesian grazed on pasture and managed under different feed allowances. Journal of Dairy Science 91, 1693–1707.
| A comparison of three strains of Holstein-Friesian grazed on pasture and managed under different feed allowances.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXktVeltLw%3D&md5=80b2a63f70bd09c3e8fafa8f199f7d18CAS | 18349263PubMed |
Malcolm B, Smith KF, Jacobs JL (2014a) Perennial pasture persistence: the economic perspective. Crop & Pasture Science 65, 713–720.
| Perennial pasture persistence: the economic perspective.Crossref | GoogleScholarGoogle Scholar |
Malcolm BJ, Cameron KC, Di HJ, Edwards GR, Moir JL (2014b) The effect of four different pasture species compositions on nitrate leaching losses under high N loading. Soil Use and Management 30, 58–68.
| The effect of four different pasture species compositions on nitrate leaching losses under high N loading.Crossref | GoogleScholarGoogle Scholar |
Malinowski DP, Belesky DP (2000) Adaptations of endophyte-infected cool-season grasses to environmental stresses: mechanisms of drought and mineral stress tolerance. Crop Science 40, 923–940.
| Adaptations of endophyte-infected cool-season grasses to environmental stresses: mechanisms of drought and mineral stress tolerance.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3cXns1Gqsb8%3D&md5=361ed284707daed87753e3572ae41d28CAS |
Matthew C, Assuero SG, Black CK, Sackville Hamilton NR (2000) Tiller dynamics of grazed swards. In ‘Grassland ecophysiology and grazing behaviour’. (Eds G Lemaire, J Hodgson, A de Moraes, C Nabinger, PC de F Carvahlo) pp. 127–150. (CAB International: Wallingford, UK)
McEvoy M, O’Donovan M, Shalloo L (2011) Development and application of an economic ranking index for perennial ryegrass cultivars. Journal of Dairy Science 94, 1627–1639.
| Development and application of an economic ranking index for perennial ryegrass cultivars.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXmvFeitLg%3D&md5=8f93a6ba8e1f4a4abf13affe761710b6CAS | 21338830PubMed |
Mercer CF (Ed.) (2011) ‘Pasture persistence symposium. Grassland research and practice series no. 15.’ (New Zealand Grassland Association: Dunedin, New Zealand)
Moir JL, Edwards GR, Berry LN (2013) Nitrogen uptake and leaching loss of thirteen temperate grass species under high N loading. Grass and Forage Science 68, 313–325.
| Nitrogen uptake and leaching loss of thirteen temperate grass species under high N loading.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3sXmtlahs7s%3D&md5=891bf66843c9e20a0a42b5fdf4f07ac2CAS |
Moorby JM (2014) Relationship between the composition of fresh grass-based diets and the excretion of dietary nitrogen from dairy cows. In ‘EGF at 50: the future of European grasslands’. (Eds A Hopkins, RP Collins, MD Fraser, VR King, DC Lloyd, JM Moorby, PRH Robson) pp. 686–689. (European Grassland Federation: Aberystwyth, UK)
Morrison J (2011) ‘2011 forage review. The future of forage improvement to support New Zealand’s dairy industry and the wider pastoral farming sector.’ (DairyNZ: Hamilton, New Zealand)
Nicol AM, Edwards GR (2011) Why is clover better than ryegrass? Proceedings of the New Zealand Grassland Association 71, 71–78.
O’Donovan M, Delaby L (2005) A comparison of perennial ryegrass cultivars differing in heading date and grass ploidy with spring calving dairy cows at two stocking rates. Animal Research 54, 337–350.
| A comparison of perennial ryegrass cultivars differing in heading date and grass ploidy with spring calving dairy cows at two stocking rates.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28XhsVI%3D&md5=fe7b53964f83db85772ac766de956d27CAS |
O’Donovan M, Lewis E, O’Kiely P (2011) Requirements of future grass-based ruminant production systems in Ireland. Irish Journal of Agricultural and Food Research 50, 1–21.
