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Grasses For The Future

01 April 2011

Dr Michael Casler, United States Department of Agriculture’s Agriculture Research Service, summarises the main points from the international conference ‘Perennial ryegrasses: current and future genetic potential’, which took place last October, at Teagasc, Ireland.

The ‘Grasses for the Future’ conference drew an audience of nearly 300 people over two days, representing the elite of Irish forage and livestock producers, many members of the grass seed industry, numerous grass breeders representing both public and private programmes, and grassland and livestock researchers from several locations in Ireland. Nine speakers presented papers on a range of topics related to future needs for grass production in Ireland, generating considerable discussion following each paper and during the second day of the conference. This report contains a brief summary of the most important points of each paper, followed by conclusions from the breakout discussion sessions of the second day.

Summaries

DR MICHAEL O’DONOVAN, Animal & Grassland Research and Innovation Centre, Teagasc, Moorepark, demonstrated the huge value of grass-based grazing systems to Irish farmers, particularly in the face of lower commodity prices, proposed removal of subsidies and tariffs, and rising input costs. Approximately 130,000 Irish farmers are involved in ruminant production, with a farm-gate value of €4.7 billion in 2009. Research has demonstrated that grass utilisation by grazing represents the most profitable and sustainable system of livestock production in Ireland. “To maintain a competitive edge, improved winter/spring growth, increased nutritional value, more favourable sward structure for grazing, and persistence under farm conditions should become traits of greater emphasis in breeding programmes,” explained Dr O’Donovan. “There is also a need for improved synchronisation and communication between grassland farmers and researchers, evaluators and breeders.”

DR PETER WILKINS, IBERS, Aberystwyth, showed that annual yield and persistence of perennial ryegrass in Europe has increased by about 20-25 per cent during the past 40 years because of selection and breeding. “Considerably greater gains have been made in more recent years with the employment of intensive recurrent selection schemes adapted from maize breeding, largely by selection within fairly narrow populations. It is clear that there is considerable potential to continue making genetic improvements to perennial ryegrass, not only for annual yield, but for other traits as well,” said Dr Wilkins.

DR ALAN STEWART, PGG Wrightson Seeds, New Zealand, provided an international perspective on perennial ryegrass breeding, illustrating that only 2,000 hectares of seed production are required to meet Ireland’s annual seed needs. “Future investments in breeding are highly dependent on the economic success of seed companies and are not likely to increase. Ryegrass breeding is complicated by the need for multiple-trait selection, taking into account numerous traits that fall into the broad categories of yield, quality and persistence, each of which may interfere with gains to be made for other traits,” explained Dr Stewart.

DR PATRICK CONAGHAN, Crops, Environment and Land Use Research Centre, Teagasc, Oak Park, Carlow, reported on the potential of utilising biotechnology in a practical breeding programme, demonstrating how DNA markers may provide very large increases in the rate of progress made by grass breeders. “Cost of technology development is the greatest impediment to utilisation of marker-selection technologies, but dairy cattle models can be utilised to develop shared marker resources, while maintaining marker-trait associations as proprietary technologies owned separately for each partner,” he said.

DERMOT GROGAN, Crops Evaluation and Certification Division, Department of Agriculture, Fisheries and Food, Backweston Farm, Co Kildare, presented results of grass evaluation programmes in both the Republic of Ireland and Northern Ireland. Reducing the number of test sites used for decision-making increased the “breeder’s risk” of having an improved variety incorrectly rejected. “Due to genotype–environment interactions, a minimum number of locations and years is necessary to maintain the integrity of the evaluation system. Both National Lists and Recommended Lists are highly influential, as nearly all varieties sold were recommended in one or both jurisdictions. Current initiatives are focused on development of a variety index that will incorporate multiple traits and trait weights to more efficiently rank varieties for suitability to a specific livestock management system.”

DR MARY McEVOY, Animal & Grassland Research and Innovation Centre, Teagasc, Moorepark, reported on the initial development of the Economic Selection Index for grass varieties, using the Moorepark Dairy Systems Model as the basis for assigning economic weights to individual traits. “The model was highly robust with respect to changes in production scenario, resulting in no changes to variety rankings. The feasibility of an Economic Selection Index to more efficiently and effectively rank varieties for their suitability to specific livestock production systems was effectively demonstrated,” said Dr McEvoy.

