Perennial ryegrass breeding in New Zealand: A dairy industry perspective

Lee, Julia M.; Matthew, C.; Thom, E. R.; Chapman, D. F.

doi:10.1071/cp11282

Cited by 99 publications

(99 citation statements)

References 140 publications

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“…Such a long timeframe is required to make a meaningful measure of genetic progress as breeding new ryegrass varieties is a progressive long term process. During this period, the major technological advancements in plant breeding (Humphreys 2005) and innovations in biology and genetics have helped provide improved perennial ryegrass breeding strategies (Lee et al 2012). This does not however explain the fluctuating patterns of yield increases observed in the current study.…”

Section: Discussionmentioning

confidence: 99%

Genetic gain in perennial ryegrass (Lolium perenne) varieties 1973 to 2013

et al. 2016

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Perennial ryegrass (Lolium perenne) forms the basis of grassland production in temperate pastures and is globally one of the most important forage grasses. Consequently, there has been large plant breeding industry investment over the past 40 years in producing new varieties and independent testing systems designed to identify and list those with the most improved performances. This study was conducted at the Plant Testing Station, Crossnacreevy, Northern Ireland and compared the DM yield and sward density of new varieties submitted from 1973 to 2013 and grass digestibility from 1980 to 2013, under conservation and simulated grazing managements. A variety 9 years matrix was compiled for each parameter and comparable means between varieties never in side by side performance trials were produced. Dry matter yields showed an overall significant (p \ 0.001) average annual increase of 0.52 % under conservation and 0.35 % under simulated grazing, with similar gain levels within maturity groups or ploidies. These rates were not constant over time, and periods of no gain occurred in various variety groupings. Sward density of the examined varieties did not change significantly. Herbage digestibility showed no improvement over the timeframe but had the largest differences between concurrent varieties, indicating that improvements were possible in the future. The study indicated that plant breeding gains were primarily DM yield focused with sward density remaining stagnant over the 40 years, while the lack of grass digestibility improvement appeared to only require more time to overcome. Evidence of benefits and risks of variety testing influences on plant breeding objectives was discussed.

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Section: Discussionmentioning

confidence: 99%

Genetic gain in perennial ryegrass (Lolium perenne) varieties 1973 to 2013

et al. 2016

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“…Informed by empirical data on utilized dry matter yield of 10 Mg ha −1 yr −1 (Chapman et al, 2006) and 0.5% genetic gain yr −1 (Lee et al, 2012), a value of 50 kg was calculated for the Increased_Yield annual for the conventional program (10,000 kg ha −1 ´ 0.005). This was calculated as Cost annual / Increased_Yield annual , with a specific end point of 20 yr to define a clear baseline for comparisons among different scenarios.…”

Section: Genomic Prediction Cost and Inbreedingmentioning

confidence: 99%

“…Such selection measures mainly rely on phenotypic records for key traits, occasionally combined with pedigree and progeny information (Humphreys, 2005). Conventional selection schemes achieve an approximate genetic gain of between 0.5 and 0.7% per year for dry matter yield (Wilkins and Humphreys, 2003;Lee et al, 2012).Genomic selection (GS) (Meuwissen et al, 2001) is an effective strategy for speeding up genetic gain in breeding programs. Breeding cycles are typically long (10-14 yr), because phenotypes for many key traits (such as dry matter yield and persistency) can only be reliably measured in plot conditions over the multiple years required to assess the effects of competition among plants (Hayes et al, 2013).…”

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confidence: 99%

Optimizing Resource Allocation in a Genomic Breeding Program for Perennial Ryegrass to Balance Genetic Gain, Cost, and Inbreeding

et al. 2017

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243ReseaRch C urrent breeding programs for the important temperate pasture grass species perennial ryegrass (Lolium perenne L.) are based on recurrent phenotypic selection. Such selection measures mainly rely on phenotypic records for key traits, occasionally combined with pedigree and progeny information (Humphreys, 2005). A breeding cycle may include several selection steps on individual plants and/or plots. Breeding cycles are typically long (10-14 yr), because phenotypes for many key traits (such as dry matter yield and persistency) can only be reliably measured in plot conditions over the multiple years required to assess the effects of competition among plants (Hayes et al., 2013). Conventional selection schemes achieve an approximate genetic gain of between 0.5 and 0.7% per year for dry matter yield (Wilkins and Humphreys, 2003;Lee et al., 2012).Genomic selection (GS) (Meuwissen et al., 2001) is an effective strategy for speeding up genetic gain in breeding programs. The application of GS requires the generation of a DNA marker prediction ABSTRACT Genomic selection (GS) has been recognized as offering numerous potential benefits for ryegrass (Lolium perenne L.) breeding. While the theoretical benefits of GS in ryegrass breeding are clear, the best way to apply GS in practical breeding programs remains to be determined. The present study aimed to investigate genomic breeding options that best balance genetic gain, breeding costs, and the level of inbreeding using stochastic simulation.

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“…Thirdly, the genetic diversity of cultivars available in the NZ market is now much greater [66]. Breeding objectives during the 1990s and 2000s emphasised later flowering [67], using Mediterranean germplasm and polyploidy to delay maturity, reduce the magnitude of the traditional mid-spring peak in growth, and increase growth rates in summer and autumn. Some of these traits, especially tetraploidy, are well-documented as facilitating greater dry matter intake [68] allowing better control of post-grazing sward state.…”

Section: The Extended Ryegrass Phenome and Its Implications For Grazimentioning

confidence: 99%

Using Ecophysiology to Improve Farm Efficiency: Application in Temperate Dairy Grazing Systems

Chapman

2016

Agriculture

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Information on the physiological ecology of grass-dominant pastures has made a substantial contribution to the development of practices that optimise the amount of feed harvested by grazing animals in temperate livestock systems. However, the contribution of ecophysiology is often under-stated, and the need for further research in this field is sometimes questioned. The challenge for ecophysiolgists, therefore, is to demonstrate how ecophysiological knowledge can help solve significant problems looming for grassland farming in temperate regions while also removing constraints to improved productivity from grazed pastures. To do this, ecophysiological research needs to align more closely with related disciplines, particularly genetics/genomics, agronomy, and farming systems, including systems modelling. This review considers how ecophysiological information has contributed to the development of grazing management practices in the New Zealand dairy industry, an industry that is generally regarded as a world leader in the efficiency with which pasture is grown and utilised for animal production. Even so, there are clear opportunities for further gains in pasture utilisation through the refinement of grazing management practices and the harnessing of those practices to improved pasture plant cultivars with phenotypes that facilitate greater grazing efficiency. Meanwhile, sub-optimal persistence of new pastures continues to constrain productivity in some environments. The underlying plant and population processes associated with this have not been clearly defined. Ecophysiological information, placed in the context of trait identification, grounded in well-designed agronomic studies and linked to plant improvements programmes, is required to address this.

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Perennial ryegrass breeding in New Zealand: A dairy industry perspective

Cited by 99 publications

References 140 publications

Genetic gain in perennial ryegrass (Lolium perenne) varieties 1973 to 2013

Genetic gain in perennial ryegrass (Lolium perenne) varieties 1973 to 2013

Optimizing Resource Allocation in a Genomic Breeding Program for Perennial Ryegrass to Balance Genetic Gain, Cost, and Inbreeding

Using Ecophysiology to Improve Farm Efficiency: Application in Temperate Dairy Grazing Systems

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