Orr RJ, Cook RA, Champion RA, Penning PD, Rook AJ (2003) Intake characteristics of perennial ryegrass varieties when grazed by sheep under continuous stocking management. Euphytica 134, 247–260.
| Intake characteristics of perennial ryegrass varieties when grazed by sheep under continuous stocking management.Crossref | GoogleScholarGoogle Scholar |
Pacheco D, Waghorn GC (2008) Dietary nitrogen: definitions, digestion, excretion and consequences of excess for grazing ruminants. Proceedings of the New Zealand Grassland Association 70, 107–116.
Parsons AJ, Edwards GR, Newton PCD, Chapman DF, Caradus JR, Rasmussen S, Rowarth JS (2011) Past lessons and future prospects: plant breeding for yield and persistence in cool-temperate pastures. Grass and Forage Science 66, 153–172.
| Past lessons and future prospects: plant breeding for yield and persistence in cool-temperate pastures.Crossref | GoogleScholarGoogle Scholar |
Parsons AJ, Rasmussen S, Liu Q, Xue H, Ball C, Shaw C (2013) Plant growth: resource or strategy limited: insights from responses to gibberellin. Grass and Forage Science 68, 577–588.
| Plant growth: resource or strategy limited: insights from responses to gibberellin.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3sXhs12lsrbI&md5=d81a7e1a5fd7ce03c302afb8b16d58f3CAS |
Pembleton KG, Tozer KN, Edwards GR, Jacobs JL, Turner LR (2015) Simple versus diverse pastures: opportunities and challenges in dairy systems. Animal Production Science 55, 893–901.
| Simple versus diverse pastures: opportunities and challenges in dairy systems.Crossref | GoogleScholarGoogle Scholar |
Pollock CJ, Jones T (1979) Seasonal patterns of fructan metabolism in forage grasses. New Phytologist 83, 9–15.
| Seasonal patterns of fructan metabolism in forage grasses.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL3MXlsVOhtrw%3D&md5=d00485d2443fd26f41f0be46de0b0138CAS |
Popay AJ, Crush JR (2010) Influence of different forage grasses on nitrate capture and leaching loss from a pumice soil. Grass and Forage Science 65, 28–37.
| Influence of different forage grasses on nitrate capture and leaching loss from a pumice soil.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXktlSnurw%3D&md5=87d6f87b5ef7e664848bb8cc97539e45CAS |
Popay AJ, Hume DE (2011) Endophytes improve persistence by controlling insects. In ‘Pasture persistence symposium. Grassland research and practice series no. 15’. (Ed. CF Mercer) pp. 149–156. (New Zealand Grassland Association: Dunedin, New Zealand)
Popay AJ, Hume DE, Davis KL, Tapper BA (2003) Interactions between endophyte (Neotyphodium spp.) and ploidy in hybrid and perennial ryegrass cultivars and their effects on Argentine stem weevil (Listronotus bonariensis). New Zealand Journal of Agricultural Research 46, 311–319.
| Interactions between endophyte (Neotyphodium spp.) and ploidy in hybrid and perennial ryegrass cultivars and their effects on Argentine stem weevil (Listronotus bonariensis).Crossref | GoogleScholarGoogle Scholar |
Robson MJ (1982) The growth and carbon economy of selection lines of Lolium perenne cv. 23 with differing rates of dark respiration. 1. Grown as simulated swards during a regrowth period. Annals of Botany 49, 321–329.
Rossi L, McDonagh J, McEvoy M, O’Donovan M, Lee JM, Chapman DF, Edwards GR (2014) Implications of species and management interactions for ranking perennial ryegrass (Lolium perenne L.) cultivars: a progress report from two hemispheres. In ‘Proceedings of the 6th Australasian dairy science symposium’. (Ed. JR Roche) pp. 259–262.