DR LAURENCE SHALLOO, Animal & Grassland Research and Innovation Centre, Teagasc, Moorepark, showed that the annual reseeding rate for perennial ryegrass in Ireland is only about 2 per cent of the land on commercial dairy farms. “Economic simulation models showed that an additional €923 could be earned on a 40 hectare dairy farm by each additional 1 per cent increase in annual seeding rate. Reseeding is expected to have a significant and positive effect on profitability, due to increases in production per hectare and to the ability to increase stocking rate and herbage utilisation,” he said.

DR TREVOR GILLILAND, Agri-Food Biosciences Institute, Crossnacreevy, Co Down, Northern Ireland, reported research results on perennial ryegrass seed mixtures, demonstrating that mixture yields did not differ from their theoretical yields, based on the components. “The advantage of mixtures derives from their increased yield stability, expressed as flatter seasonal yield production profiles. Mixtures with the widest range in heading date among the variety components had the greatest yield stability across years, but were also associated with declining yield advantage over time compared to the weighted average of their components. Tetraploids were generally more competitive than diploids, particularly so for the diploids with a dense sward growth habit. Manipulation of component ratios can be used to influence the sward composition over time,” Dr Gilliland concluded.

DAVID LONG, Barenbrug UK Ltd, reported on the process and logistics of variety development with a private sector perspective. “The average cost of variety development is €600,000 and requires 16 years from initial cross to initial seed sales. Much less than 1 per cent of materials developed by the breeder will ever reach the marketplace. Most of the costs in breeding varieties derive from extensive regional testing of large numbers of early-generation materials, entry into obligatory national and recommended list trials, several generations of seed multiplication, and marketing investments. A successful grass breeding programme involves expertise in the development of market-aware breeding goals, implementation of those goals in a field-based screening and evaluation

Conclusions

Breeding goals

The seeds sown at this conference will require time before their benefits are realised. Grass breeders can respond fairly rapidly to changes in breeding goals, but the length of time required for official trials and seed multiplication are generally fixed. Changes in breeding goals are not trivial and should take careful account of Ireland’s future, particularly as influenced by:

  1. Anticipated climate change.
  2. Predicted changes in livestock genetics and management.
  3. Needs for improved nutrient and energy efficiencies.
  4. Producer and consumer preferences and pressures.
Room for improvement

Grass-based grazing systems are currently the most profitable form of livestock production in Ireland, but there is considerable room for improvement in profitability and sustainability. New grass varieties should be developed to allow farmers to respond to any and all of the above factors of change. Emphasis should be placed on traits that allow:

  1. Reduction of input costs.
  2. Maximum possible grazing days on pasture.
  3. Maximum flexibility across a range of environmental conditions and management systems.

Considerable consensus was achieved that breeding programmes should begin to place some emphasis on some new breeding objectives, including:

  1. Increased winter/spring productivity to support calving and lactation.
  2. Increased summer quality to support reproduction.
  3. Increased extent and stability of persistence to support a more sustainable production system.

Considerable concern was expressed about the known trade-offs between increased winter production and decreased winter hardiness, providing some caution to breeders and evaluators to design imaginative and fundamentally sound screening procedures to preserve the value and ensure the success of new varieties.

Biotechnology could play a significant role in this process, provided development funds are available, increasing the rate of gain per year, but not necessarily producing new varieties more rapidly.

Economic Selection Index

Development of an Economic Selection Index appears to be a significant step towards linking breeding objectives, evaluation programmes and farmers’ needs. There was strong support during the conference to strengthen these linkages through enhanced lines of communication, education programmes, and increased use of livestock in the breeding and evaluation processes.

The index provides a mechanism to enhance these linkages, by quantifying the economic value of traits and providing a direct measure of the economic value of a variety in a specific grass and livestock management system. Both breeding and evaluation programmes may be required to expand their objectives in order to meet the needs of multiple environmental considerations and management systems, e.g., grazing vs. silage-based systems or different climatic zones.

In plant breeding and variety evaluation, “you get what you select”. There was clear consensus that some modification of both breeding and evaluation programmes will be necessary to respond to farmers’ needs as outlined above. There was a general consensus that development of new varieties with desirable traits would lead to increased reseeding rates. There was also some desire, among the top forage and livestock producers, for an opportunity to try monocultures of a single top variety on their farms.

March 2011

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