New, improved AFBI grass varieties – tools to underpin sustainable productivity in dairy farming

Date published: 12 August 2025

NI’s greatest natural resource is its grasslands and NI’s climate is well suited to grow grass and in turn is well suited to support milk production. Optimizing milk production from grass and forage, no matter what system is adopted, will minimize production costs, maximize profitability and will also make a significant contribution to lowering the environmental impact of dairy systems.

In the UK, livestock production depends largely on grasslands and in Europe, ryegrasses account for over 60% of agricultural grass seed used.  Perennial ryegrass remains the backbone of grass swards in NI due to its improved digestibility, persistence and management properties compared with other grass species. Like any biological system, genetic advances represent the backbone of sustained and persistent improvements. As such new ryegrass varieties produced from AFBI’s grass breeding programme, continue to advance improvements in yield, digestibility, persistence and disease resistance for the benefit of NI farmers.  Going forward these varieties will also build resilience into swards to mitigate the impacts of our changing climate.

In NI alone, over 70% of the 3000 tonnes of seed mixtures sold contain one or more AFBI varieties.  Most recently, two new varieties have become available – Castlewellan and Ardress.  They offer improved spring performance, yields and above average ME yield.   Characteristics which will support increases in profitability for farmers while also supporting the reduction in greenhouse gases (due to higher ME).

Castlewellan and Ardress (both tetraploid ryegrasses), have been added to the 2025/2026 Recommended Grass and Clover Lists (RGCL), bringing the total number of AFBI-bred varieties on the lists to 22.

Intermediate tetraploid ryegrass Castlewellan enters the list as the top performing variety for early grazing and grazing spring yield, producing more grass than ever before at this critical time of year. Castlewellan produced 126% of the mean of the intermediate tetraploid control varieties for early grazing yield and 116% of the mean for grazing spring yield. The inclusion of Castlewellan brings the ratio of AFBI-bred perennial ryegrasses on the RGCL in the intermediate tetraploid category to 50%, reflecting the highly successful strategy of AFBI to develop a wide range of high-performing varieties for use on-farm targeted towards specific farming systems. Another example of this successful strategy is Banbridge, which produced the highest 1st and 2nd cut ME yield under conservation management with 111% of the mean of the intermediate tetraploid control varieties.

Late tetraploid ryegrass Ardress enters the list as an excellent all-around performer across the season, producing high annual yields of good quality grass under both grazing and silage management. The variety produced 107% of the mean grazing ME yield and 108% of 1st and 2nd cut ME yield under conservation compared with the mean of the late tetraploid control varieties. Ardress joins Ballintoy, Richhill and Gracehill as high quality late tetraploid varieties recommended for use on farm by the RGCL.

The development of Castlewellan and Ardress has taken a long time to reach this end-point, with grass varieties typically taking up to 15 years to develop. The success of the AFBI grass breeding development pipeline has largely been derived from a focus on the incorporation of high-quality science into its breeding pipeline. At the core of AFBI’s tetraploid variety development has been the successful use of induced tetraploidization to double chromosome number and develop high-quality tetraploid pre-breeding material from diploid parents. As we traverse a new era of grass breeding in which other technologies such as genomics take center stage, the AFBI grass breeding research programme will continue to seek to apply novel techniques to its pre-breeding strategies to target varieties with novel traits to the point of need on farm.

The Grass Breeding Research Programme at AFBI Loughgall is supported by funding from the Department of Agriculture, Environment and Rural Affairs (DAERA), with varieties marketed by AFBI’s commercial partner Barenbrug UK Ltd.