Sampoux J-P, Baudouin P, Bayle B, Beguier V, Bourdon P, Chosson J-F, Deneufbourg F, Galbrun C, Ghesquiere M, Noel D, Pietraszek W, Tharel B, Viguie A (2011) Breeding perennial grasses for forage use: An experimental assessment of trait changes in diploid perennial ryegrass (Lolium perenne L.) cultivars released in the last four decades. Field Crops Research 123, 117–129.
| Breeding perennial grasses for forage use: An experimental assessment of trait changes in diploid perennial ryegrass (Lolium perenne L.) cultivars released in the last four decades.Crossref | GoogleScholarGoogle Scholar |
Scott I (2013) Innovation at Scott Farms, Tirau. Proceedings of the New Zealand Grassland Association 75, 67–69.
Solomon JKQ, Macoon B, Lang DJ, Vann RC, Ward S (2014) Cattle grazing preference among tetraploid and diploid annual ryegrass cultivars. Crop Science 54, 430–438.
| Cattle grazing preference among tetraploid and diploid annual ryegrass cultivars.Crossref | GoogleScholarGoogle Scholar |
Stewart AV (2006) Genetic origins of perennial ryegrass (Lolium perenne) for New Zealand pastures. In ‘Breeding for success: diversity in action. Proceedings of the 13th Australasian plant breeding conference’, Christchurch, New Zealand, 18–21 April 2006. (Ed. CF Mercer) pp. 11–20. (New Zealand Grassland Association: Dunedin, New Zealand)
Stewart A, Hayes R (2011) Ryegrass breeding: balancing trait priorities. Irish Journal of Agricultural and Food Research 50, 31–46.
Thom ER, Waugh CD, McCabe RJ (1998) Growth and persistence of perennial and hybrid ryegrasses when grazed by dairy cows in the central Waikato region of New Zealand. New Zealand Journal of Agricultural Research 41, 477–486.
| Growth and persistence of perennial and hybrid ryegrasses when grazed by dairy cows in the central Waikato region of New Zealand.Crossref | GoogleScholarGoogle Scholar |
Thom ER, Popay AJ, Hume DE, Fletcher LR (2012) Evaluating the performance of endophytes in farm systems to improve farmer outcomes: a review. Crop & Pasture Science 63, 927–943.
| Evaluating the performance of endophytes in farm systems to improve farmer outcomes: a review.Crossref | GoogleScholarGoogle Scholar |
Thomson AJ, Rogers HH (1971) The interrelationship of some components of forage quality. The Journal of Agricultural Science 76, 283–293.
| The interrelationship of some components of forage quality.Crossref | GoogleScholarGoogle Scholar |
Tozer KN, Cameron CA, Thom ER (2011) Pasture persistence: farmer observations and field measurements. In ‘Pasture persistence symposium. Grassland research and practice series No. 15’. (Ed. CF Mercer) pp. 25–30. (New Zealand Grassland Association: Dunedin, New Zealand)
Valentine J, Charles AH (1979) The association of dry matter yield with nitrogen and soluble carbohydrate concentration in perennial ryegrass (Lolium perenne L.). The Journal of Agricultural Science 93, 657–667.
| The association of dry matter yield with nitrogen and soluble carbohydrate concentration in perennial ryegrass (Lolium perenne L.).Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL3cXlslCjsA%3D%3D&md5=6b215cca1de5be3e637517e07d643c7eCAS |
Van Bysterveldt A, Christie R (2007) Dairy farmer adoption of science demonstrated by a commercially-focussed dairy farm. In ‘Proceedings of the 3rd Australasian dairy science symposium.’ (Eds DF Chapman, DA Clark, KL Macmillan, DP Nation) pp. 535–540. (National Dairy Alliance: Melbourne)
Van Loo EN, Schapendonk AHCM, de Vos ALF (1992) Effect of nitrogen supply on tillering dynamics and regrowth of perennial ryegrass populations. Netherlands Journal of Agricultural Science 40, 381–400.
Vogeler I, Beukes P, Burggraaf V (2013) Evaluation of mitigation strategies for nitrate leaching in pasture-based dairy systems. Agricultural Systems 115, 21–28.
| Evaluation of mitigation strategies for nitrate leaching in pasture-based dairy systems.Crossref | GoogleScholarGoogle Scholar |
Waghorn GC (2002) Can forages match concentrate diets for dairy production? Proceedings of the New Zealand Society of Animal Production 62, 261–266.
