Pastoral Genomics is developing technology to help seed companies breed better ryegrass and clover varieties faster so farmers can enjoy the benefits sooner. The target of this cuttingedge research is to lift genetic gain from the current level of about 0.5 percent/year to 2 percent/year. This would translate into an additional $50/ha/year, or $500/ha/decade, in operating profit for farmers compared with current breeding gains.
Why is this research needed?
It currently takes 12 to 14 years to bring a new ryegrass cultivar to market using current breeding methods. About half that time is spent in several cycles of crossing and selection to find the best offspring to take forward for larger-scale trials and seed multiplication. The current breeding strategy to ‘cross the best with the best’ is producing positive gains but, in animal breeding, genomic selection has made a significant improvement to the rate of gain.
With so much variation to deal with, it’s a challenge for the breeders to decide which crosses to focus on. To help in this challenge, Pastoral Genomics is developing genomic selection tools that will:
- provide breeders with more information on each plant in their breeding pools so they can make more informed decisions about which crosses to carry out
- reduce the number of crossing and selection cycles required, and therefore the time required to breed a cultivar.
What is genomic selection?
Genomic selection involves analysing the DNA of individual plants and linking this to their yield and other important traits, such as disease resistance. Relationships can then be developed, allowing the breeders to predict which crosses should give the best offspring for the traits of interest. This technology has been applied extensively in animal breeding and is commonly used in New Zealand in the sheep, dairy and beef industries.
While this sounds relatively simple, it requires a lot of data. Working with the Agriseeds and PGG Wrightson breeders, the AgResearch Pastoral Genomics team has planted out more than 1000 elite perennial ryegrass and white clover plants at multiple sites across New Zealand. The team has characterised the DNA of those plants, and then monitored their ‘phenotype’ (i.e. their growth and other traits).
Using models developed in Pastoral Genomics, the team can then calculate genomic selection values for each parent plant.
When will farmers see the benefits?
By the end of this year, both breeding companies will have this information for their elite ryegrass pools, and will be able to deploy it alongside their current methods to gauge how much extra gain they can extract. Information for the elite white clover breeding pools will follow over the next two years, which means the breeders can also start applying genomics in their clover breeding.
Although the benefits of this research will take up to a decade to start flowing, this is all part of the vital background work being supported by the levy to build on our competitive advantage of low-cost, high-quality feed.
Pastoral Genomics is funded by DairyNZ, Beef + Lamb New Zealand, Dairy Australia, the Ministry of Business, Innovation and Employment, PGG Wrightson Seeds, Agriseeds and AgResearch.
This article was originally published in Inside Dairy October 2017