Waghorn GC (2007) What is metabolisable energy? Proceedings of the New Zealand Grassland Association 69, 153–169.
Waghorn GC, Adams NR, Woodfield DR (2002) Deleterious substances in grazed pastures. In ‘Sheep nutrition’. (Eds M Freer, H Dove) pp. 333–356. (CABI Publishing: Wallingford, UK)
Waghorn GC, Burke JL, Kolver ES (2007) Principles of feeding value. In ‘Pasture and supplements for grazing animals’. (Eds PV Rattray, IM Brookes, AM Nicol) pp. 35–59. (New Zealand Society of Animal Production: Hamilton, New Zealand)
Whitehead DC (2000) ‘Nutrient elements in grassland: Soil–plant–animal relationships.’ (CAB International: Wallingford, UK)
Wilkins PW (1991) Breeding perennial ryegrass for agriculture. Euphytica 52, 201–214.
| Breeding perennial ryegrass for agriculture.Crossref | GoogleScholarGoogle Scholar |
Wilkins PW, Macduff JH, Raistrick N, Collinson M (1997) Varietal differences in perennial ryegrass for nitrogen use efficiency in leaf growth following defoliation: performance in flowing solution culture and its relationship to simulated grazing in the field. Euphytica 98, 109–119.
| Varietal differences in perennial ryegrass for nitrogen use efficiency in leaf growth following defoliation: performance in flowing solution culture and its relationship to simulated grazing in the field.Crossref | GoogleScholarGoogle Scholar |
Wilkins PW, Allen DK, Mytton LR (2000) Differences in the nitrogen use efficiency of perennial ryegrass varieties under simulated rotational grazing and their effects on nitrogen recovery and herbage nitrogen content. Grass and Forage Science 55, 69–76.
| Differences in the nitrogen use efficiency of perennial ryegrass varieties under simulated rotational grazing and their effects on nitrogen recovery and herbage nitrogen content.Crossref | GoogleScholarGoogle Scholar |
Williams WM, Easton HS, Jones CS (2007) Future options and targets for pasture plant breeding in New Zealand. New Zealand Journal of Agricultural Research 50, 223–248.
| Future options and targets for pasture plant breeding in New Zealand.Crossref | GoogleScholarGoogle Scholar |
Wilson D (1975) Variation in leaf respiration in relation to growth and photosynthesis in Lolium. Annals of Applied Biology 80, 323–338.
| Variation in leaf respiration in relation to growth and photosynthesis in Lolium.Crossref | GoogleScholarGoogle Scholar |
Wims CM, McEvoy M, Delaby L, Boland TM, O’Donovan M (2013) Effect of perennial ryegrass (Lolium perenne L.) cultivars on the milk yield of grazing dairy cows. Animal 7, 410–421.
| Effect of perennial ryegrass (Lolium perenne L.) cultivars on the milk yield of grazing dairy cows.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BC3s%2FitlSqtA%3D%3D&md5=1aa690098b7579bacccd98d39898b33aCAS | 23034142PubMed |
Wims CM, Jacobs JL, Chapman DF (2014) Determining genetic gain in pasture species: integrating multiple traits and economic values. In ‘Proceedings of the 6th Australasian dairy science symposium’. (Ed. JR Roche) pp. 232–234.
Woodfield DR, Easton HS (2004) Advances in pasture plant breeding for animal productivity and health. New Zealand Veterinary Journal 52, 300–310.
| Advances in pasture plant breeding for animal productivity and health.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD2M7js1aguw%3D%3D&md5=29835a658159fb355d21a3eacadeda61CAS | 15768130PubMed |
Yan W, Hunt LA, Johnson P, Stewart G, Lu X (2002) On-farm strip trials vs. replicated performance trials for cultivar evaluation. Crop Science 42, 385–392.
